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The Classification o; West A;rican Livestock. ($1.50) 10s. 6d.I. L. Mason. (1951)

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RECENT DEVELOPMENTS AFFECTING

LIVESTOCK PRODUCTION

IN THE AMERICAS

FAO Agricultural Development Paper No. 55

FOOD AND AGRICULTURE ORGANIZATIONOF THE UNITED NATIONS

ROME, 1956

mCENT DEVELOP ENTS AFFECTDGLIVESTOCK PRODUCTION

IN THE AMERICAS

Edited by

RALPH W. PHILLIPSDeputy Director

Agriculture Division

CONYERS ON TABLE

1 yard 3 feet 0.91 meters

1. mile 1,609 kilometers

1 square mile 2.59 square kilometers

1 hectare 1,000 square meters

2.2 lb. 1 kilogram

© FAO 1956Printed in Italy

FOREWORD

This publication, like others in the series, is designed to makeavailable to member countries of the Food and Agriculture Organiza-tion of the United Nations information that should be usefid to themin planning and implementing agricultural improvement programs.This Agricultural Development Paper is based on material presentedto the Third FAO Meeting on Livestock Production in the Americasby delegations from 18 countries (Argentina, Bolivia, Brazil, Canada,Chile, Costa Rica, Dominican Republic, Ecuador, France, Guatemala,the Netherlands, Panama, Paraguay, Peru, United Kingdom, Uruguay,the United States of America and Venezuela), and by staff metnbers ofthe Agriculture Division of FAO and the Inter-American Institute ofAgricultural Sciences (1A1AS). Material submitted by the Governmentof El Salvador has also been used in preparing this publication. Thenames of those who participated in the meeting in the delegationsfrom countries or as observers from organizations, and who contributedto the discussions, are listed in the introduction." Also, observerswere present from the Caribbean Commission, the internationalOffice of Epizootics, the International Association of Hydatid Disease,the Pan-American Sanitary Bureau and the World Federation ofUnited Nations Associations. The following members of the staffof the Agriculture Division of FAO and of the Inter-Americanhastitute of Agricultural Sciences participated in the Meeting astechnical secretaries, and collaborated in th,e editing of the report fromwhich much of the material in this Development Paper was drawn:

Mr. W. A. Beattie Adviser to the Government of Uruguayon range and pasture management,FAO.

iV1r. Gerardo E. Bildesheim Program Analysis Specialist on LatinAmerica, FAO.

Sir Thomas Dalling Veterinarian, FAO.Dr. Hans J. Engler Poultry Specialist, F AO.Dr. B. O. Retzer Consultant on Analysis and Design of

Experiments, 1 A JAS.Dr. Douglas H. K. Lee Consultant on Animal Climatology, FAO.

Dr. José 111arull

Mr. Roald A. Peterson,Dr. R. O. WhyteDr. S lf/o.rls;

Acting Director, Southern Zone Center,IAIAS.Southern Zone Center, IAIAS.Agronomist, FA O.Agricultural Adviser, FAO North me-rican Regional Office.

The full report of the Buenos Aires meeting was issued as a mimeo-graphed document in English and Spanish in the FAO AgricultureDivision's Meeting Report Series as No. 1955/11. Reports ofthe ,first and second meetings, held in Turrialba, Costa, Rica andBaurzi, Brazil, respectively, lvere issued as FAO Agricultural De-velopment Papers Nos. 8 and 33, prior to the establishment of anumbered series of meeting reports by the Agriculture Division.

v

CONTENTS

Page

INTRODUCTION 1

IMPROVING LIVESTOCK THROUGH BREEDING 5

Animal Climatology 5Research Facilities and Effects of Hot Climates 10Effects of High Altitudes 13Adaptability of Breeds to Unfavorable En.vironments 15Zoological and Ecologial Maps 17Literature Cited regarding Animal Climatology 20

Herdbooks and Performance Tests 21General Problems 21Recent Developments in Various Countries 27Literature Cited regarding Herdbooks and Performance Tests 41

Artificial Insemination an.d Storage of Semen 42Literature Cited regarding Storage of Semen 47

IMPROVING LIVESTOCK PRODUCTION THROUGH IMPROVED 49NUTRITION AND MANAGEMENT

National Planning and Management Aspects of the Grazing 49Industry

Technical Problems in the Use of Grasslands 58Conservation of Forage as Silage an.d Hay 79Nutritional Deaciencies in Livestock 83

General Considerations 83Observations in Countries 86

Selected References regarding Nutrition. and Management 96

IMPROVING LIVESTOCK PRODUCTION THROUGH BETTER DISEASE 99AND PARASITE CONTROL

Control of Foot-and-Mouth Disease 99Control of Brucellosis 104

Recent Developments in Various Countries 105Import Regulations Concerning Reactions to the Agglutina- 108

tion Test in Vaccinated AnimalsInternational Standards 109

Control of Parasitic Infestation and of the Diseases Parasites 110are Known to Transmit

Literature Cited regardin.g Disease and Parasite Control 116

vi,i

STATUS OF THE POULTRY INDUSTRY AND POSSIBLE PROGRAMS 117FOR IMPROVEMENT

General Considerations 117Current Situation and Recent Technical Developments in 122

Various CountriesLiterature Cited regarding Poultry 140

INTERPRETATION AND EVALUATION OF THE RESULTS OF ANIMAL 141HUSBANDRY AND VETERINARY EXPERIMENTS

Planning of Experiments 142Methods for Increasing Accuracy of Experiments 145

Size of Experiment 146Refining Experimental Techniques 147Proper Handling of Experimental Material 149

Experimental Designs 150Complete Block Designs 150Incomplete Block Designs 153

Analysis and Interpretation of Results 155Literature Cited regarding Statistical Analysis 156

_NATIONAL SERVICES TO THE LIVESTOCK INDUSTRY 158

PROPOSALS TO FACILITATE CO-OPERATION AMONG THE COUNTRIES 172

Glossary of Animal Husbandry Terms 172Literature Cited regarding Glossaries 174

Proposals for Further Meetings and for a Working Party and 175Sub-groups to Facilitate Co-operation between Meetings

CoNcLusioN 180

INTRODUCTION

Recognizing that the livestock industry is important to all ofits member countries in North, Central an.d South America andin the Caribbean area, the Food an.d Agriculture Organization ofthe United Nations organized three meetings in which delegatesfrom these countries had opportunities to discuss the problems oftheir respective countries, to exchange information on the research,extension and educational programs they are conducting aimedat the solution of those problems and to consider co-ordinated actionon problems of common concern to two or more countries.

These meetings were:

The Inter-American Meeting on Livestock Production,held in Turrialba, Costa Rica, from 9 to 20 October 1950,and attended by delegations from Costa Rica, El Salvador,Honduras, Guatemala, Nicaragua, Panama, Peru, theNetherlands, the United Kingdom, the United States ofAmerica, and Venezuela;

The Second Inter-American Meeting on Livestock Produc-tion, held in Bauni, Brazil, from 8 to 15 December1952, and attended by delegations from Argentina,Brazil, Chile, Colombia, Costa Rica, Dominican Republic,Ecuador, El Salvador, France, Haiti, the Netherlands,Nicaragua, Panama, Paraguay, Peru, the United Kingdom,the United States of America, Uruguay and Venezuela;and

The Third FAO Meeting on Livestock Production in theAmericas held in Buenos Aires, Argentina, from 18to 30 April 1955, and attended by delegations fromArgentina, Bolivia, Brazil, Canada, Chile, Costa Rica,Dominican Republic, Ecuador, France, Guatemala, theNetherlands, Panama, Paraguay, Peru, the United King-dom, Uruguay, the United States of America and Vene-zuela..

The reports of the first and second meetings in this series wereissued as FAO Agricultural Development Papers Nos. 8 and 33

respectively, prior to the establishment of a regular series of re-ports of agricultural meetings conven.ed by FAO. The report ofthe third meeting has been issued in this new mimeographedseries as Meeting Report No. 1955/11. In order that the greatamount of ne-w information made available to the Buenos Airesmeeting may be more generally available to government officials andother leaders concerned with the improvement of livestock produc-tion in the Americas, much of the material presented at that meetinghas been extracted from the Report, edited, and published in thisDevelopment Paper. This includes not only new information ofa technical nature, but also information on organizational arrange-ments which may facilitate co-operation among countries in thesolution of their problems.

The information in this Developm.ent Paper concerning thework in the various countries was presented to the Buenos Airesmeeting by the followin.g workers, who, in many cases, were present-ing the results of work by their colleagues who were unable toattend the meeting:

Delegates and Observers from Member Countries

ARGENTINA

S.E.D. Carlos Alberto Hogan.; Dr. Juan José Moreno; S.E.D.Conrado Carlos Beckmann; S.S. Dr. Carlos Alberto Pichot; D.Adolfo Pedro Lacu; Ing. Agr. D. Juan José Billard; Dr. NorbertoA.R. Reichart; Dr. Roberto Escobal; Dr. Carlos Piazza ; Dr. Gre-gorio A. Caro; Dr. Augusto D. Dellepian.e Galli; Dr. José MaríaQuevedo; Dr. Fernando A. Languasco; Dr. Valentin. Conti; Dr.Osvaldo J. Gómez; Dr. Raúl Martín Mendy; Cont. Público Na-cional Pedro J. Graziano; D. José F. Dubini; Ing. Agr. Oscar P.S.Ronco; Ing. Agr. René P. Delpeche; Ing. Agr. Isidro F.J. Carlevari;Dr. Raúl A. Antequeda; Dr. Enrique D.U. Pierángeli; Dr. DanielF. Rupoli; Ing. José A. Cappelletti; Ing. Rafael H.F. Bellagamba;Ing. Silvio A. Tosello; In.g. Agr. José Carlos Vidal; Ing. Agr.Alfredo Spinelli; D. Antonio López Arias; D. Mariano O. RodríguezAguilar; D. Santos Plutarco Calvo; D. Carlos Alberto Stura;D. José María Grillo Torrado; D. Adolfo Tarelli; Ing. Agr. PedroA.D. Sarasqueta; Ing. Agr. Osvaldo Boelcke; Ing. Agr. NorbertoHugo Comerio; D. halo José Peretti; D. Astolfo Muñiz Saavedra;an.d D. Jorge Edgardo Ostolaza.

BOLIVIA

D. Alfredo Franco Guachalla; D. Ciro Humboldt Barrero.BRAZIL

D. Paulo Cabral de Mello.

9

CANADA

William Frederick Hillhouse.

CHILE

Ing. Agr. Mario Habit; D. Pedro Arentsert Sauer; Ing. Agr.Roberto Cabezas; Ing. Agr. Waldo Rojas.

COSTA RICA

D. Doménico M. Bucci.

DOMINICAN REPUBLICD. Salvador Monclus.

ECUADOR

D. Gonzalo Sotomayor Navas.FRANCE

M. Charles Vincent.

GUATEMALA

D. Luis E. Archila Peña.

THE NETHERLANDS

Dr. Luis Bar; Mr. Jacobus Wagenaar; Mr. Henrich Verschuyl.

PANAMA

D.A. Méndez; D. Bolivar Pefialba.PARAGUAY

Dr. Tomás Romero Ortiz; Dr. Ramón Codas; D. Rogelio VargasMorel; Thomas S. Darrow.

PERÙDr. Teodoro Ramos Sacro.

UNITED KINGDOMDr. Roger M. Arnold; Dr. Thomas P. Lecky.

URAGUAY

Dr. Mario J. Lusiardo; Ing. Agr. Ernesto J. Cortabarria; Ing.Juan S. Hatchondo; Dr. Oscar Latourette.

UNITED STATES OF AMERICADr. 011ie E. Reed; Dr. Angus A. Hanson; Frederich G. Renner;William L. Rodman.

VENEZUELA

Ing. Agr. J.J. Loreto Jiménez; Dr. Horacio Rosales Gil; Ing.Agr. Osvaldo Hernández León.

3

Observers

THE CARIBBEAN COMMISSION. Dr. Roger M. Arnold.THE INTERNATIONAL OFFICE OF EPIZOOTICS. Dr. Carlos Ruiz

Martínez.THE INTERNATIONAL ASSOCIATION OF HYDATID DISEASES. Dr. Alfre-

do Ferro.THE PAN-AMERICAN SANITARY BUREAU. Dr. Benjamin D. Blood

and Dr. Erwin A. Eichhorn.THE WORLD FEDERATION OF UNITED NATIONS ASSOCIATIONS.

J. J. Aphalo and Susana Larguira.The staff members of the Food and Agriculture Organization

and of the Inter-American Institute of Agricultural Sciences (IAIAS)who contributed technical material to the meeting and who par-ticipated in the editing of the report ar listed in the Foreword.In addition, Mr. Eduardo S. Bello, of IAIAS, participated in thediscussions, and Dr. Jorge de Alba, also of TAJAS, preparedmaterial for the use of the meeting.

In view of the many sources from which participants drewthe information presented at the meeting, it is impossible to givecredit to all those sources in this publication. References thatwere available with regard to published information or personalcommunications are noted at the ends of chapters, or section.sof chapters, and the contributions of all others who cannot beso recognized or are not listed above are gratefully acknowledged.

In the Turrialba and Bauni meetings, attention was given toall phases of livestock production and, arising out of the discussionsat these first two meetings, items that appeared to be of particularimportance and current interest were selected for inclusion in theagenda of the third meeting in Buenos Aires. Therefore, thematerial contained in this Development Paper is related only tothose subjects selected for consideration at the Buenos Airesmeetings, and no attempt has been made to assemble an.d presentmaterial on other aspects of livestock production.

The material contained in the report of the Buenos Aires meeting,which has been made available only in limited numbers as amimeographed document, has been recast in the form of a reviewof importan.t developments. Thus, some material which was per-tinent to the report but which does not have continuing referencevalue has been deleted, while material on some subjects has beenexpanded by incorporating additional details and in some casesillustrations which could not be included in the report of theBuenos Aires meeting.

IMPROVING LIVESTOCKTHROUGH BREEDING

in the first discussions of this subject at the Turrialba meet-ing, attention was given primarily to the basic scientific approachthat is required if maximum progress is to be made in the improve-ment of livestock through breeding. Therefore, the discussion.centered around tNvo -topics, namely, physiological and geneticstudies as applied to livestock impro-vement. These subjects werepursued further at the Baurú meeting, where, on the genetic side,special attention was given to improving local types of livestock,to pure breeds and their use in cross-breeding and, grading up, todeveloping new types of livestock, and to measuring performance.Regarding animal climatology, particular attention was given tothe methods that could be used in laboratory and field studies ofthe reactions of livestock to climatic stress (Phillips, 1950 and 1953).

It became apparent'from the discussions at the Baurú meetingthat delegates were partic-ularly interested in the development ofanimal climatology', including its application both to the tropicaland the high .Andean areas. IVIuch interest was also expressedin the methods of keeping herdbooks and organizing performancetests in cattle. These items were, therefore, included in th.cagenda of the Buenos Aires meeting, together with artificial insem-ination, for which a special request had been made by the Baurtimeeting owing to the growing interest in the possibilities of storingsemen by deep freezing. Thus, this chapter is divided into threesections covering these three topics.

AnimaI Climatology

Climatic conditions un.d.er -which livestock are produced in theAmericas vary over an extremely wide range. They include thelush pasture and forage producing areas in intensive farming areasin the temperate zones where advantage is taken either of naturalrainfall or irrigation.. They also include the semi-arid grazingareas, such as those in southern Argentina and in the southwesternportion of the United States of America. There are also the loi,vwet tropics and the high Andean areas, to mention only a fewof the variable types of environmental conditions under whichlivestock are produced.

Man has also developed highly variable -types of livestock in hisefforts ,to wrest a satisfactory living from the land under thesevarying environmental conditions. These variations are well known,but may be emphasized by comparing the highly specialized dairycow grazing on lush pastures with the vicuña searching for food in asemi--wild state under the sparse grazing conditions at 14,000 ft.in the Andean highlands.

Under these highly variable conditions, each country has itsown particular problem or set of problems relating to the deter-mination of the best adapted type or t-ypes of livestock to use,or in some cases to the development of a type or types adapted.to particular conditions. To meet these prnblems, the sciencesof gene-tics and physiology, must both be utilized. Both are rela-tively young sciences, especially in their application to the improve-ment of livestock, and physiologists have only very recently takenup active work on a substantial scale in this field. Therefore,the following section is devoted to research facilities and personn.elbefore turning to time effects of hot climates and high altitudesand the adaptability- of breeds to unfavorable environments inthe three succeeding sections.

Research Facilities and Personnel

A first attempt was made during the Turrialba meeting toprepare a list of the facilities available in the Americas for thestudy of animal climatology. This list was later expanded bythe staff of FAO, and is summarized below, partly as a means ofindicating the places where research is being undertaken, but prim-arily to point out places where advanced students or professionalworkers may be able to secure special training in the applicationof physiology and other sciences to the study of animal climatology.

Institution Facilities

INTER-AMERICAN INSTITUTE OF A large climatic chamber is availableAGRICULTURAL SCIENCES which includes provision for solar(Turrialba, Costa Rica) radiation studies. Various breeds and

crossbreeds of dairy and beef cattle,including zebu types, are availablefor study, as are also swine and poultry.Arrangements may be made for credittowards a master's d.egree and facilitiesmay be provided for research workersindependent of studies leading to adegree.

6

AGRICULTURAL AND ME CHAN-ICAL COLLEGE OF TEXAS(College Station, Texas, U.S.A)

JOHNS HOPKIiNTS UNIVERSITY(Baltimore, Maryland, U.S.A.)

The Departments of Animal Husbandry,Dairy Husbandry and Genetics, respec-tively, are all concerned with thestudy of animal climatology. Breedingwork is in progress with both beefand dairy cattle. Advanced studentsmay work for higher degrees, but thereare only limited opportunities for in-dependent investigators.

Various projects related to animal clim-atology are under way within theuniversity, and in co-operation withthe United Sta-tes Department of Agri-culture at Beltsville, Maryland. Gra-duate studies in bio-climatology maybe pursued within the biological sciencesgroup of the university, and, aftercompletion of the necessary basiccourses, advanced students may- con-centrate upon the specialized aspectsof animal climatology or physiologicalclimatology. Work may be taken lead-ing to the master's degree or the degreeof Doctor of Philosophy, and opportun.-ities for special work for advancednon-degree students may be arranged.

UNIVERSITY OF MISSOURI The Departments of Dairy Husbandry(Columbia, Missouri, U.S.A.) and Agricultural Engineering, respec-

tively, give particular attention to ani-mal climatology studies. Special equip-ment includes two 6-cow chambers,and small chambers for laboratoryanimals, with facilities for controllingtemperature, humidity, air movementand radiation, and for measuring met-abolic processes, especially heat produc-tion. Advanced students may be ac-cepted for the master's and doctor'sdegrees. Visiting workers seeking spe-cial experience may arrange for thiswithout taking work leading to a degree.

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UNIVERSITY OF ILLINOIS(Urbana, Illinois, U.S.A.)

LOUISIANA STATE Ui IVERSITY(Baton. Rouge, Louisiana,U.S.A.)

NORTH CAROLINA STATECOLLEGE(Raleigh, North CarolinaU.S.A.)

The Department of Animal Scienceis particularly con.cerned with projectsin animal climatology and facilitiesinclude a large, controlled environmentroom with air conditioned scales andentrance locker room attached, a respir-ator): chamber for indirect calorimetry,and two pneumatic chambers for res-piration work on calves, sheep or swine.Advanced students may be acceptedas candidates for the master's ordoctor's degree, and post-doctorate stu-dents may work on problems of theirown selection provided they fit in withthe general type of research that theDepartment is best able to conduct.

The Department of Dairyin.g is the oneprimarily concerned with studies ofanimal climatology arid, in additionto work at the university, studies arealso carried out at the New IberiaLivestock Station, Jeanerette, and theNorth Louisiana Hill Farm Experi-ment Station, Homer, Louisiana. Heattolerance studies are being conductedwith various types of dairy cattle ofthe European breeds and with crossesof these breeds with the Sindhi. Stud-ents may be accepted for graduatetraining leading to the Master ofScience or the Doctor of Philosophydegrees and arran.gements may be madefor special work by persons not wishingto take a degree.

The Department of Animal Industryis the one primarily concerned withstudies of animal climatology and theeffects of various environmental factorson livestock are being studied.Advance studies may be taken leadingto the master and doctor degrees.The available equipment includes two2-cow chambers with equipment formaintaining and measuring temperature,humidity an.d light.

8

UNIVERSITY OF CALIFORNIA The Departments of Animal Husbandry,(D avis. California) Poultry Husbandry and Agricultural

Engineering, respectively-, are concernedwith research on animal climatology.Facilities for large animals include ananimal psychometric chamber and thereis also a small chamber for laboratoryanimals. In addition to facilities atDavis, field facilities are available atthe imperial Valley Station near El.Centro and at the San Joaquin Experi-mental Range, East of Madera, Cali-fornia. For poultry there is one climaticchamber for controlling temperaturesand several projects are under way deal-ing with reactions of poultry to climaticand other environmental circumstances.Arrangements may be made for gradu-ate work leading to the Master of Scienceand Doctor of Philosophy degrees.

FAO has given attention to this problem of animal climatologynot only through the organization of discussions in nieetings suchas those held in Turrialba, Baurii and Buenos Aires, but also throughthe issuing of publications for the use of leaders in this field. Thesepublications have included one dealing with the over-all problemsof breeding livestock adapted to unfavorable environments (Phillips,1948), and one describing the zebu cattle of India and Pakistan,these breeds being particularly adapted to hot climates (Joshiand Phillips, 1953). Also, a manual of field methods for the studyof heat tolerance of domestic animals has been issued, (Lee, 1953),which is intended primarily to show how the available techniquesmay be applied under field conditions where, often, good labora-tory facilities are not available in the vicinity. Such publicationsare of restricted usefulness to a country, however, unless there isat least one person in th.at country who is well trained in the scient-ific principles involved in animal climatology and -w-ho can giveguidance in the planning and interpretation of studies carried outunder local conditions. Governments wishing to undertake workin this field, and who do not already have available trained wor-kers to lead such work, should give consideration either to theselection of promising young men for training or to the selectionof professionally trained workers who may be given special train-ing. At the same time, facilities already available in countriesshould be fully utilized, for it is often possible to carry out importantwork in this field even with limited facilities and personnel.

9

Research Facilities and Effe cts of liot Climates

Current research tends to attach greater importance to evapor-ation of 'water from the skin in the heat regulation of mammalsthan was formerly given, but at the same time to suggest thatthe difference in hear .tolerance between one animal and anotheris due rather to differences in heat formation than to differencesin ability -to lose heat. If this is true, the efficiency of an animalin converting food energy into useful products becomes doublyimportant in hot countries: first, it means that the more efficientanimal forms less heat, and is, therefore, less bothered in hotclimates by a given amount of product; and second, that the moreefficient animal consumes less food for the given amount of pro-duct. This would mean that the search for the efficient animalwould be doubly rewarding., in that it -would give an animal .whichis not only more heat tolerant, but also more economic under allconditions. The proof of this point will require much more elab-orate research than has hitherto been conducted, and the pro-blem of readily recognizi g the efficient animal will still remain.In this respect, how-ever, nutritional and climat c research -wouldllave a common goal.

The view expressed in the preceding paragraph gains somesupport from the work under way at Beltsville, Maryland, U. S. A.,where workers had been unable to satisfy themselves that theanimal with better heat tolerance owes that tolerance tO betterfacilities for losing heat to environment. First generation Sindhi-Jersey crossbred cows are distinctly more tolerant to heat thantheir Jersey dams, but they do not have any greater proportionof surface area to mass (McDowell, Lee and Fohrman, 19'53), ormore rapid evaporation of water from the skin (McDowell, Leeand Fohrman, 1954), or greater evaporation through respiratoryactivity. (McDowell, Lee, Fohrman and Andersen, 1953). Theinvestigators were being driven to the belief that the more tolerantanimals owe their su.periority to a lower rate of heat production.If this is true, that is, if two gro-ups of animals kept under identicalcircumstances and producing the same amount of milk show con-sistent differences in heat production., it can only mean that onegroup is using its food energy more efficiently than the other.This suggests that, in the present state of our knowledge, it wouldbe unwise to attempt to select animals for hot conditions on thebasis of morphological characters, but rather that more emphasisshould be placed upon selecting- those animals which show smallerrises of temperature when exposed as heifers Or drY COWS to hotconditions, show less urge to seek shade or stop eating on hotdays, or show a greater conversion ratio of fodder to milk whenstudied in the test barn..

10

The -w-ork at Beltsville, to which reference is made on p. 10, i5part of a program being carried out by the Dairy Husbandry Re-search Branch of the U. S. Department of Agriculture at Beltsville,.Maryland, in collaboration with agricultural experimental station5of several southern states. It is a seven-point program of studieson the adaptability of dairy cattle to hot conditions:

determination of " normal " valuespulse rate, respiration rate, etc.;measurement of climatic conditionsexposed in different areas;systematic study of the reactions of various breeds andat different ages and stages of lactation, to fixedmosphere;investigation of the characteristicsmore tolerante than another;elaboration of methods for studyconduct of field studies; andsystematic study of the relativefactors, such as humidity, -temperature,rrient, etc., upon animal reaction.

11

a

which make

of animals in

-temperature,

animals are

one

crosses,hot at-

animal

the field;

nfitienee of various climatic

In addition to the facilities at Beltsville and several state exper-imental stations, those a-t the U. S. Department of AgricultureIberia Livestock Farm at Jeanerette, Louisiana, are also being used.

Work is also under way at several places in the United Statesof America on other aspects of animal climatology, including studiesin which dairy cattle, beef cattle, sheep and swine are utilized.Some of the results are summarized briefly below.

Most of the work on hogs at the California Agricultural Exper-iment Station has been concentrated in the optimum to hightemperature range (Heitman, Kelly and Bond, 1954). Hogs below140 lb. liveweight were found to use feed more efficiently at -tem-peratures around 750F. (240C.) while those above 140 lb. grewmore efficiently near 60°F. (160C.). The rate of growth fell offrapidly as -temperatures increased above the optimum.

Work in California with artificial shades for beef cattle andhogs (Inner, Bond and. Kelly, 1954) indicates that the summersun may raise the effective temperature around the animal veryconsiderably, with retardation of growth and inefficient use offeed. Shades, free air movement, and cooling of drinking waterare valuable in protecting animals from solar heat and high airtemperatures.

Tests in the Missouri Agricultural Experiment Station's labor-atory indicate significant reductions in the milk production ofdairy' cows at temperatures abo-ve 850F. (290C.), with wide varia-

to which

for rectal

radiation, air move-

((i)

tions in the heat tolerance between animals of the same breed aswell as between breeds (Worstell an.d Brody, 1953). Work nowin progress there concerns the influence of climatic factors on.the growth of calves. When the temperature was cycled each daybetween 700 and 1000F. (220 and 27°C.) the milk production.declined 8 percent in Jerseys and 20 percent in Holsteins. It isbelieved that the stressful effects of high diurnal temperatures dependnot only upon the range of temperature but also on the numberof hours spent under the hotter and colder con.dition.s respectively.

The Missouri Station also has some evidence that the develop-ment of lighter hair color observed in animals kept in high en.viron.-mental temperatures is due to depressed thyroid activity; but moresignificant than change in color with changing -temperatures ischange in the texture of the coat (Brody et al., 1954). As thetemperature rises the coarse, shaggy hair is replaced by fine glossyhair that may be more reflective to solar radiation..

Investigators in Louisiana have concl-u.ded that, on the average,there is a 2.14 lb. decrease in the daily yield of fat-corrected milkfor each 10F. (10C.) rise in body temperature above normal (Branton,Johnston an.d Miller, 1953). They recommend selecting cowswhose body temperature rises least on hot days.

At the North Carolina Agricultural Experiment Station (Casady,Myers and Legates, 1953) impaired spermatogenesis was foun.dwhen bulls were exposed to temperatures of approximately 100°F.(370C.) for two weeks, or 860F. (300C.) for five weeks. The semenof some bulls did not return to normal for several weeks after thetemperature had been reduced. Temperature also affected thefertility of rams. Rams kept in a room at 450 to 48°F. (7° to 9°C.)from May until the breeding time in August settled 64 percent ofthe ewes, while only 26 percent were settled by a correspondinggroup of rams exposed to higher summer "temperatures (Dun an.dSimpson., 1954).

Other studies relating to the effect of temperatures on fertilityin rams have been carried out at the agricultural experiment stationsin Kentucky and Wisconsin. The Kentucky workers (Dutt an.d.Simpson, 1954) kept rams in an air-conditioned room at 450 to480F. during the summer months and compared them with controlrams kept at ordinary temperatures. Fertilization rates were64.2 and 26 percent respectively for the cooled and control rams,an.d. lambin.g percentages were 50 and 14.3 percent respectively.The Wisconsin. workers (Hulet, El Sheikh, Pope an.d Casida, 1954)compared rams which had been sheared in April with rams thatwere re-sheared at monthly intervals until breeding was completed.Fertilization rate was significantly higher in the rams which hadbeen re-sheared at monthly intervals. These studies, aimed atincreasing the fertility of rams during the early portion of the

12

breeding season in arcas where temperatures are still high at thattime, follow the initial work carried out at the Missouri Stationon the thermo-regulatory function and mechanism of the scrotum(Phillips and McKenzie, 1934). Similar beneficial effects of coolingon dairy bulls have been found by Patrick, et al. (1954).

E ects of High Altitudes

It is only in the lower latitudes that animals can be maintainedat really high altitudes, since the heavy snow cover at higher latitudesrestricts pasturage to quite low levels in winter, and permits graz-ing at only intermediate levels in summer. The problem of yearround maintenance of livestock at really high altitudes in the Amer-icas is, therefore, a peculiarly South American problem, the solutionof which must be sought at the instigation of countries whoseborders include high Andean regions. The Andean scene presentsa number of stresses .Lo newly introd.uced domestic animals, theeffects of which are hard, to disentangle. Low oxygen tension,cold, rugged terrain and poor pasturage occur together, althoughin varying proportions. Lack of oxygen tend,s to reduce theefficiency of all bodily processes in animals not especially adaptedto it and so tends to restrict growth and productivity as well asto interfere with reproduction. The burden put upon the circula-tion by the high concentration of red blood cells may result in spe-cific disturbances, such as edema of dependent parts (" brisketdisease "). Sterility is frequently attributed to the same cause.Cold increases the food requirements of the animal, while restrict-ing the growth, of forage, thereby putting -the animal in a difficultposition. In order to acquire sufficient protection against the coldthe animal must either grow a thick coat, lay down subcutaneousfat, or keep up a high rate of heat formation.. All these processesmake heavy demands upon. nutrition. It is probable also that onlycertain types have the genetic potential for adequate response.

Delegates to the Bauril meeting, recognizing the importanceof giving attention to this complex problem, reconimended that,in view of the special problems encountered in the production oflivestock in high altitudes such as are foun.d in Andean countries,also because of the special types of livestock such as llamas, alpacasand vicuñas, which are important in certain areas of high altitude,governments in the Andean region should consider he setting-up of a center for high altitude livestock and/or the developmentof co-operative programs aimed at utilizing all the facilities avail-able in the several countries, and the Food and A.griculture Organiz-ation of the United Nations sho-uld be requested by the governnientsconcerned to assist in planning and implementing this proposal.

Further attention WaS given at the Buenos Aires meeting to

13

the 'possibility of a co-ordinated approach to this problem, basedon information the FAO staff had been able to assemble throughpersonal communication.s from workers in the Andean region andfrom publications (Cook and Pace, 1952; Instituto Nacional de Bio-logía Andina, 1949; Keys, 1936; Korff, 1954; Monge an.d Hurtado1947; an.d Moore and Price, 1948). The need for more extensiveand bet-ter organized studies of the problems of animal productionat high altitudes in the Andes was recognized, and it was recom-mended that governments in that region should form small nationalcommittees to review the present state of the problem, advise theirgovernments on measures necessary for the improvement of pro-duction., and indicate the types of assistance that might be neededfrom outside each country in dealing with the problem. A work-ing group for inter-country consultation was also suggested. Thesesuggestions were aimed at improving the present position in whichonly limited research projects llave been undertaken (and thesemostly on a personal basis); there is little intercommunicationamong workers, and no over-all systematic plan of approach hasbeen made. Insufficient use is being made of the informationobtain.ed and techniques developed in studies of the effects of al-titude upon man. It is not possible at this stage to say whatmay be the relative importan.ce of low oxygen -tension, cold, an.dpoor n.utrition in producing the observed effects. The positionappears to warrant systematic study by modern research methods,with utilization and probable extension of all the facilities thatnow exist.

The problem is recognized in Colombia, where attention hasbeen given to the description of high altitude disturbances in live-stock, together with a critical consideration of the pathology andexperimental treatment. The clinical picture is often confusedby inter-current events. Ail animal may show no symptonas ofaltitude sickness as long as it is healthy and not subjected to aheavy work load or pregnancy, but fail quite rapidly when disease,malnutrition, pregnancy, or heavy -work intervenes. In such casestreatment of the precipitating factor may result in relief of thecon.dition, but the animal is still close to its maximum -toleranceof altitude, and will be likely to fail at any time when an addition-al stress is imposed. Subcutaneous administration of oxygenwas found in man.y in.stances to bring about relief of both cardiacand local disturbances where there was no serious complicatingfactor such as infection. Administration of iron., cobalt and coppertogether had some effect, especially in newly introduced animals.It has been recommended that newly introduced animals be sparedany additional stress, such as pregnancy, during the first 12 months.

In Peru the problem has also been recognized by some workersas one of great importance to the agricultural economy of that

14

country. In the course of the well known studies carried out byMonge and Hurtado (1947) on human effects, numerous small ani-mals have been subjected to investigation and attempts are nowbeing made to extend this work to larger animals. There is agovernment farm for alpacas at La Raya, and it is hoped to utilizefacilities made available by the Institute of Andean. Biology atHuancayo for studies on sheep.

In Argentina, some attention is being given to the improvementof sheep in the northwestern portion of the country by crossingthe local ewes with Merino rams. The native animals yield onlysmall amounts of wool (1.74 lb.) with short fibers of uneven quality.A plan of improvement by the use of Merino rams has been putinto operation, since these animals have shown themselves moreadaptable to the conditions than any other pure breed. Theresults to date indicate that:

in the northwestern regions, which are hilly or mountainousand subject to dry periods, introduction of Merino strains isdesirable for the improvement of wool and meat charac-teristics, especially as that breed resembles most closely thelocal stock;the Merino adapts itself very well at 5,000 ft., and recoversits fertility after five months;

(e) the crossbred progeny are strong and healthy;this method cannot be used at very high altitudes or onvery poor pastures, since the reproductive ability of thepurebred animals is greatly reduced;certain basic difficulties in management, largely attributableto long established customs, need to be rectified.

There is a danger of disturbing the biological adaptation ofanimals maintained for a long time under difficult conditions, whenattempts are made to improve them by crossing with breeds notadapted to those conditions, especially since increased productioninvariably calls for increased feedin.g. The genetic potentialities,food supply, and management must be improved simultaneouslyin a balanced fashion.

In Pertt, two methods of combatting lamb loss have been used.The first is to mark those ewes whose offspring die and to discardany one which loses two lambs in succession. The other is torotate the lambing corrals, so that organisms responsible for infec-tion of the n.ewborn do n.ot become endemically established.

Adaptability of Breeds to Unfavorable Environments

This subject received consideration in both the Turrialba andBaurú meetings, where information was presen.ted on a number

] 5

of types of livestock which had been developed in various countriesor introduced in pure form for use in. a country (Phillips, 1950 and1953). Some additional information was made available at theBuenos Aires meeting.

In Colombia, the Blanco Orejinegro breed of cattle appears tohave a -wide range of adaptability, varying from the tropical low-lands to the cold mountain regions at altitudes of as much as7,877 ft. It is also reported to have a high resistance to parasitessuch as Dermatobia (" nuche " or " torsola "). It has been suggest-ed that this breed should be developed for use in the " coffee zoneof Colombia, where other -types cannot be m.aintained successfullybecause of heavy parasite infestation and Nvhere there is a shortageof milk and a high infant mortality.

In Panama, estimates have been made of the relative accepta-bility of different breeds under the conditions prevailing in thatcountry. Of milking cattle, Jerseys imported from Jamaica provedmost acceptable, and Brown Swiss next. Holsteins, by contrast,did not maintain production unless one quarter of criollo -type wasintroduced by crossing. Aberdeen. Angus and Hereford cattle,introduced from the United States of America, failed to maintain-their condition. Among swine, Duroc and Hampshire breeds haveproved acceptable, but of the two the Hampshire is the moreacceptable because the ears are less apt to catch on wire and otherobstructions, and it yields a greater percentage of meat. Improvedstrains require greater care -than native types, however, and thisis sometimes a limiting factor in the amount of improvement thatcan be effected. In fact, the subject which probably calls forgreatcst consideration. in the immediate future is the determinationof the suitability of pure strains and -their crosses for the variouslevels of management which pre-vail.

The situation in Panama may be considered typical of thatgenerally prevailing. Attempts made by the FAO staff to collectinformation from all available sources have made it quite evidentthat our present knowledge is very incomplete, and that a systematicstudy of the heat tolerance of time various breeds of livestock invarious parts of the -tropics and sub-tropics is badly needed. Itis quite important that such studies be conducted upon a reasonablyuniform basis, so that fair comparisons can be made of the reactionsof different breeds under similar circumstances, and of the samebreeds under different circumstan.ces. It is also important thatthe information be made generally available as rapidly as possible.Only as the results of such a systematic survey become availablewill breeders be able to select foundation stock with confidencethat the ecological d,ernands will be met.

16

Zoological and Ecological Maps

The Baurd meeting heard a report on the preparation of azootechnical map in Argentina, which at that time was only par--Gaily completed. There was much interest among the delegatesand they recommended the making, as expeditiously as possible,of zootechnical and ecological maps shawing the current distribu-tion of types and breeds of cattle, and of environmental conditions.

Draft maps have now been prepared in Argentina, one show-ing subdivisions into ecological zones (Parodi, 1947), and anotherbased on the prevailing climatic conditions and vegetation andrelated to the carrying capacity for various clases of livestock.Attention is being given by the National Meteorological Instituteto classifying the climatic conditions in such a -way that correla-tions may be established between the various climatic factors amithe responses, such as growth, wool weight, milk production, etc.,of animals maintained in different parts of the country. It ishoped by these means Lo help producers in deciding what typesof animals should be maintained, an.d the most suitable times atwhich to carry out certain phases of, th.eir management programs.

A small scale reproduction of one of -these maps is shown inFigure 1. It illustrates the zones currently used for varioustypes of cattle production.

A series of maps has been produced in Paraguay indicating thedistribution of important climatic and geographic factors, forcomparison with other maps showing the present distributionof agricultural production. Paraguay is divided into two areaswhich are completely different in soils, climate and vegetation.The region 'Lo the east of the Paraguay river has rich pastures,while that to the west carries many inedible species. Each regionis divisible imito three types of country: lowlands, dry highlandsand plateaux. The vegetation and other conditions aff'ect animalwelfare. Now that the distribution of -these conditions has beenmapped, it remains to determine the extent to which they affectthe carrying capacity- of the land and the most profitable formof land. use. Cattle now contribute only 13.4 percent of the nationalincome, but this could probably be increased by 50 percent, espe-cially if some way were found of utilizing time northwestern portionof the country to greater advantage. One of the great difficultiesin time southern regions is the great amount of surface water, whichmakes for coarse grass and dense vegetation, as well as promot-ing swarms of insects. The maps referred to in this paragraphhave been prepared in connection with a reconnaissance soil andland classification of Paraguay (Tirado-Sulsona, Hammon andRamírez, 1952), A further map, outlining the major types ofproduction areas in Paraguay is shown in Figure 2.

17

Figure 1. Map showing the major types of areas for cattle production in Argentina:A. Breeding zone; B. Fattening zone; C. Marginal fattening zone; D. Dairy area;E. Marginal livestock area; F. Northern breeding zone; G. Marginal breeding zone;H. Marginal dairy area; i. Sub-tropical livestock - principal zone of crossing with zebu,criollo and hybrids; J. Breeding zone (north sub-Andean); K. Breeding zone (southsub-Andean); L. Agricultural zone - eventual sub-tropical livestock area; M. Breedingzone of the " Litoral " area; N. Zone of breeding and slow fattening (Courtesy of theGovernment of Argentina).

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These maps are cited as examples of the products of studieswhich have been initiated in two countries. Their makers wouldnot claim that they provide a fully adequate basis for determin-ing the best type of livestock an.d livestock management practicesto recommen.d in each portion of the areas covered. However,they represent important contributions, and should provide auseful example for work in other countries.

LEGENDLivestockCrop producto,Hiked cropproduction ond livestock

ESSal Forest and ltvestockESMI Forest

af»n,11111114

CA L E 11004002

V

Figure 2. Map showing the major types of animal production areas inParaguay (Courtesy Government of Paraguay).

Attention is still needed to the question of the criteria t o beused in preparing maps for use in planning for the improvementof animal production.. Information that would be most desirablefor heat tolerance studies would be the distribution of temperature,vapor pressure and radiative conditions, preferably with indica-tions of the range of variations to be expected. Mapping one factorwhich may affect livestock production is a relatively- simple matter

19

A

0.

E

4i. 4,,

PARAGUAY

ECONOMIC AREAS

8

once the data are available for an adequate number of points inthe area to be mapped. However, the preparation of a single mapor a group of maps small enough in number to be useful in judgingthe combined effects of the several important factors which affectlivestock production is far from a simple task. It is worthy ofconsiderable attention, and it is the type of project in which themeteorologist, the physiologist and the animal husbandman shouldjoin forces.

Literature Cited Regarding Animal Climatology

BRANTON, C., JOHNSTON, J.E., and MILLER, G.D. Physiological and.Hereditary Responses of Lactating Holstein-Friesian an.d JerseyCows to Natural Environmental Temperature and Humidity..J. Dairy Sci. 36: 585, 1953.

BRODY, S., RAGSDALE, A.C., THOMPSON, H.J., and WORSTELL, D.M..The Thermal Effects of Radiation Intensity (light) on Milk Pro-duction, Feed and Water Consumption and Body Weight. in Hol-stein, Jersey and Brahman Cows at Air Temp eratures 450, 700 and.80°F. Univ. Mo. Col. Agri. Res. Bull. 556, 1954.

CASADY, R.B., MYERS, R. M. and LEGATES, J.E. The Effect of Exposureto High Ambient Temperature on Spermatogenesis in the DairyBull. J. Dairy Sci. 36: 14, 1953.

COOK, S.F. and PACE, N. White Mountain High Altitude ResearchStation. Science, 116: 697, 1952.

DUTT, R.H. and SIMPSON, E.C. Environmental Temperature and Fer-tility of Southdown Rams early in the Breeding Season. J. Anim.Sci. 13: 1019, 1954.

HEITMAN, H., KELLY, C.F. and BOND, T.E. The Relation of AmbientTemperature to Weight Gain in Swine. J. Anim. Sci. 13: 1021, 1954.

HULET, C.V., El SHEIKH, A., POPE, A.L. and CASIDA, L.E. The Effectof Shearing and Level of Feeding on Fertility in Sheep. J. Anim.Sci. 13: 1022-23. 1954.

INSTITUTO NACIONAL DE BIOLOGÍA ANDINA, El estudio de la biologíade las grandes alturas en las regiones andinas del Perú, Facultadde Medicina de Lima, 1949.

ITTNER, N.R., BOND, T.E. and KELLY, C.P. Increasing Summer Gainsof Livestock. J. Anim. Sci. 13: 867, 1954.

JOSHI, N.R. and PHILLIPS, R.W. Zebu Cattle in India and Pakistan.FAO Agricultural Study No. 19, 1953, Food and Agriculture Organ-ization of the United. Nations, Rome, Italy.

KEYS, A. The Physiology of Life at High Altitudes. Scientific Mon.43: 289, 1936.

20

KO FF, S.A. The World's High Altitude Researcia Stations. Research Divi,sion, College of Engineering, New York University, New York, 1954.

LEE, D.H.K. Manual of Field Studies on the Heat Toleranceof DomesticAnimals. FAO Development Paper No. 38, 1953, Food and AgricultureOrganization of the United Nations. Rome, Italy.

MCDOWELL, R.E., LEE, D.H.K., and FOIIRMAN, M.H. The Relationshipof Surface Area to Heat Tolerance in Jerse-ys and Sindlii-Jersey(F1) Crossbred Cows. J. Anim. Sci. 12: 747, 1953.

. The Measurement of Water Evaporation from Limited Areasof a Normal Body Surface. J. Anim. Sci. 13: 405, 1954.

and Anderson, R.S. Respiratory Activity as an Index ofHeat Tolerance in Jersey and Sindlii-jersey (F1) Crossbred COWS.J. Anim. Sci. 12: 573, 1953.

MONGE, C. and, HURTADO, A. institute of Andean. Biology Laboratoryat High Altitudes. J. Amer. med. Ass. 135: 375, 1947.

MOORE, C.R. and PRICE, D. Acquisition and Maintenance of Endocrin.eFunction at High Altitudes. Science, 107: 457, 1948.

PARODI, L. Geografía de la Republica argentina. -Vol. 8. Sociedad Ar-gentina de Estudios Geografía S.A., Buenos Aires, 1947.

PATRICK, T.E., JOHNSTON, J.E., KELLGREN, H.C., FRYE, J.B., D'ARENS-BOURG, G. and BRANTON C. Effects of Hot Weather and HighHumidity on Semen Production and Fertility of the Dairy Bull.J. Anim. Sci. 13: 1028, 1954.

PHILLus, RALPH W. Breeding Livestock Adapted to Unfavorable En-vironments. FAO Agricultural Study No. 1, 1948, Food andAgriculture Organization of the 'United Nations, Rome, Italy.

and MCKENZIE, F.F. The Therrno-Regulatory Function audMechanism of the Scrotum. Mo. Agri. Exp. Sta. Bull. N.o 217, 1934.

TIRADO-SULSONA, P., HAIVIMON, J.B. and RAMÍREZ, I.R. A .11econnais-sance Soil and Land Classification of Paraguay. Division of Agri-cultural and Natural Resources, U.S. Operations Mission to Paraguay,Asunción, 1952. (Published also in Spanish under the title Clasi-ficación preliminar de los suelos y tierras del Paraguay).

WORSTELL, D.M. and BRODY, S. Comparative Physiological Reactionsof European and Indian Cattle to Changing Temperature. Univ.Mo. Col. Agri. Res. Bull. 515, 1953.

