University of Nebraska Cooperative Extension EC 02-219-A ...University of Nebraska Cooperative Extension EC 02-219-A NEBRASKA SWINE REPORT lNutrition lGenetics lReproduction lEconomics

University of Nebraska Cooperative Extension EC 02-219-A

NEBRASKASWINEREPORT

l Nutrition

l Genetics

l Reproduction

l Economics

l Housing

l Meats

2002

Cooperative Extension DivisionAgricultural Research Division

Institute of Agriculture and Natural ResourcesUniversity of Nebraska-Lincoln

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperationwith the U.S. Department of Agriculture. Elbert C. Dickey, Dean and Director of Cooperative Extension,

University of Nebraska, Institute of Agriculture and Natural Resources.

University of Nebraska Cooperative Extension educational programs abide with the non-discrimination policies of the University of Nebraska-Lincolnand the United States Department of Agriculture.

Prepared by the staff in Animal Science and cooperating Departments for use inExtension, Teaching and Research programs.

Web site:www.ianr.unl.edu/pubs/swine/pigpdf.htm

2002 Nebraska Swine Report — Page 2

Table of ContentsNutrition

Comparison of Swine Performance When Fed Diets Containing Roundup Ready® Corn, Parental Line Corn,or Two Commercial Corns............................................................................................................................................................... 7

Niacin and Vitamin B12

Requirements of Weanling Pigs...................................................................................................................... 12Phytase Sources in Pelleted Diets.......................................................................................................................................................... 15Managing Swine Dietary Phosphorus to Meet Manure Management Goals..................................................................................... 18Update on the Economics of Feeding Ractopamine (PayleanTM) to Finishing Pigs............................................................................ 21Defining the Optimal Feed Budget System for Terminal-Crossed, Growing-Finishing Barrows..................................................... 25Effects of Glutamine on Growth Performance and Small Intestine Villus Height in Weanling Pigs................................................. 29Influence of Linoleic Acid Isomers on Body Fat.................................................................................................................................. 32Dietary Amino Acid Utilization for Body Protein Deposition-Current and Future Research......................................................... 35

GeneticsReproductive Responses in the NE Index Line Estimated in Pure-line and Crossbred Litters......................................................... 37Growth and Carcass Responses in the NE Index Line Estimated in Pure-line and Crossbred Litters............................................. 41Economic Analysis of the Selection Response to the NE Index Line................................................................................................. 44PAYLEAN® Improves Growth and Carcass Merit of Pigs with 25% and 50% Nebraska Index Line Genes................................ 47Economic Analyses of Feeding 18 g per ton PAYLEAN® to Crosses of the NE Index Line........................................................... 51

HousingApplicability of High-Rise™ Hog Housing For Finishing Operations............................................................................................... 55Sorting and Mixing Effects in a Wean-to-Finish Facility..................................................................................................................... 59

Industry IssuesCompetition - It’s Not Just “Cost” of Production.............................................................................................................................. 61

MeatsFactors Affecting Bacon Color and Composition................................................................................................................................. 66

Youth EducationEffectiveness of Pork Quality Assurance Training for Youth............................................................................................................. 70

AppendixExplanation of the Statistics Used in this Report................................................................................................................................ 74

Issued January 2002, 3,750

The 2002 Nebraska Swine Reportwas compiled by Duane Reese,Associate Professor, Departmentof Animal Science.

2002 Nebraska Swine Report

Editor: Marcia OetjenTypesetting & Design: Anne Moore

Nebraska Swine Report Acknowledgments for 2002

Alpharma, Inc, Ft. Lee, NJBASF Corp. Mt. Olive, NJ

Cooperative Extension Division, University of NE, Lincoln, NECotswold USA, Alden, IA

Danbred USA, Inc., Dorchester, NEDeKalb Swine Breeders, Inc, Dekalb, ILElanco Animal Health, Indianapolis, IN

4M Farms, Inc., New Madison, OHFort Recovery Equipment, Inc., Fort Recovery, OH

Guilini-Ladenburg, Simi Valley, CAHeartland Pork Enterprises, Inc., Alden, IA

McGill University Health Center, Montreal, QuebecMillard Processing Service, Millard, NE