Herdbooks and Performance Tests

General Problems

The organization of h.erdbooks and the safeguarding of in.terestsof breeders has been discussed at various international congressesand meetings. As a result of such discussions an international

21

convention for the standardization of methods of keeping and oper-ating herdbooks was signed in Rome under the auspices of theformer International Institute of Agriculture in 1936. This con-vention was signed by 20 governments among which were thoseof Brazil, Guatemala, Nicaragua, Paraguay and the United Statesof America in the -Western Hemisphere. It was ratified by tengovernments, including the Government of Brazil, and the Go-vernment of Colombia also notified its adherence to the convent-ion, which entered into force. One stipulation of this conventionprovides for consultation among experts of the governmentsadhering to it after five years of its entering into force. Sincehe war prevented the timely convening of such a meeting,this took place only in 1947 and was convened by FAO inRome, FAO having become the custodian of this and otherconventions prepared under the auspices of the former Institute.AL this meeting, in which only European countries were repre-sented, it was stated that the, aims envisaged in this conventionwere of primary interest to all countries in which frequent exchangeof breeding stock occurred, but that it had been found that theoriginal convention was out-of-date in certain respects and shouldbe amended in order to make it more effective. In this connection,the experts present at this meeting stressed the iinportance of stan-dardizing the methods of milk-butterfat recording, since, withoutthis, a comparison of the data indicated in the different herdbooksrelative to the yields of cows was impossible. They felt., further-more, that if uniformity in measuring productivity ni dairy anddual-purpose cattle could be brought about, within the limitationsof the management practices of the various countries, improvementprograms might be carried out more effectively. They stated thatthis would facilitate considerably the selection, distribution andmaximum use of efficient breeding stock, including time exchangeof breeding stock among the countries. The meeting recommended,therefore, that FAO should endeavor to bring about an agreementon the standardization of milk-butterfat recording methods. Aftercareful preparations, a standardized scheme was worked out, suit-able for European conditions, and representatives of Europeannational organizations responsible for milk-butterfat recordingwere invited o consider and eventually adopt time proposed Scheme.This meeting took place in Rome in March 1951 and after minormodifications, time proposed scheme was unanimously adopted bythe representatives of such national milk-butterfat recording or-ganizations as were interested then in it. Since then, more organ-izations have adhered to the agreement and, at present, this schemeis in operation in 12 countries. Further steps are now being takenwhich may eve,ntually make it feasible to revise the conventionon methods of keeping and operating- herdbooks, signed in 1936,

including the collection by FAO, in co-operation with the EuropeanAssociation for Animal Production (EAAP), of material on themethods used in the keeping and operating herdbooks for cattlein the various European. countries. The outcome of this workwill be of much interest to countries in the Americas, particularlythose which are parties to the convention.

At the Turrialba meeting it was recognized that national orarea-wide impro-vement in the productive capacity of any typeof livestock will, in most cases, be based on males produced from_a very small percentage of the liv-estock population and in rela-tively few flocks or herds, maintained either by private breedersor government-owned studs. Granting this, it must be recognized_that any improvement which may be possible in the producingcapacity of commercial stock is in the long run dependent uponcontinued genetic improvement in the stud stock. At the Baurtimeeting much interest was shown in the use of imported breedingstock in many countries and the need for safeguarding the interestsof breeders in the importing countries was noted. Having regardfor the importance of higher genetic quality in the imported animalsand the adaptability to living conditions of the types being import-ed, it was pointed out that governments should take steps to ensurethat documents setting forth the origin and qualities of animalsto be imported should be examined and approved by appropriateand well qualified authorities in the importing country beforeshipment is made, and that breeders interested in importing desir-able stock should be assisted by the provision of advice on sources,selection an.d utilization of animals. These statements show clearlya recognition of the need for careful organization of herdbookkeeping, which should provide for accurate and reliable informationfor the use of breeders.

When considering the manner in which herdbook keeping might.be improved it must be recalled that herdbooks developed in assoc-iation with the so-called pure breeds and that the concept of purebreeds is relatively new in the history of the animal industry. Greatprogress in the formation of purebred cattle had already beenachieved before breeders' associations had been organized. Someof the modern breeds of livestock owe their origin to the workof a few outstanding breeders who were particularly successfulin improving their stock over and above that raised by theirneighbors. The influence of the work of these breeders upon theexisting local type of animals gave such renown to these particularbreeds that it was considered advisable to avoid crossing themwith cattle of other regions. When the associations -which wereentrusted with maintaining the purity of breeds were formed,rules were laid down as to which cattle were to be accepted forregistration in the herdbooks as being " pure. " The purity did

23

not refer to the gen.etic constitution of the animals but simply totheir appearance. In this way, for example, all red animals wereat once discarded from the -first herdbooks in the region.s wherethe original Aberdeen Angus was bred. The new breed beganto be pure as far as its black color was concerned, but the gene forred, being recessive in relation to the black, remained unperceivedin many of the selected animals. It was intended to producepure breeds because it was found that in the hands of good breedersthey produced better quality stock. The Aberdeen. Angus becamefamous not because of its uniform black color but because, inthe hands of some breeders, it produced more meat an.d was moreeconomical. One way to recognize this useful animal was to giveit a distin.guishing mark. The color provided such a mark, easyto understand and relatively simple genetically.

The development of the science of gen.etics based upon Mendel'sLaw gave great force to the concept of pure breeds. Certainlythe particular marks of some of the breeds could be explained byMendelian genetics. It was shown that the red color was controlledby a gene allelic to the one for black, the latter being domin.antto the former in exactly the same way as had been shown to bethe case for certain colors in flowers. Although Mendelian geneticshelped to explain the particular marks of the breeds, this con.ceptwas inadequate to explain hereditability in.sofar as it concernedquantitative characteristics. The magnitude of this difference inbehavior of quantitative characteristics has only recently beenfully appreciated. Research has led to the conclusion that thehereditary factors controlling productivity in animals are verynumerous (Shrode and Lush, 1947).

The concept of a pure breed assumed that once the basic ani-mals had been foun.d, they should be used exclusively as sires forfuture generations and so the breed would maintain its purityforever. For some characteristics this con.cept held good; as regardsthose features which are of importance economically, it has beenshown in practice that it is impossible to maintain a herd pure asfar as productive qualities are concerned.

Some degree of homozygosity may be acquired due to animalsbeing kept in restricted groups and by the process of intensific-ation in the use of the offspring of outstanding bulls instead ofusin.g bulls chosen at random. Lush (1945) calculates that themere fact of not introducing n.ew blood into a breed for a hundredyears would only entail the loss of barely 10 percent of its hetero-zygosity. Failure to m.aintain the standard of purity in the herd-book, registration errors and mutation.s would almost destroy thisprogress in genetic purity. The increase in homozygosity dependsupon the extent to which breeders utilize certain preferential blood.In this respect, no observed breed has ever acquired greater purity

24

than the Shorthorn at the time of the Collins brothers who inten-sified the use of a single bull and his offspring (Favourite). Yetin spite of this, from the formation of the breed up to 1920 theShorthorn had barely lost 30 percen.t of its heterzygosity.

Upon the formation of breeders' associations for " pure " breeds,a new term was employed, i. e. " registered " cattle. The termsimply refers to cattle which, havin.g met certain requirements,are entered in the herdbooks of the association. Were the animaladmitted solely upon visual inspection, the concept of " registeredas a synonym for " pure " partakes of the error of believing thatthe inspection of an animal and its admittan.ce to the herdbookin some way guarantees the manner in which it is going to reproduce.The error grows when the associations close their books to outsideblood and only register the offspring of animals whose progenitorsappear in the herdbook. The variability or the impurity of theanimals which w-ere registered in the first place bein.g recognized,accepting -the registration of all their offspring is tantamount toallowing haphazard reproduction of those animals which mayconstitute the lowest grade within that breed; that is to say thatanimals, which barely deserve to be admitted upon the basis ofinspection, have the same chance to be sires of registered stockas the most outstanding specimens of the bred. The future'provement of the breed is left to the breeders' discretion. Thisslight guarantee given by the term " registered " as far as it con-cerns productivity, has given rise to attempts to establish " meritbooks " within the general herdbooks, thus takin.g account of theneed to recognize qualities superior to those implied within theconcept of registration.

As regards breeds or associations where the inspection of an.yanimal previous to its registration in the books is maintained, itis assumed that an official organization exists in order to eliminateconstantly from the nucleus of the race the " tails " or lower speci-mens of the breed. This is true of nearly all European reoisterassociations and in South America, the most notable example ofinspection previous to registration may be found in Brazil withthe zebu breeds.

The danger of registering through inspection lies in the use ofan excessively uniform selective standard. Uniformity may bedesirable in a breed but it may be carried too far. Even assum.-ing that the inspectors are highly efficient or that they judge bybreed standards accepted by a majority, it does not follow thatthey are accurate in their judgment of what is most desirable.Some breeders working towards different goals may in time provethat their ideas are the best. For example, in nearly all thedairy cattle associations, a wide, short head is preferred. However,statistical evidence indicates the existence of a correlation between

25

a long head an.d high production. An independent breeder work-ing against the majority may eventually render some service tothe breed.

The worst mistake in registering through inspection lies perhapsin stressing small points while overlooking completely the productiveor reproductive qualities of the animal. This appraisal remains,naturally, in the hands of the breeder. A conflict between inspec-tion and the breeders' appraisal will be inevitable in the case ofanimals that, having -won prizes in cattle shows and being admiredby the breeders' association.s in accord with their standards of ex-cellence, have proved to be mediocre sires. The breeder, therefore,continues to be the keystone of breeding programs for improvementin any system of registration which may be adopted.

Another disadvantage of the sy-stem of registration throughinspection is its cost, which may be so high that it can only bemaintained with government subsidies. Although most of thelong established herdbooks are now closed, many herdbook assoc-iation.s admitted grade animals in their books at the outset, andsome of the new breeds (such as Santa Gertrudis) admit in theirherdbooks high grade animals. There is much to be said in favorof such a system if production and excellency standards are adoptedfor the acceptance of grade animals. This method may be usefulto introduce desirable genes into a breed. This is especially im-portant when adapting a breed to surro-undings different fromthe original ones.

The method of includin.g in a herdbook all the offspring ofanimals already registered, but establishing special herdbooks forsuperior animals, has great advantages. It does not impose anyrestrictions upon. the breeder in his selection. methods. It doesn.ot discriminate directly against inferior animals, but it implicitlyrecognizes that they do not qualify for the merit herdbook. Itdoes not imply a reduction in the profits of the breeders' associationby reducing the number of qualified animals. This is an importantpoint. The fin.ancial solvency of herdbook societies is usuallybased on the fees for entering animals.

Those responsible for these merit herdbooks in the WesternHemisphere generally have not made great efforts to determineif an animal is a good transmitter of its qualities. Some countriesin Europe have made progress (Lush and Gilliard, 1955), espe-cially Denmark (Helger, 1954). Central testin.g stations are estab-lished there to investigate the progeny of different bulls, underuniform management and feedin.g conditions.

There are certain other problems in connection with the estab-lishment of herdbooks since, with the exception of countries suchas Argentina, Canada, Uruguay, the United States of Americaand a few others in the Western Hemisphere, the numbers of ani-

26

mals to be registered in any one country are so small that it is diffi-cult to support breed associations on registration fees alone. Thisproblem might be overcome in small countries by the establish-ment of a central registry system which would provide facilitiesfor the registration of animals of several different breeds. Anotherproblem arises from the fact that many areas in Latin Americahave climatic conditions which impose limitations on livestockproduction. Thus, the importation of pure breeds from temperatezones, where good conditions of climate and feeding exist, maylead to the establishment of herdbooks for these breeds and emphasison types not well adapted to local conditions. Therefore, consid-eration needs to be given to the kind of registration systems whichare best suited to the prom.otion of breeds adapted to difficultenviron.mental conditions, such as those encountered in the tropicsand sub-tropics. This would involve the recognition of somemeasures of merit through which both. production characters andthose reflecting adaptability to environmental conditions might berecorded. Thus, the mistake of simply adopting herdbook systemsused in other areas without considering how they should be bestadapted to serve conditions in such areas should be avoided.

In relation to the last point in the preceding paragraph, andrecognizing that types which have been developed in particularenvironments may make important contributions to livestockimprovement in those or similar areas even though they are notgen.erally recognized as important breeds, the FAO staff are prepar-in.g a catalog of cattle stocks originating in the Americas. Thisshould provide the basis for a publication similar to the on.e alreadyissued on the zebu cattle of India and Pakistan (Joshi and Phillips,1953), an.d on.e which is in preparation describing the importanttypes of cattle originating in Africa. It is intended to make avail-able to governments information on the conditions under whichthese American breeds or types originated, and the physical cha-racteristics and performance of those types in their native areasand in other areas if they have been exported.

Recent Developments in Various Countries

In preparation for the Buenos Aires meeting, governmentswere requested to submit information on the nature and extentof the herdbook and performance testing activities in their coun-tries, particularly with regard to cattle. Much current informa-tion was brought together as a result, including some on livestockspecies other than cattle. It was prepared in somewhat differentforms by various countries; it is not comparable in all respectsfrom country to country, and no data are available for manycountries. However, it is sufficient to give a good indication of

27

the present position in those countries which have established reg-istration systems, and the information from Argentina, Canada,Chile, El Salvador, the United Kingdom (for Jamaica) and theUnited States of America is summarized below.

In Argentina, herdbooks are managed by a leading breeders'association the Argentine Rural Society which handles theherdbooks for nearly all breeds and types. Only studbooks forpurebred racehorses and horses of the Arab breed are managedby a specialized official department, while the registration of poultryand rabbi-Ls is han.dled by a department of the Ministry of Agri-culture and Livestock.

In 1954, the Government passed a law setting up governmentcontrol of herdbooks, which is to be applied as soon as rules havebeen formulated. A feature of the Argentine herdbooks is thatthe 'majority have no -provision for admitting new blood, only theoffspring of purebred stock being eligible for registration. Thereare a few new open herdbooks in three parts, i. e., basic registra-tions; first, second and third preliminary registrations; and finalregistrations for certain breeds already established an.d whose en-largement on the basis of pedigree is about.to be termin.ated. Thisis the case, for example, with the " criollo " breed of horses. Also,some experimental approaches are being made with several herd-books, some of which have been definitely established. Amongthe latter are to be found herdbooks for the Anglo-Argentine horse,the Argentine Santa Gertrudis cattle and the breed of goats whichis to be designated as " Argentine " or " National. " However,the ten.dency is to utilize the so-called closed herdbook.

The Association of " blando " Argentina Breeders, underofficial supervision, has established a herdbook for " half-pedigreecattle (referred to as " purebred by cross ") which will permit,after selection., preliminary registration after inspection and appro-val of the type, and upon the basis of a fixed minimum milk pro-duction. The offspring of those animals registered in the prepara-tory herdbooks, upon approval of type and meeting the minimummilk production, will be registered in the final herdbook. Theseherdbooks are being established with the object of improving an.dstandardizing type and in.creasin.g milk output. The existenceof this herdbook does not mean that those animals registered wouldbe considered as purebred. They remain as " purebred by cross,but after five gen.erations, the offsprin.g may be recorded autom.a-tically as " purebred by cross.

As regards beef cattle yield trials, work in Argentina has beenlimited to that carried out with purebred herds. With a preciseknowledge of the differen.t forages fed to the cattle over a fixedperiod and the relative -weight increase, the results obtained haveallowed for an assessment of the importance of selection of sires

28

which transmit their digestive capacity r efficiency of feed utiliz-atior to their offspring.

The numbers of animals registered in various herdbooks forcattle in Argentina since thc,se herdbooks were established until31 December 1954 are shown in Table 1. It will be noted thatthe bre( ds which the largest numbers of animals have been

red ale the Shorthorn, Aberdeen Angus and Hereford. Forthese three breeds, the numbers registered from 30 June 1953 to30 June 1954 were 19,000, 24,000 ad 12,000, respectively.

TAB! F. 1 NUMBERS OF CATTLE REGISTERED IN VARIOUS HERDBOOKS IN ARGENTINA SINCETHOSE HERDBOOKS WERE ESTABLISHED TO 31 DECEMBER 1954

In Canada, livestock is registered and herdbooks subsequentlypublished -under the authority of an Act of the Government ofCan.ada respecting the incorporation of purebred livestock recordassociations. The Act is commonly cited as the Livestock Pedi-gree Act 1949. The Act provides the authority for a purebredassociation or recording association to become incorporated andprotects such bodies from competing association.s of the same breedor species. Each association incorporated under the Act has com-plete freedom with respect to the constitution and bylaws but theinitial constitution must be approved by the Department of Agri-culture and all amendments to the constitution must be likewiseapproved. Approval of con.stitutions an.d amendments theretoare not withheld unless they are in conflict with the Act underwhich the associations enjoy their privilege.

The Livestock Pedigree Act also provides for the affiliation ofrecording associations under the Canadian National Livestock

29

BreedYear

HerdbookFounded

Total Numbers Registeredsince Founding of Herdbook

Males Females Both Sexes

Shorthorn 1888 385 609 380 023 765 632Polled Shorthorn 1909 360 394 754Aberdeen Angus 1901 162 967 128 246 291 213Hereford 1889 121 554 128 246 249 800Polled Hereford 1944 4 363 4 486 8 849Holstein-Friesian 1920 28 719 31 454 60 173Brahman 1920 149 170 319

Dexter 1920 114 148 262Flemish 1920 1 640 2 267 3 907Galloway 1920 127 102 229

Jersey 1920 726 866 1 592Normandy 1920 1 199 1 326 2 525Red Polled 1920 2 505 3 432 5 937Brown Swiss 1920 873 932 1 805

West Highland 1920 147 157 304

Records. The affiliation is composed of thirty active associationswhich combine for the purpose of the processing of certificates ofregistration and publishing herdbooks. The general policy of theCanadian. National Livestock Records is determined by a board,composed of representation from each of the affiliated associa-tion.s from which is elected a records committee operations of theCanadian National Livestock Records. The organization is a non-profit one, and charges for services to affiliated associations arebased on actual cost. All associations incorporated under the Actare so affiliated, with the exception of the Canadian. Holstein-Friesian Association.

The Canadian Nation.al Livestock Records maintains what istermed a General Stud and Herdbook for the registration ofanimals of -those breeds too small in numbers to maintain an activeassociatio-n.

The federal government provides office accomodation and acash grant of $ 25,000 annually to the Canadian National LivestockRecords as a mean.s of supporting the efforts of the affiliated asso-ciations in the cost of registration. Apart from this assistance,no subsidies are provided for the keeping and operation of herd-books.

The data recorded in the herdbooks include a listing in num-erical order of allotted registration numbers, the name of thebreeder, the name of the animal, the sex, the names of the sire anddam and the identification (if tattoed or ear-tagged) and in certaininstances the color is noted. Animals are registered -upon appli-cation by the breeder who certifies the parentage, except in thecase of Hunter horses where final registration is delayed for threeye ars.

All herdbooks operated under the authority of the LivestockPedigree Act are closed with the exception of books recordingClydesdale horses and Standard Bred horses. With these breedsregistration is possible after four crosses with purebred stallions.

The certificate of registration issued. by the Canadian NationalLivestock Records is a simple birth certificate including two gene-rations of parentage. In the case of the Holstein-Friesian breed,only the sire and dam are recorded in the certificate of registration.Facilities are provided by the Canadian National Livestock Re-cords and the Canadian Holstein-Friesian Association for a moreelaborate pedigree for a fee based on. cost. The Canadian Holstein.-Friesian Association an.d the Canadian Ayrshire Breeders' Associ-ation require that bulls to be registered must be from dams withthe required minimum for inspection as to breed -type and milkand butterfat production. All certificates of registration processedby the Canadian. National Li-v-estock Records are approved by the

30

Chief Registration Officer of the Canada Department of Agriculturebefore they are issued.

The numbers of animals registered in 1953 and the total re-gistration under the Livestock Pedigree Act of 1949 are shownin Table 2.

TABLE 2 LIVESTOCK RECORDING ASSOCIATIONS OPERATING UNDER THE LIVESTOCKPEDIGREE ACT 1949 IN CANADA, AND NUMBERS RECORDED

31

AssociationRegistrations

1953

TotalRegistrations

Canadian Aberdeen Angus Association 7 329 128 568

Canadian American-Saddle Horse Breeder's Association 35 619

Canadian Ayrshire Breeder's Association . 12 778 408 849

Canadian Belgian Horse Association 138 10 941

Canadian Cattle Breeder's Association 866 36 333

Canadian Horse Breeders' Association 21 3 568

National Chinchilla Breeders of Canada 8 074 28 848

Clydesdale Horse Association of Canada . . 86 91 710

Canadian French Coach Horse Breeders' Association 158

Canadian Galloway Association . . . 80 3 618

Canadian Goat Society 237 5 443

Canadian Guernsey Breeders' Association 4 169 68 861

Canadian Hackney Horse Society 54 3 975

Canadian Hereford Association . . 33 537 393 647

Canadian Holstein-Friesian Association 67 650 1 351 200

Canadian Hunter Society 59 405

Canadian Jersey Cattle Club 12 715 387 207

The Canadian Kennel Club . . 13 905 332 464

Canadian National Silver Fox Breeders' Association 377 472 806

Canadian Palomino Horse Association 391 391

Canadian Percheron Association . . . 144 43 213

Canadian Pony Society . . 66 2 320

Canadian Red Poll Association . . 315 21 038

Canadian Sheep Breeders' Association 13 550 537 763

Canadian Shire Fiorse Association 3 124

Canadian Shorthorn Association . . . 20 301 783 053

Canadian Standard Bred Horse Society 757 12 822

Canadian Suffolk Horse Society 3 766

Canadian Swine Breeders' Association 15 019 651 213

Canadian Thoroughbred Horse Society 488 14 526

General Stud Herdbook

Arabian Horse 27 132

Brown Swiss Cattle 64 3 722

Devon Cattle 5 5

German Coach Horse 1 23

Highland Cattle 48 247

Jacks and Jennetts 1

Lincoln Red Shorthorn 45

Morgan Horse 5 24

Tennessee Walking Horse 13

In Canada also, there is no federal program for eval-uatin.g orappraising the sires of beef-producing breeds. The Province ofOntario conducts a testing program which provides for the feedingout after weaning of the steer and bull progeny of bulls. Fourprogeny are tested and results are available on feed consumption.,rate of gain and carcass quality. Apart from this, the appraisalof bulls of the beef breeds is still in the exploratory stage.

With respect to dairy cattle, the situation is somewhat different.The federal Department of Agriculture for a great many years hasprovided a service whereby the breeders of purebred dairy cattlemay have their herds tested for milk an.d butterfat production.The objective of this service, which includes a staff of 150field inspectors, is to provide 12 inspectional visits per year,each visit covering 24 hours when the production an.d butter-fat content of each individual cow in the herd is checked andreported. There are two plans in operation. Plan A is basedon the individual -weights taken by the herd owners and checkedup to 12 times per year by the inspectors, and Plan B underwhich the herd owner does not record daily production of milkbut the individual cow's performance is based on the in.spector'sweights and butterfat test taken at monthly or n.ear-monthlyintervals. The federal Department of Agriculture issues a certi-ficate of production at the end of each lactation and In ese certi-ficates are accumulative in that to the end of a cow's producinglifetime, her certificate will carry the official record of each ofher lactations. A report is published annually, which includesthe lactation records of each cow finishing a lactation within theyear of publication. The cows' names and registration numbersare listed under their sires.

Most of the provinces of Canada where dairy cattle productionis of importance have official services for the recording of dairycattle production. Their operations are design.ed primarily forservicing the owners of non-registered herds, but none of theprovincial services are at present recognized for the selective registra-tion of cattle. The dairy cattle breed associations, which do not requireproduction performance for registration, use the Record of Perfor-mance certification in a variety of ways in the classification of bulls.

There is at the present time no national program for the eva-luation of dairy cattle sires although the rapid development ofartificial insemination is increasing the advisability of a nationalservice. The province of British Columbia has for many yearsprovided annually information on the performance of bulls basedon. the Record of Performance service results and the provincialcow testing program results. At present, results are publishedon all bulls with five or more daughter/dam comparisons. Aservice is in the process of development within the fabric of

32

the breed associations to provide information on the performanceof bulls used at artificial insemination units. There is increasingevidence to indicate that this service is being used effectively bythe units in discarding bulls if not as yet in the procuring of bulls.

in Chile, there are three agricultural societies (National Agri-cultural Society, Agricultural Society of Temuco, AgriculturalSociety of Osorno) and one breed association (Association of Magal-lanes) which have official sanction to maintain herdbooks. Ani-mals are registered according to class and breed, the classificationby breeds being subdivided into purebreds, high grades and lowgrades. The agricultural societies register animals of all classes,while the Breed Association of Magallanes only registers sheep.The number of animals registered by the four organizations in1954 is shown in Tables 3 to 6.TABLE 3 NUMBERS OF CATTLE OF VARIOUS BREEDS REGISTER D BY CHILEAN AGRICULTURAL

SOCIETIES IN 1954

TABLE 4 NUMBERS OF HORSES OF VARIOUS BREEDS REGISTERED BY CHILEAN AGRICULTURALSOCIETIES IN 1954

33

Breed

NationalAgricultural

Society(S.N.A.1

Agricultura/Society ofTemuco(S.0.F.0.)

AgriculturalSociety of

Osorno(S.A.G.0.)

Total

Purebred Purebred Grade Purebred Grade Purebred Grade

Dutch Lowland 1 143 121 121 1 300 347 2 564 468German Lovvland 23 473 957 603 694 1 099 1 651Holstein-Friesian 17 17 17 17Brown Swiss 7 7

Norman 68 21 50 89 50Simmenthaler _ 22 22Durham Shorthorn 2 -- -- 2

Aberdeen Angus 30 30

Hereford 10 10

Total 1 276 632 1 152 1 925 1 041 3 833 2 193

Breed

NationalAgricultural

Society(5.N.A.)

AgriculturalSociety of

Temuco(S.0,F.0.)

AgriculturalSociety of

Osorno(S.A..G.0.)

Total

ChileanThoroughbred

)ercheron-lackney

Purebred Grade Purebred Purebred Purebred Grade

1 5897

16

30

3

2

..._

56

_3elgian

154 1 7997

16

30

3

Total 1 645 2 56 154 1 855 2

TABLE 5 NUMBERS OF SHEEP AND GOATS OF VARIOUS BREEDS REGISTERED BY CHILEANAGRICULTURAL AND BREED ASSOCIATIONS IN 1954

TABLE 6 NUMBERS OF PUREBRED HOGS OF VARIOUS BREEDS REGISTERED BY CHILEAN AGRI-CULTURAL SOCIETIES IN 1954

The council charged by the Chilean. Ministry of Agriculturewith the responsibility of adnainistering the registry of livestockconsists of the National Director of Agriculture, the Director ofthe Department of Livestock Production, one representative ofeach of the three agric-ultural societies, the Breed Association. ofMagallanes, the Dutch Lowland Cattle Association and one repre-sentative of any new association which might be formed. Noneof the organizations maintaining herdbooks is subsidized by theGovernm.ent. The information the breeder must furnish with hisapplication for registry of his animals is essentially the same asthat required by most breed associations. The three agriculturalsocieties m.entioned on page 33 have immediate control over the cowtesting program now in _operation in Chile.

34

Breed

NationalAgricultural

Society(S.N.A.)

Agricultu ratSociety ofTetnuco

(S.O.F.0.)

Agricult.Society ofOsorno

(S.A.G.0.)

BreedAssociation

ofMagallanes

Total

Purebred Grade Purebred Grade Purebred Purebred Purebred Grade

Ham ps hi re Down 730 10 46 36 8 5 789 46Oxford Down __ 7 7

German Merino 669 69 669 69

French Merino 619 233 __ 619 233

Australian Merino 328 __ 20 348

Corriedale 82 -- _ 18 1 446 1 546 ---Suffolk. Down 88 69 88 69

Ideal 18 -- __. 18

Isle of France 10 -- __ __ 10

Romney Marsh -- 167 371 538 --

Total 2 544 381 46 36 193 1 849 4 632 417

Anglo Nublan 16 __. 16

Berkshi re 384 27 171 582Duroc 42 42German Landrace 70 292 4 366German Saddleback -V 52 52

Total 496 319 -- 227 - 1 042

National Agricultural AgriculturalAgricultural Society of Society of

Breed TotalSociety Temuco of Osorno(S.N.A.) (S.O.F.0.) (S.A.G.0.)

The Government of El Salvador has established a register forthe individual production of dairy cows in the 1V1inistry of Agri-culture. Data in Table 7 show the progress of this work sinceFebruary 1953.

TABLE 7 INCREASE IN RECORDING OF MI K PRODUCTION IN EL SALVADOR

February 1953January 1955

Time Numberof Herds

35

Number of Animals

Pu re Mixed Criollo

Total(Cows)

This recording of the performance of the animals is a part ofthe Ministry of Agriculture's program for selecting the betterproducing females and the males that sire progeny of higher pro-ductive capabilities than their dams, and for improving (he careof the herds and the quality of the milk. There are three agents,one of -whoni visits each herd every rnonth to record the weightsof milk produced by each COW and to take sanaples for determin-ing the butterfat content in the laboratory of the dairy section.For every- pound of milk produced, 5 cc. are taken for analysis foreach coN% producing less than 10 lb.; 3 cc. for each pound forthose producing 10 to 20 lb.; 2 cc. for those producing 20 to 30 lb.and 1 cc. for -those producing 30 lb. or more. Samples of milkare also sent to the laboratory of animal pathology to be testedfor brucellosis. Each herd is -tested at intervals of -three months.Th.ese records of milk and butterfat production and brucellosisare assembled in the central dairy office and sent to each dairymanwith recommendations for the quantities of concentrated feed eachcow should have to maintain and improve her produCtion.

In summarizing the records of practically 1,000 cows from1 Novermber 1953 to 31 October 1954, 140 purebred cows averaged25 lb. of milk daily; 241 cows of mixed breedin,9- averaged 14 lb.-while 379 criollo cows, fed concentrates, averaged7101/2 lb. and 229criollo cows, without concentrates, averaged 7.8 lb. of milk daily.A study of the average production of all the cows by monthsshows remarkable uniformity, varying from a minimum of 11.2 lb.in November to a maximum of 13.6 lb. in March., and 13.4 lb.in May and August, with an average of 12.9 lb. for the twelve-month -period. Time fact that most of the cows received concen-trates to supplement pasturage accounts largely for this uniformproduction. However, it should be noted that the purebredsfailed to maintain th.eir production at a uniform level. It dropped,from 29 lb. in November 1953 to 21 lb. in September 1954 onaccount of a 40 percent slump in tlie production of one herd. The

3 25 30 5 6534 154 286 951 1 391

study of these records emphasizes the vital importance of the bestfeeding and management in order to obtain high production frompurebred cattle. The records show that while cows of mixedbreeding produced 2.1 lb. of milk for each pound of concentratefed, and the criollos 2.5 lb., the purebred cows produced only1.8 lb. of milk for each pound of concentrates fed. However,as noted above, the average daily production of the purebredswas more than twice that of the criollos. Accordingly, it isconsidered quite probable in El Salvador that the purebreds weremore profitable producers on account of the larger volume of totalproduction even though they produced less in re-turn for thesupplemental concentrates fed.

In Jamaica, four herdbooks are maintained; the names of thesocieties are listed below, together with the numbers of animalsregistered_ to date:

36

Animals RegisteredName

Males Fermales

The Department of Agriculture is the responsible authority foreach of -these herdbooks, and while the records are kept by thesecretary of the society concerned, pedigrees and other forms aresigned by the secretary and a government officer. There is nodirect subsidy of these herdbooks, but government officials carryout appraisals of cattle in connection with provisional registrationand milk recording, and do clerical work in connection with herd-book registrations. Data recorded are: date of birth, markings,tattoo and brand number of the animal and the name and herdbooknumer of the sire and dam. Calves must be registered within120 days of birth. Declaration of service prior to birth is notrequired. Operation of the first closed herdbook began in January1955 for the Jamaica Brahman breed. Other herdbooks are open,and animals are entered in a provisional register pending appraisalby a team of government officials and breeders for three successiveyears. First appraisals are made at two years of age. If declaredeligible, they are included in the final herdbook when it is closed.In the beef breeds, when the visual examination is made, considera-tion is also given to breeding history, quality of progeny and/orsibs. In the dairy breeds, production is assessed in terms of

Jamaica Brahman Breeders' Society 300 1 630Jamaica Black Cattle Breeders' Society 30 400Jamaica Hope Cattle Breeders' Society 210 1 550Jamaica Red Cattle Breeders' Society 220 1 610

milk produced, and while most farmers keep records there is alsoan official government milk recording scheme in connection withthe Jamaica Hope Cattle Breeding Society. Government sponsoredbulls, which are issued on loan to dairy farmers an.d placed at studcenters for use by peasants and for artificial insemination, exerciseconsiderable influence. In 1954, approximately 12,000 calves wereborn to such services out of an estimated dairy cow populationof 55,000.

All purebred animals in the Jamaica Hope breed were producedat the outset on the government farm. All other animals whichare registered arise from the use of bulls from this farm, andonly animals resultin.g from four top crosses or more by thesebulls can be registered. Five breeding sections are maintained inthe government herd to prevent any substantial amount of in-breeding. Since registered animals may be produced from outsidestock only by top crossin.g from bulls produced at the governmentfarm, the latter has become the sire-producing center for the im-provement of cattle in the island.

In the United States of America the registration of cattle is inthe hands of breed associations which keep a record of the pedigreesof all registered animals. There are 84 breed registry organizationsfor the various kinds of livestock, summarized by types as follows:horses 20; cattle 23; sheep 23; goats 3; swine 14; andasses 1.

Tables 8 to 12 contain available and approximate figures onthe n.umbers of purebred livestock registered in the United Statesof America during each of the five years beginning with 1949,grouped according to their utility -type or purpose. In addition,1,950 asses had been registered.

The terms applied to books of record of various classes oflivestock are as follows: studbook for horses and asses; herdbookfor cattle, goats and swine; and flockbook for sheep; while theterm studbook is used as a collective term to describe all -types.

The books originally were printed for distribution and sale tointerested breeders, but many of the breed organizations havediscontin.ued publication of their records due to the increasedcosts of printing. These discontinued books include Jerseys, inthe dairy cattle breeds, and Shorthorns, in the beef cattle breeds.Only on.e flockbook the American Hampshire Down FlockBook is published for sheep, and no book is published forswine. Some of the light breeds of horses, such as Thoroughbred,American Saddle Horse, American Standardbred, and the MorganHorse are listed in published books but none is published for draftbreeds.

The Federal Government in the United States of America hasno authority over purebred registration. Howe ver, the organiza-

37

TABLE 8 CATTLE REGBTERED IN THE UNITED STATES OF AMERICA

TABLE 9 HORSES REGISTERED IN THE UNITED STATES OF AMERICA

38

TABLE 10 SHEEP REGISTERED IN THE UNITED STATES OF AMERICA

TABLE 11 GOATS REGISTERED IN THE UNITED STATES OF AMERICA

TABLE 12 SWINE REGISTERED IN THE UNITED STATES OF AMERICA

Purpose 1953 1952 1951 1950 1949

ledium woo! 77 242 97 061 89 721 87 207 80 595cine wool 10 182 13 810 14 664 14 383 8 5942oarse wool (long) 19 931 19 622 18 384 16 543 14 530:ur (Karakul) 323 301 320 661

Total 107 678 130 794 123 089 118 133 104 380

Purpose 1953 1952 1951 1950 1949

Bacon 16 077 14 574 4 715 18 859 13 376Lard 531 694 225 515 313 400 325 404 343 417

Total 547 771 240 089 718 115 344 263 356 793

Purpose 1953 1952 1951 1950 1949

Beef 828 952 872 701 736 277 657 309 565 300

Dairy 396 448 421 450 403 108 394 746 381 130

Dual purpose 30 181 35 963 40 139 35 799 34 000

Total 1 255 581 1 330 114 1 179 524 I 1 087 854 980 430

Purpose 1953 1952 1951 1950 1949

Mohair 5 463 4 708 5 269 4 265 3 454Milk 7 153 6 847 2 275 2 760 6 976

Total 12 616 11 555 7 544 7 025 10 430

Purpose 1953 1952 1951 1950 1949

Draft 357 311 364 403 606

Light 33 994 29 795 19 576 15 627 14 831

Total 34 351 30 106 19 940 16 030 15 437

-Lions sponsoring the different record books are practically allchartered by the various states in which the societies originateand operate. The Federal Government has exerted an influencein developing and perpetuating certain useful breeds employedin agriculture, such as the Morgan horse, long popular in thenortheastern section of the country, the Santa Gertrudis cattle,and Columbia and Targhee sheep. The U.S. Department of Agri-culture has likewise exercised a significan.t influence, through re-search, in the development of new breeds of swine from h-ybridfoundations of Danish Landrace and other breeds developed in,or imported into, the United States of America. This developmentled to the organization of the Inbred Livestock Registry Association,which records animals in new breeds as they are formed. Theyinclude the Minnesota No. 1 and No. 2, formed from crossesof the Danish Landrace x Tamworth, and Yorkshire x PolandChina, respectively, the Beltsville No. 1 and No. 2, formed fromcrosses of the Landrace x Poland China, and Yorkshire x Duroc xLandrace x Hampshire crosses, respectively, and the MontanaNo. 1 and -Maryland No. 1, formed from crosses of the Laridracewith Hampshire and Berkshire, respectively. Registration of theselin.es is in the hands of the Inbred Livestock Registry Association,St., Paul, Minnesota.

Regarding the formation of new breeds of cattle through crossin.g,the Sindhi Breed is being crossed with the Jersey, Holstein andBrown Swiss breeds in an attempt to develop strains possessinghigh resistance to heat. Detailed records are being kept on allanimals so as to provide a sound basis for selection of the mostdesirable individuals. It is expected that these strains will even-tually have their own herdbooks.

Most of the prominent and active breeds used in the agricultureof the United States of America originated in Europe, particularlyEn.gland, and the registration.s of these animals trace to the stud-books abroad. There have been a number of breeds developed inthe United States, e.g., the American Saddle Horse, the MorganHorse, and the Standardbred Horse. The Columbia, Mon.tdale,Romeldale and Targhee sheep breeds are of United States origin.In addition to the swine breeds registered by the Inbred LivestockRegistry Association, the following are of American origin: PolandChina, Spotted Poland China, Chester White, Duroc and Hereford.In all of these instan.ces, private breeders and fanciers have under-taken a careful and organized breeding plan with a definite idealin mind, directed towards the fixation of type in th.e animalsinvolved and a consequent perpetuation of this type so that theindividuals will breed reasonably true to the standard desired.

In the United States of America the most common system forrecording animals is by numerical registration. In some books

39

the numerical registration is -without regard to sex, while in othersa separate section is de-voted to each sex. This plan is followedentirely by all the cattle, sheep and goat breeds. In the case ofthe Thoroughbred horse, animals are registered under their damsarid a record given therein of the produce of an individual. d.anafor a period of years. This is patterned after the General Stud13ook in England. and other prominent throughbred studbooksthroughout the world. The usual record for an animal in a stud-book includes the animal's name, registry- n.umber, sex, color,marks of identification, date of birth, a record of the breed.er andhis address, and subsequent owners. In instances involving cattleand sheep, swine and goats, time record of markings includes thoseof tattoo marks and possibly ear -tags.

Of equal importance, and as an accompaniment to the main-tenance of a studbook, is the registry association's issuance of aregistration certificate. This is the breeder's or livestockman'scredential substantiating that the animal is a purebred of theparticular breed involved. The registration certificate containsnot only the pedigree of an animal, but certifies that it is regis-tered in the book of record of the association issuing the document.It is prepared on a prescribed form of the association and comprises,in brief, essentials as follows: name, registry, number, color, mark-ings, date of birth, name and add.ress of breeder. Provision isusually made in the certificate for subsequent owners which, inmost instances, are officially recorded by the registry association.With few exceptions, cattle, sheep, goats and swine are identifiedby tattoo markings and such markings should be entered on thecertificate. Marked cattle, such as Holstein-Friesians and Ayr-shires, are generally identified by charts or photographs, which areusually given on the reverse sicle of the certificate. The certificatemust include at least the name and registry numbers of the re-corded animal's sire and dam and some of the certificates showtwo or more generations of ancestry.

Each association in the United States of America has its ownrules, although the rules of the various associations are ver y si-milar. To be eligible for registry an animal must be from registeredparents, th.e only exception being the Milking Shorthorn, SantaGertrudis and Red Dan.e breeds. In the Milking Shorthorn and.the Red Dane breed. -three and four top crosses are necessary foreligibility of females and males, -respectively. In the Red Danebreed, representatives of which were first imported into -the UnitedStates of America in 1935, CONS'S are eligible only if they have amilk and butterfat record. This record, regardless of its size, isstamped on the cows' registration papers. TI e various dairy cattleassociations also keep milk and butterfat records on all cows testedin cow testing associations.

40

Regarding the methods used in record of performance -testingof beef cattle, -the work is done co-operatively among 38 statesand the -U.S. Department of Agriculture. The testing involvesthe selection of yoimg bulls from herds of commercial breeds.The bulls are put on test at weaning time and are fed for150 days under environmental conditions similar to those foundin commercial herds. Weight and feed consumption records arekept on each bull. Average daily gain has been found to varyfrom approximately 11/,to 3 lb. indicating that there arelarge differences in economy- of production even when dealingwith animals as closely related as full brothers. Many of thesebulls are later sold to interested breeders. The record made bythe bulls in the feed lot has been found to influence the price-which breeders have been willing Lo pay The records are madeavailable to any interested party, including the extension serviceand local press agents. Regarding the effect of selection for rateof growth on other economically important characteristics in cattle,it was pointed out that this would depend on whether the charactersin question were genetically correlated. The best way to guardagainst any undesirable changes which might occur in one characterwhen selecting for another character would be to construct aselection index giving proper consideration to the economic im-portance of characteristics for which improvement is sought.

Literature Cited Regarding Herdbooks and Performance Tests

HoLGER, A_EsoE. Animal Husbandry Research and its Applicaiion inDenmark, Anim. Breed. Abstr. 22: 87-95, 1954.

JOSITI, N.R. ad PHILLH-s, RALPH W. Zebu Cattle of India and Pakistan.FAO Agricultural Study No. 19, 256 pp. illus. 1953.

KNAPP, B. and CLARK, R.T. Revised Estimates of Hereditability of Eco-nomic Characteristics in Beef Cattle. J. Anim. Sci. 9: 582-587, 1950.

and NORDSKOG, A.W. Hereditability of Growth and Efficiencyin Beef Cattle. J. Amin. Sci. 5: 62-70, 1946.

Lusu, J.L. Animal Breeding Plans. fowa State College Press, 1945.

, and Mc GILLIAM), L.D. Proving Dairy Sires and Dams. J. DairvSci. 38: 163-180, 1955.

SHRODE, R. and Lusn, J.L. The Genetics of Cattle - Advances in Gene-tics, Vol. 1, pp. 209-261, 1947.

41

Artificial Insemination and Storage of Semen

The Baurú meeting gave some attention to the subject ofartificial insemination, and a fe-w delegations submitted reportson the progress made in their own countries. The possibilitiesof wider application owing to the development of the deepfreezing technique were considered, and the FAO staff were request-ed to make available to countries information on new developmentsin this field. This was done at the Buenos Aires meeting and asummary of the information is presented here.

The use of deep frozen semen was introduced following studiesin the United Kingdom on the value of glycerol in protecting sper-matozoa from the damaging effects of freezing and thawing. Thelatest available results from the United Kingdom show that semenstill caused conception after storage for at least two years at-79°C. The development of this technique may be summarizedas follows: early indications of a method followed the observationof Polge, Smith and Parkes (1949) who showed that spermatozoain fowl semen containing 15 percent glycerol and frozen at -79°C.were still capable of fertilizing eggs from which normal chickswere hatched. Polge and Rowson (1952 a, 1952 b) showed thatbull spermatozoa could be protected against the damaging effectsof freezing and thawing by the addition of glycerol: and Polge andRowson (1952 c) reported that glycerol-tested bull semen retainednormal fertilizing capacity when kept at -79°C. up to 31 weeks.Further results reported by Rowson an.d Polge (1953) showedthat bull semen, diluted 1 in 4, in the presence of 10 percentglycerol maintained normal fertilizing capacity during one year'sstorage at -790C. and that 7 out of 12 cows became pregnant fol-lowing insemination with semen diluted 1 in 100 and kept frozenat -79°C. for 2 to 24 days. These authors also stated that theygained the impression that live spermatozoa in bulls' semen storedfor 16 months at -79°C. became slightly reduced in number ascompared with semen stored for .shorter periods. Similar resultswere obtained by workers at Cornell University (Bratten, Cruthers,Wearden, Foote, and Dunn, 1954) in Wisconsin (Dunn, HafsBuckner, Young and Conrad, 1954), and by workers at the -Univer-sity of Illinois (Van Demark and Kinney, 1954). The effects ofthawing temperatures and composition of the extender have beenstudied by Hafs and Elliot (1954).

The -technique now recommended in the deep freezing of bullsemen is to collect the sample in the usual way and dilute itat once -to the required extent with a buffer made from equalquantities of egg yolk and 3.92 percent sodium citrate, the operationbeing carried out at a temperature of 82.4° F. (280C.). Thediluted semen is then placed in the refrigerator at a temperature

42

of 230F. (-50C.) and when the semen has reached this temperaturevan equal part of a mixture composed of 3 parts 3.92 percentsodium citrate solution and one part glycerol (this gives a concen-tration of 10 percent glycerol by volume) is added to the sample.The mixture is kept overnight in the refrigerator at 23°F. andnext day -freezing is carried out by the use of solid carbon dioxideand alcohol. The -freezing operation cOnsists of two parts, (a)reduction of temperature from 23°F. to 140F. (-100C,.) over a periodof 30 minutes, and (b) reduction of temperature from 140F. to-79°C. over a period of 20 minutes. These times of reduction oftemperature are considered to be of much importance. The frozenseinen is then stored at -79°C. in the deep freeze apparatus. Whenrequired for use, the frozen semen can be thawed in a. water bottleat 104°F. (400C.) and used -within a few hours, but the commonpractice is to remo-ve the sample from the deep freeze apparatusand take it to the farm in a vacuum flask, thawing being carriedout at the farm.

Although satisfactory conception rates are reported from theuse of semen so treated and stored up to -CWO years, -there arestill problems to be solved before practicability of its wide usewill have been proved. They include the cause and methods ofprevention of the death of some 20 percent of the spermatozoaduring freezing and thawing operations, the reasons for betterresults with semen with a low- spermatozoa count but, where theyare highly active, variation in the response of semen of differentbulls to the treatment and satisfactory methods of -transport ofdeep frozen semen over long distances.

Following upon development of deep frozen semen and thelikelihood of increased export and import of semen, considerationhas been given to conditions and regulations. A recent Europeanmeeting, convened by FAO in Cainbridge, England, studied thesubject and agreed that it is still too early to suggest internationalregulations. Recommendations, however, were formulated, andthey may form a basis for, firstly, national requirements and laterinternational use. The subjects dealt with included tests to ensurefreedom from transmission of disease in the use of semen; standardmethods of calculating fertility of semen; international identifica-tion of semen; packing and transport of semen; and methods ofprogeny-testing of bulls, including considerations of lethal andsemi-lethal factors.

In connection with the problem of disease-transmission, atten-tion should be drawn particularly to trichomoniasis and genitalvibriosis as causes of infertility. A meeting of experts convenedby FAO and held in Copenhagen, Denmark, in December 1954,considered these diseases and a report has been issued by FAOcontaining information on the recent findings on the diagnosis

43

and control, especially- of bovine genital vibriosis. It is expectedthat an account will be published soon, based on a study in whichvibrio fetus was found in Costa Rica.

Information concerning recent developments in the use of arti-ficial insemination in several countries is siumnarized below, in-cluding reference to the use of deep frozen semen where attemptshave been made to use it.

In .Argentina, there has been an increase in the practice ofartificial insemination and. new centers have been opened. Bothdairy and beef cattle are included in the schenies and highly valu-able pedigree bulls of the required t.ype, either already in thecountry or specially imported, are used. In the shipment of semenall means of transport are used, depending on the geographicalposition of the center and the farm.s. Semen has been sent suc-cessfully to other countries, including Paraguay. Full arrangementsconcerning technique and transport for artificial insemination indistant parte; of the country have n.ot -5,Tet been made, but concep-tions follo-wing first service, of 30 to 40 percent and parturitionsup to 70 percent have been obtained from the methods noi,v- inuse. Except for artificial insemination within a herd, the Ministryof Agriculture controls all the operations The control of infertility isalso being studied in Argentina and it has been found that brucellosisis mainly concern.ed. Deep frozen semen produced in the countryhas not yet been used b-u.t some has been received. from Callada.

In Canada, artificial insemination is sponsored chiefly by theprovincial departments of agriculture and in some inStances bythe federal Department of A.griculture. The operation is conductedmostly on a non--profit basis as a program of cattle improvementand is confined almost entirely to dairy cattle. Bull studs aremaintained in several provinces, by the provincial departmentsof agriculture; in other provinces, the artificial breeding units areorganized by the d.airy breeders. The organization of artificialinsemination is governed by provincial government legislation,either in the form of an :Artificial Insemination. Act or specialregulations. In 1953, some 433,000 cattle were bred by thismethod. Artificial insemination of sheep is not practised in Ca-nada. Research work in the handling, storage and deep freezin.gof semen is in progress and deep frozen semen is now in dailyuse in some areas. Semen may be imported into Canada onlywith permission of the Veterinary Director-General. Export ofsemen takes place, for example, to the United States of Americaand some shipments have been made to Great Britain.

In Chile, in 1952, the Ministry of Agriculture decided to sup-port artificial insemination in the country. It was planned to buildwell equipped centers and to have official control over them andthe whole of artificial insemination -work for some years. Dairy

44

co-operatives will -take over the centers at the end of this periodand will repay financial investments. Up to the present, twocenters have been established for cattle work and a further sixfor cattle and one for sheep, are contemplated. It has beenshown that brucellosis, tuberculosis, trichomoniasis and genitalvibriosis exist in Chile; all may be transmitted through breeding.Attention is being given. -to the details of the working of centesin all respects and. to the use of high quality bulls.

In Columbia, there has been considerable development in theuse of artificial insemination in the different parts of that country,and further plans have been made. In the past, difficulties havebeen experienced consisting largely of a lack of appreciation offarmers of the benefits to be derived from this method of breeding,failure always to give or maintain a satisfactory service to thefarmers, indifference of livestock owners to d.evelopment of moderntechnical methods, lack of satisfactory transport and th.e trans-ference of veterinarians engaged in artificial insemination to othermore urgent wOrk, such as the control of foot-and-mouth disease.In 1955, better all-round co-operation was plann.ed, to,_aether witha withdrawal of artificial insemination services from areas in -whichmany difficulties had been. encountered, provision of better roadswhere a d.emand existed, especially in dairy districts, the provisionof better service from centers and the development of more andbetter propaganda ainong farmers.

In 1952, the Government of E/ Salvador began a program forthe artificial i.lisernination of dairy cows. 'lie Ministry of Agri-culture and Livestock designated the sum of 125,082.65 colones tocarry it out. Eleven routes, each of which was covered by aninseminator, were established in the regi.ons of the greatest dairycattle population. The difficulties encountered over two vears gaverise to a reorganized plan to-wards the end of 1954. fJoder thisnew system the country is divided into seven zones, each of whichis supervised by a technician of the Ministry, and served by asmall group of inseminators, trained at the National LivestockSchool of Santa Ana. These inseminators are employed by thefarmers. Records are kept of each insemination so that the per-centage of conception and live calves can be determined. Recordsare also being kept of the fertility levels of the bulls. In co-operation with the Animal Health Department, a study is beingnnule of the diseases in the herds affecting reproduction. At present,four Brown Swiss, five Holstein., five Ayrshire and four Jerseybulls are bein.g used. Young bulls of good pedigree and 'conform-ation 'b.ave been imported from the United States of America..According to .plans, the Jerseys will be replaced by the other breedsas -there is not much demand for their semen. There is a tendencyamong the dairymen to use the semen from bulls of different

breeds rather than from one breed, indicating no marked pre-ference for any one of the other three breeds. Inseminations llaveincreased from less than 1,000 in 1952 to OVer 9,000 in 1954,'which indicates the growing popularity of the program.

In Panama, schemes have been developed for the artificialinsemination of cattle and horses. It is proposed to carry outexperimental work Oil the American Brown_ Swiss cattle and. Amer-ican Holstein-Friesians. Beef cattle are also to be included inthe scheme, using Aberdeen-Angus bulls. Plans for the developmentof artificial insemination in horses are also being made.

In Paraguay, attention is being given to the development andpractice of artificial insemination and there has been an. :increaseil the use of this method of breeding.

In Peru, artificial insemination has been practised only indairy cattle and the operations were carried out under the super-visio11 of the National School of Agriculture working in conjunctionwith -th.e Ministry of A.griculture. In some dairy districts, up to50 percent of the cows were being bred by this method. Al-though artificial insemination is a satisfactory method for impro-vinglivestock, the Peruvian officials recognize that the dangers asso-ciated -with its 1180 should not be overlooked.. These dangersinclude the transmission of diseases of a venereal character suchas trichomoniasis and brucellosis. The need for satisfactory regu-lations to prevent such occurences is recogniZed.

In Jamaica, technical difficulties have been encountered mainlyin .tran.sport and the failure of owners to recognize estrus: sub-eStrUS is prevalent throughout the county. There is one main centerand three. sub-centers and the scheme is operated by the Govern-ment. Artificial insemination has no marked effect on diseasecontrol: such diseases as brucellosis and genial vibriosis arc of-minor importance as causes of infertility. Deep frozen semenhas been used only to a limited extent.

In the United States of _America., artificial insemination is in-creasing rapidly particularly among dairy cattle; more than 20percent of dairy cows are now being bred by this method. Thereare three general types of organizations concerned, namely, co-operative farmer-owned and farmer-operated associations, in whichsemen is produced and used on members' cattle; pri.vate corpor-ations which, produce and sell semen and give an inseminationservice to individual farmers and breeders; and individual enter-prises in which farmers and breeders use artificial inseminationwithin -their own herds. The co-operative is much the mostpopular 'type of organization. An organization, kn.own as theNational Association of Artificial Breeders, rnad.e up of a largenumber of the individual co-operatives and corporations, has beenformed to advance the artificial insemination business, to establish

46

uniform policies and :procedures, and to promote research andeducation in. the subject. Artificial insemination organizationsare required. to abide by the applicable organizational faws in thestate to 'which they belong.

Artificial insemination in beef cattle in the United States ofAmerica, however, is practised only to a limited extent. In 1954,a total of 177 beef bulls were used mainly for the production ofhybrid calves, while some 2,400 bulls, of -which only 800 wereprog,eny-tested, were used for semen production for dairy cowsin ihe same .year. One of the important problems is -Lo obtainbulls of the right type. This difficulty will be partly o-vercome bythe use of deep :frozen semen because the whole of each ejac-ulate can be used, and -thus, more semen will be available forma small number of bulls. Artificial insemination is also carriedout in sheep mainly on a research basis and in private flocks.This method of breeding is also being applied to .poultry and bees.

Deep frozen semen, as now used in the United States of America,is giving even better conception rates than those obtained withnon-frozen semen. One of the important advantages oí deepfrozen semen is that fivestock breeders are able to obtain a "nom-inated " service from any desired sire. Research work is in pro-,gress on the causes and control of infertility in its many aspects.Very little semen is imported into the country. Quarantine arrange-ments prohibit importation from most countries.

When the practice of artificial insemination was first introduced,fears were expressed by many lest the resulting offspring wouldnot be normal in all respects. Similar fears now attend the intro-duction of the frozen semen technique. Two points in favor ofthe latter as compared with non-frozen semen are generallyrecognized, i.e., the possible utilization of the whole of eachejaculation with consequent prevention of wastage, with an ul-timate reduction in the necessary- number of semen-producingbulls, leading to th.eir better selection; and .the greater availabilityof " nominated " services, which many livestock :breeders desire.On the other hand, it may be necessary to carry out some fur-ther investigations imito deep frozen semen from the point of viewof the effect of low temperatures on spermatozoa with regard totheir possible subsequent influence on the genetic constitution ofoffspring derived from them, in order to clarify the doubts whichnow exist in some quarters on this point.

Selected References Regarding Storage of Semen

BRATTON CRUTHERS, JOAN, C., WEARDEN, S., FOOTE, R.H.and PUNN, H.O. The Fertility of Frozen Bovine Spermatozoaafter Seven Days' Storage at -79°C. j. Anim. Sci. 13: 1016, 1954.

47

DUNN, H.O., HAFS, H.D., BUCKNER, P.J., YOUNG, G.F. and CONRAD, E.O.A Comparison of Fertility of Bovine Spermatozoa Stored at 5°C.and - 79°C., J. Dairy Sci., XXXVII, No. 12, 1954.

H../u7s, H.D. and ELLIOTT, F.I. Effect of Thawing Temperature andExtender Composition on the Fertility of Frozen Bull Semen.J. Anim. Sci. 13: 958-959, 1954.

POLGE, C., SMITH, A.W., and PARKES, A.S., Nature, London, 164, 666,1949.

POLGE, C., and ROWSON, L.E.A., Nature, London, 169, 626, 1952. (a.).

. Second Intern. Cong. Physiol. and Path. of Animal Reprod.and Artificial Insemination, Copenhagen), 3, 90, 1952 b.

. Results with Bull Semen Stored at -79°C. Vet. Rec. 64, 851,1952. (c).

RowsoN, L.E.A., and POLGE, C. Storage of Bull Semen at -79°C. andFertility Results for up to 12 Months. Vet. Rec. 65, 667, 1953.

VAN DEMARK, N.L. and KINNEY, W.C., JNR., The Freezability of BullSperm as Affected by Inter-actions of Glycerol Levels., Rates ofFreezing and Sub-zero Storage Temperatures. J. Anim. Sci. 13:1034, 1954.

48

IMPROVING LIVESTOCK PRODUCTIONTHROUGH IMPROVED NUTRITION

AND MANAGEMENT

Attention was given in the Turrialba and Baurd meetin.gs tomany phases of livestock management, nutrition and feedingpractices (Phillips, 1950 and 1953). It became apparent from thediscussions at -those meetings that four problems, which were ofimportance to many countries and of substantial current interest,should be selected for further consideration at the Buenos Airesmeeting. Two of these relate particularly to the livestock grazingin.dustry, one o the conservation of fodder, and one to n.utritionaldeficiencies. The material in this chapter is, therefore, arrangedunder four sub-headings, according to the topics upon which govern-ments have supplied information.

National Planning and Management Aspectsof the Grazing Industry

G-razing, either on open or fenced permanent ranges and pas-tures, and on pastures grown in rotation with other crops, is animportant aspect of agriculture in most countries in the Americas.This point is emphasized by the figures in Table 13 showing thenumbers of various types of livestock in the Americas. It willbe seen that the numbers of the cattle and sheep are not onlylarge, but that cattle numbers had increased substantially fromthe prewar level during the last two decades, while sheep numbershad increased in South America and decreased in North America.

Methods which can be adopted to improve the efficiency ofthe livestock industry include the improvenient of livestock bybreeding and selection, the increasing of productivity of grasslan.dand fodder crops, and the addition of measures for animal health.To livestock owners, all these methods call for an increased outlayof funds for investment in their enterprises, but the incentive forsuch investment will not be found unless the return is at leastequal to that which may be obtained in alternative projects. InArgentina, for example, it is said -tha-t the return from a farmingenterprise is of the nature of 2 percent whereas it is possible toobtain 12 percent for mortgages.

In many American countries, as in other parts of the world,insecurity of land tenure, and in some cases unecomic sizes ofholdings, are important factors limiting investment and develop-

49

ment. Un.der this general heading, consideration should also begiven to duration of leases, private ownership as related to govern-ment ownership, grazing permits on public or other lan.ds, andthe question of forest grazing on land which has timber resourcesand value as a catchment area.

TABLE 13 NUMBERS (IN M/LLIONS) OF MAJOR LIVESTOCK SPECIES IN NORTH AND SOUTHAMERICA 2

' For the prewar period, the latest estimates up to 31 December, 1939, except for a few 1940figures, have been used.

24From 1952 FAO Yearbook of Food and Agricultural Statistics (Vol. VI, Part 1, p. 109)

In view of the importance of the grazing industry, a majorquestion to be considered is the extent to which n.ational plannersare at present taking account of the special interests and require-ments of the livestock industry.

Under the modern system of land use based on the con.servationof natural resources and their improvement, costs are necessarilyhigher than under the exploitative system. The cheap food era,which was possbile only with uncontrolled exploitation of thenatural resources of the producing countries, is being replaced bya period in which there is increasing realization of this fact, andof the urgent necessity to restore the damage which has beendone. The next stage will have to be the building-up of theproductive capacity of the land to meet the needs of a growingpopulation.. The main items of cost in such a program are:

(i) Interest on the capital invested. If this is inadequate, moneywill be invested elsewhere.

(2) Wages. These are governed largely by the size of the indi-vidual holding, the purpose for which it is used, and thenecessity of attracting .to this work people of sufficient knowledgeto learn and apply modern methods; the wage must be ata level which will compete substantially with that paid inindustry.

50

Years and Area Horses Mules Asses Cattle Pigs Sheep

North and Central 'America

Prewar ' 18.0 5.5 3.2 100 64 60

1948/49 12.4 4.0 3.5 110 72 39

1950/51 11.0 3.8 3.6 118 79 38

South America

Prewar ' 13.2 3.9 2.7 106 30 95

1948)49 18.3 4.4 3.5 132 34 120

1950/51 18.4 4.4 3.7 136 37 123

51

Depreciation and obsolescence. In addition to normal deprecia-tion, as new methods of farming are introduced, equipmentwill become out-of-date and much. will have to be writtenoff, otherwise the work will be done unecon.omically, old houseswill have to be dismantled and modern housing built toattract skilled labor.Rent, taxes, insurance and general contributions. By virtueof their comparative isolation, rural farmers are called uponto meet expenses in connection with education, holid.ays andlocal social activities which are greater than those to be metby people in industrial centers; these should be a charge onthe industry.

Nation.al planning has one basic purpose, that of creating anatmosphere for efficiency of operation on the individual level. Thereare several factors which governments need to con.sider if nationalplanning is to be effective, namely :

analysis of future trends, i.e., the relation between popu-lation and needs for livestock products, information whichmust be placed in the hands of producers by 5 or 10-yearperiods, so that they can make long range plans;

examination of the needs for research in relation to criticalanimal problems, and orientation_ of the program to meetthe needs;

provision of technical services to carry new information tothe producer; and

provision for the orderly marketing of products.

A primary need in national planning is an in-ventory and classi-fication of naturalr esources, namely, soil, water and vegetation. Itwould also be important to obtain information on the potentialdemand and availability of both major and minor plant nutrientswhich are essential for improvement of grassland and -fodderresources to the level required by an efficient livestock industry.

Water is an especially important item in national plannin.g.A major problem is the depletion of underground water storesan occurrence -w-hich is at present a critical problem in the plainsof Argentina and elsewhere in the hemisphere. A new techniquehas been developed in Australia to reduce evaporation of waterin open storage through the use of powdered cetyl-alcohol, which,when scattered on the surface forms a thin film, one molecule-thick. Water supplies and resources, their use and depletion ifn.ot wisely managed, are multiple, and it becomes necessary to

consider and co-ordinate conflicting interests. Some type of hydro-logical service might well be established in each country to protectexisting water sources, reconcile interested users, and formulateplans for use on a national :basis, in cases where such bodies donot exist.

Programs of national planning should -Lake into accou.nt thebalance between the natural, economic and social factors in agiven country. For example, in the River Plate region, therehas been much improvement in the animals themselves, but nocomparable improvement in other aspects of animal productionsuch as the maintenance of soil fertility, pasture management, etc.A. need exists for an inventory of human, natural and, economicresources, which is lacking in many countries. Only through thiswill it be possible to determine what resources are available, howthey can be used, and which iproblems require solution. Throughouta considerable part of the Americas 'there is little relation betweenresearch and extension activities, rior is the researcher in many casesthoroughly familiar with the problems of the producer. A greatneed exists, therefore, for a closer 3.7elation between extension,research and the producer.

One fundamental step is the adequate training of capable per-sonnel. Such -technicians, who have practical knowledge of theproblems, can arrive at -their solutions after careful study an.danalysis and. with the help of the people. Only after the prod.ucershave adopted 'the new practices and procedures will the desiredprogress result.

Information on current developments in a number of the coun-tries in the Americas is summarized in the following paragraphs.

The Government of Argentina has taken steps towards makingpublic lands in Patagonia available for sale to those who areactually working on these areas. Some 490,625 square miles areinvolved in the whole region south of the Rio Negro. The previoushistory of these lands has been maximum exploitation by lessees-under the short-term leases prevailing. Since 1950, new laws haveprovided not only for private ownership by resident operators,but also for economic operational units, calculated to provide anadequate standard of living based on the number of sheep whichcan be grazed on a given holding. The Government of Argentinahas also had a national program of seed multiplication and distribu-tion since 1948. In the last year, there were sortie 60 to 70 co-operators in this work.

Chile has in operation a national program to improve, amongother things, the lives-Lock industry-. The operation is beingcarried out in three areas under a scheme which can be describedas the " Plan Chinn "; this covers the provinces of Maule, Nubleand Concepción. In addition, there is a plan for the southern

part of the Central Zone of Chile, specially for the Province ofCautin, and another for Magallanes. The " Plan Chillán " laysconsiderable emphasis on pasture management and improvement,soil conservation and the production of seed of introduced speciesof pasture and fodder plants. New techniques are introduced intofarming practice through extension work. In the province ofCautin, -while the work is primarily concerned with the conservationand restoration of soils, the establishment of permanent pasturesis of great importance under the special conditions of the zone.The region covered by the " Plan Magallanes " is almost entirelydevoted to livestock production (sheep); the objective here is toincrease this production by the improvement of existing pasturesand the establishment of n.ew improved pastures. A reconnaissancesoil survey of the country has been practically completed. Thereis some concern. in Chile over the instability created under existingsystems of land tenure for those who rent from the State. TheGovernment of Chile has sent a message to the Chamber of De-puties, aimed at modifying existing land tenancy legislation andforesees the possibility of the sale of government lands in theextreme south.

In Costa Rica, there is full recognition that agricultural pros-perity depends largely on livestock production based on the de-velopment and more effective utilization of the grassland and fod-der resources of the country. This development will not reactunfavorably on the coffee crop which has been the main sourceof export revenue up to the present; in fact, the indications arethat coffee production will be higher if this is integrated withdairy farming. A program is being planned on a national scalean.d envisages the progressive development of milk, meat, porkand egg production for which there are three inseparable, inter-dependent and fundamental requirements:

inherently productive livestock adapted to the environment;adequate feed supplies throughout the year equal to thenutritional standards required; anda standard of management which ensures effective utilizationof feed and the maintenance of livestock in a healthy con-dition.

Since none of these fundamental aspects are of perman.ent valuewithout the others, the ecological approach has been adopted infull recognition of the relation.ships between plant, animal andman, and the complete interdepen.dence of the on.e upon theother. It is realized that, as the program develops, many newproblems will emerge which can be solved only by research andsome may require facilities not yet available in Costa Rica. How-

53

ever, the country is developing these as rapidly as possible andis seeking outside assistance, where necessary.

In El Salvador, about 685,000 ha., or 32 percent of the landin that country, has been classified as pasture. Of this 17,528 ha.are cultivated, and the remainder is natural range. The variationsin carrying capacity llave not been determined. According tothe 1953 census there were 132,932 draft oxen; 694,498 head ofother cattle, 261,252 hogs. 32,858 mules, 3,187 asses, 15,098 goats,5,453 sheep and 2,243,851 poultry. It is calculated that the peopleconsume on an average only about 27V2 lb. of meat, fish andpoultry per person, per year. Milk consumption is low. Cheese ismade by rudimentary methods in places very distant from fluidmilk markets. For many years there has been a considerablemigration of cattle and hogs from Honduras and Nicaragua toEl Salvador. Some of them continue to Guatemala on foot orby train, and sonae of the cattle remain for a time, fattening onpastures before entering Guatemala or being shipped to Peru.

In 1952, more than 4,000 steers and 30,000 hogs entering thecountry in this manner remained for slaughter and local consump-tion.

In Paraguay, studies under way as part of a national plan togive guidance to the stockmen ine'lude the following: the rationaluse of pasture; introd.uction of new legume species; establishmentof improved pastures; the value of lime and fertilizers for pastureproduction; elimination of -undesirable plants; practices to improvesoil structure and moisture; best combination of grasses and legumesin relation to carrying capacity; improvement in the quality ofcattle; animal disease control; breeding and management practices;provision of mineral supplements to animals on pastures; andimproved handling and transport facilities.

Panama has a national project under way to map and classifyall the soils of the country; most work at present is in the regionof Chiriqui. While land tenancy studies have been concluded bythe Statistic and. Census Section of the Ministry of Finance, theresults have not yet been analyzed or made available as a helpto the livestock industry. Soil conservation is a problem due tovarious factors. However, in Chiriqui, land contour demonstrationshave been established, as also have demonstrations to point outthe harm of burning pasture lands.

The United States of America has under -way a number ofactivities which relate to the national planning and managementaspects of the grazing industry in that country, where grazing maybe considered of two major -types: A, grazing as a part of thefarming enterprise in the more humid or irrigated parts of thecountry; and B, grazing as a major enterprise in arid and semi-arid portions of the country. Grazing, in -these two types of

54

enterprise, involves the use of more than half of the total landarea of the United States. It is practised on 168 million ha. ofopen permanent pasture or rangelands, 55 million ha. of foreston farms, 28 million ha. of cropland in farms, and approximately162 million ha. of forested and non-forested rangeland 'outside offarm boundaries. Of the total land area used for grazing, about121 million ha. are in federal ownership and about 26 million ha.are owned by state and local governments.

National planning and management, as it affects the grazingindustry based on these lands, has concentrated largely on at-tempts by the federal government to create an atmosphere inwhich livestock producers can operate efficiently. Such planninginvolves the national study and analysis of situations or problemswithin, or affecting, theindustry. Needed action may be translatedin the form of development orientation, and operation of:

research programs;educational facilities involving federal and state extensionservices and other channels;aids in the form of technical services and financial assistance.,where needed to proinote wider use of technological improve-ments in the industry, and to promote conservation of soiland other resources, and

4. rules for the protection of public health, and for the orderlyoperation of transportation and marketing facilities.

National planning aids the federal, state and local governmentsin taking those actions which will help the grazing industry toovercome its problems or lessen thei:r effects.

As a phase of such national planning, recent studies of thefuture needs for agricultural production have been made, basedon probable increase in population, trends in consumers' tastes,trends in the use of agricultural products in industry, and changesin total consumption which might be possible with a high levelof employment and continued active economy. By 1975, ananticipated increase of between 6 to 8 percent per capita in con-sumption of agricultural products, and population in.crease of32 percent will require an over-all increase in farm production of30 percent over present levels.

Of major importance to the grazing industry, these studiesshow that as part of the over-all increase in farm production,there will need to be an increase of an estimated 38 percent invirtually all livestock and livestock products. This is in contrastto a needed increase in all crop production of 24 percent overthe 1951-53 level. This lower increase is the result of presentproduction of several major crops in excess of consumer require-

55

men.ts. Notable among these is the production of wheat as afood grain. Shifts in production are required to meet the 1975requirements, most pressing of which is shift from production ofwheat as a food grain towards more livestock and livestock pro-.ducts. Such a shift is of significance to the grazing industry andpresents several major problems. Associated with the shifts andthe need for higher livestock production is another problemthat of obtaining more adequate supplies of high protein coricen.-trate feeds.

To meet the increased needs for agricultural commodities by1975 -will require increased yields per acre of virtually all agricul-tural commodities except wheat. Nearly all land suitable foragriculture in the United States of America is now in use; a netincrease of only 6 percent in the acreage of cropland is probableby 1975. Some land can be used more intensively; other land,in the interests of conservation, doubtless should be used lessintensively. As it applies to the grazing industry an.d use ofgrazing lands, to obtain these increased needs for livestock pro-duction efficiently will require continued efforts to encourage useof present kn.own improved production techniques, and contin.uedresearch along many lines to increase the output of grazing lan.dsand grazing animals.

The need for attaining greater forage production on pastureand rangelands is an.other major problem facing the grazing in-dustry. The increased production of forage on pastures and ranges,specially that of the ranges, has n.ot kept pace with the increasesin yields per acre of agricultural lands devoted to other crops.An increase of approximately 30 to 35 percent in the yields peracre of pasture and grazing lands would be needed to meet therequirements for livestock production. by 1975.

Statistics on labor used in grazing phases of the livestockin.dustry are not available separate from the labor requirementsof major enterprises of agriculture. The agricultural industry ofthe United States of America is estimated to have required 15thousand million man-hours of labor in 1953 as compared toan annual average requirement of more than 23 thousand millionman-hours in the 1910-1914 period. A steady and significantdecline has occurred during the past 40 years. Sheep and cattleproduction, as compared with other agricultural commodities,have always been relatively low consumers of labor. in 1953,they used only slightly more than 1 thousand million hours oflabor. Labor efficiency in the sheep and cattle industry hasin.creased, but relatively less than with other major aspects ofagriculture. Further in.creases are still possible.

Soil and water conservation is taken into account a great deal inn.ational planning and operations in the United States of America.

56

This affects the grazing industry-, just as it does other phases ofagriculture. As a result of suci planning:, several significant legis-lative actions have been taken by the federal government Jag's-lation establishing the Soil Conservation Service to provide leader-ship and assistance in a national program of soil and waterconservation, and to provide means for the federal goveriarn.ent.L0 share with farmers and ranchers the cost of establishing approvedconservation practices lo be administered by the AgriculturalConservation Program Service has been -taken. Recent legislationhas provided for both direct and insured loans for conservationwork through the Farmers Home Administration of the Departmentof Agriculture; permission Lo landown.ers who establish conservation,practices to deduct, as expenses, the cost of such practices, ifrorntheir income in calculating income taxes; and a national programof soil and water conservation and flood retardation in smallwatersheds which provides a means for time federal government toshare with local .units of governments the eost of planning andapplying complete watershed treatinent programs.

'Federal departments administering federally-owned land alsogive major emphasis in planning and action programs to soil andwater conservation, and to the management and improvement ofranges. Since about 121 of the 184 million ha. of public landadministered by the federal government is used for grazing, thisplanning and action influence the grazing industry in a major way.

A shift from government to private ownership of some publiclands, such as reported by time :Argentine delegation, is beingconsidered in the 'United Sta-tes of .Am.erica. For these areas re-maining under public domain, the present policy is, :firstly, towardsa longer tenure, -which is no-w 10 years and is renewable, and se-condly, towards a growing tendency to give the user of the landsome responsibility for its care and management, thus, in effect,enabling consideration of. the leased land as th.ough it werehis o-wn.

Problems such as land tenure, transportation facilities, livestockprices, and others facing the grazing industry are also consideredin national planning. Situations are analyzed, and necessarysteps of research., education, technical or financial assistance and,.legislation are, taken as needed by federal, state and local unitsof- g-overnment. Additional steps ma-y also be taken by associa-tions of livestock producers, or through national meetings attendedby representatives of agriculture, industry and government.

The National Foundation Seed Project was established in theUnited States of America to provide a rapid and improved 3upplyof seeds of hay and pasture crop varieties. This assures that theamounts of certified seed required by farmers are readily available.It was initiated in 1948.

It is considered in the United States of America that continuingattention needs to be given to all of these many phases whichconcern the grazing industry. One of the major phases essentialto national planning on which new work is n.eeded is a nationalinventory of pasture and rangelands, with specific attention totheir condition, improvement, needs and grazing capacity.

Technical Problems in the Use of Grasslands

Much interest was shown in the various -technical problemsinvolved in the improvement of range and pasture lands at theTurrialba and Bann.'" meetings, and the information made avail-able on the work in various countries has already been published(Phillips, 1950 an.d 1953). A growing awareness of the importanceof work in this field was reflected by the large amount of infor-mation made available to the Buenos Aires meeting, and whichis summarized in this section. The information for each countryis presented in sequence to give an in.dication of the amo ant andtype of work reported for each country.

In Argentina, nine major ecological zones are recognized withparticular reference to their value for grazing . A publication is inpreparation which gives details on the extent of each zone, itsclimate, soil, vegetation, natural and cultivated forage plants,pasture and feeding problems. In most of the regions, overgrazinghas caused deterioration of the soil and vegetation and thus hasaffected the livestock population. The regions are as follows:

Patagonian steppe;western low scrub;Pampean open woodlands;northwestern mountain steppe;central mountain grasslands;Chaco woodland;Chaco parkland;northeastern open woodlandsand savannas; andPampean grasslands.

Two-thirds of the surface of Argentina is arid or semi-arid;the livestock of these regions (sheep, cattle and goats) subsistentirely on the natural vegetation. The prolonged dry period anduncontrolled use of the land have resulted in serious deteriorationin the vegetation cover and soil, markedly reducing the carryingcapacity; this whole process has led to serious erosion. In order

58

to cope with this situation, the Ministry of Agriculture and Live-stock has initiated a series of studies to regenerate these lands toa condition in which they will maintain an optimal number oflivestock, while at the same time ensuring conservation in all itsaspects. The studies noted below have been initiated in Pata-

10-o and will be extended to the north of the country as soonas facilities permit;

Preparation of a manual of the flora of the Patagonian semi-desert.

(2) Study- of the vegetation.. A map of the vegetation of theChubut region has been published (Soriano, 1950) which showsthe floristic districts, the areas characterized by species orpopulations that are lacking or rare in adjacent areas. Amap has just been completed of all the floristic districts southof the 42nd parallel, which were surveyed by the line transectmethod.The effect on the vegetation o-f elimination of grazing. Anetwork of hare-proof enclosures 1 ha. in size has been setup in vegetation types representative of extensive areas;this system Nvill be extended to the Central Pampa. Thechanges are being observed using Parker's method (Parker,1950). Marked increases in density and height of grass andother species have been noted as a result of protectionfor less than Orle year.Ecology of dominant, useful and undesirable species. Anattempt, is being made to ascertain the characters or mechan-isms -which give advantage to one species o-yer another.Studies are being made on germination., establishment, rootsystems and amount and longevity of buried seeds, as wellas on environmental factors.Seeding -trials. About 20 indigenous and introduced peren-nial grass and browse species are being tested in five re-presentative sites. On one si.te a, very palatable indigenousplant, Bromus macranthus, was the only species which ger-minated and grew well in a year when the precipitation. was54 mm. of rain. and 16 cm. of snow. In an.other locality -with500 mm. of rain ..4gropyron desertorum and A. intermediumappeared promising.

Action has been taken by Argentina during recent years tomake adequate quantities of seed of adapted and improved speciesand strains available to farmers. This includes the planning andco-ordin.ation_ of work in progress at the various experimental sta-tions of the Ministry of Agriculture and Livestock; in 1954, there

(1)

(3)

59

were 27 forage crop improvement projects under way, apart fromthe work concerned with the multiplication of seed of new foragevarieties and introductions. A special experimental station atAnguil was created to work primarily with the improvement andmanagement of forage species. Improved strains of forage piarasavailable to date in Argentina include:

Plant Strai n Remarks

Alfalfa

Alfalfa

Alfalfa

Alfalfa

B arley

BarleyBromus carthaticttsBromus carthaticusOatsPhalaris tuberosaPh. tuberosaPh. tuberosa x

Ph. arundinaceaPh. minorPh. minarPerennial rye grass(Lolium perenne)Black sorghum(Sorghutn almum)Sudan Grass(Sorghum sudanen,se)Sweet Sorghum(Sorghum saccharatum)Vicia sativa

General San .Martin FAV

Nemasint FAV, syntheticvariety

Selección Pergamino MAG

Magnif, M1 and M5

Negra de Manfredi MAG

Gautrache Araucana MAGSelección Angel GallardoSelección Pergamino MAGSanta Fé, No. 3Selección Pergamino MAGSelección Castelar MAGHibrido Castelar (synthetic

allopolyploid)Selección Pergamino MAGSelección Castelar MAGSelección Pergamino MAG

Magnif 504 MAG

Oliveras Paraná MAG

Oliveras Carcarafia MAG

Selección Pergamino MAG

The superiority of the nevv- selections has been verified in regional trials.These varieties are now being multiplied for introduction into culti-vation on a large scaie; several are already available to farmers in lim-ited quantities. In additimi to the above-mentioned types work isin progress on ,other species including Phalaris arundinacea, Dactylisglomer ata, Vicia and sweet clover.

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Resistant -to stemnematode

Resistant to sternnematode

Resistant to rootrot

Resistant to stemn.ematode

Resistant to aphids(Schizaphis graminum)

In view of the interest expressed in hardy types of oats forwinter fodder, it should be noted that su.ch types have been de-veloped in Argentina; it is considered that these may be of use incountries with a warm climate, since they are resistant to yellowrust (Puccinia coronarium). A need is recognized in Argentina toorganize seed exchange between the various countries in LatinAmerica, particularly for those plants which grow well and arevaluable forage species in a certain region, but which do not matureseed under the environment of the country.

In Chile, work is under way in the cold climate of Magallanes,where the Ministry of Agriculture and Livestock is planning toestablish eight demonstration centers. The type of grasslanddominated by " coiron " (species of Festuca and Stipa) has dete-riorated greatly owing to excessive grazing by sheep. The palat-able soft grasses are often eradicated by continuous summergrazing on the higher lands. On the other hand, the coarserbunch grasses are grazed in the winter and with too heavy grazingmay be eliminated. This occurs on the lowlands which are usedin winter. The heavy winds cause " blow-outs " as a result ofthe depletion of the soil cover by this method of management.These pastures are being improved by protecting them from grazingfor one year. Seeding of suitable areas with grasses and legumesis also practised, using Agropyron elongatum. A. intermedium.Festuca elatior, alfalfa (Ranger and Rhizoma), and in some partsDactylis glomerata. Seed of in.digenous species of Elymus, whichpromises to be of value for re-seeding, is being multiplied.

Overgrazing and rabbit infestations have led, in some cases,to the formation of large sand dunes which may move at a rateof up to 5 km. per annum. Elymus arenarius and Ammophilaarenaria are used for their control, together with complete protec-tion from grazing by all animals for at least 5 years. Similarresults have been obtained with these species in the part of Tierradel Fuego belongin.g to Argentina.

Following the report of the Baurti. meeting, -the Govern.mentof Chile has taken action on the biological control of the rabbitthrough the use of the myxomatosis virus. In Australia andother countries, the virus has been transmitted by an insect vectorsuch as the mosquito; in Tierra del Fuego, it is spread by directcontact of one rabbit with another. This action is having a markedeffect in reducing their n.umbers. A similar problem exists in theArgentine part of Tierra del Fuego, north of the Rio Chico, whererabbits have been increasing rapidly in numbers. The hardwinter of 1954 greatly reduced the rabbit population. The spreadof myxomatosis from the Chilean part of Tierra del Fuego is alsohaving its effect.

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An. experiment is being conducted in the Magallanes region ofChile to improve the carrying capacity of the range land coveredby Mata negra (Verbena tridens) and Mata verde (Chiliotrichumdiffusum). As a result of the mechanical elimination of theseunpalatable species, and reseeding, the carying capacity of the,experimental area has, in two years, increased 80 times (from oneanimal per 20 ha. to 4 animals per ha.). Rainfall in this areaapproximates 250 mm. per annum.

The following tabulation shows the present status of land de-velopment in Chile:

Of the area under cultivation, 1,285,700 ha. are in an.nual crops,141,198 ha. in fruit trees and. 555,000 ha. in fallow land. Thereare pasture lands, as follows:

Experiments in progress indicate that the carrying capacity ofthe irrigated artificial pastures may be greatly increased by theuse of superior species, proper fertilizers and control of grazingby the electric fence. It is also believed that the 430,000 ha. ofirrigated natural pastures could, with advantage, be plowed upand sown to superior mixtures which would greatly raise livestockproduction.

Some years ago, Chile began to prepare a soil map an.d 1101Vonly a few areas rem.ain to be surveyed. This map shows notonly the soil -types b-ut also gives climatological data, and furnishes'a sound basis for planning the pasture work in the different zonesof the country. The chief problems are prolonged dry periodsin spring, sum_mer and autumn and low tem.peratures in winter;these, added to bad management and a gradual deteriorationin soil fertility, are resulting in the disappearance of the mostvaluable species and their replacement by unpalatable speciesand -weeds.

Artificial pastures which have, until recently, been basedalmost exclusively on alfalfa, red clover (Trifolium pratense) andperennial rye grass (Lolium perenne) have shown a lack of resis-

6 2

Total area of country .....Area usable for agricultureArea under agricultural rotation .Irrigated areaArea under cultivation

7429

5

1

2

177000903342536

000000200000898

(39%)

On land not subject to rotation 6 800 000On unwatered land under cultivation 3 107 000On irrigated land under cultivation 733 000

Total 10 640 000

tance to adverse conditions of soil and climate. Prolonged inves-tigations have now shown that the following pasture species areof value to the dry zone: Sanguisorba minor, Trifoliuni incarnatum,Phalaris tuberosa, Festuca pratensis, A rrhenatlieruni elatius, Era-.grostis curvula, E. lehtnanniana, Dactylis glomerata. Th.ese speciesare planted in pure stands or mixtures, according to the possibil-ities shown by the soil map of Chile. -

Ladino clover (Trifolium repens var. giganteum) has given ex-cellent results on soil with medium to heavy- texture on whichalfalfa and red clo-ver did not do well. Tall oat grass (Arrhena-therum elatius) is adapted to the Andean Precordillera and thecoastal terrace lands, on light soils which are largely coveredwith poor annual species.

The species of pastures and fodder crops which are grown onthe dry and irrigated artificial pastures are indicated in Table 14.

TABLE 14 AMOUNTS OF PASTURES OF VARIOUS TYPES IN CHILE

63

Parallel to the pasture program in Chile for some years-there has been in operation a-plan for forage seed production underthe Minis-try of Agriculture and with the co-operation. of the far-mers. There are at pzresent about 3,000 ha. in seed production,yielding enough seed of the differe-nt species to in.eet the country'sneeds.

In Colombia, with the exception of a few ranges, the usualpractic.e is to maintain the livestock under extensive pastureconditions without any particular management. The cattle grazethrougli.t -th.e year on swards formed by Para, Guinea, Indiaand Yacagua grasses. To sustain an animal, 1.6 ha. are required.It is felt that improvements in pasture management, includingseeding and the use of the pastures in the young stage, might

Alfalfa 100 000 3 000 103 000

Arrhenatherum efatius -- 6 000 6 000

Dactylis glomerate 2 000 246 000 248 000

Red Clover 190 000 135 000 325 000

Holcus lanatus 121 000 121 000

Lolium perenne 6 000 10 000 16 000

Trifolium incarnatum 5 000 5 000

Mixtures 5 000 300 000 305 000

Others 16 000 16 000

Total 303 000 842 000 1 145 000

-

Type of Pasture Irrigated Land Dry Land Total

improve the nutritive condition of the animals. The use of themowing machine is advised to favor the growth of legumes, toeliminate weeds, and to maintain the pasture in a short and morepalatable condition; these steps should help to increase the carry-ing capacity- per unit area.

In Costa Rica, several productive species are now well estab-lished including, the following:

Grass Species

Bahia Paspalum notatuniCarpet Axonopus compressusElephant Pennesitum purpureumGanialote Paspalum conjugatum

uinea Panicum maximumImperial Axonopus scopariumHonduras Ixophorits unisetusK ikuyu Pennisetum clandestinumMolasses Melinis minutifloraPara Brachyaria purpurascensYaragua ilyparrhenin rufa

As the pastures are at present deficient in legumes, a concentratedeffort is being made to discover types which can be establishedand to maintain a grass/legume mixture for the production ofbalanced herbage with a higher protein and mineral content.Some of the promising indigenous legumes are being collected andand tested as pure species and in mixtures with grasses.

Work in progress indicates that, in the highlands (temperatezone), Kikuyu grass with white or subterranean clover (Trifoliumsubterraneum) makes excellent pastures, and that in the inter-mediate zone (8,752 to 17,304 ft.), Molasses grass (Melinis minuti-flora) blends well with white clover (Trifolium repens). In thelower lands of Guanacaste, mixtures of Yaragua (the dominantgrass in this area) can be made with tropical Kudzu (Puerariajavanica), velvet bean (Stizolobium deeringianum) and Alsike clo-ver (Trifolium hybridum).

Strains of common grasses are being -tested for higher produc-tion of better quality herbage, and the effects of fertilizers andanimal manure on the yield and composition of herbage are beingobserved. Laboratory facilities have been provided at " El Altofor the analysis of samples of herbage cut at different stages ofgrowth an.d under different systems of treatment and management.

It is considered that one of the fundamentals for successfullivestock production, namely " a standard of management whichensures effective utilization of feed and the maintenance of stock

64

in constant good health " is the most difficult part of the programto achieve because it embraces simultaneously the managementof both grass and animals. This depends very much on thosewho carry out the daily routine tasks and many have not yetacquired the necessary skill in modern methods of pasture andlivestock management. In helping to overcome this difficult),the extension service, established in 1948, and now having over60 officers at 32 centers, has been most useful.

At the " El Alto " animal research center and at " El Capulinresearch covers different methods of grazing, varying intensitiesof defoliation, use and effects of fire for grass control, and theconservation of surplus grass as hay and silage. Suitable farmsare being used for the demonstration of practices and the needfor concentrates and mineral mixtures is being studied. A soilsurvey of the country is now well advanced and this is beingfollo-wed by research into mineral deficiencies which may be re-flected in deficiencies in the forage and in animal health andproduction

In El Salvador, technicians of the Ministry of Agriculture andFOA (recently- re-named In.ternational Co-operation Administration)are conducting experiments to compare Para, coastal BermudaPangola and other grasses for fattening steers. Also, on accountof the very high price of corn, root crops are being tested for thefeeding of swine.

In Panama, laboratory and field facilities have been establishedfor investigations and demonstrations of pasture problems, butsufficient personnel is still lacking. Plants used for pasture im-provement include: Pueraria javanica, Panicum barbinode, andHyperrhenia rufa.

In Paraguay, in the work of STICA, a number of specieshave been found of special value. An indigenous species, Paspa-lum guenoarum, (P. rojasii pasto rojas), has given excellentresults, being superior to Hyperrhenia rufa (Yaragua) or Chlorisgavana (Rhodes grass) in the maintenance of a uniform level ofproduction throughout the year; seed production is also good.Avena strigosa var. glabrescens is proving valuable for winter graz-ing. Among the legumes, two indigenous species of Vicia (V. selloiiand V. graminea) are promising, an.d introductions of Vicia obscura,Trifolium repens, T. Hirtum and T. pratense have shown goodbehavior. At present, improved pastures are based on the use ofPaspalum guenoarum, Chloris gayana, Hyperrhenia rufa, Pennisetumpurpureum, Panicum maximum and cereal rye.

In Uruguay, trials are being con.dueted at " La Estanzuela "on the effect of mineral fertilizers and in.oculation on the yieldof legumes. A pasture fertilized with 1,760 lb. of superphosphateper ha. prod.uced 17.5 tons more green weight per hectare than

65

the Control; more than half the vegetation was composed of na-tive clovers and fine grasses, -while the control plots containedspecies of Stipa and weeds. Similar results were obtained on amixture of alfalfa an.d rye grass L.E. 284 (..Lolium multiflorum);the degree of response to the fertilizer was related to the propor-tion of alfalfa in the mixture.

In all soils a favorable reaction to phosphatic fertilizer w-asfound which was not the case for lime. In these cases the hyper-phosphate was more economic than the use of lime and super-phosphate. In alkaline or neutral areas superphosphates or similarfertilizers should be used.

The experiments with fertilization and rotation have shownthat it is more convenient to use phosphatic fertilizers on legumeswhich precede cereals rather than directly on cereals not precededby crops -which increase organic rn.atter content and improve soiltexture.

Experiments on pastures have shown that both quality andproduction increase after the application of phosphorus.

In trials initiated in 1948 on a crop rotation of fertilized al-falfa (2 to 4 years) with wheat, maize, oats and flax, the yieldof wheat was doubled as compared with the control plots. Theintegration o-f crop and livestock husbandry constitutes a decisivefactor in preventing any further decrease in cereal yields, evenon. lands -which have been in continuous crop production for 50years. Experimentally it has been shown that this procedurehas resulted in the.recovery of the productive capacity of the soil.

In the Forage Crop Departrnent at " La Estanzuela, " trialsare in progress on the pasture value and seed produ.ction of thefollowing grasses an.d legumes:

Agropyron elongatumA. intermediumArrhenatherum elatius

var. tualati,nBromus cartltaticusDactylis glomerata

Dactylis maritimaFestuca elatiorLolium muluflorumL. perenneLotus corniculatusMedicago sativa

Phalaris arundinaceaTrifolium pratenseT. procumbensT. repensT. subterraneum

A special service has been set up in Uruguay for -the multi-plication and distribution of various grasses and legume seeds.In the year 1954/55, the production by the station at " La Estan-zuela " of seed of forage plants for intensive multiplication insubsequent years was as follows:

Italian rye grass (Loliuni multiflorum) . 22 050 lb.Vicia ... ............ . . . . . 11 025 lb.

66

In. Jamaica, pasture research is closely related to work on live-stock breeding, husbandry and nutrition. The officers dealingwith the different sections work together as a team and so ensurethat -the work has a practical application and that the economiesof the industry -will be considered. There are -three stages:

A search for new species or va.rieties to give greater carryingcapacity and for a grass which will supplement the other grassesduring, periods of dormancy or reduced. yield. Drought-resistantstrains are required. A wide range of species and varieties hasbeen introduced but so far only very few have shown promise.Most of the legumes have given -very disappointing results.

Establishment of observation plots for promising types, tomake recordings Of chemical tests, weights, leaf/stern ratio,growth behavior and fertilizer requirements. The resultsobtained. are -used in selecting varieties for further tests, notto determine their potential value as pasture species.

Planting several acres of the best gasses for pasture trials.These are fertilized and yields are recorded. The steers usedin the experiments are weighed through the 'trials to determinetheir yield of beef per acre. Trials on management and com-parisons with other grasses are also made. The first 'year isused Lo develop the technique of pasturing the species to thebest advantage and the actual -trial begins after this.

The following are some of the results obtained in .thepasture trials:

(a) The native flat grasses predominantly stettotaphum secundatumhave been tested for six y-ears to determine feeding -valueand management. Yields conld be increased appreciably bysubdivision, moWing, rotational grazing and the applicationof fertilizers, but they are still too low- for economic produc-tion and the response to treatment -too small to cover thecosts. The carrying capacity is: 3 o 5 acres per steer. Live-weight increases of up to 1 lb. per head per day were ob-tained, but these were still uneconomical. This species is-the chief grass in .the undeveloped upland pastures. Becauseof its limitations, attention is now being directed towardsPang-ola grass (Digitaria decumbens) and Coas tal Bermudagrass (Cynodon dactylon).

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Rye (for grazing) 13 230 lb.Red clover (Trifolium pratettse) 3 307 lb.Alfalfa 880 lb.

Feeding trials have been conducted for six years on Napiergrass (Pennisetum putpureum) with promising results. Twelvesteers were maintained on 9 acres and gave an average in-crease of about 2 lb. per 'head per day for 9 mouths duringthe growing season. During the past two years, enoughfodder was cut to make silage for the time of shortage. Anundesirable character of this grass is its long resting periodin the autumn. and -winter months. Experience has shownthe need of grazing for no more than 4 days at each timeof pasturing. Eighteen pastures are necessary- for the bestrotation.. Napier grass requires heavy application of ferti-lizers. When the grass is cut, it lasts for only 2 to 3 years,whereas it can be maintained for 6 years when .pastured.A trial is in progress at present to work out the ratio ofacreage of Pangola and Napier grasses necessary to providefodder throughout the year; both grasses have differentresting periods and complement each other.In 1950, Pangola grass was introduced and has so far beenthe most promising species. Liveweight increases of 2 to2, lb. per head per day have been obtained during periodsof good growth. Extensive feeding trials have been madeto compare Pangola with Guinea grass (Panicum maximum)and Coastal Bermuda, as well as studies of methods ofmanagement and response Lo fertilizer. Pang°la has about24 percent dry matter compared with 16 percent in Napiergrass, and it is much more leafy.Research on Guinea grass is in progress at the dairy cattlebreeding center. This is the best grass for the coastal plains.it is difficult to pasture in such a way as to maintain maxi-mum production. When properly managed, a higher milkproduction has been obtained. Eighteen pastures are neces-sary for proper feeding and to maintain the pastures them-,selves in good condition. One hundred and fifty cows, drystock and heifers are maintained on 230 acres (about 0.8 acreper cow). The land is irrigated and the average dailytemperature is between 850 to 90°F. (29.4° to 32.2°C.). Theyield per acre is approximately 7,000 lb. of milk (5 percentbutterfat) in 305 days with twice daily 'milking. Pangolagrass is now being grazed at this station, and has not so farincreased the yield of milk as compared with Guinea.

In the United States af America, the mapping of the soils anddetermination of the conditions of pasture and range land, basedon the botanical composition, are an integral part of the technicalassistance extended to co-operators in the grazing industry in soilconservation districts. Soil maps and land capability- information

68

are used for conservation planning of the crop land and tamepasture areas. Plans for correct management of ran.ge land arebased on site and condition inventories supplied to the land oper-ators. Agencies administering federal grazing land also mapthese an.d determine grazing capacities in order to be able to adviseon the improvement of these lan.ds for the grazing industry.Substantial progress is being made in the mapping and determin-ation of the productive capacity of privately and publicly ownedland in soil conservation districts. A national inventory of allpasture and range lan.ds is urgently required, with particular re-ference to -their potential composition., ecological status, presentcondition, prod.uctive capacity and possibility for improvement.

Research and demonstration programs for grassland managementin the United States of America are conducted primarily by theAgricultural Research Service, the Forest Service and the SoilConservation Service of the Departmen.t of Agriculture, the Bureauof Land Management of the Department of the Interior, and thestate agricultural experiment station.s.

In the work of the Agricultural Research Service, most of whichis co-operative with the states, the state experiment stations gen-erally furnish office, laboratory, greenhouse and field facilities.Centers provided primarily by federal funds include Plant IndustryStation, Beltsville, Maryland; Regional Pasture Laboratory, StateCollege, Pennsylvania; Northern Great Plains Field. Station, Man-dan, North Dakota; U.S. Range Livestock Experiment Station,Miles City, Montana; Central Plains Experimental Range, Nunn,Colorado; Southern Great Plains Field Station, Woodward, Okla-homa; and the Jornada Experimental Range, Las Cruces, NewMexico. At the Pasture Laboratory, excellent laboratory, climaticcontrol chamber, and greenhouse facilities are provided for fun-damental work in physiology, nutrition, genetics, pathology, andsoils phases of grasslands. Extensive land facilities are requiredfor range management studies in the Great Plains. For example,at the Southern Great Plains Experimental Range there are ap-proximately 4,000 acres involving 60 different pastures varyingin size from 60 to 200 acres. On the Jornada Experimental Rangethere are 105,000 acres, including 18 different pastures. The Cen-tral Plains Experimental Range includes 30 pastures totaling9,500 acres. At Mandan, North Dakota, and Miles City, Montana,the acreage involved is 1,200 an.d 1,800, respectively. In thehumid regions land required for pasture experiments is much less,with individual pastures us-ually varying in size from one-half to4 acres. Small plot studies involving plots about 6 x 20 ft. insize are cond.ucted at a number of locations.

In the Forest Service program a network of 15 major experi-mental ranges or field laboratories forms the backbone of research

69

on management and improvement of ran.ge lands for maximumproduction of forage, livestock and livestock products. One ormore of these field laboratories is located in each of seven majornative vegetation types of the western and southeastern UnitedStates of America used for grazing by livestock. Each of these,in addition to providing centralized locations for field research,provides demonstration in grassland management an.d improvement.

The Soil Conservation Service assists farmers and ranchers inapproximately 2,650 soil conservation districts in the United States.These distric-ts cover four-fifths of the farm and ran.ge lands inthe country, including more than 90 percent of individual farmsand ranches. The basic purpose of the program is to assistbringing about adjustments in land uses and treatments and inthe use of water and forage resources, establishing a permanentand balanced agriculture, and reducing the hazards of floods andsedimentation. This purpose is served by the development of awell rounded, co-ordinated program of soil, water and plant con-servation and land use. The program involves making conserva-tion plans for individual farms and ranches, assisting groups oflan.do-wners in. improving facilities for the use and disposal ofwater, work with soil conservation districts and on watersheds andother use areas; and the application and maintenance of all knownadapted conservation practices and treatments on the differentkinds of land in accordance with their needs and capabilities asshown by detailed land capability surveys. Approximately 2,500technicians are specifically employed to help farmers under theSoil Conservation Service program.

Emphasis on research in grasslands is placed on development ofsuperior varieties, improved cultural, production and managementpractices, an.d better methods of seed production. Basic studiesof plant diseases, physiology, breeding behavior, and other factorsof forage plants related to their improvement and culture arestressed. -Research is under way on species and species combina-tion.s to meet the wide variety of climate, soil, and use conditionsthroughout the country; methods of establishment, culture andmanagement to provide the most economical and stable returnswith various species and under different conditions; methods ofweed and brush control in pasture and ran.ges; measures for thecontrol of hazards to stands and production such as diseases,insects, unfavorable weather, and misuse by man or the grazinganimal, and methods of harvesting and preserving forage for sub-sequen.t use in adverse or stress periods. Closely coupled with thedemand for impro-ved varieties has been the need for rapid increaseof seed of new varieties in sufficient volume for general use on thefarm.

It is not feasible to list all significant accomplishments in the

'70

grassland improvement program and the following are merelyindicative of the progress from recent studies in the United States.

Spectacular increases in yi.eld are being obtained in improvedpastures and ranges th.rough the use of more productive speciescombinations, improved varieties, renovation, adequate fertiliz-ation, better grazing management, and other techniques developedby research. Increases in production of 4 to 6 ,fold are notcommon. From this research program have come deep-rooted,tall growing, productive grasses and legumes such as brome grass(Bromus inermis), Ladino clover (Trifolitun repens var. giganteum),and alfalfa for the northern part of the East; orchard grass (Dae-t)'lis glomerata) and Ladino clover for the middle latitu.des; tallfescue (Festuea arundinaeea), Ladino and crimson clovers (Trifo-lium inearnatum), Bermuda grass (Cynodon daetylon), Dallis grass(Paspalunt dilatatum) and Bahia grass (Paspalum notaturn) forthe South, and crested wheat grass (Agropyron eristaturn) andother -wheat grasses for the -West. Notable artn.ong improvedstrains of -these species are: Lincoln brome grass; 'Pilgrim -whiteclover (large type similar Lo Ladino); Dixie crimson clover; Ranger,Buffalo., Atlantic, 'Williamsburg, Narragansett and Vernal Alfalfa;Coastal and SuwanceBermuda grass; Nordan crested wheat grass.

:Birdsfoot trefoil (Lotus cornieulatus) is becoming increasinglyimportant as a legume in hay and pasture. In triany areas, ithas given better stand survival than Ladino clover and, the bloatiffoblem is less acute. A_t the Dixon Springs, Illinois, station,after two successive dry years, birdsfoot was one of the few pasturelegumes which survived- and it produced over 3 tons of dry- matterper acre. Lambs fattened on this pasture for early- market soldin June for $ 29.50 per cwt. Lambs on pasture grass alone did notfatten and were sold the following autumn, after feeding, for only$ 20.00 per cwt.

:Dallis grass (Paspalum dilatatum) is 011C of the most importantperennial pasture grasses in the South, but its usefulness is limitedby its total susceptibility- to the ergot fungus. Because of thissusceptibility, seed supplies of Dallis grass are limited and thereis danger of ergot poisoning of livestock. The Mississippi stationis making good progress in the development of seed producingand ergot-resistant strains. Progeny from a Dallis grass x Paspalummulachoph,yllum h-ybrid have proved to be highly resistant to ergot.

Fundamental taxonomic, physiological arid ecological studiesare contributing to the understanding of factors responsible forrange deterioration or improvement, of relationships between cli-matic variation and plant growth, and to the development ofimproved grazing practices.

Research on range measurement techniques seeks to developmethods fo.r the appraisal of grazing capacity, the relative condition_

71

and trend, and other features of range lands essential to evaluation,management and improvement of such lands. An objective me-thod for determining range condition has recently been developedby technicians of the Soil Conservation Service.

Pasture renovation by thorough working of the sod, fertilizingand seeding to produce tall growing species mixtures, such asorchard grass-Ladino clover, brome grass-alfalfa, or Bermuda grass-clover, greatly increases total production and distribution of pro-duction. Research has shown that renovation can more thandouble production from unimproved pastures. The quality offorage is improved by the introduction of nutritious grasses andlegumes and by fertilization.

Dryland seeded pastures decrease in productivity, even thoughmaintaining stands, as they become older. The Wyoming Station(co-operative USDA) learned that crested wheat grass (Agropyroncristatum), Russian wild rye (Elymus junceus), and western wheatgrass (Agropyron smithii) respond to severe renovation as well as toapplications of nitrogen. The degree of response, however, isdirectly related to the amount of spring moisture. The combinationof renovation and fertilization gives higher production than eitherfertilization or renovation alone. In years of low amounts ofspring moisture the increased production does not pay for thecost of applying fertilizer, but with ample rainfall a new gain ofmore than $ 15.00 per acre above the cost of the fertilizer andits application is obtained.

An awakening to the fact that species with high yielding po-ten-tial will respond to relatively large applications of fertilizerand that plant feeds applied to pastures will give as economicalreturns as such applications on cultivated crops has been a bigstep forward in pasture improvement. Coastal Bermuda grass(Cynodon dactylon), fertilized with 200 lb. per acre of nitrogen, hasproduced over 700 lb. of beef per acre. Species such as Ladinoclover and alfalfa are potash-loving plants, and recent studies haveshown greater response to potash than to phosphate on manysoils. In some of the range areas of the West, sulphur and nitrogenhave given outstanding results.

Research on mountain meadows by the Colorado station nowsuggests the possibility of producing " super hay" which may takethe place of costly protein supplements in winter feeding.Controlled irrigation and the application of 480 lb. of nitrogen peracre produced hay containing 2,400 lb. of crude protein per acre. Iffurther feeding tests prove to be satisfactory, it ma-y be possible forranchers to set aside areas of their meadows to raise the high pro-tein hay and thus avoid the necessity of buying protein. supplements.

The importance of knowing the reaction of all types of foracreplants to fertilization is shown by studies at th.e Oklahoma Station

72

where it was found that the influence of fertilization on the qualityof protein varies in different plants. With Sudan grass (Sorcrhumsudanense), although the yields were greatly in.creased by fertilizers,the relative amounts of the principal amino acids remained essen-tially the same. On the other hand, fertilization of alfalfa broughtabout a substantial variation in the leaf/stem ratio and, since thecomposition of the leaf and stem protein differs, the compositionof the whole plant is affected by fertilizer treatments.

The irrigation of pastures in humid areas is a comparativelyrecent development but recent research has shown that supple-mental irrigation plays as important a part on pastures as itdoes for cereal or row crops. The Indiana station found no dif-ference in animai daily gains on irrigated and non-irrigated pastures,but a heavily grazed irrigated Ladino clover-brome grass pastureproduced about 500 more sheep-days per acre for the grazingseason than did a similar non-irrigated pasture.

Durin.g an exceptionally dry pasture season. the North Carolinastation found that s-upplemental irrigation increased milk produc-tion 35 percent, total digestible nutrient yield 109 percent, daysgrazed 70 percent, an.d carrying capacity 100 percent. It ispointed out, however, that only high yielding, well fertilized pas-tures can be irrigated profitably.

The Massachusetts station has reported that, by applyin.g ade-quate potash, increases of 30 to 80 percent in hay productionwere obtain.ed for the first 3 harvest years. Although liberalamounts of potash fertilizer were applied 3 times each year, thegrasses studied removed 79 to 94 percent of the application durin.gthe 3 years.

Perennial and annu.al weeds result in approximately 9% reduc-tion of potential forage yield on the 1,200 million, acres of pastureand range lands in the United States of America. Research hasshown that a 20 to 60 percent increase in forage production willresult from the chemical control of -weeds on infested pasture andrange lands.

Recent results on salt-desert-shrub winter ranges in Utah an.dponderosa pine ranges in Colorado continue to confirm thatmoderate grazing (50 percent or less of current production ofdesirable native range plants) plus other good grazing practicesimprove the forage cover, nearly double the income, and controlundesirable range plants.

Development of methods for managing and improving rangegrazed by herbivorus big game animals and correlation of thisuse with grazing by livestock is being studied. General principlesapplying to intensity of range use by livestock also apply to rangeused by big game animals. Big game and livestock use, in com-mon, many of the same plants and range areas, but the degree

73

of competition varies with animal and plant species, and seasonand intensity of use. All of these factors must be considered indetermining optimum stocking for either game or livestock, andin manipulating the forage supply through management.

Research on grazing influences shows that grazing of landsuseful also as timber producing lands or watersheds (catchmentareas) May require additional consideration of the grazing practicesor timber harvesting practices for optimum production of timber,water and forage. Research on the relation of grazing to rodentpopulation has shown that grazing practices may influence thesepopulations and, in turn, the impact they may have on rangegrazing capacity.

An intensive series of studies in Colorado and New Mexicoshowed that as ranges improved in condition as a result of con-servation management the green feed season is lengthened, calfcrops are higher, calf ages are more uniform, individual cow andcalf weights are heavier, and the gross yield of beef is invariablyincreased. The average of all ranches studied sho-wed that thosein poor condition produced 405 lb. of forage and 8 lb. of beefper acre. Potentially similar ranches with their range in goodcondition produced 1,026 lb. of forage and 14 lb. of beef per acre,an increase of 253 percent in the forage yield and 175 percentin beef production.

After 20 years of federal range management under the guidingprinciples of the Taylor Grazing Act, the major destructive usesof the public grazing lands have been eliminated. An outstandingexample of the results of effective range management has occuredon. the Nipple Rim area of Colorado Grazing District No. 6. Adetailed study indicated that over a 13-year period from 1937 to1950, with range use in accordance with grazing capacities andproper seasonal use, the downward trend of forage values and eco-logical plant succession occurring prior to managed grazing hadbeen stopped. An up-ward -trend was being maintained in qualityand quantity in forage. An outstanding increase in abundance,vigor and distribution of grass species in all range types was .theearliest significant response to proper management. In some placesgrass increased at least tenfold. The protective cover developedby increased vegetation has had a marked effect on reducingsurface run-off of water and increasing percolation. Litter and humusare building up, raw draining channels are becoming sloped andcovered with perennial vegetation, and hea:d cutting of gullies hasbeen slowed or stopped.

The Nebraska station compared lactating cows on an irrigatedLadino (Trifolium repens var. giganteum) brome grass (Bromasinermis) pasture with a comparable group in dry lot. The pasturesaved 5 lb. of hay, 35.9 lb. of silage, and 4.1 lb. of grain per

7

cow day and these savings amounted to $ 114.00 per acre forthe grazing season.

A federal forage crop improvement program in the United States.of America is divided into research projects devoted to breeding,and cultural work in each of the following fields: (i) soybean;(ii) alfalfa; (iii) clovers (Trifolium and Melilotus sp.), (iv) grasses,

lespedeza (Lespedeza sp.) lotus (Lotus sp.) and southern. legumes,pasture and range production in humid areas, (vii) pasture

and range investigations in arid and sub-humid areas, and.(viii) foundation seed production. Federal workers are en-couraged to con.duct fundamental studies on methods of breeding,cytogenetics and other pathological and physiological investiga-tions, directed toward assisting 017 stimulating applied breedingbreeding work at state experiment stations. Many federal per-sonnel are located at state agricultural experiment stations andtheir programs are supported to varying degrees by state funds.Although the type of federal program conducted at a given locationvaries with needs and conditions these programs are initiated onthe premise that federal personnel have regional responsibilitiesand consequently any breeding work should be directed towardsthe region in which they are loeated. "legions will generallyinvolve several states or more restricted areas depending on cli-mate, soils and th.e species in-volved in the program. Activeco-operation among state-supported grass and/or legume breedingprograms and the co-operative state-federal programs mentionedabove is encouraged. Co-operation is realized through conferencesand the .exchange of reports and experimental material, and byvirtue of the fact that federal workers are located at state ex-perimental stations.

At the present time breeding work is in progress in the UnitedStates of America with the following legumes:

Alfalfa (Medicago sativa)Lespedeza cuneataL. stiputueeaLotus corniculatusLupillUS sp.

T. subterraneam

Thc main grasses that are receiving attention include:

A adropogon gerardi Bouteloua eartipendulaAgropyron eristatam B. gracilisA. intermedium Rromus inermisA. triehophorum BrOMUS carthaticus

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Soybeans (Glycine max.)Sweet clover (Melilotus sp.)Trifolium inearnatumT. pratenseT. repens

Buchloe dactyloidesCynodon dactylonDactylis glomerataElymus junceusEragrostis sp.Festuca arundinaceaLolium multiflorumOryzopsis hymenoidesPanicum virgatumPaspalum dilatatum

Paspalum notatumPennisetum glaucumP. PurpureumPhalaris arundinaceaPhleum pratensePoa pratensisSorghastrum natunaSorghum halepenseS. sudanenseS. vulgare

Plant introduction is basic to, and forms the initial step in,grass and legume breeding. There are at least two principalreasons for this emphasis on plant introduction. Firstly, a consid-erable portion of the livestock industry in the United States ofAmerica is based on legumes and grasses introduced from othercountries. All of the 40 to 45 major legume species and approx-imately two-thirds of the 80 or so major forage grasses used onimproved pastures were introduced into the United States fromforeign. lands. The range land of the great plains and westernintermountain states consists primarily of native species, but thusfar introduced grasses have been used more extensively in re-seed-ing abandoned farmlan.d and deteriorated range than have then.ative species. Naturally, there is a good expectation that newintroductions can result in bringing other valuable species to thefarmers and ranchers of the United States. Secondly, the largenumber of forage species together with limited personn.el and fi-nancial support, means that concentrated breeding work cannotbe devoted to each and every species. At the present time breedingwork with some important grasses and legumes is very limitedand many species are not receiving any attention whatsoever.Introductions provide an aven.ue for isolating superior strains inthe absence of organized breeding programs.

Interspecific hybrids have been obtained between Paspalumdilatatum and Paspalum malachophylluin which have given rise toDallis grass segregates that are immune or highly resistant toergot (Claviceps paspali). Johnson. grass (Sorghum halepense)sorghum (Sorghum vulgare) hybrids have led to the production ofperennial sorghum types an.d sweet Johnson grass lines. Selectionwork is continuing with the ergot-resistant Dallis grass lines whileseed of the experimental Johnson grass-sorghum hybrids was to bedistributed for -testing in 1955. Hybrids have also been obtainedby crossing Lolium multiflorum and Festuca elatior an.d Loliumperenne. These hybrids are sterile, but results suggest that itshould be possible to restore fertility by utilizing colchicine. Theobjective of these programs is the production of fescue strains

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which are vigorous and palatable. Many other examples couldhe listed here, including a wide variety of crosses among speciesof Poa an.d Dactylis. In addition, some work has been done withAgropyron-Triticum hybridization but in comnion with similarprograms in other countries, most of this work has been directedtowards wheat grass improvement. Continuation of this work willemphasize the development of forage types. Other Agropyronhybrids, especially Agropyron-Hordeum and Agropyron-Elymus, arein the process of being examined for possible economic utilization..A natural hybrid between Oryzopsis hymenoides and, Stipa viridulahas been in.creased and is being evaluated in regional tests.

Interspecific h-ybridization in the leguminosae has been discour-aging. Hybrids have been difficult to obtain and where crosseshave succeeded, the resulting hybrids either fail to develop or arehighly. sterile. Nevertheless, interspecific hybridization in the le-gumes present some fascinating possibilities and should be expanded.Thus, it has been possible to transfer the low coumarin genesof Melilotus dentata to Melilotus alba. The cross between Meli-lotus alba and Mallows dentata is successful, but the resulting;hybrid seedlings are deficient in chlorophyll and do not developbeyond the cotyledon stage. Hybrids llave been grown to matur-ity, however, by grafting them on to stalks of normal plants:. Theculture of these hybrids has provided a source of low coumarinthat has been incorporated successfully into sweet cl.over breedingprograms.

After a new variety has been developed serious problems ma-yarise M producing satisfactory supplies of breeder and foundationseed to initiate a substantial in.crease of certified seed for farmuse. Until recently some rather promising varieties were deve-loped which eventually passed out of existence because of thelac,k of sufficient, seed stock.

In 1948, the National Foundation Seed Project was establishedin the Forage and Range Section of the U.S. Department of Agri-culture -with the express purpose of :facilitating the multiplicationof seed of improved forage crop varieties. In this program breederseed of accepted varieties is allocated to seed producing stateswhere foundation seed i.s grown under government contract.Production goals for a given variety are determined by estimatesof possible .seed usage in the regions where the variety is ad.aptedfor forage. Varieties must he recommended. to the planningcommittee of the National Foundation Seed Project by a regionalforage crop technical committee and this recommendation mustbe supported by evidence of superiority. The planning committeeincludes two representatives designated by each of the four re-gional forage crops technical committees, two from -the Inter-national Crop Improvement Association, two from tl e ,American

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Seed. Trade and four from. the U.S. Department of Agriculture.This project provid.es a means whereby promising varieties can beincreased rapidly and the seed made available to farmers interestedin using them. At present there are five alfalfa varieties, threered clover (Trifolium pratense) varieties and one sudan grass(Sorghum su(ianense) in the project and there was a good possibilitythat an orchard grass (Dactylis glomerata) variety would be addedin 1955.

Through the allocation of breeder seed to regions that are wellequipped and suited for seed production, it has been possible tobring about a rapid increase in the available supply of certifiedseed. The progress in building seed. supplies of Vernal alfalfaunder the auspices of the Foundation Seed Project -will serve asan exanaple of Nvhat planning can do to shorten the time betweenthe release of a new variety by an agricultural experiment stationand the time when seed is available to the consuming farmers.Vernal was approved by the planning conference of -Lhe FoundationSeed Project in. February 1953. Foundation seed fields wereestablished in Utah and Washington in April of that year. .Atthe same time, 10 lb. of stock seed were planted in Californiafor certified. seed production. in six months there were 7,888 lb.of foundation Vernal from a 31-acre field in Washington and 6,400lb. of certified seed, frorn California. The foundation seed wasallocated by th.e planning conference of th.e :Foundation Seed Projectto states interested in producing seed of this variety. As a resultof this co-operative effort, approximately two million. lb. of certi-fied Vernal alfalfa seed was made available in 1954 18 monthsafter the initial plantings were lnade with breeder seed. in 1955,an estimated six million lb. of certified seed was produced.This rapid increase of certified seed contrasts sharply with theslow increase that was possible prior to the initiation of the Foun-dation Seed Project. Certified seed supplies of Ranger and Buf-falo alfalfa can be cited as further evidence of the program's valueIn 1949, the production of certified Ranger seed was 1,101,250 lb.while in 1953, -there were 27,160,000 lb. of certified seed. Theincrease in Buffalo alfalfa was from slightly over 300,000 lb. in1949 to almost nine million lb. in 1953.

A grassland problem of particular concern to Argentina, Brazil,Paraguay and Uruguay ,is the lack of winter-growing species inthe natural pastures of Northern Argentina, Southern Brazil, Pa-raguay and Uruguay. There is generall-y adequate grazing in thesenatural pastures in the spring, summer and autumn, but thei% inperiod is critical. Cattle which gain up to 440 lb. fromspring to autumn may lose half of this gain in weight in thesubsequent winter, and it usually takes 4 51/, years forsteers to reach a market weight of 1,100 lb. Research on indigenous

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and exotic species suitable for winter grazing would, in associationwith fodder conservation programs, contribute greatly to the so-lution of the problem.

Conservation of Fodder as Silage and Hay

In tropical regions where there is a marked variation in growthbetween the wet and dry seasons, conservation of forage consti-tutes one of the important means by which the shortage of grazingin the dry season may be offset. In other areas, s-uch as the onementioned at th.e end of the previous section of this chapter, live-stock producers are more interested in the possibility of provisionof winter grazing, but also have a definite interest in fodder con-servation to supplement winter grazing and to meet emergencies.

In either type of area there are special problems related tosilage crops adapted to growth and conservation in these areas,to legumes which may be used in silage to increase the proteincontent of the ration, to efficient methods of harvesting, to theuse of preservatives in silage making, and to feeding practiceswhen silage is used. The costs of harvesting and of feeding silagemust also be taken into accou.nt in relation to the advantagesgained through more adequate feeding. Much interest was ex-pressed in this subject at the Baurti meeting and participants inthe Buenos Aires meeting were, therefore, asked to present newinformation on the developments in thei.r countries. That in-formation is summarized in the following paragraphs.

In Argentina, silage production and preservation in farm prac-tice includes the use of maize, alfalfa, sorghums and grass/legumemixtures. The types of silos used vary with the zones of the countryand the character of the subsoil. Temporary silos of the stacktype are commonly used where there is a relatively impermeableclay subsoil. Trench silos are used in dry or well drained soilsand the material may be stored for many years as an ernergencyfodder reserve. 'rower silos are rarely used apart from certaindairy farms. It is essential to mechanize the harvesting andtransporting of the green material to reduce the cost of the opera-tion. Crops to be ensiled should have a high yield per unit areaand silage q-uality is higher if the crop is free of weeds. Efficientuse of pastures in Argentina often involves makin.g of feed reserves,such as silage, during the lush periods. For example, in the Pro-vince of Buenos Aires there are two production peaks in alfalfaduring the year, the more important in the spring and the otherin the autumn. Production reaches the lowest level during the-winter. Thus, storage of surplus forage during the spring is es-sential if a constant number of animals are to be fed more or less

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uiaiformly during the year from a given land area. Variationsin protein content of several crops used for silage in Argentinaare shown in Table 15.

TABLE 15 - PROTEIN CONTENT OF VARIOUS SILAGES IN ARGENTINA*

*Analysis made by Ing. Agr. M.A.L. Reichart

In Chile, there are great variations in climatic conditions, bothfrom high to low altitudes and from the north to the south ofthe country. In the irrigated valleys many tower silos had beenbuilt with government credit, but there is n.ow some questionas to -whether pastures with cool season species, properly fertilized,may not make silage unnecessary. Silos are of particular valuein the cold climates with long winter seasons; it is, however,always desirable to attempt to produce pastures particularly suit-able for winter grazing before undertaking the makin.g of silage.

In El Salvador, the principal problem in the production ofcattle is their maintenance during the severe part of the dry seasonextending from January through April. During this period thecattle suffer severely from lack of forage and water, often becomingvery emaciated and sometimes dying. There are abundant rainsfrom May- to October and light rains from October to January.While it is a common practice to move cattle from the highlandsto the fertile lowlands during the dry season, some progress hasbeen made in the use of silos to store a part of the green forageduring the rainy season to feed the animals during the dry season.As part of a campaign started by the Agricultural Extension Ser-vice in 1948, agents help in planning an.d filling the silos and

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DigestibleStage of Crude Digestible

Crop Moisture Protein inGrowth Protein Protein Dry Matter

Percentage

Mixture of alfalfa,whiteclover, and ryegrass

Grasses andlegumes

blooming

5.35 1.29 52.10 2.69

Bromus catharticus and

Phalaris minor

Mixture of alfalfa and Blooming 4.65 1.65 73.41 6.20Bromus catharticus

Alfalfa Blooming 7.35 2.73 67.40 8.37Weedy cut of Alfalfa Blooming 5.58 2.75 67.10 8.35Sweet Sudan Ripe grain 1.97 0.45 82.25 2.53Sweet Sorghum 2.92 0.85 75.50 3.46Silybum marianum Before blooming 2.59 0.71 83.00 4.17

Peas Green grain 3.84 69.00 7.58(plants and pods) 2.35

return for the opening of new silos to advise the farmers onthe use of silage. Guinea grass (Panicum maximum), Yaragua(Hyperrhenia rufa), Para (Panicum purpuroscens), elephant oTass(Pennisetum purpureum), corn, sorghum, pigeon. peas (Cajanuscajan) and frijol criollo (Phaseolus sp.) are being used. The le-gumes are always used with grasses such as sugar carte tops,and sorghum. Trench silos are commonest because of their lowcost. Beginning with one silo in 1948, the n.umber built hasincreased each year until 1954 when 39 were built, making 111in all. It is believed that there are an equal number which havenot been supervised and counted by the Extension Service, Thereis no longer a prejudice against the use of silage and dairymenand consumers no longer suffer from a marked shortage of milkduring the dry season.

No silage is made in French Guiana.In Panama, the crops used for silage include: maize, sorghum,

beans, kudzu (Pueraria javanica), Crotalaria, Guatemala grass(Tripsacum dactyloides), Para grass (Brachyaria purpurascens),Guinea grass (Panicum maximum), imperial grass (Axonopus sco-parius) and Yaragua grass (Hyperrhenia rufa). The best monthsin which to make silage are October and November, towards theend of the rainy season.

The United States of America had, according to the 1950 census,680,000 silos, 90 percent of which were tower silos an.d the remainderchiefly trench silos. The average capacity was 103 tons. Cropsen.siled include maize (73 percent of all silage), grass crops (9 percen.t)and sorghum (of great importance in the dryland areas of theGreat Plains and the South). Attempts made to self-feed silagefrom the base of tower silos have not been entirely successful;some degree of mechanization has been successful in top unloadersan.d bottom unloaders. Extraction of silage from trench silos isefficiently effected by mean.s of hydraulic manure scoops to loadthe material in.to wagon.s or trucks for -transport to the livestock.Many operators are self-feeding silage from the trench by meansof a movable barrier at the face of the silage.

Results published by the U.S. Department of Agriculture(Shepherd et al., 1954) have shown the increased efficiency ofmaking the alfalfa crop into silage rather than hay; about 12percent more milk per acre can be produced. When the haysuffers damage by rain, about 28 percent more milk was produceddue to greater retention of the leaves in the crop. The resulthas been a higher content of total dry matter, protein and caro-tene in the silage than in the hay, with equivalent demands onmotor and manpower.

The use of chemical preservatives is now receiving considerableattention in the United States of America, Recently a commercial

81

product named " Kylage " has become available, produced underpatent rights and similar to a German product " Kofa. " It con-sists largely of a mixture of calcium formate and sodium nitrate.

In many parts of the United States, silage made from haycrops is being -u.sed to supplement pastures -durin.g periods of lowrainfall in the summer, thus providing a more uniform level offeeding and leading to increased livestock production.

The making of hay is very difficult under tropical conditions.However, it is of such potential importance that efforts shouldbe made to develop he special -techniques which may be n.eces-sary. Such methods might be based on the utilization of thegreat heat of the s-un's rays, while at the same time ensuringprotection for the herbage against their direct influence, to preventloss of caroten.e. The storage of baled hay through a rainy seasonfrequently presents special difficulties in the tropics. In studiesof hay making and the use of hay, three problerns should be con-sidered:

the need to cut the grass while it still has considerablenutritive value;the prevention of deterioration in baled and stacked haydue to molds; andthe undesirability of excessive cutting of grasses which mayeradicate them and favor weeds.

Relatively little new information on these problems or on waysof solving them is available.

In Argentina, there is no research specifically on hays orhaymaking. Hay produced in irrigated zones is green, leafy andof high quality; hay from dry zones is poor in quality, manyleaves are lost in handling, and the color is poor. Eight cutsare obtained from some irrigated land and three or more cutsfrom dry land, with a yield 5,500 lb. to 7,700 lb. per ha. percut. Both the old-fashioned and more modern methods of cutting,loading and transporting are used. Alfalfa is practically the only-hay crop. The effect of unfavorable weather durin.g the haymak-ing season may be reduced by the use of modern farm machinery.The use of round bales practically prevents darnage by rain inthe field..

Haymaking, particularly of alfalfa, is most important econo-mically in Chile. The methods already noted for Argentina arepractised. In the colder southern part of the country, alfalfa isreplaced by red clover, but the crop is frequently damaged dueto variable weather conditions. Oats are used for hay in theextreme south.

In French. Guiana, conditions are most difficult for haymaking,

82

particularly in the lowland. areas -which are accessible only inthe dry season. It is not yet known whether baled hay of theseswamp grasses will keep free of mold during the wet season.

In Paraguay, haymaking is a problem due to heavy rains andoverheating of the stored material, and the whole subject requiresdetailed study.

In Uruguay, good hay can be made consistently only in mid-summer. Dews are heavy at other seasons of the year. Alfalfa

the main hay crop.

Nutritional Deficiencies in Livestock

An FAO Agricultural Study, No. 5, prepared. by Allman andHamilton (1948), brought -together information from various partsof the world on the nature and incidence of various kinds of nutri-tional deficiencies which had been observed in various types oflivestock and poultry. This Study provided the main basis fordiscussion at th.e Turrialba meeting, at -which some new inform-ation on the occurrence of deficiencies in the Americas was pre-sented, and further information was forthcoming at the Baurtimeeting (Phillips, 1950 and 1953). Additional infortnation wasdiscussed at the Buenos Aires meeting, and an attempt has beenmade: in the compilation of Table 16 to list the countries in which-variou.s types of deficiencies have been observed in tire Americas.Obviously., this constitutes a very generalized approach, but itdoes indicate the scope of the problem. Some general observations,also some details concerning occurrences of deficiencies in -variouscountries, which will be of interest to nutrition workers, are sum-marized below:

General Considerations

Energy shortages are not uncommon even in some sections oftire most advanced countries where tire level of economic develop-ment is low. They are often found in the semi-arid grazing t-treas,and in grazing areas characterized by dry and wet seasons, owingto inadequate feed reserves for the dry season.

Protein d.eficiencies, particularly qualitative deficiencies, arealso responsible for slow growth rates, lowered milk yields and othertroubles in many areas. Such deficiencies are apt to be found,for example, during the long dry season which. characterizes muchof the Pacific slope, Such deficiencies may be remedied by tireuse of protein-rich concentrates, or by the adoption of systems

83

TABLE 16 MINERAL EXCESSES OR DEFICIENCIES CAUSING NUTRITIONAL PROBLEMS IN THEAMERICAS*

Countryoo

E

84

*In addition to conditions involving specific minerals, reports of lack of vitamin A have been re-ported from Jamaica and Chile, urolithic conditions in Haiti and Argentina, lack of vitamin E inJamaica and lack of vitamin D in Chile and acetonaemia in Argentina.

of forage production which ensure either adequate grazing or anadequate supply of stored feed during the dry season.

Improper balance between energy supplies and protein stillremains a problem in many areas, since such rations are oftenwasteful owing to inefficient utilization of the total feed supply.

The use of antibiotics in animal nutrition is a relatively newphase. Study of them has been intensified owing to conditionscreated by highly specialized production systems and by the need

oX

oOo

°C)

E

o

ai

Ce

E

C-0.a

Oo. _C

oo

-6z0 o o O

OC/1

O.

RiCu

ooco 3

0- -0o

O.o.o

Antigua(British Leewards)

ArgentinaBoliviaBrazilCanada

ChileColombiaCosta RicaEcuador

GuatemalaGuiana, BritishGuiana, DutchHaitiHondurasHonduras, BritishJamaica

MexicoNicaraguaPanama

Paraguay

PeruEl SalvadorUruguayU.S.A. X X X X

Venezuela

for greater efficiency owing to increased costs of production. Theyhave received particular attention in the United States of America.Other problems are perhaps worthy of higher priority in countrieswhere intensive systems of livestock and poultry production arenot yet in general use. The same may be said of hormones whichare also receiving considerable attention in attempts to find treat-ments that will increase the efficiency of livestock and poultryproduction. At the same time, developments arising from researchin these fields should be watched carefully to see where they mayfind effective :practical application.

Much of the work on nutritional deficiencies has been relatedto mineral deficiencies. In this connection it is becoming moregenerally recognized among animal husbandmen, that the mineralcontent and availability to plants of the minerals in the soilshave an important relationship to the health of animals fed onplants grown on those soils. Also, studies of the signs of mineraldeficiencies in plants are making available information of muc.himportance to the livestock producer by enabling him to foreseefrom observations on the plants the d.eficiencies which may occurin his animals. However, such information cannot replace precisedata on the mineral content of feeds and on the specific require-ments of the animals.

The need for specific vitamins varies with the kind of animal.But for all, it can be said that good quality green roughage orpasture will take care of most need.s. Thus, more attention shouldbe paid to pasture improvement and management, and .to betterways of conserving forage for use during, non-growing periods.Ruminants, in particular, due to microorganisms in the rumen,have the ability to synthesize certain vitamins. But even non-ruminants do I;etter if they have access .to natural feeds in va-riety.

Care is necessary in considering .the deficiency problem forseveral reasons. Bone chewing and other signs of apparently de-praved appetite may be due to general upset, -Lo deficiency ofprotein and to generally ill-defined hunger, which finds its outletor expression in this way. The trouble may be temporaly andconnected with such things as the coming of new teeth in a younganimal. It is, therefore, important to ascertain the -true cause ofdepraved appetite with great attention to detail and -then torenaedy the trouble in the most direct and economical way.

The economics of combatting a deficiency should also be con-sidered. Frequently, it is more economical to provide the mineralswhich are lacking through the drinking Water or in the form ofpalatable licks, rather than by a direct application to the pasture.

The interconnection between minerals should also be considered.if, for example, an animal receives too little molybdenum, copper

85

might build up to toxic proportions. The complete copper-molyb-denum story is not yet fully worked out, and it seems as thoughsulphur in some specific form may enter into the final picture.

The general status of the soil, inclu.ding its acidity or alkalinity,may also affect not the amount but the 'availability to the animalsof certain essential mineral elements. Similarly, minerals in thedrinking water of the animals may have an effect, not only onthe palatability of the water itself (thus seriously limiting normalwater intake), but may affect the appetite and health of the animalsand, in addition, have a bearing on mineral imbalance.

Fu.rther, it is not enough to ascertain all these things relativeto improved nutrition, nor merely to publish the information inscientific, or even popular, journals. The message must be carriedto the producers themselves, so that they can put the practicesi.nto common use. Search should be made for intelligent, willingco-operators to demonstrate in each community the value of the'findings. Such work, and. related activities in the extension ofknowledge of improved methods of livestock production, opens upa whole new field for -trained animal husbandmen in many countries,and'one which is basic to increasing the supply of animal proteins.The problems will not be easy of solution in many areas since achief stumbling block will be the price structure for saleable pro-ducts, compared with the increased cost of obtaining the product.The stockmen should be shown, for instance, that even with nochange of milk or meat prices, by adopting the improved nutri-tional practices, only half the number of COWS will need to bemilked; or that beef production per acre can be increased. It isessential., therefore, to show the producer how to increase hisincome, and, at the same time, keep prices within the reach ofthe consumer.

Observations in Countries

A type of avitaminosis in ruminants resulting from the conti-nuous ingestion of Cynodon hirsutas and C. daetylon is rather com-mon in Argentina. The TICN liberated from these species in therumen of the animals seems to destroy the microorganisms whichsynthesize the B complex vitamins. The situation is aggravatedfollowing the first frosts. Affected animals have responded veryfavorably to injections containing a mixture of aneurin, nicotinicacid, riboflavin and adenine.

Urolithiasis is reported not to exist in some zones in Argentina,but there have been sporadic outbreaks, mainly in sheep, in certainparts of the Buenos Aires province, and in Patagonia, North ofthe Santa Cruz river. Grass tetany, principally in cattle, is re-

86

ported as occurring frequently throughout the livestock grazingarea. Types of pasture giving rise to the illness are oat, wheat,barley, etc., especially when the environmental conditions favorconsumption of forage with a high moisture content.

In addition, hypomagn.esemia and acetonemia are reported tooccur in dairy cows, as well as various non-specified vitamin de-ficiencies. In limited areas, a lack of iodine and cobalt affectscattle and goats; the former is deficient in certain valleys of theProvince of Salta. The need for cobalt has been recognized inrestricted areas of the Province of Buenos Aires, and perhaps incertain parts of Patagonia. The wool of sheep in these latterareas is characterized by brittleness which can be remedied bysmall doses of cobalt.

While species of Astragalas known to have a facility for con-centrating selenium in their tissues are found in Argentina, noclinical symptoms of selenium toxicity in animals have been re-ported, nor was selenium found in the analyses of these plants.Also, no cases of iron deficien.cies are known.

In Argentina, the appearance of " anteque seco " is reportedto be related to deficiencies of phosphorus and rnanganese in thenative pastures. Affected animals reacted favorably to mineral sup-plements at the rate of 5 g. of sodium acid phosphate (Na211PO4)and 0.2 g. of manganese sulphate per head per day.

In Brazil, information has been recorded concerning the Sta-teof Piaui, where it has been most dry for three or more years,showing that many diseases described, as Broca, Oca, Mal daPonta, Mal do Chifre, etc., all have the same syndrome. It hasbeen suggested that all have a common cause in a nutritionaldeficiency; the area may be deficient in zinc, copper and probablycobalt. Post mortem examination an.d analysis of livers and spleensof cattle indicate a copper deficiency. Incidentall-y, heavy internalparasitism adds to the picture of malnutrition.

In a study of infertility of cows made in the State of MinasGerais clinical observation.s included hypophosphorosis. Particular-ly near the Municipio de Pará in the eastern part of the state,groups of cows were encountered in which several years had passedsince previous calving. Most of these cows were extremely ema-ciated, walked rigidly, had perverse appetites and low milk pro-duction. When bone meal was offered -to these animals it wasconsumed avidly.

The ruminant (cattle) disease, commonly known as " Chorona ,"" Pela Rabo ," " Rabugem " or " Toca, " occurs in the Zona daMata of the State of Minas Gerais at altitudes above 1,370 ft.Striking emaciation is characteristic of all the conditions describedby different names. Recovery is spontaneous upon removal tonew pastures. Lack of copper or cobalt or both is attributed to be the

87

cause, or perhaps plant toxicity. Since copper sulphate medicationproduced fai_r results, it is believed this is a metabolic disease.

Congenital goiter is frequent in Minas Gerais State, especiallyin calves. Mineral supplementation or tincture of iodine treat-ment resolves the problem.

Deficiencies of Vitamin A and D have been reported in theNorth and Central Zones of Chile; lack of vitamin A in cattle,together with deficiencies in calcium and magnesium; and avita-minosis and mineral deficiencies in fowls in the southern zones.Specific local deficiencies have not yet been determined, althoughit is possible that they exist. Forage, both natural and intro-duced, in the various zones of the country, is being analyzedwith a view to determining its mineral and vitamin content.

In Ecuador, numerous cases of osteoporosis and osteomalacia,indicating a Ca/P imbalance, have been reported; goiter in sheephas been reported at 8,230 ft. Sulphur may be lacking, as hadbeen indicated by improvement observed following its adminis-tration in sulphurized salt blocks. The main experimental workbeing done is concerned with methods of overcoming the defi-ciencies, and so far the best results at lower elevations appear tocome from injections of phosphorus calcium gluconate.

In El Salvador, the animal scientists are getting some oftheir answers from the plantsmen. Agronomic studies indicatethat forage grasses are not only deficient in nitrogen, but also intrace minerals such as manganese, cobalt and zinc. The additionof these fertility elements to the soil materially improved plantgrowth. Iodine is lacking, as evidenced by goiter in humans andhairlessness in young pigs. However, data on which to baseconclusions are meager, not only on stock feeds, but also on soils.

Reports from Guatemala indicate a number of areas deficientin one or more of the essential minerals, as determined from bloodserum studies. Because the problem is complex and time consum-ing, no other actual research has been carried out. However, apractical solution has been successfully arrived at -through the useof a mineral mixture that contains all the required elements. Con-tinued observations show that goiter is a real problem in theGuatemala highlands. In humans, both potassium iodine andpotassium iodate effected marked reduction of endemic goiter.

In Haiti, no direct relationship has been established betweensoil and plant composition and animal nutrition problems. Never-theless, it is reported that, in a general way, Haitian soils arehigh in calcium and deficient in phosphorus an.d potassium. Ani-mals suffering from a lack of potassium have been observed ina considerable area between Declay and Cap Haitien on the northcoast, and in the drainage area behind Hinche (Papaye BreedingStation) in the north central region. Other areas reported as

88

calcium deficient are found around Kenscoff and behind Miragoane;on the other hand, at Anse a Pitre, a calcium excess is reportedin the soil. Salt areas (and thus highly alkaline) have been ob-served aroun.d Port-au-Prince and on the shores of the Artibo-nite delta. Where soil composition is known in the ArtiboniteValley, calcium is definitely in excess, and potassium and phos-phorus deficient. In the Camp Parrin. and Les Cayes region.,where soil minerals have also been studied, phosphorus, potassiumand calcium are deficient.

Reports from Honduras indicate that animal nutrition surveysare quite incomplete. In general, the soils of the country are lowin phosphorus but sufficient in potash. Indications of mineralimbalance are reports of cases of grass tetany and non-pathologicalabortions in cattle. On the north coast, animals drink waterhigh in calcium obtained from deep wells. Evidences of osteoma-lacia have been reported, indicating a Ca/P imbalance. There isalso some reason to believe that certain other animal losses maybe due to minor element deficiencies, or to maladies associated withlack of minerals. A new laboratory for the analysis of soils, plantsand aniinals has recently been established, which should be invalu-able to the work of animal improvement.

Mexico, like most large countries, has a wide variety of condi-tions. No general account of the soils seems available, althoughrather complete analyses are at hand for at least two areasthe Comarca Legunera in the western part of Jalisco State, and aregion in the north comprising parts of Durango and Coahuilastates. In an extensive area around Salinas, lambs have died withsymptoms in.dicative of a cobalt deficiency. This malady onlyappeared as the local sheep type was being changed to the morerobust Rambouillet, through a grading-up program. Here, a verysignificant point exists. A most important aspect of adaptabilityis concerned with local breeds and types which, through the cen-turies, have accustomed themselves to a certain dietary and man-agement regime. Any sudden change, su.ch as increased sizedue to grading up, will result in a higher mainten.ance requirementand, possibly, increased production.. This gives rise to a needfor more nutrients which, if not supplied, will cause a generalupset in the organism as it attempts to meet these demands.If the environmental level (nutrition and proper management)changes concurrently, uninterrupted progress can be expected.Thus, there is a very real need for the animal breeder and theanimal nutritionist to work together most closely.

Northern South America may well offer most excellent opportu-nities for livestock development because of year-round grazing.However, a real deterrent under present conditions is the lack ofknowledge of the mineral needs of forages and animals. The

89

Guianas represent an area about which little is kno-wn from thestandpoint of animal nutrition.

In Surinam, which is part of this area it is suspected thatmineral deficiencies exist. As an insurance, it is becoming a com-mon practice to feed all cattle a rather complete mineral supple-ment. On the plant side, on heavy clay soils no deficiencies haveappeared. However, sandy soils are reported, generally lackingin zinc. Studies on citrus soils have revealed a shortage of man-ganese, copper and magnesium. A serious problem in cattle hasnot yet been resolved; it does not seem related to a lack ofcopper or Vitamin A. During long periods, co-sArs fail to come intoheat. While authorities are satisfied the problem is related tominerai 017 -vitamin metabolism, no specific study, other than oneinvelaag unsuccessful gross therapy, has been reported.

Serious hypocalcemia is reportan,1 to occur in many parts ofay, where soils are Very acid._Peru, 'feeding trinis with sheep ha-ve been under way for

a year in which animals fed. Ih lb. of cottonseed cale per dayhave showed increases in body weight, have given l*th to largerlambs and have produced more milk for their i thar,ordinary range-fed control animals.

A recent report of the Gove.: of .British Guiana indicat i'sat the vast areas inlanu e,Ann the coast of northern _';.{.n.nfn

e Ica are nro-_,ably la certa: elements. I-

to basic slagland savannah pastnres responded tren,(P plu,,, :-. ay :minor elernen!s) al d Po as e Lions. However,costs r - , n=1-0,Hn in improvement. : uunu p;neni-; (J.

TIMM, ,,;,;:' :' c,- r ( ': on Wallabe 7H. , -n-portedcon Linn o ns , . ,_ _.r f. r ',-,vlinid Freisian ce, c. In s)ite of tae n:an-n,,,e, of fe ri: 's sin,enn-1:,frn ,n. an,,-!. !ysi r a- pu 3 i) e ,,.-, t , I, ( s . . , . al C

.. 1.y estaished ill. the . The region, reported npon i.sat thn junction of th.e Essequi:na and Mazarum rivers.

In variety trials of forage (Tens at Ebini, sor millets, andCoine lachryina- I obi ,-1n),..?ai- InarL-e-fv chlorotic. t7awever, Pangola

,L.,rassnla.kes laarmendoiTai n ev.H1. iu 'a --:eafy sward. Analyses rna:leaon (1.; CI'; :N-flt s ..1.2r rii eS of r: ative r.. : !n, ungrazed and unb urned,during i..... ..:- nrerious 13 months shenz P9 05 to range from 0.18Lo 0.31 nereelyt; CaO to range from 0.15 to 0.55 percent; andK90 with a rang,e of 0.08 to 0.28 :2ercen t. Pirnorinably this ison the b;..-15,is of the total ash, w'nieh varied from 6.0 to 7.0percent. 1: !.:1.licatiorts of 1.2 cwt. of 36 percent sunc;-nhosphateper acre raieej the yield of native range grass frrim 8A to 13.0erwts, acre on the basis of 6 months growili.

Studies made at the Rothamsted Station in England on brownsand soils from the Ehini station gave the followin: analyses inparts per million: Cr 45; Ni 40; V 50; Mn 90; Mo 4; -Yt 5; Sri 10;

90

CO 5; Pb 50; Cn 8. -Workers in the country believe cattleexhibit a phosphorus and cobalt deficiency. Without doubt,these areas in British Guiana are indicative of ;nuch of the terrainof nortll.orn South America, soil need to be stu-died, finf..!gs would have some value for adjae t regions of Braziland -V-o-o:.:nela.

The Islands oj-phenomenon.

ha:;paris e,descijizz-ttd SO' +rjC

ise".7;.

tc(1955) have ,nadein greater doi_oil thedisease' . in view of the facLtemed in va-;:ious 1-,,lacs in khe.ne_per by Arnold

given aLike s- ,o occurs

9 1

t :Rd

1')Lz .Ler infer,n cLan and h z. dascribeJichao.e;es associated this

;..ott this conc-rtiien has beenT. rOpiCS, seve,zal ii.tstraiioua fri7;) _73

-.as are -,..e-T-,-1..eflueed in Figures 3 to sothat the details m c.Taay be ger.11y avai-Lle to workers who en-counter the disease.

Other diseases rehled to mineral metabolism appear in Jamaica.Among these are I---:./..;omagnesemia,' milk fever and urolithiasis.Norte are common, however.

0In the United States America, total losses through nutritional

1,'aribbean represen 'ail interesting geologic

except for a -kc 7.,.ave new volcanic soils, at theLIT.te ancient oigie origin,

sarne time, problems opportunities in animal .los-_":,eind.ry.

From Jamcicis _ reported tl-at some work on nHaeral de-ficiencies has f_2'licsinhocus deficiency is widespread

1E:Jere area of granite -rock.except inIn the eyeesses of calcium, a.nreL c;:aand, 011,1.113, : %.1 -t.:, ,volviTI

srs of e soil confirmphorus.lack of of cobalt, cc s and manga-

o L C COW. ' :i.or are they coT.:rmed throughneseklov,-cver, the!..e is a pec of cattle,fe(: 1;

eteyize,z, by wasting, stik.fnes, - - joints,-,--2-711-2toras asso-el-with il-on,ared e:.:,e ,.cification o2 the elc-z:.c

t-:- , of 0-,,,.. -i;od-v, . -, ',le gr,-,Y.i.

Avhich n.'e': c,.;''e' k. l 1: !, 4....,,

group of ealca-::o. : rind zoldalurn:ti,a --',7:d. whie.: '..--ii_-.1-1.i ,.-, ,.1_,Ln 0-res.name for th, 2,',-oi.- -,7',/atti-s-- Disease. '''finite ae-ft7: is not yet 1, :,;E..Hte, I:;-Fiut it s,_--2-lizs le b',. ret:.- 7

thOri Li (C.'S lcv i yl'cticcJ'rV7'1soe;: 191`,.-L) :-eod thcLaLLi

Grosi,o area asid. dos 5al-.1-;os, 1947). A s*,To

Haw-aH ('- ot, 1942) 1,07::.s A. certain

Figure 3. Heifer affected with Manchester Wasting Disease (After Arnold and Bras)

Figure 4. Grossaspects of the leftventricle and aorta inManchester WastingDisease, showing ru-gosity of aorta dueto calcific deposits.The semilunar valvesare thickened andrigid (After Arnoldand Bras, 1955)

Figure 5. Gross aspect of the lung, showing calcification inManchester Wasting Disease (After Arnold. and Bras, 1955)

Figure 6. Ulceration and degeneration of articular surface o.f a joint in.Manchester -Wasting Disease (After Arnold and Bras, 1955)

41,.

Figure 7. Cross-section of endocardium (x 43) showing sub-endoca dial calcification inManchester Wasting Disease (After Arnold and Bras, 1955)

Figure 8. Cross-section of a small artery (x 43) showing calcification of the sub-endo-thelium and media in Manchester Wasting Disease (After Arnold and Bras, 1955)

ti

,

95

Figure 9. Cross-section of lung tissue (x 260) showing- thickened alveolar septa withcalcification and colla genization in Manches ter Wasting Disease. (After Arnold andBras, 1955)

deficiencies still represent large figures in finan.cial terms, hencethere is a constant attack on old and new problems of nutrition.Work in animal nutrition is carried out in all the states an.d terri-tories, roughly in proportion to the size of the livestock industryin each. Numerous private organizations also contribute greatly.The results of all this research are conveyed to the people bymeans of federal and state agricultural extension activities, thefarm press, and through private organizations, including radio andtelevision.

Progress in the identification and mapping of nutritional de-ficiencies (and toxicities) has centered around the mineral nutrients.In the coastal plain of North and South Carolina, extensive sur-veys of soil and geological conditions, and study of the micro-nutrient element content of native forages, have revealed certainareas deficient in cobalt. Similar studies in New York and NewHampshire have also shown a lack of cobalt, and may reveal othertrace element deficiencies.

The problem of toxicities resulting from excessive absorptionof mineral elements from soils is assuming greater importance incertain portions of the United States of America. There are indic-ations that the high manganese content of grasses in certain. areas

in North Carolina may be .responsible for certain ailments. Mo-lybdenum and selenium are problems in California, 'Wyoming andSouth. Dakota.

Studies in protein, energy, phosphorus ami -vitamins are notbeing neglected. The pastures and ranges in the western andsouthern states are often low in energy, protein, phosphorus andcarotene during certain times of the year and during droughts.Farmers and ranchers are beginning to recognize these situations,and are taking action to overcome them.

The U.S. National Research Council has done much to establishand publish nutrient requirements for the: several classes of farmanimals, and is constantly attempting, by sponsored research, tolia.crease the knowledge in this field. As a result, a commonstandard practice tO COITect certain mineral deficiencies, known orsuspected, has been achieved by the use of mixed mineral supple-ments, including the trace elements. Ilinyroved reproduction andincreased gains in -weight have resulted. Studies on .toxic mi-nerals, such as selenium, :fluorine and. molybdenum, are revealingrelationships -which are clarifying, problems. Occurrences of vi-tarnin A deficiency have served to focus attention on the factthat green leafy roughage, or, in i-ts lack, a vitamin. A supple-ment, will solve this problem. Lack of -vitamin D in the northernstates is corrected by therapy, during the winter months, or incases of Ca/P imbalance. A problem in lambs (stiff Iamb disease)and in calves (white muscle disease) is related to vitamin E de-ficiency. Benefits have generally followed the use of concentratedsources of the vitamin or of vitamin E-rich feeds.

In the growing shortage (due to increased demand) of protein.-rich by-product feed supplements in the United States of Americathe use of non-protein-nitrogen (urea) to increase or extend thesuppl-y of protein for feeding ruminants has been a subject ofconsiderable interest.

Selected References Regarding Nutrition and ManagementALLMAN, RICHARD T. and T.S. ILvaLToN. Nutritional Deficiencies in

Livestock. FAO Agricultural Study No. 5. FAO, Washington, D.C.,U.S.A. and Rome, Italy. 1948.

ANON. Mineral Deficiency Symptoms in Strawberry Leaves. 616 In-vestment Bldg., FAO, Washington, D.C. 1954.

ARNOLD, R.M. and BRAS, G. Observations on the Morbid Anatomyand Histology of Manchester -Wasting Disease of Cattle in Jamaica,.

A paper from the Department of Agriculture and theUniversity. College of the 'West Indies, Jamaica, B.W.I., presentedto the Third FAO Meeting on Livestock Production in the Americas,.Buenos Aires, Argentina, 18-30 April, 1955.

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ARNOLD, R.M. and FINCHAM., I.H. .I. comp. Path. 60: 51, 1950.BECKER, R.B.P.T., Dix, ARNOLD, KIRK, W.G., DAVIS, GEORGE K., andKIDDER, R.W. Minerals for Dairy and Beef Cattle. Fla. Agr. Exp.

Sta. Bull. 513. 1953.

EVERIST, SELWYN L. Special (unprinted) report made to Section onTropical Grasslands, VI international Grasslands Congress. Penn-sylvania State College, U.S.A. 1952.

HENDERSHOT, J.M. Rep. Vet. Off. Hawaii. 1942.

HOGG, PETER G. Research Program for Livestock Improvementand Grassland Management at the Ebini Livestock Station.British Guiana Department of Agriculture, Georgetown, BritishGuiana. 1953.

LIGNIÈRES, J. REV. Zootechnology, Vol. 4. (Translation in Amer. Vet.Rev., 44: 284). 1912.

MAGALHAES, LEONIDAS MACHADO. Estudio preliminar sobre umadoenca nao identificada ainda em Minas G-erais: a " Chorona ."Arq. Esc. Sup. Vet Est Minas Gerais, Vol. II, pp. 67-82. 1949.

MEGALE, FRANCISCO. Sobre a incidencia da esterlidade em vacas noestado de Minas G-erais. Arq. Esc. Sup. Vet. Est Minas Gerais.Belo Horizonte, Brazil. Vol. V, pp. 17-27, 1949.

. Contribucao ao Estudo do Bocio Congenito nos Bezerros, noEstado de Minas G-erais, Arq. Ese. Sup. Vet. Est. Minas Gerais,Vol. VII, pp. 143-150. 1949.

PARDI, M.C. and Dos SANTOS, J.A. Veterinaria, Vol. 1, No. 3. 1947.

PHILLIPS, RALPH W. (Editor). Report of the Inter-American Meetingon Livestock Production. FAO Development Paper No. 8, FAO,Washington, D.C. U.S.A. and Rome, Italy-. 1950.

. Report of the Second Inter-American Meeting on Livestock Pro-duction,. FAO Agricultural Development Paper No. 33, FAO,Rome Italy. 1953.

SARIANO, A. La vegetación del Chubut. Rev. argent. Agron. 17 (1): 30-68.1950.

SCRIMSHAW, NEVIN S., CABEZAS, ADELA, FABIO Y CASTILLO F. and JOSEMENDEZ. Resultados de la administración de yodato de potasio,yoduro de potasio y placebos sobre el bocio endemico y sobre losniveles de yodo ligado a la proteina entre grupos de escolares.Bol. Ofic. sanit. pan-amer. Supl. No. I. FAO, Washington, D.C.,U.S.A. 1953.

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SHEPHERD, J.B, WISEMAN, H.G., ELY, R.E., MELIN, C.G., SWEETMAN,W.J. GORDON, G.H., SCHOENLEBER, L.G., WAGNER, R.E., CAMPBELL,L.E. and ROANE, G.D.. Experiments in Harvesting and PreservingAlfalfa for Dairy Cattle Feed. U.S. DepU rtment of Agriculture Tech.Bull. No. 1079, Revised. 1954.

WORK, SAMUEL. Informe de los anos 1944-1948. Centro Nacional deAgronomia. Ministerio de Agricultura e Industria. San Salvador,El Salvador. pp. 53-54. 1949.

, VAN SEVEREN, MARIO LEWY, and ESCALON P. Luis. Informepreliminar del valor de la pulpa seca de cafe como substituto delmaiz en la ración de las vacas lecheras. El cafe de El Salvador,No. 185, p. 8. 1946.

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IMPROVING LIVESTOCK PRODUCTIONTHROUGH BETTER DISEASE

AND PARASITE CONTROL

The Turrialba meeting not only considered the broad problemsof improving veterinary services, but also gave particular atten-tion to the control of external parasites, internal parasites, foot-and-mouth disease, brucellosis, tuberculosis and rabies, and tothe inspection of meats and other foods of animal origin. Inaddition to urther consideration of the diseases just mentioned,the Baurti meeting also gave attention to hog cholera, and para-tuberculosis or Johne's Disease, and to quarantine problems (Phil-lips, 1950 and 1953). In the light of the interest shown in varioussubjects in the discussions at Turrialba and Baurti, talksat ihe Buenos Aires meeting were limited to consideration of thecontrol of foot-and-mouth disease and brucellosis, and to thecontrol of parasitic infestation and of the diseases which parasitesare known to transmit. Important information arising from thediscussions in Buenos Aires is therefore summarized below underthree headings.

Control of Foot-and-Mouth Disease

A number of recent events and technical developments havinga bearing on the control of foot-and-mouth disease are summarizedbriefly in the following paragraphs.

Vaccines produced from " culture " virus are coming into moreextensive use in 'some parts of the world. Some evidence has beenproduced to indicate that the degree of immunity set up by vac-cines prepared from " culture " virus in use today may be slightlylower than that prepared from " natural " virus, but it is generallyadmitted that, for practical field purposes, " culture " virus-vaccinegives rise to a sufficient degree of resistance to natural infection.The duration of immunity produced by each type of vaccine hasnot yet been established under controlled conditions although fieldevidence in some countries indicates that animals injected with" natural " virus-vaccine, have withstood infection for at least12 months following vaccination. The establishment, by controlledexperiments, of the duration of immunity of a satisfactory levelto withstand infection with foot-and-mouth disease virus is ofmuch importance from the point of view of advising on the inter-vals between vaccinations in countries in which extensive use of

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vaccine is a policy for control for the disease. In some countriesin Europe extensive vaccination programs are being carried out;they vary from vaccination of all cattle in the country to vac-cination in areas or zones surroun.ding outbreaks. In other coun-tries, a " stamping-out " or slaughter policy is strictly adhered toor is practised together with vaccination. The occurrence of" variants " or " mutants " within the three different types offoot-and-mouth disease viruses has given rise to some difficultiesin carrying out successful vaccination schemes; the results of re-search work are overcoming this limiting factor. Evidence fromfield observation is accumulating that a mixture of vaccines injectedsubcutaneously in one dose will successfully imm.unize cattle againstall the types of virus from which the vaccin.es are prepared, butfurther work on the subject is necessary. Such research work iscon.sidered important in order definitely to ascertain whether thisconvenient method of administration of vaccine can be acceptedas a satisfactory and efficient field procedure.

Although it is realized and appreciated that the eradicationof foot-and-mouth disease must eventually consist of a " stamping-out " or slaughter policy, the use of vaccine will continue to havean important place in some countries for practical and econ.omicreasuns and, therefore, detailed attention should still be given toits satisfactory production and use.

The immunization of pigs still presents some difficulty, butthere are hopeful signs from the result of work carried out inDenmark that virus recovered from infected cattle may be adaptedto the pig and that from such an adapted strain a satisfactoryimmunizing product for pigs may be produced.

A major attempt at regional co-operation in the control offoot-and-mouth diseas.e has been initiated in Europe through theformation of the European Commission for the Control of Foot-and-Mouth Disease within the framework of FAO. Eleven countriesare now co-operating in this new venture, which should be watchedwith interest by other regions where co-operation among countriesrnay be essential to the effective control of the disease. The objectsof the Commission are to assist European countries by inter-national effort to control the spread of the disease in Europe andto arrange and adopt measures for the prevention of its entryinto Europe. Such regional measures are essential before world-wide control of the disease can be hoped for.

There is general recognition of the urgent need for internationalaction for the control of foot-and-mou th disease in the Americasand the operation of an agreed policy on preventive measures toensure continued freedom in the countries in which the disease isabsent. The efficacy of methods of control now being applied inseveral countries to suppress outbreaks and to prevent spread of

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the infection, the occurrence of vesicular disease which m.ay si-mulate foot-and-mouth disease an.d the need to ensure accuratediagnosis, and the part played by native wild animals as reservoirsand vectors of the virus, are all problems of major interest.

New developments reported in a number of countries and ob-servation on the current situation are summarized in the followingparagraphs.

In Argentina, progress has been made in the control of foot-and-mouth disease and difficulties which arose from considerations suchas the large number of livestock in the country and the extensivelivestock movements throughout the country have been partiallyovercome. Until 1945, when a special decree was enacted, muchof the control of the disease was vested in local authorities. Thedecree provides for over-all n.ational powers of the Ministry ofAgriculture, and since 1945, the general position has improved.Special precautions are taken to prevent time entrance of the in-fection into Patagonia which, because of its geographical position.,lends itself to the exclusion of the disease. Cattle destin.ed forPatagonia, for example, should be vaccinated an.d the supplying areashould be free from foot-and-mouth disease for at least 15 daysprior to the movement of the animals. The area of origin of cattlefor export to foreign countries should be free for at least 30 days.Notification of outbreaks is compulsory and control consists in the.application of restrictions on movement, sanitary police measures.and extensive vaccination in the area surrounding an outbreak.

Vaccination against foot-and-mouth disease in Argentina isnot compulsory but is usually practised. Many farmers adoptvaccination as a preventive plan. Compulsory vaccination is en-visaged and pilot experiments are being carried out in differentparts of the country. Experience has shown that when infectionappears among vaccinated cattle, the symptoms of the diseaseare mild and the lesions slight. Vaccin.ation carried out imme-diately in an area surrounding an outbreak is reported to be usuallyfollowed by a clearing-up of the epizootic in about 15 days. Incalves, good results are reported following a combin.ation of proteintherapy and vaccination and this method of treatment is nowreceivin.g detailed study.

In Argentina, it is believed that vaccination should be carriedout every four months in order to maintain a satisfactory levelof immunity, since experiments had shown that after four months,the immunity drops sharply to a level below that accepted asefficient for protective purposes. By the adoption of a 4-monthlyvaccination policy and the practice of sanitary control and move-ment restrictions, Argentine authorities report that foot-and-mouthdisease is bein.g effectively controlled.

In 1939, a National Foot-and-Mouth Disease Institute was

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established. Its activities comprise research work on the many-aspects of the disease and the control of the large q-uantitiesof vaccirie produced by the 15 private or semi-private laboratoriesin Argentina. Different processes for the production of vaccineare being studied, e.g., the methods of Frenkel, Thomas, Belin, etc.,and it was hoped that by the end of 1955 information regardinga new rnethod for the production of vaccine might be available.Concentrated vaccine in doses of 2 c.c. injected intrad.ermallywas said to produce satisfactory results.

Canada has been free from foot-and-mouth disease since May1952. The Animal Contagions Diseases Act provides the authorityfor all necessary measures to ensure freedom from the disease.Control of the disease is handied entirely by the federal government..Arrangements exist for diagnosis work, and courses of instructionfor deoartment, veterinarians are regularly held. No vaccine is

produced or used in Callada, complete eradication being themethod of dealing with outbreaks.

In Chile, foot-and-mout71 disease is enzootic -1.nd all -threetypes of virus enist, alth.oi;fa type C is seldom found to be thecause of orithreals. Contro. plazas have final eradica.:.ion of thedisease as the objective. The plans are on the fonwing lines:in each of the 'orovinces a trivalent vaccine will be !.sed in thefirst instance, anti then mono- or bi-valent vaccine, every six monthsfor two or three years, depen,:iin.g impon the incidence of the disease.The schelAe includes the ly ovennAlt of the ope,ratol's from one zoneto anotlne- at stated intervas, and provides for t7!-!_e vaccination ofcalves. In eH.ition, -there will be in operation, sanitary polic-ymeasures, aanHet control, nuarantines and livestock traffic control.The aim is tin t by the cnd of a few years foot-and-mouth d.isease

iil be under ,,-.400d ean::rol. in the country.In El Er±Vr, Linee is no foot-and-mouth disease. No faei-

ties are available to a possible outbreak. However,or.qcials are 0 vb-rking.,

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of F.'AO technicians, to draftlaich. o ovide a L: -,--ieeting the proilem of keep-

ing the coutary -f''rew. from the disaase.In _Panama, ed.ueational ca-m-naig;ls are in operation. -whereby

livestock owners are acquainteti withi the symptomology of foot-and-mouth disease and vesicular diseases in general, arie,. the -argentneed to report any suspiciously affected animals. At present,Panama is free from time disease, but there is in existence a decreein which regulations are laid down for the control of the entranceof the infection into the country. The Pan-American SanitaryBureau (PASB) co-operates in diagnosis -work; up to the presentall outbreaks of vesicular disease,have been diagnosed as vesicularstomatitis, type " NeW Jersey.

In Peru, foot-and-mouth disease is usually confined to a re-

stricted area in the valley of Lima and rarely extends .from thislocality. Imported cattle are usually fhe sources of outbreaks.Cattle from abroad must now be vaccinated and the disease is nolonger a serious problem. :Because of geographical (..;onditionsthe comrtry, e.g., rivers forming natural fiarriers, the spread ofthe infeoion is not difficult to control. Outbreaks are controlledby the use of v(ac(....!ine, injected subcutaneously. Vesicular stoinatitisin dairy cows, in 'which the lesions occur on the udder a.ud -whichgives rise to mastitis, do OeCUT. The disease may he ci..mfused'.with cow pox-.

Jamaica is free from foot-and-mouth di.s3east., , and there isrecent legislation on methods of control of the disease, should itappear in tile country. Provision has been made for the opt,u,'ationof a " slaughter " policy, without thti. use of vaccines.

In titiA. 1.-t1ited States -of ..A.nicrica, the last outbreak of foot-and-mouth disease as in 1.929. 'Measures for the c.fmtroi arul<Bate eradication. of outbreaks of -the disease exist and include pro-visions that die federal authority may take action independentlyor in co-operation -with L1i a ftecte.I sta.tes; the im-;..)osition. of EeS-tricted livel.stoek movment; the immediate Slaughter of all infectedand c.- ,:posed. animals and the pa.yllient cf com.pensation; the in-spection of premises within and outside the affected avea; sr(. .strie-tioli. of movement of people; Lind -the application of disinfectingprocedures. ,Also in, the United States, a co.rps of veterinarydiagnosticiails, specially 1:rained in differentid (ilagnoSeS Of VeSi-etda diSeaSeS i .-L.:ratc.!gically located, throughout the country.Facilities are avaihible for i t.i7.-70.E3 of 'i's; ie -use -vac-cine is not contemplated. Toi:vJ t.; by slaughteringinfected and exposed is c,red the surefA, and Mostpractical mean of estactic.i:ing the should it appear in theUnited .:-:tates, .Rescarch work. is eh) <-).: ear,E.if: (1 out in recentlyopened laboratories located on an islan-d.

iv l'renezzela, sineo 1950., differciaii-, ap,-eneiesct b nused. indealing 1,6th foot-and-mouth disease. liere is now a Foot-4aul--Mouth Disease Department in the, Ministry of Agriculture.special laboratory has been set up 1:or purposes of diagnosis andvaccine production. Throughout ti-,w receirt outbreaks, type 0virus -W as pl.evalent, type A. being much, less eOninlOnlyand 'WaS eOnfined -Lo limited., small arcas.. The actual numberof outbreaks recorded. and types of infecting Virus are a8 follows:1.950 - 44 (0); 1.951 - 58 (0), 6(A_); '1952 - 21 (0); 1.953 - 5(0ii(A); 1954 - 4(0), 3(A); making a total of 142 outbreaks in 132of which the virus was 0 and in 10, A.

The general control methods in Venezuela are extensive -vac-cination, some slaughtering, the enforcement of sanitary p °licemeasures and the restriction of movement of livestock. In the

1 03

early stages of the recent outbreaks, slaughter was not practised;later, the slaughter of infected animals was introduced togetherwith extensive vaccination. No indemnity is paid for slaughteredanimals. The successful results obtained by this procedure madeit possible to divide the country into zones that were clean;those freed from the disease; those under observation., and thosein which vaccination was carried out. It has been reported thatno outbreaks have been confirmed since July, 1954.

Vaccines in use are always mono-valen.t and if it is foundnecessary to protect against two types of virus, two mono-valen.tvaccines are used. In the north of the country, vaccinationis carried out every four months, but in the south, because ofdifficult geographical and other conditions, the interval is sixmonths. There have been no confirmed outbreaks in the southsince 1953. Vaccine, in doses of 2 ml., is injected intradermally.The Frenkel type of vaccine has not yet been used. Only alimited study has yet been made on strains of virus; vaccin.esare prepared from strains recovered from infected animals. Thelabora-tory has produced 24,145,334 doses of Type 0 vaccine and217,750 of Type A, and keeps a large reserve stock of epitheliumfor preparing both types of vaccin.e.

Regulations in Venezuela provide for the notification of theoccurrence of any vesicular type of lesion in an animal to theappropriate authority and samples of tissue are sent to the la-boratory. Quarantine measures are applied at once; if foot-and-mouth disease is not diagnosed, the restriction.s are removed, butif the disease is confirmed, the above-mentioned procedure is putinto operation.

The Pan-American Sanitary Bureau maintains a Foot-and-Mouth Disease Center in Rio de Janeiro for the benefit of membersof the Organization of American. States. Its usefulness to thevarious countries is generally recognized. In addition to directassistance to countries, information concerning foot-and-mouthdisease and other vesicular types of disease in Central and SouthAmerica is compiled.

Control of Brucellosis

A second meeting of the Joint FAO/WHO Expert Committeeon Brucellosis, the report of which was published in 1953, reachedconclusions which are of importance to countries in the Americasand elsewhere. Some of the conclusions are summarized in thisparagraph. The most important basis of control of brucella in-fection concerns detection and elimination, or effective isolation,of the infected animals. Sero-agglutination tests should remain of

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primary diagnostic im,portance for individual animals. Screeningtests to locate infected herds are, however, of considerable value,examples of the tests being the milk ring or ABR test, .theplate test and the milk-capillary-tube test. Results of th.e milk.whey agglutin,ation test indicate its value in differentiating betweencattle showing sero-agglutination reactions caused by :Br. abortas,strain 19, and those showing similar reactions caused by naturalinfection. It has been shown that a high percentage of wheysamples from uninfected, strain 19-vaccin.ated animals show noagglutinations below the minimum diagnostic level while a highpercentage from infected animals show agglutinin titres above thediagnostic level. It has to be pointed out, however, that thetest loses accuracy- when it is applied during the early and latestages of lactation. No reports llave been published of a moresatisfactory vaccine than that produced from Br. abortus s'train 19.It is still 'recommended that pregnant cattle should not be vacci-nated, for although permanent infection in them does not resultfrom vaccination, the injected,strain may be excreted from theuterus or udder for a period, up to one week following parturition.It is now considered that, in herds in which the results of agglu-tination tests are not taken into account in controlling brucellosisbut in which vaccination is being practised, young bulls of 6 to8 months of age may be vaccinated as well as heifers. The avail-able evidence indicates that animals vaccinated once as calves arestill resistant -Lo infection up to five pregnancies. Some observersbelieve that the continuing :resistance may be related to age andthat, therefore, revaccination after the first or subsequent calvingis not likely to be necessary.

Rece it Developments in Various Countries

In Argentina, considerable importance is attached to the milkring test. Studies have been mad.e in dairies and milk pasteurizingplants on the incidence of brucellosis ini animals, as shown bythis test. It has been suggested that some scheme might be ope-rated -whereby premiums might be paid for milk from non-infectedherds and so farmers might be induced to clear their herds ofinfection. Similarly, agglutination tests, using w-hole blood fromcattle at abattoirs, packing stations, etc., had been carried outand have given rapid results of a satisfactory nature. ManythOusands of animals had been -tested, by this m.ethod, and infectedherds had been located.

Following the satisfactory results of -the use of vaccine preparedfrom Br. abortas, strain 19, as an immunizing agent of high valueand its safety in 1949, the Government of Argentina adopted this

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as the only vaccine to be used in the country. This dispensed withthe use, arnong other vaccines, of live cultures which had actuallyspread the disease. A policy of slaughter of infected animalsand vaccination of healthy animals as an ideal procedure presentsdifficulties in a country like Argentina with a cattle population ofsome 43 million and a scarcity of -trained teams of workers to carryout diagnosis work, hence such a policy could not be carried out.Calfhood vaccination was, therefore, adopted in 1947 as a govern-ment-sporisored, though voluntary, control measure. Followingthe formulation and adoption of a plan to control the vaccine,the official vaccination scheme was begun. Some farmers objectedto the scheme, largely because of the agglutination reactions fol-lowing vaccination. The Government then limited vaccinationto calves and advised against repeat vaccinations so that reactionsin adult animals, vaccinated as calves, would be reduced to aminimum. It was also felt that, if the immunity set up by calf-hood vaccination persisted at a satisfactory level for say 5 or 6lactations, the economic life of the dairy cattle would be covered.Bulls were not included in the vaccination scheme because of thepersistence of sero-agglutination reactions, following the use of thevaccine. It is now considered that the time will soon arrive when,in small areas, a " stamping out " plan with slaughter of infectedcattle and the payment of compensation may be considered.

The program of prophylaxis in Argentina includes educationalwork, given both orally and by the use of written material. Fielddemonstrations of the carrying out of control practices are provingof value not only from an educational point of view but also be-cause, from them, information is obtained on the spread of bru-cellosis and appropriate measures for its control can be taken.The practical value of the sero-agglutination test for individualanimals and the screening tests for herds in the dairy zones hasbeen demonstrated.

In Canada, brucellosis is controlled through either the brucel-losis-free listed herd plan, based on the results of the sero-agglutin-ation tests, or the federal-provincial brucellosis calf herd vaccinationprogram. Brucellosis is not a notifiable disease in Canada. Sero-agglutination. tests are compulsory only for imported animals,animals for export, herds under the brucellosis-free listed herd planand for cattle at-tending certain national livestock shows. Researchwork is confined to specific problems arising from the control mea-sures. Quarantines are not imposed on outbreaks of the disease.The educational campaign in Canada is limited to the distributionof pamphlets by provincial governments.

In Chile, the control program includes sero-agglutination tests ofcattle, progressive elimination of reactors throughout the country,vaccination of calves between 4 and 6 months of age, and ex-

106

tension work. The production and use of vaccine is controlled,by the Government. There is also a strict control of importedanimals. Official declarations of freedom from brucellosis arerequired for imported breeding cattle, for cattle sent to shows,'for the purchase and sale of high quality breedin.g animals andand for all cattle in some parts of the country. A control cam-paign carried out jointly by the National Health Service an.d theMinistry of Agriculture, similar to that for cattle, is in operationfor goats in the Province of Santiago; animals in which infectionis diagn.osed by sero-agglutination test are eliminated. Educationalcampaigns in Chile include the dissemination of information on thedisease through the press, radio and publication.s.

In El Salvador, the highest incidence of brucellosis in cattleis in the central and coastal zones of the country. Of 3,104 sero-agglutination tests carried out in these regions, 12.6 percen.t werepositive and the reaction in a further 18.6 percent was consideredas indefinite. The tests are carried out with antigen, standardizedaccording to the recommended international method.. The ringtest has been used for samples of milk taken from the market.In 1954, of 6,816 samples examined, 32.4 percent were positive;in 1955, of 2,287 samples, 10.5 percent were positive. Most ofthe milk examined came from the area around the capital andfrom the western zone. Similar tests carried out on 391 samplesfrom the eastern zOn.e prov-ed negative, while in 109 samples fromthe Santa Ana area, 11 percen.t were positive. There is no legislationfor the control of brucellosis, but some livestock owners are, vo-luntarily, following the ad-vice given by government veterinarians.The introduction into the country of a vaccine against brucellosis isprohibited. It is only for purebred cattle that tests are carried out-Lo ensure freedom from brucellosis on. importation.

In Jamaica, although brucellosis is a notifiable disease noregulations are in force concerning its control, nor is the diseasecon.sidered of sufficient economic importance to justify the appli-cation of permanent control measures. Vaccine prepared from Br.abortus, strain 19, is used to a limited extent, and the features ofthe disease and methods of control are publicized -throughout thecountry. In diagnosis work, the international standard Br. abortusanti-serum is the basis of sero-agglutin.ation tests, although thereis no regulation for the compulsory carrying out of such tests.No quarantine regulations are in operation; government veterinaryofficers give advice as required.

In Panama, the control of brucellosis is still in a preliminarystage and regulations have not yet been passed on the subject.

In Peru, the control scheme for brucellosis is practically iden-tical with that carried out in Argentina. The central campaignis being carried out on a voluntary basis u.nder official control,

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and it is expected that it will be possible to reduce the inciden.ceof the disease to such a low level that more drastic measures canbe taken. Although no statistics exist to show the effects ofvaccination in the incidence of the disease, it is significant thatthere are many fewer abortions and cases of retention of the pla-centa in the vaccinated herds; and further, that it is now possibleto re-populate dairy cattle areas with animals produced_ in Peru,whereas, formerly, replacements had to be imported.

In the United States of America, there has been a constantincrease in the funds made available for work on brucellosis, bycounty and state governments' control and eradication proceduresbeing developed jointly by the federal government and the states.An extensive educational program is in operation; many agenciesare co-operatin.g in this work. The eradication program now inoperation aims at the eventual elimination of the disease. Primaryattention is given to systematic sero-agglutination tests, .the eli-mination of reactors, the disinfection of premises and replacementswith healthy cattle. Calfhood vaccination with Br. abortus, strain.19, is an important part in the program. Research work is stillprogressing, especially on the titre interpretation of the results ofsero-agglutination tests in cattle vaccinated in calfhood, non-specificreactions to the sero-agglutination and milk ring tests, brucella typesinfecting cattle, swine and goats, and improvement of immunizingagents.

In Venezuela, a campaign for control of brucellosis is beingundertaken. For sero-agglutination tests the Br. abortus anti-serum used for standardization of antigens throughout the countryis controlled by the State Veterinary Laboratory.

Import Regulations Concerning Reactions to the Agglutination Testin Vaccinated Animals

There is general agreement on the need for further researchto establish the possible variations in the results of the sero-agglu-tination test in naturally infected and in vaccinated livestock inrelation to gestation and post partum periods.

In Argentina, with regard to the importation of cattle, vac-cinated with Br. abortus, strain 19, vaccine, -there are in existencespecial regulations with which the countries of origin have tocomply. Modifications of the regulations are now being studiedbecause of the finding that sero-agglutination reactions in vacci-nated animals may persist for longer periods than was at onetime thought.

The subject of the duration of sero-agglutination reactions atdifferent titres is a highly technical matter, however, which requires

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further study and careful consideration by a group of experts suchas the Joint FAO/WHO Expert Committee on Brucellosis. Amon.gthe points requirin.g further attention is the question of variationin the -titres of sero-agglutination reactions during and immediatelyfollowing pregn.ancy for which some experiments show that thereis a considerable depression during this period and that, therefore,results might be misleading. Also, in Argentina, an increase hasbeen noted in the titre of the sero-aggiutination reaction of strain19 vaccinated animals for a period subsequent to vaccination withfoot-and-mouth disease vaccine.

_international Standards

This subject was discussed at the Baurii meeting, where atten-tion was drawn to the adoption by the Committee on the Stan-dardization of Biological Products of the World Health Organizationof the anti-serum evolved under the auspices of the InternationalOffice of Epizootics (OIE), as the international standard by whichBr. abortus antigens, used in sero-agglutination tests could be stan-dardized. Such standardization is essential if the results of agglu-tion tests carried out in various countries are to be readily com-parable.

In Argentina, the antigens produced are reported to correspondwith the international standards. The Ministry of Agriculture hasdecided that all antigens used in the country should be so stan-dardized and standard anti-serum is being distributed for thispurpose.

In Chile, the Institute of Veterinary Research is responsiblefor diagn.ostic and antigen production techniques, and internationalstandardization methods are used.

In Canada, the international standard Br. abortus anti-serumhas not been adopted. However, there is much exchan.ge of in-formation on sero-agglutination tests with the United Kingdomand the United States of America.

The Pan-American Sanitary Bureau, (PASB), which is also a re-gional office of the World Health Organization, takes an active partin standardization. A study carried out in 1951/52 showed markeddifferences in antigens from both medical and veterinary labora-tories throughout Latin American countries. Seminars were heldin 1951 and 1952, one for countries in South America and theother for those in Central and North America. Each countrywas represented, often by personnel concern.ed with both publichealth and livestock interests. Emphasis had been laid on theneed and advisability to designate one or two laboratories in eachcountry to be responsible for standardization of antigens. Few

109

countries have as yet seen fit, however, to implement this recom-mendation.

Although some differences of opinion exist, there appears to berather good agreement that governments should take the necessaryaction to affect the standardization of procedures for the diagnosisof brucellosis and especially of antigens for use in the sero-agglu-tination test, through the designation of a central national authorityto accomplish this purpose by following the standards agreed andrecommended by the OIE, FAO, WHO and PASB.

Control of Parasitic Infestation and of the Diseases Pa-

rasites are Knovvn to Transmit

The economic effect of parasitic infestations is not confinedto losses by deaths of infested animals, but is largely concernedwith lowering of normal production of animal products, includingmilk and mea-t, low yields of wool, damage to skins and hides .andimpaired labor activity of draft cattle. It is impossible, even ingeneral -terms, to e-valuate the total loss from the various condi-tions arising from parasitic infestations, but it is agreed that theyare extremely high in all countries. -

Although some of the more recently introduced medicamentsused for anthelmintic purposes are of marked' value, -there arestill some parasites for which adequate control treatment doesnot exist; fu.rther research is need.ed. Again, it has to be pointedout that the use of anthelmintics alone, although playing an impor-.tant part in its control of parasitic infestations, cannot produceentirely satisfactory results. The practice of improved methodsof husbandry, together with the provision of suitable nutrition,with special attention to minor or trace elements, must also occupyan important place. Research is still needed on the influence ofnutrition on parasitic infestations.

While total eradication of certain parasites may be possible,with others, especially those infesting the gastro-intestinal tract,the aim should be to reduce the numbers that the level of infest-ation does not markedly influence the economic position of thelivestock in question.

Improvements in pastures mean that an increased n.umber oflives-Lock may be maintained in a given area. The effect onparasitic infestation may be great, unless attention is given tohusbandry and the use of suitable anthehnintics.

Attention should also be directed towards the dang-er of intro-ducing types of parasites Leto a country which is free from them,through irnporta.tion of livestock.

In planning control measures to be used in a country for the

110

control of parasites, due regard should be given to climatic condi-tions which may influence the life cycle of the parasites; climatic con-ditions may, for example, determine the interval between theapplications of insecticides for the control of some ecto-parasites.

In the field of zoonoses, some parasites assum.e an importantrole in both human health and livestock economy, and campaignsfor control are, therefore, of special importance.

Recent activities in various countries, aimed at the control ofparasites, are summarized in the following paragraphs.

in Argentina, some 6 million ha. have be,en cleaned of ticksduring the past ten years. The method consists of the regulartreatment of cattle with satisfactory insecticides over a period,-taking into consideration the duration of the stages of the, lifecycle of the tick under different climatic conditions when arrangingthe intervals between treatments. Stress has been laid on theneed for rotation of insecticides used in -treatment because of thetendency of ticks to become, resistant to some of the prod.uctsin use; and to the value, in land clearing schemes, of harrowinp-the land in the area. In woodland districts, such -treatment ori

the land cannot be carried out and eradication may, therefore,be a more difficult problem in such areas. It is essential that allthe cattle in .the area be subjected to treatment with insecticidesin any eradication scheme. There are n.ow in progress somefurther pilot experimen.ts in different parts of the country, repre-sentative of the various climatic and general hu.sbandry condition.sfound in Argentina. In some, it has been found that -ticks canbe eradicated in about two years.

There is also a parasite, Thysanosoma actin,oides, found in Pata-gonia and in the vicinity of Buenos Aires, which causes death ofinfested cattle. The life cyele of this parasite is unknown; however,there is evidence that a vector is necessary for its completion.

Distomatosis is commonly found in cattle,, sheep and pigs; goodcontrol results follo-w the usual methods of preventive treatment,and, vv-hen attention is given to the calcium content of the foodof the aniinals, the commonly used drugs, such as carbon tetra-chloride, can be safely administered.

The -treatment of cattle imported into tick-infested areas from-tick-free countries or areas to pre,-immunize them is also practised;for this purpose the blood of infected animals is used. Treatment ofthose which become infected with anaplasmosis or piroplasmosisis also carried out. Such drugs as trypan blue, acaprin and acri-flavin are used.

In Canada, diseases transmitted by ticks are not a problem.There are no regulatory pro-visions under the Animal ContagiousDiseases Act with respect to tick or tick-transmitted diseases.Blood-sucking flies, Tabanidae, exist but have not been known. to

transmit disease to livestock. The only outbreak of trypanoso-miasis in Canada occurred in 1952; the infected cattle herd wasdestroyed and buried. Mange (scabies) in cattle, sheep and horsesis a notifiable disease. Affected herds or flocks are quarantinedand treated under official supervision. The control of endo-parasitesis carried out by private veterinary practitioners, and educationalpamphlets from official cources are distributed. Anthelminticdrugs and pasture control are used. Human tapeworm infestations,livestock cysticercosis, fascioliasis and hydatidosis exist, but are notun.der official control, except that there is compulsory cooking ofall garbage fed to pigs and poultry.

In Chile, the -tick family Ixodidae is prevalent and althoughthe Boophilus type is found on cattle imported for slaughter pur-poses, it appears that this tick may not be adaptable to the con-ditions of the country. Trypanosomiasis does not exist in cattlein the country, nor are Dermatobia or Hypoderma found. Inconnection with Hypoderma, it has been noted that, althoughimported cattle sometimes carry the larvae, the adult fly does notdevelop.

Thysanosoma actinoides is commonly found in sheep, and hyda-tidosis, trichinosis and cysticercosis are also present. Comp aignsare in operation for the control of hydatidosis. Distomatosis inits acute phase is responsible for deaths in sheep; the disease isnow being controlled in both cattle and sheep. Parasitologicalinvestigations are carried out at the Institute of Veterinary Re-search.

In Ecuador, anaplosmosis has been found in zebu cattle, espe-cially bulls imported from countries which for a long time havebeen tick-free. Thus, there is need for pre-immunization eitherbefore the animals leave the country or inmediately on their arrivalin Ecuador.

There are two different types of country: the mountainousregion, and the loin, tropical region.. Parasites infestin.g the gastro-intestinal and respiratory tracts are commonly found in both typesof country. On the other hand, distomatosis is found onlyin the high altitudes, for although eggs of the liver fluke findtheir way into streams, and are conveyed to the lower parts ofthe country, the mature flukes do n.ot develop there. Researchis in progress to determine the reason. The parasite, Oestrus ovis,gives rise to a considerable amount of loss in sheep, and is beingonly partly controlled by the methods in practice. Trichinosis doesnot exist in the country, and the incidences of hydatidosis andcysticercosis are insignificant.

In El Salvador, external parasites are among the principalcauses of livestock losses. In the case of ticks, Boophilus spp.and Amblyomma spp. appear to be the rnost common but there

112

has been no study of their distribution. They transmit piroplas-mosis and an.aplosmosis. No rickettsiasis nor trypanosomiasis hasbeen reported. Excepting the distribution of propaganda, thereis no provision, such as a law or national program, for the controlor eradication of ticks and other parasites. However, more andmore individual farms and ranches are using pesticides to combatthem.

Tarsal() (Dermatobia hominis) is not severe. The majority ofthe infested cattle come from the frontiers borderin.g Hondurasand Nicaragua. The central zone is practically free. In addition,there are a few isolated cases of infestation with Sarcoptes andPsoroptes.

Internal parasites are a very serious source of loss to thelivestock industry as they infest about 99 percent of the animals.The principal ones are: in cattle Haemonchus contortus; inhorses: Strongylus spp; in swine: Ascaris lumbricoides, Cysticercuscelluloae (affecting approximately 15 percent of the hogs), but noTrichinella spiralis; in poultry: Coccidia and Haeterakis gallina.Individual farmers are using anthelmintics such as phenothia-zine, kamala and carbon tetrachloride.

Information obtained concerning the occurrence of plathel-minths in humans and of cysticercosis and Fasciola hepatica indomestic animals is being used as propaganda in the drive toobtain adequate laws to serve as a foundation for fightin.g thesepests on a nation-wide basis. FAO technicians are advising onthe framing of a law to meet these problems in El Salvador.

In Jamaica, the ticks commonly found are Boophilus annulatusvar. microplus) and Amblyomma cayennense in cattle, Dermacenterniteus in horses, and Rhipicephalus sanguineus in dogs. Anaplas-mosis and piroplasmosis are enzootic in native livestock, andimported animals suffer severely. There are no rickettsial diseases.

Ticks are controlled by dipping and spraying, using appro-priate insecticides. There is no law for compulsory treatment.Biting flies and horn flies are present, but are not serious pests;trypanosomiasis is not present. Screw worms are found buttorsalo is absent. Advice is given on the control of internal pa-rasites by visits of veterinary officers to an area, following ob-servations made in the abattoirs.

In Peru, no marked official effort has been made to controlparasites and parasitic infestations. However, some work is underway. For example, one private corporation is now employingeight veterinarians on parasite control in the sheep. Mortality hasbeen reduced from 26 to 2.5 percent; average wool yield had beenraised from 3.5 to 6.5 lb., and average carcass weight had risen24 to 42 lb. The number of sheep now owned by this corporationhas increased from 160,000 to 200,000.

113

The faculty of Veterinary Medicine has undertaken a surve-yfroni which th.ere will be available a complete picture of the typesand locations of livestock parasites in the country.

As in some oth.er countries, much care is taken with diseasesof virus and bacterial origin; but little or no attention is givento para.sites, with the result that parasites, not present in acountry, rnay be introduced by imported livestock. An exampleis the introduction of the parasite Thysanosoma actinoides. whichis responsible for some cattle losses and im.paired production.

The prevalence of hydatidosis has been noted and. there isurgent need for its prevention from both the public health andlivestock economy points of view. In collaboration with theInter-American Health Service, the Faculty of Veterinary Medicineis -to carry out a survey of the condition, for which veterinarystudents will be used.

The United States of America enjoys a virtual freedom frompiroplasmosis, theileriasis and trypanosomiasis, but heavy lossesoccur from cattle grubs, screw WOrMS, horn flies, lice, ticks andmites. There are already some in.dications that the oral adminis-tration of phenothiazine, the medicament corranonly used in .thecontrol of SOILIe gastro-intestinal parasites, may also have somevalue in reducing the intensity and incidence of grub (warble)infestation. Observations are being made on the value of othermedicaments. In controlling mange (scabies) in the different speciesof livestock, and SCreW worms, lice and certain flies, a majorprobleIll with newer insecticidal dips is the disproportionate removalof the suspended particles of active ingredients by the passage ofanimals through the fluid; and a practical difficulty is the lackof a suitable biological or chemical test of dip strength.

in connection with the endo-parasites, considerable progress hasbeen made in the United States of America in the control ofof coccidiosis, trichomoniasis and anaplasmosis in cattle. Improvedhusban.dry, n.ewer chemo-therapeutical agents, artificial inseminationand better methods of diagnosis have all contributed to bettercontrol results. In cattle, there llave been recognized some 40species of helminths of more or less economic iraportance.though available medicaments are of value in controlling some ofthese worms, th.ere is as yet, no appropriate treatment for morethan half of them..

In pigs, helminths are the most important parasites causingeconomic losses. Some 18 species are recognized.. Problems ofcontrol are complicated. by the presence of certain other parasites,of which the commonest are kidney worms, lung worrns, larvaltapeworms, thorn-headed worms, trichinae, threadworms andwhipworms. The annual loss in swine is esti ated al more thanIlf.S.$ 200 million.

111

Parasites of sheep an.d goats are of special importance -through-out the country, the proportionate loss from helminth infestationsbeing higher in these than in any other classes of livestock. Theuse of available anthelmintics is causin, an encouragin.g reduction.It is recognized, however, that the use of antiparasitic drugscannot alone solve practical problems of parasite control.

In Uruguay, so far as ectoparasites are con.cerned, mangescabies) and lice infestation are no longer problems, but tick control

is still of considerable importance. A new law is about to beenacted in this connection. With the improvement of pasturesit will be possible to concentrate more sheep in a given area.This means there will be more opportunity for the developmentof gastro-intestinal and lung W01711 infestations, and attention willhave to be given to rotation of the sheep stock and the necessary.anthelmintic treatment, both arranged according to the durationof the stages of the life history and the parasites under the dif-ferent climatic conditions.

In Venezuela, the livestock, as in the majority of the Americancountries, suffer the pernicious effects of ectoparasites, the mostimportant among which are Amblyomma eayennense, Boophilus mi-croplus, Dermatobia hominis, Lyperosia irritans and Stomoxys calei-trans. The Venezuelan Ministry of Agriculture, through its Ecto-parasite Department, has been conducting intensive control ofthese parasites since 1936. As the first step in the campaign,arsenical di-ps were employed and it was possible to clear ticksfrom one part of the country (Aragua State) which specialzies inmilk production. After ten years of control, a problem cropped-up in that the new tick generations had become resistant to arsenic.Fortunately, by that time there had been discovered chlorinatedhydrocarbon insecticides which are harmless for warm-bloodedanimals, but lethal to eetoparasites, and are very persistent in theiraction.

After these insecticides had been the subjects of experimentationby the Departinent, plans were made for control with these pro-ducts which are applied by means of spray pumps. In time caseof toxaphene, it was found that the -toxic dose for animals is 40mg. per 2.2 lb. of live-weight. With the sprayers used, no animalreceived more than 10 g. of the active principle, in fine suspension,which is equivalent, for an animal -weighing say 880 lb. to halfthe toxic dose per 2.2 lb. Up-to-date some 22. million sprayingshave been carried out without any cases of poisoning, nor, haveskin lesion.s been caused by the -treatment. The chief advantageof -toxaphene, compared with other ectoparasiticides, is its greaterpersistency. The campaign is welcomed by the stock farmersbecause of the benefits it has brought to -them in the control ofticks, bot flies and other external parasites of livestock.

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Literature Cited Regarding Disease and Parasite Control

PHILLIPS, RALPH W. (Editor). Report of the Inter-American Meeting onLivestock Production. FAO Agricultural Development Paper No. 8,Food and Agriculture Organization of the United Na tions,Washington, D.C., U.S.A., and Rome, Italy. 1950.

. Report of the Second Inter-Atnerican 1VIeeting on LivestockProduction. FAO Agricultural Development Paper No. 33, Food andAgriculture Organization of the United Nations, Rome, Italy. 1953.

JOINT FAO/WHO EXPERT COMMITTEE ON BRUCELLOSIS. Joint FAOIWII-0Expert Committee on Brucellosis Second Report. FAO AgriculturalStudy No. 24, Food and Agriculture Organization of the UnitedNations, Rome, Italy. 1953.

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STATUS OF THE POULTRY INDUSTRYAND POSSIBLE PROGRAMS

FOR IMPROVEMENT

General Considerations

Poultry have received inadequate attention in man.y Americancountries in relation to their value as a source of animal protein.This seems to be the case particularly in those countries wherethe average intake of animal protein per person., per day, is esti-mated to be below 30 g. Data were in.cluded in the report of theBaurti meeting (Phillips, 1953) on the intake of animal proteinper person, per day, and of the 12 countries for which data wereavailable in the Western Hemsphere, Argentina, Uruguay, theUnited States of America and Canada had an intake higher than30 g., while Brazil, Chile, Colombia, Cuba, El Salvador, Honduras,Mexico and Peru have average intakes below this. The SecondInter-American Meeting on Livestock Production in Baurú, there-fore, recommended that governments should study the adequacy ofexistin.g programs and give increased emphasis to intensive pro-grams for poultry improvement wherever this proves to be desirable.

The wide differences which exist in the state of developmentof the poultry industry in the various countries may be illustratedby tables recently prepared by the Statistics Bran.ch of the Eco-nomics Division. of FAO showing that average egg production perhen, per year, is estimated to vary from about 38 to 175 eggs inAmerican countries (see Table 17). The data for Argentina andBrazil are official estimates, while the figure for Mexico is unofficial.There is also a great variation in the average consumption ofeggs per person., per year, in the different countries; 4.4 to 15.4 lb.in Latin Anierica, and 37.4 to 46.2 lb. in Can.ada and the UnitedStates of America. Similar variation exists in the consumptionof poultry meat, which is highest in the United States.

The importance of poultry husbandry is often underestimatedalthough it offers great possibilites for providing, rapidly andeconomically, protein of high quality, essential vitamins, and ofimproving the farmers' income. The efficien.cy of poultry produc-tion mainly depen.ds upon the level of production of each indi-vidual, whereas the actual number of birds is of minor importance.The fact is often overlooked that fast growing birds and good layersare far more efficient than birds with a low level of production.The utilization of nutrients by laying hens is a typical and striking

117

TABLE 17 AVERAGE EGG PRODUCTION OF HENS IN VARIOUS AMERICAN COUNTRIES

118

example. When the percentage of egg production is related tothe respective consumption of " total digestible n.utrients " (1 g." total digestible nutrients " corresponds to 4.1 digestible calories)required for the production of 100 g. of eggs, variants similar tothose shown in Table 18 occur (Engler, 1936).

The outstanding point o-f practical importan.ce in -this is thatthe hen which lays only 40 eggs per year may need up to 850 g.of grain and other dry feed to produce 1 normal sized egg.If a hen lays 120 eggs per year, then the total feedingstuffsrequired for 1 egg decreases to about 300 g. With an annualproduction of 240 eggs, only 180 g. of grains and layers mashare needed. Byerly (1954), based on his form.er experimentalwork, stated that a hen of 4 lb. body -weight required about 60 lb.of feed for maintenance per year. For each dozen eggs producedit would require an additional PA lb. of feed. Thus, such

Region and Country Period Number of Eggs

North America

Alaska 1952/53 140

Bermuda 1948 120

Canada 1948-53 164Hawaii 1948-53 160

United States 1948-53 175

Latin America

Argentina 1952/53 71

Brazil 1952/53 76British Guiana 1952/53 38British Honduras 1950 90

British West Indies:Jamaica 1948-51 65

Trinidad and Tobago 1948 100

Windward Islands:Dominica 1952/53 80

Chile 1948 112Colombia 1950 120

Guadeloupe 1951/52 80

Martinique 1951/52 50

Mexico 1953 80

Netherlands Antilles 1948-51 118Panama 1953 86Peru 1950-53 44Puerto Rico 1949 /50-1 951 /52 126Surinam 1952 100Uruguay 1952 87

Virgin Islands (U.S.A.) 1950 151

TABLE 18 VARIATIONS IN EFFICIENCY OF EGG PRODUCTION IN RELATION TO LAYINGCAPACITY

Percentage Egg Production100% laying capacity = 365eggs weighing each 58 g. (about2 oz.)

10

20

30

40

50

60

70

80

90

Average maintenance and pro-duction requirement expressedas total digestible nutrientsneeded to produce 0.22 lb, ofeggs by birds from about41/4 lb. liveweight

1 000550

375

300

250

210

180

160

150

Improvement of UtilizationIndex

450

175

75

50

40

30

20

a hen requires about 75 lb. of feed if it lays 10 dozen eggs ina year, or 90 lb. if it lays 20 dozen eggs. In the first in.stanceeach dozen eggs costs 7.5 lb. of feed (290 g. per egg), in the secondonly 4.5 lb. (170 g. per egg). In actual practice, of course, thesefigures would be subject to some variation on account of thebody weight, the inherited laying capacity and phen.otypical con-ditions of birds, the contents of nutrients of the ration, and thepossibly available quantities of feedin.gstuffs found in the runs orfield which will differ regionally and seasonally.

In many cases where scavenging birds pick up -their feed wher-ever they can, these nutrients would otherwise be en.tirely lostor even detrimental, e.g., weed seeds and insects, if there wereno birds. Although un.der certain conditions even low productionmay -temporarily be justified, the fact should always be kept inmind that low level of production means an unfavorable feedconversion rate.

Since production level and efficiency of poultry production areinfluenced by many factors, some of which are of a personal na-ture such as interest of the farmer in the birds, sense of orderand perseverance, the follo-wing poin.ts are of particular importance:

(1) Besides adequate housing and management, frequent cullingof unthrifty birds is recognized as an efficient step -towardsreducing -wastage of feeds and reducing th.e output and incomeper bird. On small farms and in backyards in particular,birds are frequently kept until they are too old for normalegg production. This, moreover, leads to a progressive declinein meat quality and renders disease control more difficult.Therefore, training courses for culling experts are recommended.

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(2) The fight against poultry diseases needs to be reinforced ona national scale in man.y countries by diagnosis, advice,treatment and sanitary regulations. Veterin.arians with specialtraining in poultry pathology, including some practical workill poultry husban.dry, are essential in the development ofwork in this field.

(3) In order to improve production capacity of utility birdsand to increase the number of poultry keepers possessinghealthy and efficient birds, accredited breeding stations aremost useful as has been proved, e.g., in the United Statesof America, where a " Nation.al Poultry Improvement Plan"has been operating since 1935. Its objectives are to improvethe breeding and production qualities of poultry and toreduce losses from hatchery disseminated diseases. This isbeing accomplished by:

the development of more effective state poultry improve-ment programs;

the identification of the quality of breeding stock (e.g.,ran.dom sample tests), hatching eggs and chicks byauthorized terms that are uniform and applicable in allparts of the country, and.

the establishment of an effective co-operative programthrough which n.ewer knowledge and practical experiencecan be applied to the improvement of poultry and poultry-products.

Progress in the production of efficien.t layers and quick growingtable birds (broilers) may also be achieved by selection ofinbred lines and their crossing. In principle, it is necessarynot only to in.crease average egg and meat production ca-pacity, but also natural resistance to certain diseases. Thework of utility breeders' associations should be financiallyencouraged by governments.

(4) The rearing of healthy birds as well as an increase in eggand meat production also depends largely upon feeding.Though in many cases it would be possible and desirable toutilize more locally produced feedingstuffs for poultry, it is,however, indispensable to eliminate feeding deficiencies re-sulting from the biased use of certain products like grainsan.d other carbohydrate feedingstuffs. Even a small amountof mash, rich in protein., minerals and vitamins may oftenhelp to overcome some nutrition.al deficiencies. This willresult in an improved feed conversion rate, better healthand -thus considerably increased output and reven.ue. Hence,

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special attention to the optimal use of indigenous feeding-stuffs is desirable. This involves the collection of informationon the possibilities and status of poultry feedin.g in thevarious countries and experimental and extension work.Well balanced commercial com.pound feeds are recognizedas an efficient mreans of increasing output rapidly and reducinglosses considerably. The in.creased use of antibiotics andother medicants as parts of compound feedin.gstuffs for poul-try has brought along with its gains, additional responsibi-lities to the industry (Levin.e, 1954). The nature of themedication and its innate toxicity, particularly its safety-factor, should be kept in mindFurther impetus should be given to research work, particu-larly in breeding, feedin.g and disease control. Careful plan-ning and co-ordination of experimental work as well as theuse of statistical methods in the interpretation of results arebecoming more and more indispensable. This involves thenecessity for adequate scien.tific and practical training ofcapable specialists and reliable personnel as well as the estab-lishment of well equipped and sufficiently finan.ced experi-ment stations.In all countries where the poultry industry is well advanced,such as Canada, Denmark, Israel, the Netherlands, the UnitedKingdom and the United States of America, exten.sion ser-vices exist through which poultry keepers and breeders areassisted in putting into practice improved technical methodsadapted to the existing conditions. Advisers should be welltrained and as independent as possible. Their work shouldbe supported by the distributioii of good and inexpensiveleaflets and other material for demonstration, such as plansand models of suitable and cheap poultry houses and waste-reducing feeding troughs, etc.

Governments, co-operative organizations and private firms,should pay particular attention to the level of quality and pricesof poultry products, collection and marketing of eggs and tablebirds in countries where the industry is not highly developed.In many cases, attempts might be successful to interest the publicin higher consumption of eggs and poultry meat.

Statistics and estimates on poultry numbers and productionare often out-of-date, incomplete and unreliable. Also, owing tothe diverse methods employed by different countries, it is extremelydifficult to compare these figures. Therefore, such statistics needto be standardized and revised at regular intervals in order tocomplete the basic data for food balance sheets and facilitateeconomic and technical planning.

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Current Situation and Recent Technical Developmentsin Various Countries

'Information regarding the present status of the poultry industryand possible programs for improvement in .American countries,is summarized in the following paragraphs.

In Argentina, poultry husbandry is usually carried out subsidiaryto other agricultural activities. Out of a total of approximately50,000,000 birds, about 60 percent are kept OR peasant farms. Ar-gentina offers favorable conditions for poultiy production almostthroughout the whole country. The main production period isJuly to November, -with peaks in August, September andOctober; in ibis period, about 70 percent of -the productionobtained, an.d. 30 percent during the period from Decemberto ,July. A, notable increase in poultry production took placeduring recent years, and, particularly near the big cities thereare several specialized poultry establishments in which breedingstock, table birds (broilers) and eggs are produced. Originally,most of the imported birds -w-ere White Leghorn.s, especiallybred for egg production, but more recently a tendency- toward'sdual-purpose breeds beca-me apparent, and other breeds, like RhodeIsland Reds, Wyandottes, Sussex and New Hampshires wereimported. The State supports the poultry breeders' activitiesby assisting in distributing improved breeds, particularly tofarmers. Housing, feeding and management have also beenconsiderably improved .during the last few years. There are 30accredited feed manufacturers in the country'. According to adecree which the Government made in 1951, commercial mash-formulas must be officially approved.

Poultry diseases are reported to be efficiently controlled; thisrelates partic-ularly to specialized establishments for egg andpoultry meat production on a large scale, and to the 1,500 accred.-ited breeding stations which are included in the state herdbook.The herdbook is open to the offspring of -registered birds, to dulycertified imported birds and to the offspring of non-registereahens with a minimum production of 180 eggs in the first year,mated with registered cocks which have to comply with standards.Special attention is given to the eradication of pullorum disease,and its control is extended also to poultry exhibitions. All birdsshowing a positive test reaction have to be eliminated. Thedirect control activities are complemented by extension campaigns,through meetings, publications and demonstrations.

In the main poultry zones, which coincide with the cerealzones of Argentina, the Provinces of Buenos Aires, EntreRíos, Santa Fe and parts of the provinces of Córdoba and La

122

Pampa and where about 80 percent of the birds are located, build-ings and other installations are usually of sufficient quality. Inthe north and central parts of the country, the open-front-houseis most frequently adopted, whereas in the south, according tothe environmental conditions, closed structures are preferred.Small incubators with a capacity of about 200 eggs are frequentlyused. On the large breeding establishmen.ts, incubators up to60,000 egg capacity- are available.

There are no specialized poultry experimental stations or schoolsin Argentina, but some general experimental stations, as well ascertain agricultural schools and animal breeding stations haveestablished poultry section.s and are also dealing with advisorywork in the poultry field. No important poultry co-operativesexist; however, the State has taken a very active interest in theestablishment of co-operatives for all branches of animal h.usbandryand rnany of the agricultural co-operatives have poultry sections.The Government is at present carrying out a plan for the develop-ment of the poultry industry Which covers extension work bymeans of meetings, publications, demonstrations, courses, exhibi-tions, direct advisory service, experimental work, disease controland marketing.

In Canada, 95 percent of the stock are purebred.s or crossesof the following breeds: Single Comb White Leghorns, BarredPlymouth Rocks, Light Sussex, Rhode Island Reds, Ne-w Hamp-shires, White Rocks, Columbian Rocks and White Wyandottes.About 90 percent of poultry raised on farms, or in specializedcommercial poultry establishments, are fed balanced mashes. Itis estimated that approximately 60 percent of the birds are fedcommercial mashes, and that an additional 25 percent get mashesnaade of home produced feedstuffs mixed with a *high proteinsupplement manufactured and distributed by feed companies.The poultry are kept in houses varying from those made ofstraw bales in the prairie provinces to the industrial type with acapacity up to 15,000 birds in on_e unit; however, the one-storey,gable roof house with southern exposure and constructed of woodis the most popular type being used. The present tendency isto make this house deeper. Houses being constructed at presentare about 40 ft. deep. The walls and ceiling are usually insulatedand the floor is covered with deep litter. In large pen units,electric lights are frequently used. Automatic -watering and feedingare used to a lesser extent.

A program for the eradication of pullorum disease in poultryhas been in progress for 20 years. Under this program theincidence of positive pullorum reaction has been reduced to0.12 percent. Virus and other contagious diseases of poultry arereportable under the Animal Diseases Act, and a control program

123

by vaccination is in progress. The manufacture and distributionvaccines are controlled by permit. The experimental farms of

the Canadian. Department of Agriculture carry out extensive re-search work in poultry at the experimental farm, Ottawa, and on23 branch stations spread throughout the country. Egg layingcontests were operated in Canada from 1911 -until -the beginningof the last war. Since they were given up, the breeding of poultryhas been stimulated by the " National Poultry BreedingPolicy. " It provides advice for -the mating, pedigreeing and test-ing of families on the breeder's own farm. This work has nowgrown to proportions where it has become necessary to establisha central testing station. Accomodation is -under construction forbringing samples of hatching eggs from the breeders' farms to acentral place where the eggs will be hatched and the birds rearedunder uniform conditions which will allow comparisons of theefficiency of the various strains.

Breeder organizations have been established in each provinceCanada. The poultry hatching industry has developed to a

point where each province also has a hatchery association asas a poultry products committee, made up of representatives ofthe breeding industry, hatching industry, feed industry, producersorganizations, etc. There has also been organized a poultry pro-ducts center which is financially supported by the in.dustryfor the purpose of popularizing eggs and other poultry pro-ducts. There exist also feed man.ufacturers' associations. Inaddition to the organizations maintained by the industry, eachprovincial department of agriculture and the Canadian Departmentof Agriculture maintain poultry divisions staffed with qualifiedpoultry personnel. Besides the educational and extension workdone by provincial and federal departments of agriculture, thereare seven universities with poultry departments, staffed by qualifiedspecialists. There are also several agricultural schools where poultryinstruction can be obtained. Numerous publications on poultryprod.uction in all its aspects have been issued. The industry iswell served by several co-operative sales organizations. A largevolume of the production in Alberta, Saskatchewan, Manitoba,Ontario and Quebec is marketed through producer-owned andoperated co-operative organizations.

In Colombia, poultry production is visually carried out on asmall scale. In most cases, the flocks which belong to farmers,have from 10 to 100 birds, mostly chickens and some turkeys andducks. As a rule, poultry have to find their own feed, but some-times this feeding is supplemented by small quantities of maizeor inferior wheat. Few special poultry houses exist. Th.e nativebirds produce about 60 eggs per year on the average, this lowproduction being due to bad feeding and poor selection.

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Nevertheless, poultry production occupies fifth place in economicimportance in agricultural and livestock production in Colombia,coming after coffee, milk, beef and maize. Imports in 1954were: chickens for breedin, 1,672,293 head; eggs for breeding,240,000 units; eggs for consumption, 19,790,000 units; andchickens for consumption, 105,204 lb. Three years ago, afterthe appearance of Newcastle disease, im.ports of eggs and chickens,which had not formerly taken place, became necessary. Colombiahas good possibilities for poultry development but it is necessaryto instruct farmers on the improvement of installations, selectionand feeding methods and to control diseases.

In Ecuador, the New Hampshire, Plymouth Rock, RhodeIsland Reds, Jersey Black Giant and Orpington appear to be thebest adapted improved breeds for the country. They have alsobeen used for crossing with native birds. About 80 percent ofthe poultry in the country are scavengers. In some establish-ments, the construction of special types of buildings has beenstarted; however, for the greater proportion of poultry, no specialhouses or equipment are available. Some preventive vaccinationis carried out against the most important diseases, such as fowlcholera, Newcastle disease; and ecto- and endoparasites are controlledto some extent. There are no poultry co-operatives in the country.

In El Salvador, poultry raising has always been an importantsideline with rural families. However, in the last five years theindustry has made a very unusual growth. In the principal cities(San Miguel, Santa Ana and San Salvador) there are 40,000 layinghens under official supervision. When the poultry program wasinitiated, nothin.g was known of the performance of the leadingbreeds in the tropical climate of El Salvador. Therefore, eightdifferent breeds were introduced and placed under test for threeyearS (1949-51) at the experiment station of the National Centerof Agronomy at San Andreas. The New Hampshires and Leghorn.sproved bes-L. Recently it was shown that Leghorns produce moreeggs than New Hampshires and since the price of eggs is high inrelation to meat, the Leghorns are rated highest under presentconditions. The supervised flocks are fed exclusively on balanceddiets, while the flocks commonly kept by farmers depend entirelyon grain and the insects they may obtain. Feed constitutes about70 percent of the total costs in egg production. Three firmssupply feeds. TWO of these prepare balanced mashes with homeproducts, using the minimum of imported concentrates. Thethird imports concentrates of high protein value, to be mixedwith local feed.s.

Poor nutrition and disease are the c.hief factors limiting produc-tion generally, and there is no national program of disease control.There are two poultry specialists working with 19 extension agents

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to advise and assist the poultry breeders. There is only one pub-lication devoted to this industry, but generally two articles permonth on poultry keepin.g appear in the local press.

In Jamaica, there is an increasing number of farmers rearingpoultry intensively. Most of the farmers use purebreds or cross-breds. During 1953, approximately 1,100 tons of feed were rnixedan.d sold locally as compared with 2,000 tons imported. This gapcan be expected to become narrower. Housing for poultry variesconsiderably. Deep litter is becoming increasingly popular for layingbirds, and most of the broilers are no-w raised on wire. Only afew peasants provide proper housin.g for their birds, but there isno doubt that fairly- cheap housing could be produced from localmaterials. Housing, in turn, implies intensive feeding and rearingand is thus unpopular with most of the small scale poultry far-mers who prefer their birds to forage for part, at least, of theirlivelihood.

The presence of Newcastle disease, infectious bronchitis andchronic respiratory disease have recently been confirmed. Vaccina-tion of all birds against Newcastle disease and fowl pox is recom-mended to farmers and is carried out on all chicks sold from thegovern.ment hatchery. No program backed by legislation is inforce, and, in view of the sporadic losses attributed to these diseases,it seems doubtful whether an expensive, comprehensive scheme isjustifiable.

There are one major station and three minor station.s wherea limited amount of demonstration and research work on poultryis carried out. An accredited poultry scheme has recently beenprepared in conjunction with efforts to make the island self-supportin.g for day-old chicks, and it is hoped that the schemewill be accepted and implemented in the coming year. TheDepartment of Agriculture has one full-time poultry officer withtwo assistants. In addition, the 13 Livestock Extension Officersin ,the field are competent to give advice on elementary poultryhusbandry. Extension circulars have been issued on " Startingin the Poultry Business, " " Housin.g and Feeding Poultry " and" Common Diseases of Poultry. " These are written in simpleterms but deal with the subjects to a reasonably advanced level.There is a small co-operative which markets eggs and, to a limitedexten.t, poultry meats. Other marketing is at present haphazard,but the Government is considering the promotion of an expansionof the present co-operative. There are two poultry keepers'organizations, but n.either is firmly established or representativeof the industry. An official accredited poultry scheme is soon tobe launched.

In Panama, the most common improved breeds are SingleComb White Leghorns, Plymouth Rocks, New Hampshires and

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Rhode Island Reds. The results obtain.ed with heavy breedshave not always been satisfactory, vv-hereas White Leghorns haveproved to be more successful, but only where d-u.e attention wasgiven to adequate feeding and protection against endoparasites.Leghorns have been less successful in ordinary small holdings,where the most adaptable breeds have been Rhode Islan.d Redsand New Hampshires and, to a lesser degree, Plymouth Rocks.The New Hampshire is now the most common breed, both foregg and meat production, but particularly for the latter. Verylittle balanced feeding is done at presen.t, and the majority of birdsdepend on waste grains and table refuse. However, a certainnumber of producers have already started to use balanced mashes,based on locally produced feedstuffs and, to a certain extent,on imported high protein con.centrates. The production of com-pound feedstuffs is conaparatively small, and is not supervised bythe Government. It is supposed that the use of commercial mashescould be considerably increased if manufacturin.g would be stan-dardized and officially supervised.

In poultry husbandry, little experimental work is carried outin Panama at present, but the National Institute of Agriculturekeeps a flock of birds for teaching and experimental purposes.

In Paraguay, the poultry industry has not been -developed toany significant extent for a number of reasons, among which themost im.portant are: little official support, lack of adequate tech-nical knowledge on the part of the farmers, the almost exclusiveuse of native breeds, several diseases which cause heavy losses,deficient feeding and inadequate housing and equipment, lowquality of locally produced poultry meat and eggs, marketingdifficulties, inadequate transport facilities, particularly for areaslocated at considerable distance from the consum.ption. centers.

The nati-ve type of hen on the average produces not morethan 60 eggs per year and is n.ot precocious; however, its replace-ment by imported breeds or by adequate crosses is very slow,because the farmers believe that native birds are more resistan.tto the environmental conditions and diseases. The first significantimports of improved breeds were made in 1951, when some RhodeIsland Reds came into the country, and appeared to be satisfactorilyadaptable. An official breeding farm was established, which nowhas approximately 3,500 birds, the eggs of which are distributedfor incubation. The official credit agency of the Governmentdistributes breeding stock from this station on credit. The RhodeIsland breed has certain disadvantages, however, mainly a certainsusceptibility to diseases. Furthermore, lovv- hatchability often.occurs. The recently improved. Leghorn breed has proved to bevery adap-table to the existing con.ditions in the country; however,it is less satisfactory than time Rhode Island Red, which is a dual

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purpose type. Recently also Sussex and Nelv Hampshires havebeen imp orted

Since -there is little balanced feeding in Paraguay, poultrydepend practically entirely on grains and pasture. Just recently,an attempt was made to produce poultry mashes from locallyproduced feedstuffs and imported meat meal. There are severaldiseases of considerable importance, such as fowl cholera, pullo-rum and fowl pox, but so :far Paraguay is free of Newcastle di-sease, and precautions are taken by the Government to preventits introduction.

In Trinidad and Tobago, Rhode island Reds, \Vhite Leghornsand. New Hampshires are being used to a considerable extent inbroiler production. A large part of the poultry in the Colony isowned by peasants and the birds are allowed mostly free range.However, -there is a noticeable trend towards the purchase ofimproved locally produced feeds. On the other hand, the largebroiler producers feed, almost exclusively, imported feeds. Thereis one local firm manufacturing feed and the Marketing DivisionOf the Department of Agriculture also sells poultry feeds.

No standard types of poultry houses are used. Peasant-ownedbirds roost: in trees. Certain poultry raisers have their ownplans for houses. Batteries are used for broiler production,but one raiser runs a series of broiler houses. A. few areadoptin.g the deep litter system. in view of the diversity ofownership and management, the possibility and need ofstandard housing is questionable. Specific regulations deal withthe control of Newcastle disease. Regulations also cover the fin.-portation of live and dressed poultry. 'Vaccination against NCW-castle disease, fowl pox and infectious bronchitis is practised. TWOstations within the Department of Agriculture also give attentionto poultry problems. Laying tests have not -yet been carried out,and no poultry experts at present are included in the extensionservice. The Department of Agriculture has published bulletins

A Few Practical Suggestions on. Poultry Keeping in Trinidadand Tobago, " and. " Observations on Simultaneous Vaccinationin the Control of Fowl and Newcastle Disease. There is a localpoultry association which has a beneficial influence Oil the industry.Co-operative societies do not exist.

In the United States of America, poultry production providesapproximately 10 percent of the gross farm income. There arehighly specialized production establishments where many thou-sands of birds are prod-aced on one " farm, " and chickens areraised on 78 percent of all farms. The principal grain producingstates are also the leading states in volume of poultry and eggsprodticed, yet .most poultry are fed manufactured feeds. Of alllaying hens 31 percent are in flocks of less than 100 birds, 25 per -

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cent in flocks of loo to 200 birds and less than 10 percent inflocks of over 1,600 birds.

The great majority of chickens produced in the United Sta-tesof America come from five breeds: New Hampshire, White Leg-horn, White Rock, Barred Rock and Rhod.e Island Reds, in thatorder. In recent years a significant number of birds have comefrom cross-matings. It is estimated that approximately 20 per-cent of current chick production is from cross-mated parent stock.Five years ago this percentage was probably no greater than 12.

There are only a relatively small number of primary breedersand -there is a tendency for the number to decrease and the sizeof operation to increase. Perhaps the most significant recentdevelopment is that many prim.ary breeders are now em.ploying,highly trained geneticists to conduct their breeding programs.This trend has increased the rate at which research informationfrom experiment stations and the U.S. Department of Agricultureis put into practice. In addition, the geneticists employed bycommercial breeders are contributing to the general fund ofknowledge on poultry genetics and breeding meth.ods.

There are many poultry breeders' nrganizations. The oldest isthe American Poultry Association which was organized for thepurpose of standardizing varieties.

The U.S. Record of Performance Federation is strictly a breed-ers' organization comprising the Record of Performance (R.O.P.)breeders participating in the National Poultry Improvement Plan.In most states there is an organization of the breeders and hatch-eries participating in the National Poultry Improvement Plan.The members have a voice in determining the provisions of thePlan on a national basis, and in. the establishment of state-operat-ing rules.

Breeders and hatcherymen are represen.ted in two nationaltrade organizations: the American Poultry and Hatchery Federa-tion, and the IN ational Turkey Federation. There are state affil-iates to these organizations, and numerous other state and regionalorganizations in which poultry breeders are an integral part.

State and area poultry breeders' schools have been an importantstimulus to poultry breeding in the United States of America.The Massachusetts 'Poultry Breeders School, one of the first, hasbeen held annually since 1927. Two of the well established regionalschools held annually are the Midwest Poultry Breeders Confer-ence and. the Pacific Poultry Breeders Round Table. The National.Poultry Breeders Round Table, sponsored by a group of large pri-vate breeders, is another well established breeders organization..

There has been no substantial trend toward breeders co-opera-tives. The breeding is handled almost exclusively by privatebreeders, many of which are large corporate organizations. Of

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the estimated 8,000 baby chick hatcheries, only a little over 100are co-operative hatcheries.

Standard egg-laying tests, comprising 13 selected pullets perentry, have dem.onstrated the possibilities of high egg produc-tion, and thus con.tributed to the development of the poultry indus-try in the United States. The first tests were established at Storrs,Connecticut, an.d Mountain Grove, Missouri, -1911. Within thenext 20 years, more than 40 tests were opened, but the numberdeclined to 15 in 1950 and 8 at present. Results in the standardlaying tests, which were based on highly selected samples of birds,did not accurately reflect the average production of the entran.t'sstock. Random sample tests were started with an objective ofovercoming this weakness. The entries in such tests are a ran-dom sample of hatching eggs or chicks, -taken by a disinterestedparty, of the grade of stock to be tested. There is no cullin.g andthe tests are usually continued for 500 days from the date ofhatch. The first random sample egg production tests were con-ducted at Pomona, California, in 1947/48 and 1948/49. The ac-ceptance of su.ch tests is indicated by the fact that there werein operation 6 tests of this type, and 2 additional tests havebeen announced for 1955.

Consistent with the interest in commercial broiler productionin the United States, 8 meat production tests have been estab-lished. There is a growing interest in random sample turkey pro-duction tests. One such test was conducted in Texas in 1954,and at least 1 additional test was bein.g planned for 1955.

The Nation.al Poultry Improvement Plan, a federal/state programinitiated in 1935, has been a major factor in the development ofthe poultry industry. Approximately two-thirds of the nation.'shatching egg flocks and hatcheries voluntarily participate in thePlan. The program provides for the classification of flocks, hatch-ing eggs, chicks and poults with respect to disease control (Pul-lorum and typhoid) an.d breeding improvement. Four of the breed-ing improvement classifications are based on Record of Perform-ance. The R.O.P. program includes supervised trap-nesting andpedigree breeding on the breeder's farm an.d performance recordsin random sample tests.

Approximately 61 percent of the estimated 1,680 millionchickens raised in the United States of America in 1954 werebroilers reared in confinement on commercially mixed food.The other 39 percent, comprising 621 million chickens, which include414 million laying hens and pullets, were raised on farms. Thesechickens consumed an estimated 21.8 million tons of feed. Mixedfeed supplied about 13 million -tons, leaving 8.8 million tons to besupplied by grain grown on the farm, home-made mashes andpastures. It is reasonable to believe that the smaller farm flocks

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and backyard flocks (under 50 layers) obtained some feed as tablescrap, bugs and insects. However, in the over-all production ofmeat and eggs, the quantity of food the chicken obtains by sca-vengin.g is negligible. In the smaller farm flocks, the value ofgood pastures as a feed supply should not be overlooked. Al-though the proportion of grass that the chicken can effectivelyutilize is small, it is of economic importance because it is estim.atedto save 10 percent of the grain requirements and supply vitamin Aand riboflavin. However, feed from a carefully prepared an.dplanted pasture cannot be considered s cavenger material.

The great majority of turkeys are raised under comm.ercial sys-tems, and do not have access to any food other than the m.ashesand grains fed them.

- An estimate of the poultry population and of the total food'consumed when compared with the estimated production of for-mula feeds in.dicates that at least 60 percent of the feed consumedby poultry is supplied by commercially mixed feed.

Owin.g to the varied climates encountered in the United Statesof America, poultry- houses are not limited to one or two types.Factors, such as kind of operation, and size of flock, also enterinto the planning of poultry houses. Building design differssomewhat for broiler production from that for egg production. Anoteworthy shift in recent years is to keep hens confined in indi-vidual cages. For farm flocks, poultry houses are relatively smallone-storey structures; for many of the larger flocks the housesare multiple storey. Light construction has been used for manyyears, but considerable loss has been suffered in those structuresduring the past few years owing to storms. This experience seemsto be resulting in more substantial design for poultry houses,effectively tied from roof to foundation.

In the southern part of the United States of America, indi-vidual cages are placed under comparatively simple shades. Side-walls and floors are not used. The nests and supports are so ar-ranged that removal of droppings may be done easily. Poultryhouses in the colder parts of the country are enclosed and frequent-ly well insulated, but most of these houses are equipped withwindows on at least two sides. These are opened for cross-venti-lation during summer months. In some of the northern states,houses are designed to keep the chickens occupied most of thetime over utility pits. Feeders, waterers and perches are locatedso that waste and droppings fall into the pits. These pits may beclean.ed either manually or mechanically.

Although poultry houses design has been linked closely withthe protection of birds from cold, there is accumulating evidencethat protection from excessive heat is fully as necessary. Ex-tremely hot weather (above body temperatures) often kills large

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numbers of birds. Protection sometimes is provided by sprayingthe roofs with water during the heat of the day. A plan exchangeservice is maintained whereby plans for poultry houses developedin any part of the country are catalogued so that interested poul-trymen may select a design most suitable to the particular climate.The catalogs are held in country agricultural agents' offices andplans considered suitable for a given state are available throughthe Agricultural Extension Service of that state.

National disease control programs developed by the U.S. De-partment of Agriculture for the preven.tion of poultry diseasesare the pullorum disease and fowl typhoid eradication programs,which are a part of the national poultry and turkey improvementplans, and are conducted under the auspices of the Animal andPoultry Husban.dry Research Branch of the Agricultural ResearchService, U.S. Department of Agriculture, the co-ordin.ating agencyfor the entire program. They are conducted within 47 of thestates on a voluntary basis. The Department also sponsors re-search for the control of such other diseases as infectious bronchitis,chronic respiratory disease, tuberculosis, and avian leucosis on a6o-operative basis with some of the states; however, he organiza-tion for such control is limited to the states. Basically, the controlof all poultry diseases is a problem left to the individual statesand is only done on a national basis, as in the case of pullorumdisease and fowl typhoid, when it is mutually agreed upon, exceptin the case of imports of fowl of all kin.ds. Department regulationsdesigned to prevent the introduction and dissemination of poultrydiseases of foreign origin include:

for poultry intended for importation from any part of theworld (except Callada), the importer is required to obtaina permit before such poultry are shipped from the point oforigin;all poultry- offered for importation must be accompanied bya certificate from a salaried veterinary officer of the nationalgovernment of the country of origin, shoiving freedom fromcertain diseases and exposure thereto for 60 days beforeshipment;veterinary inspection at a designated port of entry;quarantine (except for poultry from Canada) for not lessthan 15 days at the first port of entry in the United Statesof America.

Statutory authority is available, to eradicate certain diseases,should they gain entrance to the United States and threaten thepoultry industry. In 1924, an outbreak of fowl plague (Europeanfowl pest) was eradicated through strict quarantin.e measures, and

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in 1950, an outbreak of Asiatic Newcastle disease was quicklyeradicated through quarantine and slaughter of diseased and ex-posed birds, with indemnities to own.ers of such birds.

Regarding recent advances in poultry research, the followingsummary of information is indicative of some of the major develop-ments in the United States of America.

The united attack of the state agricultural experiment stationsin each of the four regions of the country North Central,Southern, Western and Northeastern in close co-operation withthe U.S. Department of Agriculture appears to be the logical wayto reach a sound and more rapid solution of poultry breedingproblems too hard to solve by individual breeders and institutions.In two of the regions, testin.g stations have been established forevaluating, under uniform conditions, the inbred lines of chickensdeveloped in the various states, as to combining ability to formhybrids with high economic qualities. In two regions the co-ordi-nated research is on chickens exclusively; in another turkeysonly, and in the fourth region, both chickens and turkeys.

A short cut in the breeding procedure is now being studied atthe Indiana Station by research workers of the U.S. Department ofAgriculture and Purdue University. Using the very prolific fruitfly as a test animal, instead of the chicken, the relative effectivenessof various systems of breeding according to egg size and produc-tion is being determined.

Normally, in prolonged breedin.g programs the qualities forwhich selection.s are made increase up to a point, after which,in many instances, the rate of improvement levels off. In order tobreak through the leveling-off period and to obtain additionalgains, X-ray treatments are administered to produce mutationsin the chromosomes. These treatments will be given through fivegenerations, an.d the genes and chromosomes of different individuals,unified and recombined.

A non-broody line of Rhode Island Red chickens has beendeveloped by the Massachusetts Station, which has shown completefreedom from the broody instinct through several ge,lleration.s. TheMaryland Station is breeding flightless chickens that have win.gs,but lose the long pinion feathers permanently at the time of firstmolt. New breeds of chickens that thrive well at high altitudesare being developed at the Wyoming Station.

The recent use of radio-active isotopes in poultry has beenfound advantageous by the Florida and Tennessee stations andthe U.S. Department of Agriculture in studies on problems involvedin growth, development and reprodu.ction. Wh.en. S35-labeledsodium sulphate was injected into newly hatched chicks, about 32percent of the sulphur was still present in the chick six days later.The sulphur was divided between two fractions: about 10 percent

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has taurine and about 22 percent associated with connective tissue..No radio-active cystin.e was detected. When 0.5 percent sodiumsulphate was fed to chicks on a sulphur deficient diet, a growth sti-mulation was obtained. The results obtained by U.S. Departmentof Agriculture workers shed some light on nutritional metabolismin the chick which is at present very poorly understood.

A vast amount of new knowledge about growth factors andantibiotics has opened up a wide horizon of research activitiesthat are bound to bring great changes in poultry production.According to the New York (Cornell) and Washington stations, thegrowth promoting factor, B12, seems to exist in several forms. Anumber of other factors, most of them important for growth ofbirds, are still un-identified. Four such unidentified growth factorshave been foun.d in a liver preparation. In addition., a " wheyfactor and an " alfalfa " factor are known to exist. Also chickshave a dietary requirement for either specific fatty acids, or foran unknown vitamin or vitamin.s present in vegetable oils, or both.A biological assay- was developed by the U.S. Department of Agricul-ture workers for determining the presence of an unidentified chickgrowth factor in feeds. Using this method, a factor(s) in condensedfish solubles was found. Efforts to isolate the factor(s) have result-ed in a concentrate which, at 0.009 percent of the diet, gives agrowth response equal to 4 percent fish solubles (a 250 to 300fold concentration). Progeny performance trials showed that .theunidentified factor is transferred from the hen to the chick whenthe breeder diet contained fish solubles. Further work is in pro-gress to concentrate the fish solubles factor and possibly establishits identity.

Although, according to the Illinois, Maryland and Washingtonstation.s, the value of " surface active agents " in stimulating growthis still doubtful, that of antibiotics is well established, as shownby research at the California, Pennsylvania, Texas and other sta-tions. Antibiotics apparently do not serve as nutrients but im-prove the microflora of the digestive tract, thus encouragingsynthesis of nutrients or permitting more complete utilization ofthose in the diet. Research at the Maryland and Texas stations,and at the U.S. Department of Agriculture shows that the feedingof an.tibiotics does not appreciably improve the growth of .chicksreared in a very clean en-vironment, whereas it causes a markedresponse in a normal environment.

The Storrs, Connecticut, Maryland, Utah stations and theU.S. Department of Agriculture have shown that a significantincrease in growth rate, improvement in feathering, and increase inefficiency of feed utilization can be obtained by supplementingcertain diets wi-th additional methionine, one of the essential aminoacids.

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The growth depression of alfalfa meal seemingly is due tosaponin.e, w-hich can be counteracted largely by cholestrol orremoved by extraction of the meal with hot water, as in.dicatedby research at the California Station.. The U.S. Department ofAgriculture has shown that the growth-inhibitin.g properties ofalfalfa vary widely with location of production, variety and cut-ting.

Successful growth and reproduction of chickens has been obtainedoil a diet of only ladino clover (as range), ground corn, and mm-erais, accordin.g to the Ohio Station. That grassland economizeson feed is concluded from research by the Michigan, Pennsylvaniaand Vermont stations.

At the Storrs, Connecticut station, a high incidence of encepha-lomacia has been produced in chicks, hatched from hens deficientin Vitamin E and raised on a low Vitamin E diet containing 2percent " Vitamin A and D feeding oil, " but a remarkableprotection is obtained by feeding an antioxidant (diphenyl-para-phenyl-enediamine) used to protect carotene in feeds.

The Wisconsin Station has found that a wood waste productfrom the paper industry, torula yeast, when replacing part of thesoybean oil meal in a chicken diet, will produce good growth.Wood sugar molasses, corn molasses, and low grade sugar, willreplace a part of a cereal grain in hen and chicken rations suc-cessfully, according to the Arkansas, Hawaii and Oregon station.s.Vegetable wastes, such as discarded broccoli, kale, rhubarb, spinachan.d carrots, when converted into measl or a homogenized fermentedmixture, have been foun.d by the Delaware and Maryland stationsto substitute well for alfalfa meal. Chicken scrap has comparedfavorably with other protein concentrates in a chick diet at theIowa, Nebraska and Wisconsin stations.

According to the HaNvaii Station, brackish water containing ashigh as 400 grains of salt (NaC1) per gallon, given to chickensin addition to a diet having 0.5 percent salt, had no adverse effecton feed consumption, body weight, or survival. Thus, it will bepossible for poultry to be raised on land in Hawaii where thesalinity of the water is high (up to 100 grain.s of salt per gallonof water).

Regardin.g physiology, there are four different families of bloodgroup characters in chickens that reflect hereditary biochemicaldifferences in the protein structure of their blood cells. By compar-ing the performance of chickens with these different blood types,the Texas Station has found it possible to determine whether theblood group genes also affect characters of economic importance.

Hen.s whose eggs show lo-w fertility, usually are able to maintainlive spermatozoa in their reproductive tracts only about on.e day,whereas those with high fertility can main.tain spermatozoa for 14

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days or more. The New York (Cornell) Station discovered that,by pretesting the females, it is possible to eliminate those in-which duration of fertility is low.

The Puerto Rico Station also found that time of hatching hasan important bearing on sexual maturity and egg production ofpullets, regardless of the relatively uniform climatic conditions onthe Island which has no seasonal extremes. Female chicks hatchedin February, for example, had earlier sexual maturity than thosehatched in March. The poultry breeder in Puerto Rico, therefore,must consider a correction or allowance for date of hatch whenbreeding for early sexual maturity.

The reticulo-endothelial system is concerned with blood-cellformation, bile formation, straining off fatty materials, phagocyticdestruction of blood cells, an.d the metabolism of iron and pigment.On the theory that this system can filter congo red particles fromthe blood stream in very much the same manner as disease-produc-ing viruses, the Alabama Station has compared the ability of dif-ferent breeds of chickens to filter out such particles. The evidencethus far indicates that disease resistance may be associated withthe reticulo-endothelial system.

It has been demonstrated by the U.S. Department of Agriculturethat the ruptured follicle plays an important role in controllingtime of lay of the egg (or ovum) which it previously contained.Following removal of the ruptured follicle, the egg was retainedin the uterus far beyond the time of normal lay. It has beenshown recently that removal of a part (approximately half) ofthe ruptured follicle results in a contrary effect, the egg beinglaid prematurely by 12 to 17 hours before the hour of expectedlay. These findings afford additional evidence that the rupturedfollicle normally participates in the control of oviposition. Workis being continued to ascertain the manner in which the rupturedfollicle exercises its regulatory function.

Management problems are also receiving full attention. Ac-cording to the Pennsylvania Station, the replacement of small,scattered laying pens with larger units in a more orderly compactarrangement; the removal of partitions between pen.s; the groupingof nests near the pen doors or the addition of nesting rooms;the installation of floor feed-boxes with overhead chutes, or, inlarge units, of a mechanical mash feeder; and the use of feed carriertrucks and frost-protected automatic waterers all have provedto be valuable as labor and time savers. A utility unit consist-ing of an automatic feeder an.d waterer installed between theroosting perches so that the chickens eat, drink and roost over adroppings pit, together with a mechanical cleaner for removal ofdroppings, has been designed.

The Ohio Station has found that the long-time use of compost

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litter for chickens under proper conditions causes no " build-upof diseases or parasites. Actually, less difficulty is experiencedfrom coccidiosis with compost litter than with bi-weekly replace-ments. Also, compost litter apparently is a source of special nutri-tional factors for confined birds. For turkeys, however, compostlitter is dangerous, so fresh litter should be used and changedfrequently.

A number of the diseases that formerly plagued the poultrymenof the United States of Am.erica are now being successfully com-batted. Roup, aspergillosis, tuberculosis, pox, pullorum and coc-cidiosis are no longer considered major problems. Rickets, perosis,gout and other nutrition.al disorders also cause little concern.Nevertheless, losses appear to mount and new diseases are beingrecognized. Lymphomatosis or leucosis has been a cause of lossamong adult chickens. U.S. Department of Agriculture resear-chers have recently found a test to detect visceral lymphomatosis(big liver disease) in live chickens. Respiratory disease andair-sac infection (chronic respiratory disease) are important. TheU.S. Department of Agriculture and the states have extensive co-operative research programs on these diseases.

In Uruguay, probably more than 75 percent of the total amountof poultry and eggs produced comes from general farms on -whichthe poultry enterprise is only a side-line business. Chickens arekept in complete liberty, usually in flocks between 50 to 200 birds,scattered around the barns and being almost en.tirely dependentupon loose grains or any other feed they can pick up in the fielksupplementary rations are given in some cases and during certain.seasons.

There is a common belief among farmers that " criollos " (indi-genous) hen.s are hardier an.d even more productive than pure-breds. The introduction of valuable production breeds like NewHampshires, Rhode Island Reds and Single Comb White Leghorns,also appears to be hampered by the diffusion of fancy birds. Since1951, the Bureau of Animal Industries prohibits the importationof hatching eggs or chickens from all countries, that are not offi-cially declared free from Newcastle disease.

There is a close relationship between the corn crop and itsprice and the number of chickens kept on general farms duringthe same year. Farmers seldom buy any feed for their chickens.There are no specialized commercial poultry feed manufacturers,but some firms, as a side-line, supply customers with ready-to-usefeed for their birds. Commercial poultry farms depend almostentirely on a subsidized ration sold by the Government at differentprice levels an.d limited to those who have been operating poultryfarms for several years.

Corn, is the main grain for poultry followed by oats, barley,

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sorghum, and wheat milling by-products. Owing to the relativeabundance of animal proteins (meat scraps, tankage, liver meal,bone meal, fish meal), -there is little use of plant protein foods,of which sunflower and linseed oil meals are mainly available.Brewer's dried yeast and dried whey are also produced in thecountry.

On general farms, neither special poultry houses nor equipmentare used, whereas specialized poultry farms make comparativelylarge investments in buildings and equipment. In view of thefavorable climate, there is no need for closed poultry houses;except brooder houses, which must protect the chicks againstheavy rainfall and strong winds that occur from time to time.

The Bureau of Animal Industries has set up a laboratóry inwhich, among other work, poultry diagnostics are performed andvaccines and pullormn antigen prepared. Disease diagnostics arealso made by the College of Veterinary Medicine in Montevideo.

The Government of Uruguay has also established within theDepartment of Agriculture a poultry service, which is operatinga poultry plant on one of the state-owned farms. This stationsells limited numbers of hatching eggs, baby chicks and breedingstock at low prices. It is also in charge of the R.O.P. program.Laying contests are organized each year. There is not yet anyorganized extension service on poultry in the country. Effortsare being made to issue leaflets and other publications relatingto poultry. There are three main poultry organizations in thecountry. Poultry co-operatives have not been successful so far,and none exists at present.

Experimental work has been carried out on the increase ofweight and feed conversion rate of New Hampshire chickens andtheir crosses from 8 to 14 weeks of age. Four hundred andthirty-seven chickens, New Hampshire, Plymouth Rock/New Hamp-pshire and White Leghorn/New Hampshire, in two groups, bothcoming from the same stock and bred in the same form, were con-trolled periodically in their weights from the amount of feed con-sumed and finishing after 14 weeks (Achenbach, 1954). Up to 14weeks, the feed conversion rate was 4.67 and 4.78, respectively, forboth lots. To the 12th week, this relation was more favorable andbelow 4. In the partial period from the 12th to the 14th -week,it increased to almost 10 in one case and to more than 11 in theother. This would indicate the advisability of initiating the mar-keting of the chickens at about 12 weeks, if the m.arket conditionswere favorable. The average weight after 14 weeks was 4 lb.,with a maximum of 5 lb. for the first lot and 34 lb. for thesecond. The average weight of the pure New Hampshire chickenswas higher than the crosses in the first lot, but lower in the se-cond, in which the crosses exceeded the purebreds by more than

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101/2 oz. each. The finishing of the pure New Hampshire wasinferior to the crosses, especially in lot No. 1. The best chicken&resulted from the crosses between a White Leghorn cock and a New-Hampshire hen.

In Venezuela, specialized poultry production is relatively new-,Since the establishment of v,rell equipped poultry farms was start-ed only about ten years ago. Earlier, poultry production was ofa purely domestic type and complementary to other agriculturalactivities. Since 1946, however, the demand for eggs and meathas considerably increased, and large amounts had to be imported.Hence, the Government decided to support the import of babychicks, which were then reared in the country. At the same time,the Government allocated credits for the establishment of poultryfarms for meat and egg production. These measures resulted ina reduction of imports, first of frozen poultry meat, and then ofbaby chicks; and since 1949, it has no longer been necessary toimport' table birds; however, chicks are still imported. The mostcommon, irnproved breeds are New Hampshires, Plymouth Rocksand Rhode Island Reds, but there is still a large stock of nativebreeds in the country. Balanced feed rations are used in industrialestablishments, but they are not yet applied on domestic farms.At present, there are six plants, for the production of compoundfeeds.

The Government of Venezuela takes an active interest in thethe control of diseases through its veterinary services. Further-more, certain vaccines, particularly against Newcastle disease, areavailable, and there is a laboratory which carries out some researchwork in poultry diseases. However, there is no specific poultryexperimental station in Venezuela. Experiments are carried outat the Faculty of Agronomy of the Central University of Venezuela,and at the Agricultural School at Maracay. At present, work isin progress on a cross between Leghorn and " Piroca blanca"which is a native breed. Favorable results have been obtained inthe fifth generation, i.e., a Monthly average of 21 eggs, sufficientbody weight, resistance to certain diseases and, in general, agood adaptability to the environmental conditions.

The most efficient support of the poultry industry has been ofan economic nature, i.e., credits for the establishment of poultryplants, and import duties. Furthermore, the Ministry of Agri-culture organizes a certain number of poultry courses throughoutthe country, and livestock shows usually include a poultrysection. Most of the poultry producers of the country aremembers of one of the following associations: Co-operativa Nacionalde Granjeros (Caracas), Asociación Venezolana de Agricultura(Caracas), Asociación de Granjeros de Miranda (Estado de Mi-randa) and Asociación de Granjeros de Zula (Estado de Zula).

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Literature Cited Regarding Poultry

A CHE1NBACH, PEDRO VON, Boletín Informativo No. 520 del Ministeriode Ganaderia y Agricultura, Montevideo, Uruguay, 29 July 1954.

BYERLY, T.C. Role of Genetics in Adapting Animals to Meet Chang-ing Requirements for Human Food. Sci. Mon., Vol. 79, No. 5,pp. 323-32, November 1954.

ENGLER, H. Futterverwertung und Legeleistung beim Huhn. VIWorld's Poultry Congress, Vol. I, pp. 249-55, Leipzig, 1936.

FOOD AND AGRICULTURE ORGANIZA TION OF THE UNITED NATIO NS.Second World Food Survey, p. 44, December 1953.

LEVINE, P.P., Use and Abuse of Medicants in the Feed. World'sPoult. Sci. J., 10 (2): 171, 1954.

PHILLIPS RALPH, W. Report of the Second Inter-American Meeting onLivestock Production, FAO Development Paper No. 33, pp. 23-25,Food and Agriculture Organization of the United Nations, Rome,Italy. 1953.

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INTERPRETATION AND EVALUATION OFTHE RESULTS OF ANIMAL HUSBANDRY

AND VETERINARY EXPERIMENTS

The object of this chapter is to present an outline of themanner in which statistics may be used to increase the efficiencyof animal husbandry and veterinary experiments and to aid theresearch worker in making his interpretations of the results ob-tained. It is based on a paper prepared by Dr. H.O. Hetzer, inconnection with the Buenos Aires meeting.

Increasingly successful use is being made of the scien.ce ofstatistics in the various biological sciences, and the establishedstatistical methods can play an important part in solving many ofthe problems faced by the livestock industry, whether the pro-blems relate to breedin.g, feeding, pasture or disease control investi-gations. Many animal husbandmen and veterinarians have nothad detailed trainin.g in statistics. However, with a general under-standing of the prin.ciples outlined below and with the assistanceof mathematicians, they can readily apply the simpler techniquesin their research work. Such applications are already bein.g madein many institutions, and the importance of more atten_tion tothe application of statistics was recognized in the Baurii meeting.

Fisher (1930) defines statistics as a branch of mathematicsapplied to observational data, statistics being concerned primarilywith (1) the study of populations, (2) the study of variation, and(3) the study of methods of the reduction of data. Snedecor(1948) says:

Statistics have been called the technology of the scientific method.In the sequence constituting that method hypothesis, experi-ment, test of hypothesis the final stage is statistical... Unlessthe hypothesis is precisely stated, and unless the experimentproduces unambiguous information about it, the test is futileand conclusions are unclear.

Variability is one of the common characteristics of all livingmatter. Even when dealing with individuals raised under similarenvironmen.tal conditions, or with in.dividuals who are identicalin their inheritance, such as identical twins in cattle, for example,no two such individuals are ever exactly alike. As Cochran andCox (1950) point out, it is this sort of variation which introducesa degree of uncertainty into any conclusions that are drawn from

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experimental results. The implication here is that results obtainedunder one set of conditions are never duplicated exactly underanother set of conditions or, if obtained under the same condi-tions, the results from trial to trial may be so different at timesas to leave their reliability in doubt. The development of methodsfor evaluating this element of uncertainty and applying statisticaltests for the accurate summarization and interpretation of experi-mental data, constitutes one of the principal functions of sta-tistics, as applied to the various biological sciences. Anotherfield in which statistics have been increasingly helpful to the researchworker in the plant and animal sciences is in the planning anddesigning of efficient experiments. Statistics may thus be con.sid-ered to aid research in two important ways. One of these con-cerns the design of experiments and the principles which mustbe observed in order to permit the drawing of valid conclusions.Space will not permite mention of more than a few of the largenumber of statistical methods currently being used by researchworkers, but some discussion is included of the rules or stepsthat must be considered in planning experiments. Examplesillustrating some of the experimental designs which appear to beparticularly applicable to problems in livestock research are notedlater.

Planning of Experiments

Consideration should first be given to the essential steps whichare basic to successful experimentation. Cox (1951) once remarkedthat an ideal situation would be for every experimenter to knowhis science an.d the science of statistics. A similar view was ex-pressed by Snedecor (1950). In dis,cussing the steps involved inplanning an experiment, Snedecor pictures the situation as fol-lows:

The experimenter specifies the conditions in -which the trial (orexperiment) is to be performed -- materials and -treatments,together with genetic and environmental circumstances andthe measumerements that can be made. The statistician selectsor invents a plan (experimental design) which will furnish un-biased and unconfounded estimates with adequate precision.The experimenter conducts the laboratory or field work, takingpains to eliminate as nearly as possible all extraneous effects.If he is successful, the ensuing measurements will contain. theinformation for which the experiment is set up. The statisti-cian uses appropriate methods for extracting all the informationbrought into the data. Finally, the experimenter interpretsthis information in the light of existing knowledge in his science.

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It should be noted that Snedecor places considerable. emphasison the selection of an experimental design w-hich, as he expressesit, " will furnish unbiased and unconfounded estimates with adequateprecision. " In other words, the experiment should be designed soas to yield results which are both accurate and free of extraneouseffects, as well as precise in that they must be repeatable undersimilar conditions. There is a very important reason for thiswhich should be kept in mind at all times. The point is thatwhatever statistical methods are used, the-y- are only tools. Touse these tools su.ccessfully, or to extract the desired informationfrom an experiment requires that the experiment be so designedas to -yield results which provide reliable information on thepoints at issue; i. e. regardless of how refined or how elaboratethe statistical methods employed, they are powerless if applied toinadequate data or to data from faulty experimental designs.

Consideration should be given to the individual rules or stepsthat should be observed in planning experiments. They are (1)a statement of the objective, (2) a description of the experiment,and (3) an outline of the statistical analysis of the results. Thereare, of course, other things that should be considered before startingan experiment, such as applicability- of the results to the solutionof a particular practical problem (i.e., economic justification), ap-proximate total cost and availability of the necessary personn.eland materials, including animals, feeds, housing, pastures, instru-ments, tools, etc. While all of these latter items are important,it is assumed here that they have been resolved before the ex-periment actually gets under way.

The first step in planning an experimen.t is to state clearlythe purpose of the work. The principal objective may be inthe form of a question to be answered, a hypothesis .to betested, a relationship to be measured, or treatment effects to beestimated.

To illustrate the importance of sound planning, a statementby Cox (1951) may be quoted as an example of faulty experimen-tation. The results were brought to a statistician with a questionabout -testing the effect of different protein supplements on rateof growth in chicken's. That is, the investigator wanted to kn.owif the treatment differences were statistically significant, or, statedin more practical language, if the differences he attributed totreatments were real in the sense that they could not reasonablybe attributed to the vagaries of mere chance. The experimentalmaterial being chickens, and knowing that males grow at a fasterrate, on the average, than females, and that quantity, as well asquality, of protein may affect rate of growth, there should be nodifficult-y- in recognizing the fallacies of the experiment describedbelow.

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The layout of the experiment, as described by Cox (1951) wasas follows:

Six kinds of protein supplements were fed to young chicks toestimate their relative effects on gain in weight. All the chicksreceivin.g treatment A were kept in Pen A, and similarly chicksreceiving each of the other five protein supplements were keptin separate enclosures. The sexes were mixed in unknown ra-tios, and the supplements were used in equal weights irrespectiveof protein content. No record was kept of individual foodconsumption. Based on the statistical an.alysis, if the lot hav-ing Treatment A gained significantly more than the lot havingTreatment B, the answer might be (a) that the concentrationof protein in A was greater than in B, or (b) that there wasa larger proportion of males in Lot A than in Lot B, or (c)the environmental conditions were more favorable in Pen A,or (d) supplement A was more appetizing than B. This mancame to the statistician to ask about the merits of various testsof significance, and he was seemingly unaware that the differ-ences he was testing could not be identified and, therefore,were meaningless.

The reason, of course, is not that the man failed to state hisproblem correctly, but that he did not plan his experiment orselect his materials in such a way as to exclude or properly ac-count for the variability caused by differences in the amounts ofprotein eaten, the general sex differences in rate of growth, andenvironmental differences due to location.

The second step which should be considered in the planningof an experiment is, as previously mentioned, a description of thethe experiment. In other words, there should be an outline ofthe plan of work, including a statement of the specific treatmentsor methods to be tested, number and kinds of experimental animalsto be used, size and kind of housing, pastures or paddocks, va-riables or performance characteristics to be studied (body weight,milk and fat production, etc.), duration of the experiment and,finally, but no less important, an outline of the experimental designincluding a statement of the methods to be used in selecting andallotting the experimental units and treatment. It should be em-phasized that a description of the experiment covering the variouspoints listed above is perhaps the best insurance -against failingto reach the particular objectives of an experiment. Needless tosay, the experiment should be so designed and conducted as toprovide the desired information in the shortest possible time, andat a minimum cost in labor and equipment. Also, the experi-

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mental design should be as simple as is consistent with the re-quirements which must be met to arrive at accurate answers.

Regarding the selection of the treatments, it is, of course,necessary for the investigator to determine how they provideinformation on the point at issue. The term 'treatment' as com-monly used by professional statisticians, may cover a variety ofoperations, such as determining the effects of continuous versusrotational grazing in a pasture experiment or of self-feeding versuscontrolled feeding in a swine feeding trial, determining the nutri-tive value of different protein con.centrates, evaluating the pro:tective power of various biological products to a particular disease,estimating the response of different breeds to a particular set ofclimatic conditions, or tes-ting the effects of a combin.ation of dif-ferent factors in the same experiment. Investigations of the lattertype call for the use of factorial experiments. An importantfeature of factorial experiments in that the effects of two or morefactors may be studied simultaneously with the same precisionas where the effects of only on.e factor are studied. Another fea-ture of factorial experiments is that, in addition to providingestimates of the main effects, they provide information on inter-actions among treatments, which is impossible in single factorstudies. A factorial experiment might, for example, involve thetestin.g of various intensities of grazing in combination with theapplication of various concentrations of a given fertilizer.

Once the objectives and plan of work have been stated, it isnext desirable to in.dicate in outline form the method of analysisthat will be used in processin.g and summarizing the experimentalresults. This means that the experimenter should h.ave sufficientknowledge of statistics as to en.able him to select the methodsappropriate for testin.g a particular hypothesis, demonstratin.ginter-relation.ships and drawin.g inferences as to the generalizationand applicability of the experimental results. There are varioustextbooks which illustrate the statistical analysis appropriate forvarious experimental design., sorne of which are cited at theend of this chapter.

Methods for Increasing Accuracy of Experiments

Cochran and Cox (1950) distinguish two main sources of ex-perimental errors as follows: " The first is inherent in the experi-mental material to which the treatments are applied... The se-cond source of variability is lack of uniformity in the physicalconduct of the experiment, or, in other words, failure to standar-dize experimental techniques. " Since either of these two sources

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for errors may introduce considerable uncertainly into both theaccuracy and the precision of the results, it is highly desirablethat the investigator incorporate into his experiment any m.ethodor combination of methods that will increase its precision. Thebasic methods, as suggested by Cochran and Cox (1950) are (1)increasing the size of the experiment, (2) refining the experimentaltechnique, an.d (3) handling the experimental material so that theeffects of variability are reduced.

Size of Experiment

The usual method of increasing the size of an experiment isto include a larger number of replications. This has the effectof decreasing the error associated with the treatment providedthat the experimental units are allotted entirely at random tothe treatments. The reason for this is to en.sure that one -treat-ment is no more likely to be favored in any replicate than another.

An idea of how the number of replications affects the proba-bility of detecting a real difference between the average effects oftwo treatments, or, in other words, how many replications arenecessary in order that a difference of a given size is likely to bedetected as significant, can be obtained from tables as suggestedby Cochran and Cox (1950). Inspection of these tables shows that,in general, there is very little guarantee of detecting differences of10 percent or smaller with two replications. It is also apparentthat the larger the error that affects the observation for the indivi-dual unit, the larger number of replicates required for detecting a gi-ven size difference at a given probability. The larger the true differ-ence in the average effect of t-wo treatments, the smaller, in turn, isthe number of replicates generally required for a given probabi-lity of obtaining significant results. Thus, if we postulate the-true difference to have a certain value, and if -sv e have some ideaof the experimental error of our observations, we can, withincertain prescribed limits, ensure the most efficient size for theexperim.ent by estimating the required number of replications, assuggested by Cochran and Cox (1950). It should be emphasizedin this connection that the values given by Cochran. an.d Cox forthe number of replications required for obtaining a significant resultare estimates based on statistical theory. Consequently, thenumber of replicates required in actual practice may vary somewhatdepending partly on the precision of the estimate of the experi-mental error, and partly on the magnitude of the true difference.

With regard to the subject of replications, attention shouldbe called to a paper by Lucas (1950), in which he outlines thesteps in determining the size of paddock and the number of ani-

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mals per paddock necessary in studies on pasture an.d grazing.Based on expressions involving variances, cost factors and carryingcapacity, Lucas has developed formulae which make it possibleto arrive at the optimum n.umber of animals per paddock, andthe optimum number of replication.s for a n.umber of differentcon.ditions, such as where the varian.ce, cost, total n.umber ofanimals, or total number of paddocks, are specified. On applyin.gestimates for the various factors represented in the equations,Lucas finds the optimum number of animals per paddock to beabout 7 for nutritive value studies, about 3 for yield studies withother animals such as non-milking dairy cattle or beef cattle.This number is considerably lower than those customarily usedin grazing work. As Lucas points out, the common situation hasbeen to carry as many as 10 to 20 animals per paddock, and touse but one paddock per treatment.

As regards the number of replications or paddocks per treat-ment, Lucas states that there is little chance of detectin.g differencesof 25 percent or less where only 2 replications are used. He esti-mates that, as a general rule, at least 4 or 5 replication.s are ne-cessary if the true difference between two treatments is 20 percentor more. It appears that the n.umber of replications requiredwould be twice as large, at least, if the real difference were10 percent or less.

Refining Experimental Techniques

Another method of increasin.g the accuracy of experimentsconsists in refining the experimental -technique. Faulty or inac-curate scales may result in weight records that are continuallybiased, or increase the experimental errors to a point where theymay actually mask the difference between treatments. To avoidbiases such as those introduced by faulty equipment, or by impro-per handling of the experimental material such as wotild resultif a particular treatment were continually favored in successivereplications by some extraneous source of variation, it is essentialhat the principle of randomization be carefully considered in plan-ning the layout of an experiment.

As was first indicated by Fisher (1947), both replication andrandomization are necessary to obtain valid estimates of experi-mental error. While various restrictions may be imposed on therandomization, one occasion where there is need for randomiza-tion is whether treatments are allotted to the experimental ma-terial. In other words, care should be taken that each experimen-tal unit included in the trial has an equal chance of being subjectedto the different treatments. Sometimes, the experimenter may find

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that there is need for the application of randomization to otheroperations as, for example, in experiments in which the equip-ment introduces variation. It should be realized, however, thatthe need for randomization does not dispense with the use ofsystematic design for, as we shall see a little later on, many ofof the experimental designs being used today involve severalrestrictions on the randomization, which is indicated by a know-ledge of potential sources of bias.

As was in.dicated above, the principal objective in refiningthe experimental technique is to prevent errors such as those causedby faulty equipment. Mention was also made of ran.domizationas the device commonly used to provide unbiased measures of theexperimental error, as well as of the -treatment effects. Otherrefinements may involve the development of more accuratemethods of measurement, more adequate control over externalenvironmental influences such as those due to changes in season.alor climatic factors, or greater care in the selection of the experi-mental. materials and treatments, so as to ensure that the ex-perimental animals, pastures, soil types, etc., are a representativesample of the population about which inferences or gen.eralizationsare to be drawn. 'While many examples could be given to illustratethe above points, two examples are cited which are of particularin.terest because of their potential value in improving the qualityof livestock research. One of these pertains to the improvedmethodology which is now bein.g developed in estimating grazingcapacity of ranges, as discussed by Stoddart (1952), and the otherconcerns the increase in the efficiency of feeding experiments withdairy cows, by use of the method of equalized feeding, as reportedby Lucas (1943). There appear to be no published data as yetregarding the relative in.crease in accuracy that might result inestimating stock carrying capacity in terms of digestible nutrients,for example, but Lucas finds that to demonstrate a given differencebetween treatments in dairy cattle as statistically significant it wouldrequire only about one-fourth as many animals when using equa-lized feeding as when using the ordinary method. This is an ex-cellent example of how gains in precision., obtained by refin.ementsof technique, may s-ubstantially reduce the cost of an experiment.

Another method by which precision may be increased is byeliminating or controlling the variation due to tangible factorsover which the experimenter has no immediate control. In certainexperiments, it may be possible to obtain measurements on vari-ables which are known to affect the performance of the experimentalunit. In an experiment designed to determine the effects of dif-ferent protein supplements on the rate of growth of pigs, for exam-ple, their initial weights may affect their subsequent performance.As it may n.ot be possible or deisrable to equalize the initial

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weight of the pigs on the different treatments, adjustmen.t of theobserved increases in weight by the technique kn.own as the ana-lysis of co-variance will largely eliminate the effect of this variablefrom the estimates of the treatment effects. A similar approachinvolvin.g the analysis of co-variance technique would be appro-priate in studies on milk production in cattle, for example, wherefactors such as age of cow, initial production rate or stage ofgestation, con.tribute to the variation of milk yield.

Proper Handling of the Experimental Material

This is the third im.portant method by means of which theexperimental error may be reduced. The approach is essentiallythat of choosing or inventin.g an experimental design which willprovide the maximum amount of information per unit of cost.Since there may be limitations on funds and facilities, the choiceof a particular design may be more or less dictated by prevailingconditions. It is impossible', therefore, to single out any onedesign as most efficient. Also, the relative efficiency of a givendesign will depen.d on the uniformity of the experimental material,as well as the number and relative importan.ce of extraneous sourcesof variation. Before deciding on a particular design, it will usuallybe desirable, therefore, to secure as much information as possibleon all potential sources of variation so that provisions be madefor their control in planning the final layout. Frequently, it ison the basis of such information that a particular design is fi-nally selected.

An example of the type of exploratory work which may helpin selecting a design is the study on " Factors Affecting Rate ofGain and their Relation to Allotment of Pigs for Feedin.g Trials,,"by Miranda, Culbertson an.d Lush (1946). These workers reportedthat 21 percent of the total variance in their data was associatedwith differences between breeds. Litter differences accoun.ted for29 percent of the total variance, or 37 percen.t of the 1,Tariancewithin breeds, while 9 percent of the variance -within litters wasdue to the difference between. sexes. The intra-litter correlationbetween initial weight and gain was 0.24. Based on the abovefindings, Miranda et al. concluded that, in-so-far as rate of gainis concerned, breed and litter might well be considered in allot-ment but that the effects of sex and initial weight were too smallto be of practical importance or to need correction. It wouldseem, therefore, that a feedin.g experiment with pigs might beimproved by allotting an equal number of pigs from each litterto each of the treatmen.ts, thereby balancing the treatment groupswith regard to litter. By allottin.g the treatmen.ts on this basis,

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other factors, such as breed, age and pre-trial environment are auto-matically balanced.

Experimental Designs

Only a few of the experimental designs from which one maychoose are discussed here, with emphasis on those which aregenerally considered to be most useful in livestock research.Treatises as those by Cochran. and Cox (1950), Goulden (1952),Lucas (1948) and others have been drawn upon for this purpose.

As Lucas points out, animal science experiments of the feedingand nutritional types may be considered as falling into either ofof two classes, i. e. " continuous trials " an.d " change-overtrials. " In the continous type of trial, an animal is subjectedto a single treatment throughout the duration of the experiment,while in the change-over type, an animal receives in sequencetwo or more treatments. It is eas-y to visualize situations whereboth types of experiments might have a place in managementstudies, pasture and grazing studies or disease and parasite controlstudies. It is not possible here to go into the advantages anddisadvantages of the two types of trials, except to point outthat by using change-over trials, the number of observations pertreatment and/or the number of treatments can be increased,-without having to increase the number of animals.

Complete Block Designs

Within both types of trials as mentioned above, a number ofdifferent design.s may be employed. To avoid confusion, it isdesirable to discuss these, using the names by which they aredecribed in most statistical textbooks. Classified broadly, ex-perimental designs fall into one of two classes, (1) complete blockdesigns, or (2) incomplete block designs. Applied to animal ex-perimentation, the term " block " generally denotes a group ofanimals similar with respect to one or more factors, either in.herentto the animals, or associated with the environment (Lucas, 1948).Complete block designs are characterized by the fact that eachblock or replicate contains a complete set of -treatments, whereasin incomplete block designs the number of treatments is largerthan the number of units per block.

In a completely randomized design., -which is the simplest -type,the animals are allotted to the treatments completely at random.This type of design has certain advantages in that any numberof treatments and replicates may be used. The principal disad-

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vantage is that there is no attempt to reduce the experimentalerrors, as might be the case if ran.domization were restricted sothat all animals receiving a giv-en treatment were similar in everymajor respect to those receiving another treatment. In order to-take care of the situation, some investigators have followed thepractice of allotting the animals so as to " balance " the effectsas factors such as breed, age, sex, condition., initial -weight, etc.,among the treatment groups. This procedure has been criticizedon the grounds that the variation within lots is made larger andthat between lots is made smaller than it would be if the animalswere allotted entirely at random. It is maintained, therefore,that the variation within lots is no longer valid for testing thesignificance of the treatment effects.

Randomized block designs differ from completely randomizedor ungrouped designs in that the animals are first divided intogroups coinciding with some major source of variation. Sub-divisionis made so that the number of animals in a group is equal to thenumber, or a multiple of the number, of treatments. The animalswithin each group are then allotted to each treatment at random.Usually several such groups are needed to obtain an estimate ofexperimental error. This is probably the most commonly useddesign in livestock research an.d many examples could be cited toillustrate its usefulness. In studies involving different breeds ofcattle or sheep, e.g., animals belon.ging to the same breed wouldlogically be considered as con.stituting a block. By applyingthe proper statistical methods, variation due to breed effectscould -thus be removed from the experimental error and therebyfrom the errors of treatment effects. Other applications of thistype of design might be appropriate in situation.s in which in.suf-ficient n.umbers of animals at a given time or place make itnecessary to conduct experiments over a period of intervals or atseveral places. In such cases, the periods or locations wouldconstitute the blocks.

The latin square design is basically a randomized block design.In the latin square, however, the treatments are arranged in com-plete replications in two ways, the grouping being done so as toprovide for control of two differen.t sources of variation simul-taneously. Another feature of the latin square is that the numberof replications always equals the number of treatments. Thus,if four treatments were being compared the design would be asfollows:

ABCDBCDACDABDABC

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where the letters represent the treatments. It will be noted thateach row and column contains a complete set of treatments, therebyfulfilling the requirements of double restriction. In an animalfeeding experiment of the continuous variety, the rows may cor-respond to four different farms or four breeds, while the columnsmay represent four kinds of housing or pastures. With an arrange-ment of the treatments, as indicated above, possible sources oferror due to variation between farms, breeds, housing or pastures,will automatically be eliminated from the estimates of treatmenteffects. In replicating the experiment, it is, of course, desirableto use a different arrangement of the treatments so as to mini-mize the danger of confounding. While there is a definite placefor la tin squares in livestock experiments, it should be noted thatthey are usually impractical when the number of treatments islarge. The same is true if the number of treatments being com-bined is less than four, unless the plan provides for two ormore replications.

The simplest change-over trials involving application of thelatin square, are the so-called switch-over or reversal designs, inwhich two treatments, A and B, are compared in two sequences,as follows:

SequenceI 2

Period 1 A BPeriod 2 B A

This design is basically a 2 x 2 latin square, with the provisionfor control of expected time trends in the animals' behavior. Theplan usually involves a group of animals, one half of which isallotted at random to each of the two treatments. An extensionof this design is the " double-reversal design " which, like theformer, compares two *treatments in two sequences, the only dif-ference being that the double-reversal design is continued through3 or more periods.

Experiments illustrating the use of the latin square design inchange-over trials have been published by several workers, notablyCochran et al. (1941), Lucas (1943) and Patterson. (1950). Theparticular design used by Lucas was a 4 x 4 square in which 4rations were compared in a feeding experiment with dairy cows.The 12 cows available for study were first divided into threegroups of four, on the basis of their producing abilities. Foursequences of treatments, each consisting of four five-week periods,were then allotted at random to the four cows of each group,with the provision that no two cows in a group would receive thesame treatment during the same period.

152

By sud-dividing the cows into three 4 x 4 squares, and choosingthe cows so as to have all cows within each group as similar aspossible, Lucas was able to demonstrate a substantial reduction inexperimental error, as compared with the error that would havebeen obtained had the animals been assigned to the treatmentcompletely at random.

Another example illustrating the application of the latin squarein change-over trials has been proposed by Lucas (1950) for grazings-tudies in which three different rates of feeding protein supplementconstitute the treatments. The d.esign is given as follows:

tc. as needede

Where the rows represent periods, the columns represent paddocks,and the numbers represent the three rates of eedin.g protein. sup-plements. The design calls for six groups of animals with twogroups receiving each supplement during a given period, and theanimals rotated from paddock to paddock within each sequence set.

Incomplete Block Designs

These designs are particularl-y- adapted for situations wherelarge numbers of treatments are to be tested as well as wherethe number of experimental units falling into a natural groupin.g,such as litters or breeds, for example, is not large enough to in-clude all treatments. Thus, an incomplete block design may bedefined as a design in which the number of experimental units ina block is smaller than the total number of treatments being com-pared. Statisticians speak of " balanced " and " partially balanced"incomplete block designs, but workers in animal science generallyhave made use only of the balanced type of designs. It shouldbe noted in this connection that, while in.complete block designsdo not provide as much accuracy between certain treatmentcomparisons as complete block designs, balanced incomplete blockdesigns are characterized by the fact that all comparisons amongpairs of treatments are made with equal precision. Another fea-ture of balanced incomplete block designs is that, while there isno limit regarding the n.umber of treatmen.ts or the number ofunits per block, the number of replications is fixed by thesevariables.

153

tc. as needede

Sequence Set I123231312123231

Sequence Set II12331223 1123312

Usin.g 4 treatments, A, B, C and D, in blocks of three experi-mental units each, a balanced incomplete block design would look asfollows:

Block 1 ABCBlock 2 ABDBlock 3 ACDBlock 4 BCD

It will be seen that each pair of treatments occurs within ablock the same number of times, filling the requirements of balance.However, in the above example, the blocks cannot be grouped inseparate replications since four is not divisible by three, thenumber of units per block.

The usefulness of incomplete block designs is best illustratedby reference to an actual experiment. The example chosen isfrom a feedin.g -trial with swin.e, described by Comstock et al. (1948).The particular design used was a 3 x 3 balance lattice design for9 treatments in blocks of three litter mates. The design, usingfour replications, was as follows:

Note that the blocks are incomplete, since each contains only3 of the 9 treatments being compared. Also note that each treat-ment occurs once in th.e same incomplete block or litter with eachof the other treatments. By removin.g the variation due to litterdifferences, the gain in efficiency of the incomplete block designas used in this particular experiment, compared to randomizedcomplete blocks designs, was about 20 percent. Other situation.sin which incomplete block designs may be found useful is wherethe number of animals at any one time or at any particular placeis smaller than the number of treatments.

There are many questions about experimental designs whichremain open for further discussion as well as for further study.What has been attempted here has been to survey the designswhich appear to be most useful in animal science experimentation.,and to point out how different designs are necessary to meet dif-ferent experimental situations. It might be well also to re-em-phasize that th.e efficiency of a particular design will vary with thenature of the experimental material, as well as with the conditionsunder which the experiment is conducted. Another important

154

Block I Block 2 Block 3Replication 1 123 456 789Replication 2 348 267 159Replication 3 147 258 369Replication 4 357 249 168

point to remember is that the experimental design should be assimple as is consistent with the requirements necessary to obtainreliable answers.

Analysis and Interpretation of Results

Having collected all the data necessary to obtain the infor-mation for which the experiment was conducted, the next step incarrying the experiment to its logical and successful conclusionis to select the appropriate statistical methods for sumni.arizingand interpreting the results. As Cox (1951) points out, " the ana-lysis of data calls for clear -thinking and for careful selection ofthe statistical tools to be used. " Also, " the statistical analysiscannot increase the validity of the data. " This adds emphasisto the point stressed earlier, i. e., regardless of how refined orhow intricate the statistical methods employed, they are powerlessif applied to data lacking the necessary precision, or to dataderived from faulty experimental designs. Assuming then thatthe experiment was properly planned and conducted, the nextimportant step is that we use the proper statistical methods inorder to extract all the pertinent information contained in thedata. Proper use of these methods, such as those employed inthe computation of averages, standard deviations, coefficients ofvariability, or t, the quantity commonly used in testing the sig-nificance of the difference between two averages, generally doesnot require more than a working knowledge of statistics. As ageneral rule, however, the parameters to be estimated and therelationships to be determined are more complex than the statis-tics just mentioned. In order to obtain the desired informationfrom such data, it would be necessary for the investigator to knowsomething about the scope and flexibility of the various statisticalmethods, including the basic assumptions underlying -their use.Fortunately, -there are several textbooks available on statisticalmethods as applied to experiments in the agricultural scien.ces.Anyon.e intent on. improving the quality of his research accomplish-ments in the animal sciences can learn a good deal just bystudying these books. In the grea-t majority of cases, however,the most effective -way of dealin.g with the situation would be forall agricultural institutions giving training at a graduate level toinclude in their curricula at least one course on experimentaldesign.s and statistical methods. In the meantime, everyoneconcerned. with quantitative studies in livestock research shouldbe encouraged to seek the advice of a qualified statistician beforeembarking on an experiment. Experience shows that a persontaking advantage of the experimental d.esigns and statistical me-

] 55

thods that are available for his use not only has less of a problemanalysing and interpreting his results, but also contributes -towardsreducing the cost of experimentation.

In addition to the material on statistical techniques sum-marized above, attention should be drawn to the importanceof statistical analyses in pointing to new clues in the solu-tion of problems. Use of the appropriate statistical methods notonly provides a means of interpreting the results in terms ofexisting knowledge, but also may actually point to new and im-portant clues regarding the solution of a particular problem. Also,if the experiment were properly designed and conducted, the resultsmight serve as a basis for prediction which, after all, is the ulti-mate purpose of any experiment.

In other words, an experiment can be considered a successonly if the results are such as to make it reasonably certain thatsimilar results will be obtain.ed un.d.er similar conditions at somefuture date. It should also be emphasized in this connection thatit is important and desirable that the investigator report nega-tive as well as positive results. By so doing, he not only helpsto clarify knowledge regarding certain phenomena, but also servesthe scientific cause by preventing duplication of effort on thepart of other investigators who, with this information, could devote-their energy to other more fruitful tasks.

Literature Cited Regarding Statistics

COCHRAN, W.G-., AUTREY K.M., and CANNON, C.Y. A Double Change-over Design for Dairy- Cattle Feeding Experiments, J. Dairy Sci.24 (11): 937-51, 1941.

COCHRAN, W.G. and G.M. Cox. Experimental Designs, John Wiley andSons, Inc., New York, 1950.

COMSTOCK, R.E., PETERSON W.J., and STEWART, H.A. An Applicationof the Balanced Lattice Design in a Feeding Trial with Swine,J. Anim. Sci. 7 (3): 320-31, 1948.

Cox, G.M. The Value and Usefulness of Statistics in Research, LectureSeries I, No. 4, U.S. Department of Agriculture. Committee onExperimental Design, Washington, D.C., U.S.A. 1951.

FISHER, R.A. Statistical Methods for Research Workers, Oliver and.Boyd, Edinburgh, Scotland. 3rd. ed., 1930.

GOULDEN, C.H. Methods of Statistical Analysis, John Wiley and Sons,Inc., New York, 1952.

156

LUCAS, H.L. A Method of Equalised Feeding for Studies with DairyCows, J. Dairy Sci. 26 (11): 1011-22, 1943.

. Design in Animal Science Research. Proc. Auburn Conf. onStatistics, 77-86. Edwards Bros., Inc., Ann Arbor, Mich., U.S.A. 1948.

Statistics and Research on Pasture and Grazing, LectureSeries I, No. 3, U.S. Department of Agriculture. Committee onExperimental Design, Washington, D.C., U.S.A. 1950.

MIRANDA, R.M. CULBERTSON C.C. and LUSH, J.L. Factors AffectingRate of Gain and their Relation. to Allotment of Pigs for FeedingTrials, J. Attini. Sci. 5 (3): 243-50, 1946.

PATTERSON, H.D. The Analysis of Change-Over Trials, J. Agr. Sci.40 (4): 375-80, 1950.

SNEDECOR, G-.W. Foreword to Proceedings Auburn Conferen.ce onStatistics, Edward Bros. Inc., Ann Arbor, Mich. U.S.A. 1948.

Statistical Methods, Iowa State College Press, Ames, Iowa,U.S.A. 4th. ed., 1950.

STODDARD, L.A., Problems in Estimating Grazing Capacity of Ranges,Proc. 6th Internationar Grassland Congress, State College, Pa.U.S.A. p. 1367-73, 1952.

157

NATIONAL SERVICES TO THELIVESTOCK INDUSTRY

The Baurti meeting recommended that governments shouldcarefully review the adequacy of their existing extension services,particularly those for the livestock producers, who often operatein more remote areas than the farmers, who specialize in theproduction of cash crops; they should make every effort to sostrengthen these services that livestock producers may have readyaccess to help and guidance on all types of livestock, pasture andrange management problems. To this end, FAO decided to askmember countries to participate in a comprehensive survey of allnational organizations devoted to servicing and improving thelivestock industry, the results of which would be discussed at theBuenos Aires meeting. Accordingly, a questionnaire was circulatedamong member countries to obtain information on physical facil-ities, personnel, financing, scope of the -work in the case of minis-tries of agriculture, agricultural colleges, agricultural experimentalstations and organizations of agricultural producers, distributorsand processors of primary livestock products. The number ofanswers to this questionnaire received was insufficient to permitthe drawing of over-all conclusions as to the adequacy of govern-ment services to the livestock industry, or to compile the infor-mation in a comparable way which could serve as guidance for futureaction. However, a considerable amount of useful informationwas assembled, which is summarized in this chapter together withsupplemental information presented at the Buenos Aires meeting.

This survey is part of a broader one, which covers go-vern-ment services to all branches of agriculture. It was initiated by FAOthree years ago, and was first discussed in the Americas during theThird FAO Regional Meeting on Agricultural Programs and Outlookin Latin America, held in Buenos Aires in September, 1954. Sincethe -tw-o surveys are closely interrelated, the conclusions drawn atthe Regional Meeting from the results of the over-all survey,and the recommendations which followed them are of interest.These are likely to apply in the same measure to governmentservices to the livestock industry. The Regional Meeting, havingexamined the n.eeds of the farming populations of the countriesof the Latin. American region, and having noted with regret thefact that, in relation to the importance of agriculture ineconomic development and in proportion to the populationengaged in agriculture, budgetary appropriations for agri-

158

cultural development are extremely low, recomrnended that -og -vernments consider the need to increase their budgetary allocations,and that government services to agriculture be strengthened inorder to carry out efficiently the plans and programs for this sectionof the national economy.

There are major problems which are still to be overcome inrelation to the improvement of national services. However, muchprogress has been achieved in recent years, particularly in thetechnical aspects of such services, also in the social, in.stitutionaland economic field. The number of agricultural schools, experi-ment stations, etc., has increased throughout the region, an.d abetter staffing of such instititutions has permit-Led an intensifica-tion of the programs they carry out. In many countries theministries of agriculture have been reorganized to adapt -themselvesbetter to modern requirements, and budgetary allocations have been,on the whole, in.creased. On the institutional side, steps have been-taken in many countries to in.erease the security of tenure offarmers, and to improve the possibilities of private ownership.improving, as a çon.sequence, the investment conditions on thefarms. Furthermore, many countries have established or improvedtheir credit systems and given active support to co-operatives.On the economic side, marketing, with its related aspects, such astransport, storage, etc., has been the object of surveys and_studies which have resulted in measures for its improvement..

Ne-v-ertheless, it must be recognized, as was done at the RegionalMeeting, that in most instances this progress has only laid the basisfor an over-all improvement, and that much remains to be done,also because progress has frequently been unbalanced and has lackedco-ordination. These latter are possibly among the basic problerns,since, in order to achieve effective results, co-ordination and simul-taneous development of all related aspects are essential. Increasedproduction requires improved marketing facilities, including trans-portation; livestock research requires adequate extension servicesto make the practical application of its results possible, and ex-tension in -turn requires good agricultural schools to provide techni-cians of a satisfactory level of training.

In response to the questionnaire sent by FAO to all the govern-ments of the region enquiring about expenditures on, and staffingof, government services to the livestock industry, several countrieshave submitted figures. These are shown in Tables 19 to 23, andgive indications of the levels to which services to the livestockindustry have been developed in the countries listed. Data onexpenditures for various types of agricultural work are shownin Table 19, for eight countries or territories, and the numbersof trained workers employed in these same countries or territoriesin agricultural -work are shown in Table 20. Data on training in

159

recent years are summarized in Tables 21, 22 and 23, since thedegrees awarded and nature of the data submitted are such thatthey could not be summarized in a single table. Data on num-bers of workers and students trained are for 1954, except in

TABLE 19 EXPENDITURE ON GOVERNMENT SERVICES IN CERTAIN COUNTRIES

Exchange rates in terms of U. S.$ in March 1954 were: $ 1.00 = 2.50 Pesos Colombianos; 17.50Sucres; 57 Guaranies; 0.3571 - sterling; 1.4285 $ B. A.; 1 70 $ B W. I.; and 3.35 Bolivares.

2 For 1954, except Trinidad and Tobago, where figures are for 1953.

TABLE 20 - NUMBERS OF TECHNICAL EMPLOYEES IN CERTAIN COUNTRIES

160

*In addition to these officers with degrees, there are officers with diplomas as follows in Jamaica:130 for all agricultural work, 32 for animal husbandry (except veterinary and forage) work, 9 forveterinary work and 3 for pasture, range and fodder work.

Colombia Pesos Colom-bianos

5 927 140 4 402 530 1 384 840 177 000

Ecuador Sucres 9 265 000 1 602 000 --Honduras, British B.H.$ 480 000 33 000 11 600 22 000

Jamaica E sterling 1 884 100 59 853 18 340 10 841

Paraguay Guaranies 13 380 000 4 055 921 685

Trinidad and Tobago B.W.I. $ 1 221 354 182 905 69 410 86 770

U.S.A. 213 300 678 10 756 141 25 625 388 25 905 987

Venezuela Bolivares 115 697 124 26 360 589 20 058 595 1 500 000

ColombiaEcuadorHonduras, BritishJamaica *

Paraguay

Trinidad and TobagoU.S.A.Venezuela

23

129

31

13

51

136

212

149

4181

20

1

3

1

30

885

22

1

63

12

15

21

7

681

793

20

829

Number of Technically Trained Employees

AnimalCountry All agricultural husbandry, Veterinary

Pasture, rangeand fodder

work except veterinaryand forage work

workwork

CountryMonetary

Unit

Annual Expenditure 2

Allagricultural

work,excludingforestry

All animalproduction

work,excludingveterinaryand forage

Allveterinary

work

All pasture,range and

fodderprod ucion

work

TABLE 21 NUMBERS OF MEN TRAINED IN RECENT YEARS IN CERTAIN COUNTRIES

* D.V.M.

TABLE 23 NUMBER OF TECHNICIANS GRADUATED IN 1950-1954 IN VENEZUELA

Subject

Average Numbers of Men Trained Annually in Percent Years

161

Diploma students from Farm School.2 None trained in Jamaica, but 6 to 10 are sent annually for study abroad.

TABLE 22 DEGREES CONFERRED IN EDUCATIONAL INSTITUTIONS IN THE UNITED STATESOF AMERICA IN AGRICULTURAL AND RELATED SUBJECTS IN THE SCHOOL YEAR 1952/53

Degree

Bachelor's I Master's Doctor's

Year " Ingenieros agrónomos" Veterinarians " Peritos agrónomos"

1950 13 10 29

1951 5 11 1

1952 4 3 18

1953 22 4 49

1954 13 13 58

Total 57 41 155

Animal Husbandry 1 140 143 40

Other agricultural subjects,excluding forestry 6 659 1 200 409

Biological Sciences 9 707 1 807 966

Veterinary Medicine 878* 29 9

Home Economics 7 517 608 47

Physical Sciences 10 414 2 711 1 714

Total 36 315 6 582 3 185

" Peritos agronomos " " Ingenieros agrónomos

Animal Pas tu re, AnimalCountry All

phases

of agri-culture

husbandryexcept

veterinaryand

forage work

Veteri-nary

medicine

rangeand

fodderproduc-

tion

Allphases

of agri-culture

husbandry,except

veterinaryand

forage work

Vete ri-narymedi-cine

Pasture,range

fodderpro-

duction

ColombiaEcuadorHonduras, BritishJamaica

Paraguay

Trinidad andTobago

--24'

560

25

15

50

16

16

20

25

6

32 1

Trinidad and Tobago where they are for 1953, and in Ecuadorwhere they constitute an average for the five recent years.

Advances in animal production and agriculture generally mustbe measured in terms of improved practices adopted by farmersand ranchers. By this standard of measurement it is apparentthat much progress is possible. There is a fundamental need forspeeding up the process of adoption of improved practices througha closer relationship amon.g research workers, extension workers,educators and producers. This mean.s that the research workermust know and study the problems being faced by the producer,the extensionist and the educa-tor must be well acquainted with,and actively disseminate, the research knowledge to the new gen-erations of students and especially to the farmers and ranchers.Clearly this can only be done when there is a close understandingand co-operation amon.g these groups which so vitally in.fluenceagricultural developmen.t.

Information on recent developments in a number of countries,in addition to that tab-u.lated in Tables 19 to 23, is summarizedin the follo-wing paragraphs.

The Government in Argentina has taken action to improvelivestock production und.er the second Five Year Plan. This in-eludes all breeding, feeding and veterinary aspects of the livestockindustry, and its object is to improve the quality of the herdsthrough the utilization of high-bred animals; to in.crease livestocknumbers by supportin.g the creation of new ran.ches, through abetter utilization of the existing ranches, and finally to improvefeeding through better pastures an.d a more intense and rationaluse of the land. This action is complemented by a nationalsupervised credit system an.d by measures to improve the marketingof livestock products. Un.der the breedin.g aspects, in spite of thehigh level reached by Argentine livestock, it has been consideredadvisable to continue to import high quality aninaals of the differentspecies. For this pm-pose, the Government allocated considerableamounts of foreign exchange for the import o-f animals fromCanada, France, the Netherlands, Switzerland, the United Kingdom,and the United States of America. Thus, in 1954, more than 1,000high-bred cattle were imported, among which were many firstprize animals o-f cattle shows in the United Kingdom and othercountries. In addition, substantial numbers of high-bred sheepand horses were imported.

The national plan for the improvement of livestock in Argentinagives high proprity to the development of artificial insemin.ation.For this purpose, two artificial insemination stations have beencreated which provide semen -without charge to 43 sub-stations,which are formed by producers and supported by the state. Boththe official and private stations receive technical advice and lab-

162

oratory facilities from the state. Parallel to this, special courseshave been organized to train personnel in artificial insemination.So far, 598 certificates have been given. Through these measures,complemented by inspection of semen used on private establish-ments, artificial insemination is now widely accepted, particularlyamong breeders of dairy cattle.

Other measures for the improvement of livestock in Argentinain.clude the organization or enlargemen.t of regional breeding sta-tions. About 30 such stations have been created in co-operation_with provincial governments and breeders' associations. Thesestations are located in outlying areas, and are provided with pure-bred animals of different species by the Ministry of Agriculture.In addition, high-bred animals are given on loan to small livestockbreeders, particularly in the outlying areas.

In regard to feeding, pastures of very high quality are abun-dant in the central zone of Argentina. However, in order toimprove further the land use as well as the quality of the pastures,several experimental station.s, such as those of Pergamino andManfredi, carry out studies on the improvement of pastures andrange management. In the outlying areas of the country, suchas the extreme north an.d Patagonia, forage problems are moredifficult. In these areas, the experimental stations of CanadonLeon (Santa Cruz) and Las Brenas (Chaco) are working on adapta-tion experiments of national and foreign species, as well as onrange improvement. Furthermore, a new experimental station hasrecently been set up in the Province of La Pampa, with an areaof 2,000 ha. which will work particularly on the improvement ofcropping methods an.d on the improvement of the carrying capacityof pastures, as well as on disease resistance of fodder crops. Inaddition to the locally produced seed, a substantial amount ofseed of foreign pastures is imported and multiplied in the countryby private farmers under the inspection of the Government. TheGovernment also purchases seeds and sells them under favorableconditions to farmers. The multiplication fields, at the same time,serve the purpose of demon.stration farms.

As to the sanitary protection of livestock, the Argentine Ministryof Agriculture has at present 130 regional veterinarians who carryout direct campaign.s against certain diseases an.d give advice tofarmers. The important national campaigns include those againstfoot-and-mouth disease, scabies, ticks, brucellosis and trichinosis.

In the case of the first of -these diseases, vaccination is nowwell established and livestock breeders have recognized the im-portance of this preven.tive measure. In addition, the State hascarried out demonstration compaigns during which 92,416 cattleand 17,795 sheep were vaccinated, with very satisfactory results.During the period 1942-1952, ticks were eradicated from more

163

than 6 million ha., and in 1953/1954 the campaign became moreintensive with another substantial area freed from this parasite.More than 31/ million sheep were treated for scabies during 1953/1954 over an area of about 10 million. ha.

The sanitary measures in connection with brucellosis includecontrol of the import and export of cattle, identification of brucel-losis infestation areas, calfhood vaccination and, finally, controlof dairy establishments. Of these latter 536 were inspected duringthe period 1949-1954, and more than 145,000 cows were vaccinated.Brucellosis is detected by use of the " ring test, " which wasapplied to 2,739 dairy establishments on which 566,785 liters ofmilk were examined. All these campaigns, and particularly thoseagainst diseases common to man and animals, are 'complementedby intensive extension activities.

Supervised agricultural credit was originally established by theNational Bank in Argentina, but has recently been extended toinclude all banks of the country. This credit system is based onthe national ecological map, as well as on economic studies of thedifferent agricultural areas of the country. This enables deter-mination of the most advisable crops or types of agriculture, andsystems of priority are established. In 1954, the National Bankallocated credits for agricultural purposes totaling 6,197 millionpesos, compared to 5,974 million pesos in 1953. In addition, theproportion of agricultural credit in relation to credit for all pur-poses has continuously increased. Thus, in 1950, agriculturalcredit was 18.2 percent of the total credits allocated by the Na-tional Bank, rising to 36.4 percent in 1954. Further, the CentralBank includes in its yearly foreign exchange budget alloc ationsfor the import of elements required by agriculture and the live-stock industry. These include mainly machinery-, spares, certifiedseed, fertilizers, products for the fight against animal and plantpests and diseases, pedigree animals and semen. For these lattertwo items, yearly allocations amount to 30 million pesos and im-ports are regulated in accordance with a plan prepared yearly bythe Ministry of Agriculture and Livestock.

There is also a policy in the field of colonization and landtenure which tends to give ample opportunity to farmers to be-come owners of the land they work either through the purchaseof public lan.ds or private land, considered unsuitable to fulfil asocial function.

In Bolivia, there has been a long evolution of the social andeconomic aspects of agriculture since the Spanish colonization andit has had its consequences on the national economy. Particu-larly in the social aspects the evolution is reported to have beensuch as to prevent the full and economic utilization of the nationalresources, due to the prevalence of extremely large estates of more

164

than 10,000 ha. Ivhich concentrated more than 70 percent of thetotal cultivable area of the country, and on which agricultureand livestock breeding were carried out in a primitive -way.

In consequence, the large Indian population liad access to onlya limited part of -the arable area and was furthermore forced to-work -without adequate remuneration on -the large estates. Thissituation has changed substantially since 1952 when several econo-mic and social. measures were enacted among which was landreform. The more important objectives of this land reform wereto enable the indigenous population to become landowners, on thecondition that they worked the whole area allocated to them, andto co-operate Nvith them. in -the modernizing of their croppin.g me-thods. Wherever possible, the traditional collective system wasretained, hoping thus to stimulate higher production and imp:rovedmarketing. Other aspects of -the reform aimed at facilitating in-vestment of ne-w capital., supporting the operation of co-operativesand providing -technical help and credit. Measures have also beentaken to stimulate internal migratory movements, in order to obtainbetter distribution of -the population throughout the country.National services of benefit to the lives-Lock industry include in-tensive action in the northeastern cattle area of the country,where foreign technicians have been engaged and substantialnumbers of pure zebus introduced. Agricultural co-operativesfor the rational exploitation and multiplication of sheep have alsobeen established.

The Government of Ecuador is carrying out, through the De-partment of Livestock Breeding, several programs of livestockimprovement. At the higher elevations of the country dairycattle prevail and in this area purebred Holstein and Brown Swisshave been imported for crossing with native cattle. The law,-tropical areas specialize in cattle for meat production. Experimentalcrosses have been made with zebus which are -then followed withcrosse,s to Hereford, Shorthorn, and Aberdeen Angus. Crosses withzebus ha-ve been satiSfactory, but no definite results are so faravailable On the others. The Government has initiated a creditprogram in support of livestock production, for -which a total ofU.S. $ 2,800,000 hav'e been allocated for two -years. These credits aregiven for -terms of 5 'years, and carry an interest of about 8 percent.-Further action is related to advisory and extension services.

The recently created Livestock Research Institute in Guayaquil,will carry out research in diseases, artificial insemination, breeding,pastures, etc. The buildings and equipment of this institute wereto be completed by the end of 1955. A similar institute exists al-ready in Quito for the high areas. The Quito institute producesvaccines, -which are sold at low prices, in disease control campaigns.Both institutes will carry out intensive studies on the livestock

165

development possibilities of the country, on which a nationalplan will be based in the near future.

In El Salvador, there has been established an Integral Demon-stration Area by the Ministry of Agriculture and Livestock. Thisarea covers approximately 38.6 square miles and is believed to berepresentative of the region where it is located. .0n it studies arecarried out concerning the management of livestock, as practisedin the area, an.d on the cost of livestock production.

Agric-ultural maps of El Salvador are also being compiled. Sofar, a land-use map showing the distribution of crops and pas-tures has been completed as well as several others concerning thelocation and size of dairy farms, their distance from consumptioncenters and the types of roads the milk has to pass over betweenthe farm and where it is con.sumed. The Govern.ment is alsomaking intensive efforts to open up the tropical coastal lowlandsby constructing a bridge over the Rio Lempa an.d a coastal high-way and by providing the area with electricity. In addition,attention is bein.g paid to the legal and practical measures for thefight against animal diseases and pests. At present, all cattleentering the country are vaccinated unless accompanied by sani-tary certificates, but no quarantine period to observe the resultsof the vaccination exists. The Ministry of Agriculture an.d Live-stock employs four veterinarian.s and six vaccinators whose servicesare free to the livestock industry. It also sells vaccines at costprices. The official vaccinators carry out the following vaccinations:cattle, against anthrax, blackleg, haemorrhagic septicemia and pneu-mo-enteritis; horses, against anthrax and with mixed bacterin; hogs,against cholera, haemorrhagie septicemia and with mixed bacterin.

The new National Livestock School of Santa Ana, El Salvador,was inagur ated on 10 March, 1954. Up to May, 1955, there hadbeen seven -terms from which 137 people graduated. The school ishaving wide acceptance by farmhands and farmers who want-their people to learn how to produce cleaner milk and take bettercare of animals. The school has accomodation for 40 students, aservice area of roughly 24,000 sq. yds. and 5 ha. for cultivationand to keep the 11 animals it owns. These include on.e bull ofeach of the following breeds: Holstein, Brown Swiss, Guernsey andJersey and seven. cows. Instruction, quarters and food are providedfree of charge and the only requisites for admission are good health,good conduct an.d ability to read and write. The -teaching staffis composed of employees of the Ministry who do not receive anyextra pay for this work. The courses are of a duration of threeweeks and cover theoretical and practical aspects of the manage-ment of dairy cattle and of the production of milk. The Ministryalso offers a two weeks' course on artificial insemination.

In the French territories in Latin America, the services to agri-

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culture and livestock industry are undergoing a process of reorgan-ization, following a change of status of these territories in relation.to France. As a consequen.ce, whereas the technical departmentsformerly were all responsible to the Ministry of Colonies, each ofthem is now directly responsible to the specialized ministry con-cerned. In French Guiana, the Agriculture and Forestry Agencywas recently created depen.dent on the Ministry of Agriculture ofFrance, This Agency, which will be responsible for action in agri-culture in French Guiana, is at present engaged in surveys onwhich to base its program, and it has recently created an experi-ment station for livestock and fodder research. This station hasinitiated a program of crosses of local cattle with Brown. Swiss,which appears to be giving good results. This station is stillrather modest, but enlargement is expected. The Agency willalso assist private enterprise through advice, demonstrations andother extension activities.

In Peru, the need for more adequate staffing of national ser-vices of the livestock industry is recognized. Well trained andcapable technicians can only become available if the educationalinstitutes of the countries are well organized and equipped, andif their programs are adapted to real needs of the countries. Theobservation applies equally to many countries in which adequatenumbers of trained workers are not yet available.

In Venezuela, the Livestock Division of the Ministry of Agri-culture cornprises three departments which are responsible fordairy cattle and hog development and for herdbooks respectively.The Ministry has established a program to increase the numberof animals also the yield per head. The first of these objectivesis very difficult due to the lack of adequate pastures on thesabanas of the cattle areas. For this reason, it is essential firstto improve and extend the pastures and to solve the problemof periodical floods, and then to carry out complementary measures,such as fencing and adequate water provision. An intensive cross-breeding campaign to raise production is at present under way,and has already given very good results. Thus, for instance, the4-year-old native animal gives a carcass yield of 352 lb. whilethe native zebu crossbreeds of 21/, years yield 484 lb. It is ex-pected that the number of crossbreeds will be increased by 400,000at the end of five years. The Ministry of Agriculture has importeda substantial number of zebu bulls which are crosed on nativecows at the experimental stations of San Carlos and Pariaguan;the offspring of these crosses are sold to livestock breeders at lowprices or on. credit.

In British Honduras, owing to the limited facilities and avail-able staff, only preliminary studies of the problems affecting thelivestock industry have so far been carried out. The general

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recommendations on the subject of the Baurti meeting are, how-ever, borne in mind.

In Trinidad and Tobago, the need for the establishment of anadequate an.d efficient extension service of the Department ofAgriculture on the livestock side is appreciated and efforts arebeing made to provide officers with increased trainin.g in animalhusban.dry. Also, arrangements are now under consideration where-by financial assistance will be given to approved livestock ownersin the form of subsidized prices for certain classes of livestock.

In the United States of America, a number of improvementsin the exten.sion or education services to the livestock in.dustryhave taken place in recent years.

The Federal Market News Service was created as a neutralagency to obtain information on marketing, movements, pricesand price trends on livestock and meats, for dissemination to allinterested persons. From its inception nearly 40 years ago ateastern wholesale meat centers and Chicago, it has gradually beenexpanded to its present coverage of 35 public livestock markets,6 large wholesale meat centers an.d the n.ational wool trade re-ported from a central point. The gradual drifting of the slaughterindustry into some of the leading livestock producin.g areas of thecountry resulted in an increased proportion of all livestock beingsold direct frona producers to packers. In order to report suchtransactions, the Market News Service extended its coverage intotwo such direct marketing areas. Information on country tradingin important cattle and sheep range areas in the western partof the United States of America is assembled in a single reporteach week. At present about 150 persons, in.cluding the clericaland statistical staff, are employed in Federal Market News work.This service includes the collection and distribution of informationnumber of livestock received at the markets each day, pricespaid by species, grade and weight, and the price trend comparedwith the previous day. Information is also collected on the supply,demand and price situation in the wholesale meat an.d wool trades.This information is disseminated through press associations, news-papers, by direct mail and on radio and television. There isconsiderable demand for an expansion of the service to includemore reports on direct sales, as well as more coverage of locallivestock markets and auctions. The development of thousands oflocal livestock 'auctions during the past 25 years, makes market n.ewscoverage both difficult and expensive. There are a number of pro-jects designed to study these need.s for additional market news serv-ices, an.d to suggest practical methods of effecting increased coverage.

A secon.d service in the United States of America is the FederalMeat Grading Service. This is voluntary and available topackers, wholesalers and retailers on a fee basis. During World

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War II and the recent Korean conflict, federal grading was condu.ctedoil a compulsory basis. At present there are about 350 personsgrading meat and another 50 persons employed in a supervisorycapacity. Nearly 50 percent of the commercial production ofbeef, veal, lamb and mutton is federally graded. Many firms inthe meat packing, wholesaling and retailing industry use federallygraded meat as a basis for comparing values and for trading inthe market places. In addition, some of the larger re-tailing chainorganizations rely on federally graded meats for developing consu-mer confidence in their retail meat merchandizing program. Im-provements in the grading service have been largely in the area ofimproved understanding of what are the standards for grades;and what the grade means in terms of variations in cooking tech-niques for each cut from each grade. Many in the meat industryfeel that the increased percentage of the consumer's meat dollarbeing spent for beef is in part a result of increased use of beefgrades as a basis for retail selling. Some students of the problemfeel that the establishment and use of grades on pork cuts mighthelp the swine industry recover some of the consumer confidencethat has been lost through the sale of pork cuts containing anexcessi-ve amount of fat.

A third major service provided for the livestock industry isthe li-vestock disease and pest control work, including the qua-rantine activity. During 1954, the Federal Government providedapproximately 1,330 man-years on disease control and diseaseeradication work. The total expenditure of funds on this particularprogram would amount to somewhat less than one-tenth of onepercent of the value of the livestock sold by farmers during the year.

Another service provided the livestock and meat industry iswork with packers and stockyards. Fin.ancial, -weight and priceprotecion is furnished the producers of livestock and poultry atpublic stockyards, livestock auction y-ears an.d poultry markets,through enforcement of the Packers and Stockyards Act. ThisAct is designed to assure producers of livestock the full true marketprice for their animals. The following measures assist in accom-plishing the purpose of the Act: open competitive bidding, accurateweights, correct accountings, adequate marketing facilities, servieesat reasonable rates, protection against unjust practices and fullbond protection of their proceeds of sale. This latter bond pro-tection is an insurance against losses due to misuse of proceedsof sale. More than 2,000 scales on which livestock and poultryare weighed, must be tested and inspected at regular intervals.Bonds are required of about 4,000 agencies selling livestock on acommission basis, as well as all dealers buying livestock. Approx-imately 80 employees are engaged in administering the provisionsof this Act at 62 terminal stockyards, 271 auction yards, and 8

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designated poultry markets. The total cost of this protection totalsabout 1/1,000 of one percent of the value of all livestock sold.

In the field of livestock and meat research in the United Statesof America the federal and state governments combined providea vast amount of service to the livestock industry. Much of the-work in breeding, feeding and management is done in the stateexperiment stations and sub-stations; these former are doing live-stock research under local pasture, roughage and grain produc-tion conditiòns. The U.S. Department of Agriculture provides.some co-ordinating services for this research work. In addition,the Department as well as the state colleges do research inli-v-estock and meat marketing. Improvements in the re-search work for livestock are many and varied. One exampleis in the rnethods of evaluating hog breeding stock for muscleversus fat. At least one midwestern state university hasrecently developed an electronic needle for measuring the depthof back fat on hogs. This might well be a major factor in theimprovement of the method of selecting hog breeding stock formeatiness. In the beef industry much attention is being givento the problem of breeding animals that will produce a higherpercentage of the more desirable beef cuts, make gains with lessfeed costs and make better use of pasture in the hot and humidareas in the Gulf Coast. In the marketing field, much researchis being done to find out what consumers want in their meatsupply. Of particular interest to research is the problem ofgetting the livestock and meat marketing system to more ac-curately reflect in the liv-e animal market consumer preferencesfor the various grades of meat.

The educational services rendered to the livestock industryinvolves the application of research results in all fields, from breed-ing to marketing. It also includes the educational work involvedin interpreting the regulatory activities of the federal and stategovernments as they apply to the livestock and meat industry.This educational program poses the very real problem of how totransfer facts and skills developed by the research workers in sucha manner that they can be understood, learned, remembered andused by farmers, marketing agencies, processors and retailers. Inthe United States of America in 1954, country agricultural ex-tension workers devoted a total amount o-f time equivalent to1,370 man-years to work with the 4 million livestock producers.There have also been approximately 130 persons devoting full timeto livestock production and marketing work on the 48 stateextension staffs. The combined work of these state and countryworkers amounts to only 1 person for each 2,500 liv-estock prodii-cers in the whole country. It should also be noted thatthese -workers also devote some time to the educational work

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with market agencies, meat processors and meat retailers.,During the last 8 years the United States has also expanded

its educational program among consumers. The general objectiveof the con.sumer education program is one of providing consumerswith information which will enable them to utilize their meatdollars better in retail stores. More specifically, this education.alprogram among consumers is design.ed to provide them withinformation on grades and cuts of meat available, as well as in-formation on seasonal fluctuations in price an.d supply. Productionof red meats has expanded at a much greater rate than the popu-lation. Thus, while consumption was less than 130 lb. per capitain the 1930's, it is now well over 150 lb. of red meat. Withan ever expanding industrial or urban. population, the demand formeat has increased. If the livestock industry is going to providethe meat that is so essential for a vigorous and productive workingpopulation, livestock production and meat distribution will needto be expanded and improved at an ever increasing rate. It shouldbe pointed out that, as the slaughter of livestock moves closerto production areas, there is an increased need for market newsand meat grading, as well as improved transportation. All of thesethings facilitate the merchandizing or marketing of meats in con-suming centers sorne distance from the point of production, market-ing and slaughter.

A re-view of the history of the educational program would indi-cate that the demonstration technique still holds great promise.The- educator must find the job that needs to be done, the re-search that needs application and then provide the in.dustry, orindividuals in the industry, with a picture of those needs. Theremust be found some way to make those improvements wanted.Possibly, they may be wanted to provide a neNv pair of boots forthe producer or a new dress for his wife; the main point, however,is that he must " want " an improvement. The extension jobarnong livestock producers is one of getting producers to under-stand the value of better breeding, feeding, management and mar-keting. It has been found that the educational worker must havethe vision to look a long way ahead for results. He must havethe knowledge to realize what is sound in the long run. He mustknow what is good business, what is practical, he must have thesympathetic understanding of the people with whom he is working.Thus, to get results, to get application of research, it would seemessential that people be trained who have an understanding of thepersons to be taught. They must be given that training whichwill enable them to transfer facts and skills developed by theresearch workers in the livestock industry. The educator mustknow how to be understood, how to get people to learn, rememberan.d use facts if this program is to be effective.

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PROPOSALS TO FACILITATE CO-OPERATIONAMONG THE COUNTRIES

Glossary of Animal Husbandry Terms

It became apparent during the Turrialba meeting that therewas a definite need for a glossary of the animal husbandry -termsused in English and Spanish, both to facilitate understanding ofthe more or less comparable terms used in the two languages, andto help in clarifying the meanings of the varying Spanish termsused in different parts of Latin America. This need found specificexpression in a recommendation of the Bauril meeting that theFood and Agriculture Organization of the United Nations shouldconsider the preparation and publication of such a glossary.

A similar need had been felt in Europe, and the Sixth Inter-national Congress of Animal Production, held in Copenhagen, Den-mark, in July 1952, had recommended the preparation of a multi-lingual glossary of animal husbandry terms. Arrangements havebeen made between FAO and the European Association of AnimalProduction to co-operate in the preparation of such a glossary inEnglish, French and German, following the recommendation ofthis congress.

A very substantial effort is required to produce a glossary evenin one language, and the effort required for a glossary in two,three or four languages must usually extend over several years.To avoid duplication of effort, and in view of the fact that consid-erable progress had already been rnade on the English-Frerich-German glossary, it was agreed at the Buenos Aires meeting thata number of governments in various geographic areas of LatinAmerica should be asked to designate workers who are competentin the field and who could co-operate with FAO in the completion ofthe Spanish section, basing their work on the material preparedfor the English-French-Gerinan sections with adaptations to includeany special terms peculiar to Latin America.

In view of the many problems which must be solved in thepreparation of a glossary, while avoiding making the task unduly-large and the glossary too cumbersome, it seems desirable to givea brief account of these problerns here. FAO has already gainedconsiderable experience in the solution of these problems in thepreparation of a multi-lingual vocabulary of soil science (Jacks,1954).

The consultants to FAO and the European Association of Ani-mal Production, and members of the FAO staff themselves who

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have been giving attention to the detailed problems of preparino-,a glossary have become increasingly aware of,the need for a glos-sary since no publication of this kind exists;;:H

There are several dictionaries devoted to agricultural terms, butsome of them are insufficiently exact. They do not cover syno-nyms, and they fail almost entirely to explain the nuances of dif-ferent words. In a number of cases, words and phrases are usedin one language which have no corresponding expression in others.In other cases words, which are very similar in different languages,have diverse meanings, and there also exist various synonyms forthe same concept. All these differences require study an.d ex-planation. In view of this, it is considered that a dictionary whichgives merely the corresponding words in various languages wouldbe insufficient, and that a publication is needed in which at leastparts of the concepts that could not be easily translated from onelanguage to another are defined. It is felt that the work planned,if executed in the way outlined below, would contribute greatly tothe uniformity of understanding which would, of course, be of greatbenefit to all workers in animal husbandry.

As regards the layout of the glossary, it was originally sug-gested that it should be assembled in alphabetical order, and notdivided up according to subject member, and with as many sec-tions as languages to be included in the work. This would greatlyincrease the printing cost, however, and consideration has beengiven to an alphabetical index in each language to give readycross reference to -terms in other languages, arranged according tosubjects. The view has also been expressed that illustration:3 anddiagrams would facilitate the work, and would dispense with leng-thy explanations in some cases. However, this would also increasethe cost substantially. It has also been emphasized that explana-tions are necessary where the concepts are not clear, and whenthey are different in the various languages, as in cases wheresimilar words have different meanings in different languages. Ifthe corresponding word has a wider or more limited meaning, itmight be indicated in italics. Where synonyms exist, these -wouldbe listed after the word indicated, and the country of origin wherethey are used would also be given where possible. More com.-monly used synonyms would be indicated in different type.

It has been decided that, at least for the time being, thework should be limited to the following fields:

(1) animal husbandry- in general (breeding, genetics, management,animal nutrition including grazing but excluding range man-agement, organization of, and research in, animal husbandrylegal terms, as far as they refer to animal production);

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horse production, don.keys an.d mules; including, to a limitedextent, the most important expressions referring to harnessing,but excluding technical racing and sporting terms;

cattle production (including buffaloes and dairy 'husbandry,but excluding dairy -technology);

sheep production.;

goat production; and

pig production.

In principle the following will be excluded:

all terms which can be easily found in an ordinary- dic-tionary, and which could not be considered technical;

all terms referring to agriculture in general, and in particularcrop husbandry and land and water use -terms;

veterin.ary terms, including anatomy and physiology (however,such terms which are concurrently used in animal husbandryand feeding could be included to a limited extent theseterms which are in very close relation to the physiology ofnutrition should also be included, as well as terms of phy-siology and anatomy which are most comm.only used in. regardto animal production), and

terms referring to the technology of processing of animalproducts.

Scientific terms should be included on a limited scale, andonly those which are more commonly used in papers referring toanimal husbandry. In general, explanation of such terms shouldbe restricted as far as possible, and omitted for terms of basicscience, such as pH, vitamin.s, antibiotics, etc. Scientific namesin Latin or Greek or chemical names should be included to a li-mited extent. Chemical formulae should be employed only whereessen.tial in giving explanation.s.

Literature Cited Regarding Glossaries

JACKS, G.V. Multi-lingual Vocabulary of Soil Science. Food and Agri-culture Organization of the United Nations, Rome, Italy, 1954.

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Proposals for Further Meetings and for a WorkingParty and Sub-Groups to Facilitate Co-operationbetween Meetings

Inter-governmental co-operation on animal production pro-.blems is a relatively new undertaking. Various types of organ-izations have been developed to serve the interests of the livestockindustry and national bodies for this purpose usually consist ofprofessional workers in the animal husbandry an.dior veterinaryfields, who have banded together to enable them to exchan.gemore readily information on the results of their research and tostrengthen their activities in other ways. In some countriesorganizations of producers also occupy an important place in thelivestock industry. In some instances, organizations are basedon a combination of producer and professional participation. Inone region, namely Europe, an association has been formed forthe benefit of animal husbandry in all the countries of the region.This is known as the European Association for Animal Production,and it is made up of national organizations, one from each parti-cipating country. These n.ational organizations vary considerablyin their make-up, ran.ging from organization.s of professional workersto producer organizations, and even to scientific organization.shaving broader academic interests. Still another type of inter-national organization is the internation.al congress. One example isthe International Congress on Animal Production, which is noworganized at intervals under the auspices of the European Associa-tion of Animal Production, and in which most of participantshave been from European countries. Another example is theInternational Veterinary Congress. These congresses are esSen-tially meetings in which scientists present papers on the results oftheir research and are not intended to serve as a basis for thedevelopment of inter-country co-operation at the governmentle-v-el. Two veterinary organizations at the inter-governmentallevel are mention.ed elsewhere in this publication. They are theInternational Office of Ephizootics, founded in 1924 with head-quarters in Paris, and the recently established European Commis-sion for the Control of Foot-and-Mouth Disease, which functionswithin the framework of FAO.

Thus, within the Kingdom of Pan, there has been a consid-erable exchange of knowledge and experience at the scientific level,but there have been few attempts to develop inter-governmentalco-operation except those aimed specifically at the control ofdisease. Even at the scien.tific level a remarkable degree of isola-tion still exists in many parts of the world.

In an effort to facilitate the exchan.ge of information among

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countries, and to provide bases for inter-country co-operationwhere such co-operation would be mutually ben.eficial to two ormore countries, FAO has organized a considerable number oftechnical meetin.gs. These have usually been on a regional ratherthan a world-wide basis, and the three meetings held in a seriesat Turrialba, Baurti. an.d Buenos Aires are examples. Thesemeetings, held in various parts of the world, have given attentionto many phases of agriculture, and the technical workers partici-pating in them as represen.tatives of their respective governmentshave generally welcomed the opportunities provided for themaking of contacts and exchanging information with their col-leagues in neighborin.g countries. There have also been nu-merous cases where -these technical consultations have led to thedevelopment of inter-country co-operation on specific problems.One result of such meetings is a demand for some more formaltype of organization to ensure the continuation of the contactsand the co-operative efforts arising therefrom.

This latter point is illustrated by the suggestion which arosefrom the Bauni Meeting that some type of organization shouldbe considered for the continuation of inter-country collaborationon livestock production problems in the Americas. The BuenosAires meeting, therefore, considered the various methods whichmight be adopted within the framework of FAO to achieve thisobjective. These methods include the following:

The formation of informal groups of correspondents, themembers of which are designated for each country by theirrespective governments, to main.tain correspondance with theappropriate staff members of FAO concerning developmentsin their own countries and to receive from FAO staff mem-bers and correspondents in other countries information thatmight benefit them an.d their colleagues in their work.The convening of meetings at intervals to deal with specificsubjects. For example, in Europe a series of eight annualmeetings have been held to deal with hybrid maize and withthe development of inbred lines for the production of hybrids.The series of three meetings on livestock production in th.eAmericas held thus far is another example of this type ofactivity. No formal, continuing organization is involved andthe meetings are convened by the Director-General of FAOafter having been included in the Program of Work approvedby the FAO Conference.Th.e establishment of continuing workin.g parties which meetat intervals, usually annu.ally or biennially, o deal withspecific -technical problems. The Working Party- on Alledi-terranean Pasture and Fodder Development is an example

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of this kind of activity. It differs from the series of annualmeetings mentioned in item 2 in that the organization issomewhat more formal. Governments are invited to desig-nate individual to serve as continuing members of theWorking Party and these members serve as contact pointsfor correspondence and other activities in the intervalsbetween meetings. Formal meetings of such working partiesare convened by the Director-General in the same manneras meetings of the type mentioned under item (2).Formation of committees of the Council or Conference ofFAO. The membership in such Committees may be open toa selected group of countries for a particular purpose, ormay be open to all countries in a particular area. TheEuropean Committee on Agriculture, in which all MemberGovernments of FAO in Europe are invited to participate,either in its meetings or other activities recommended to theDirector-General by it is an example.Formation of permanent bodies, such as the InternationalRice Commission, -which are arms of FAO. The Interna-tional Rice Commission is the only such body thus far formedin the field of agriculture. Twenty-six of the Member Go-vernments of FA.0, representing countries in all parts of theworld where rice is an important crop, have adhered to theConstitution of -this Commission. The present practice is tohold biennial meetings and to carry out most of the technicalwork through continuing working parties or ad hoc groupsset up to deal with specific technical problems. The conti-nuing parties in this case differ somewhat from -those describ-ed under item. (3) in that in most cases each governmentwhich is a member of the Commission is invited to send arepresentative to each meeting of a working party and indi-viduals are not named to represent -their countries on acontinuing basis, although. in li.tany cases the same indivi-duals come back to the meetings year after year. The -workof the Commission, insofar as it involves time and travel ofthe FAO staff, is carried out under the Regular Budget ofthe Organization. However, provision is made in the Consti-tution of the International Rice Commission whereby govern-ments may make special contributions for co-operative projects,of which the international rice hybridization scheme nowoperation is an example, and.Establishincr commissions or bodies as arms of FAO to carryout specific action programs, the only example to date in thefield of agriculture being the European Commission for theControl of Foot-and-Mouth T.)isease. This type of commis-sion differs from the one described under item (5) in that

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the participating governments agree to supply special fun.dsto finance the work of the Commission, and it is, therefore,not dependent upon funds from the regular FAO budget,although some members of the regular staff of the Organiz-ation assist in servicing the Commission.

Representatives of the governments who attended the BuenosAires meeting gave careful attention to the advantages and dis-advantages of the various approaches which might be adopted tofollow-up the Turrialba, Baurti. and Buenos Aires meetings, andthere was general agreement on the following points:

it would be desirable to llave some continuing organizationalarrangement to ensure regular contacts among livestockworkers in the Americas an.d the ready exchange of informa-tion among these workers;any organizational arrangement which might be developedfor this purpose should be informal and should not requireaction by parliaments to bring it into effect;full advantage should be -taken of existing organizations,both to prevent the development of additional organizationsunless absolutely necessary, and to take advantage of thetechnical competence of these existing organizations; andthe organizational arrangement which might be establishedshould provide for -technical consultation on a limited numberof selected subjects, and at the same time include provisionsfor over-all con.sultation on livestock problems. Technicalgroups should be set up where needed, by sub-regions or bysubjects, in such a way that -the varied problems and environ-mental con.ditions in the Americas are fully taken intoaccount.

With the above points in mind the representatives of govern-ments assembled at the Buenos Aires meeting recommendedthat the Director-General of FAO should invite governments toparticipate in a continuing working party on livestock productionto serve during the periods between livestock production meetings,in order to provide a continuing basis for consultation betweenthe technical workers in countries and the staff of FAO betweenmeetings, and for the co-ordination of preparations for meetingswithin countries, and that that working party's activities be car-ried on largely by correspondence. Governments should be invitedto designate a representative who could speak for the over-all live-stock and poultry interests of the respective countries, and whomight normally be designated by their governments to attendperiodic livestock production meetings convened by FAO at in-

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tervals of approximately three years. This wo'rking party wouldconsider over-all problems of livestock production, including poul-try, in the Americas, and would also have placed before it forconsideration the reports of any specialized sub-groups which mightbe formed. To meet the need for technical discussion.s of limitedsubjects, sub-groups should be formed where n.ecessary. Such sub-groups might deal with a variety of problems including:

animal climatology, including improvement of livestockproduction in the high Andean area, and livestock improve-ment under tropical conditions;improvement of grasslands and management of livestock ongrasslands in the temperate zones;improvement of grasslands and management of livestock ongrasslands in tropical and sub-tropical zones;control of foot-and-mouth disease;preparation of a Spanish section of the glossary of animalhusbandry terms, andlivestock and poultry- nutrition,

and others as may be required. The delegates to the BuenosAires meeting considered that it would be premature to makefirm recommendations at that stage concernin.g either the sub-groups which should be set up or the period for which each suchsub-group be established. They recommended, -therefore, thatfollo-wing the establishment of the over-all working party on live-stock production, FAO should consult the representatives desig-nated by governments, and, on the basis of their recommendations,should then decide which sub-groups should be convened.

The delegates to the Buenos Aires meeting also recommendedthat the fourth meeting of the series, which had included the Tur-rialba, Baurti and Buenos Aires meetings, should be held in Jamaicain 1958.

Steps are being taken by FAO to implement these recommen-dations.

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CONCLUSION

The series of three meetings held in Turrialba, Baurú andBuenos Aires in 1950, 1952 and 1955, respectively, to considerproblems of livestock production in the Americas, provided to themembers of delegations from participating countries opportunities:

to exchange information on -their problems and on the stepsbeing taken to deal with them -through research, extension,.training of technical workers, and other means;to see the production methods, -types of livestock, grasslands,and agricultu.ral institutions in three countries, namely-, Argen-tina, Costa Rica and Brazil each with its OWIl characteristicconditions and problems;to establish personal contacts Nvith workers in their own andclosely- related fields in oth.er countries, thus facilitating thedo-w of information between countries; andto improve their work in their own countries by applyinginformation obtained from workers in other countries and asa result of the stimulus emanating from the exchange ofideas with their fellow scientists.

The immediately tangible evidence of the work accomplishedin these meetings is found in the three reports, and in the presentpaper which is based to a large extent on the report of the thirdmeeting in Buenos Aires. Through these publications surnmariesof the most important information presented at the meetings ismade available to leaders and technical workers in the livestockindustry in all countries. But the intangible results of the meetingsare no doubt much more important because, although not readilymeasurable, they are found in improved services to the livestockindustries in the various countries, and in programs which havebeen initiated or improved as a result of the stimulus of the meet-ings which will eventually result in improved services.

The participants in these meetings, recognizing the value ofthe inter-country consultations provided for therein, consideredthat some more formal arrangement should be made to ensurecontinued contacts between countries, particularly during theintervals between meetings. They, therefore, recommended atthe Buenos Aires meeting that the Director-General of FAO shouldestablish an inter-governmental working party to provide for this

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continuing consultation on livestock problems in the Americas.Action to implement this recommendation has been initated.

At the first meeting at Turrialba, an.d again at the second onein Baurú, members of delegations had an opportunity of discussin.gproblems relating to all aspects of livestock production. On thebasis of the interest shown in various problems, and the nature ofthe problems which appeared to require special attention leadingto their solution., a limited list of topics was selected for consid-eration at the third meeting in Buenos Aires. After consideringthese topics, and deciding upon the type of organization that theywished to recommend to ensure continuing consultation, the parti-cipants selected a still more limited group of subjects to whichattention might be given by specialized sub-groups of the workingparty mentioned in the previous paragraph. This limited list willbe subjected to further review by the working party itself as oneof its first major functions after members have been designated byparticipating governments.

Thus, the three meetings have provided an opportunity forthe gradual sorting out a of relatively few subjects upon whichdefinite steps may be taken to develop inter-country co-operation.,and the work initiated at the meetings will enter a new phase.In the work thus far the emphasis has been on the exchange ofinformation.. In the phase which is now beginning -through theestablishment of a working party and consideration of the estab-lishment of sub-groups, the emphasis will be much more on thedevelopment of inter-country co-operation in limited fields, althoughthe opportunities for exchange of information in these and otherfields is expected to continue in the series of meetings, the fourthof which has been recommended to be held in Jamaica in 1958.This Development Paper may, therefore, be regarded as a bridgebetween the two phases of activity, providing an end-point forthe first phase, and a point of departure for the second phase whichtook definite form as a result of the discussions in the BuenosAires meeting.

181

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Report of the lnter-American Meeting on Livestock Prod-uction. 1950, 100 pp. (E S) $0.50 2s. 6d.

Report of the Second inter-American Meeting on LivestockProduction. June 1953, vii -I- 138 pp. (E S) $1,50 7s. 6d.

improving Livestock under Tropical and Subtropical Con-ditions. July 1950, iv + 55 pp. (E F) $0.50 2s. 6d.

joint FAO/WHO Expert Panel on Brucellosis. Second Re-port. 1953, 36 pp. (E F) $0.25 ls. 3d.

joint WHO/FAO Expert Group on Z.00noses. Report on theFirst Session, Geneva, 11-16 December, 1950. (E F) ,$0.30 ls. 6d.

Advance in the Control of Zoonoses. November 1953, 275 pp.,tables, illustrations. (E F) $3.00 15s. Od.

Manual of Field Studies on the Heat Tolerance of DomesticAnimals, by Dr. Douglas H. K. Lee. December 1953, x + 162 pp.illustrations (E F S) $2.00 10s. Od.

Improving the World's Grasslands, by A. T. Semple, Decem-ber 1951, iii + 147 pp., 107 illustrations, 12. tables. (E F S) $2.00 10s. Od.

Legumes in Agriculture, by R. O. Whyte, G. Nilsson-Leissneranc.1 H. C. Trumble. April 1953, xiii + 367 pp. (E F S) $3.00 15s. Od.

Flaying and Curing of Hides and Skins as a Rural Industry.May 195$, vii + 136 pp., illustrations (E F S) $1,50 7s. 6d.

Milk Pasteurization - Planning, Plant, Operation and Con-trol, by H. D. Kay, J. R. Cuttel, H. S. Hall, A. T. R. Mattick anclA. Rowlands, May 1953, 204 pp., illustvations (E F S) $2.50 12s. 6d.

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