Monsanto Company, St. Louis, MONational Pork Board, Des Moines, IA

Nebraska Agricultural Research Division, University of NE, Lincoln, NENebraska Pork Producers Association, Lincoln, NE

Nebraska SPF Accrediting Agency, Lincoln, NEOhio Agricultural Research and Development Center, Woostessr, OH

Red Arrow, Inc., Manitowoc, WISioux Preme Packing Co., Sioux Center, IA

U.S. Meat Animal Research Center, Clay Center, NEWaldo Farms, Inc., DeWitt, NE

Cover Photo:

Photo from USDA OnlinePhotography Center. Photoby Ken Hammond


Austin J. Lewis retired from the Animal Science Departmenton September 30, 2001 after 25 years at the University of Nebraska.Dr. Lewis was born in Poole, Dorset, England. He received his B.S.(1967) in animal production from the University of Reading,England and his Ph.D. (1971) in applied biochemistry and nutritionfrom the University of Nottingham, England. He was a postdoctoralfellow at Iowa State University from 1971-74 and a researchassociate at the University of Nebraska from 1974-75 before goingto the University of Alberta as an assistant professor in 1975. Hecame to Nebraska as an assistant professor in 1977, became anassociate professor in 1980 and was given the status of professorin 1985. During the 1996-97 academic year, Dr. Lewis was granteda sabbatical leave to do research at the Babraham Research InstituteCambridge, England. His research has been in swine nutrition with emphasis on the amino acidnutrition of swine, and this has included investigations of the amino acid requirements of allclasses of swine as well as the bioavailability of amino acids. Numerous scientific papers havebeen published based on this research. In 1987 he received the Gamma Sigma Delta ResearchAward from the Nebraska Chapter and in 1988 the Nutrition Research Award from theAmerican Society of Animal Science. Dr. Lewis has taught undergraduate and graduate courseson animal nutrition and a graduate course on protein nutrition, as well as serving as an instructorfor the Interdepartmental Nutrition Seminar. He has served as an advisor to several graduatestudents who were pursuing either a Master or Doctoral degree in swine nutrition, and as Chairof the Departmental Graduate Committee from 1998-2001. Dr. Lewis has contributed to theJournal of Animal Science as a member of the editorial board, as editor of the NonruminantNutrition section, and editor-in-chief in 1990-1993. He was a co-editor of the first and secondeditions of “Swine Nutrition” and also a co-editor of “Bioavailability of Nutrients for Animals.”He has served as a member of the subcommittees responsible for the two most recent revisionsof the “NRC Nutrient Requirements of Swine” and as a member of the Board on Agriculture,Committee on Animal Nutrition. Dr. Lewis will remain in Lincoln, where his wife, Nancy, is anAssociate Professor in the Department of Nutritional Science and Dietetics. He will continue hisaffiliation with the Animal Science Department as professor emeritus.

Austin J. Lewis


Donald G. Levis resigned his position as professor of physi-ology after 23 years at the University of Nebraska to accept aposition as coordinator of the Ohio Pork Industry Center at TheOhio State University. Dr. Levis was born in Chariton, Iowa. Hereceived a B.S. degree (Agriculture) in 1971 from NortheastMissouri State University, an M.S. degree (Animal Science) in 1972from Northwest Missouri State University and Ph.D. degree (Re-productive Physiology) in 1976 from South Dakota State. Aftercompleting his Ph.D., he moved to the Department of AnimalScience at North Carolina State University where he was anassistant professor/extension swine specialist in ReproductivePhysiology from 1976-78. In 1978 Dr. Levis moved to the Univer-sity of Nebraska, South Central Research and Extension Center, asan Assistant Professor/Extension Swine Specialist. His researchprojects on neuroendocrinology of sexual behavior of boars wasconducted at the United States Meat Animal Research Center. He became an associate professorin 1983. Don became a full professor in 1989 and moved to the Lincoln campus. During the1991-92 academic year he spent a sabbatical in Australia conducting research in reproductivephysiology at the Victorian Institute of Animal Science (Werribee, Victoria), and WesternAustralian Department of Agriculture (Perth, Western Australia). While at Nebraska his majorjob was to provide educational support in the subject matter area of swine reproductivephysiology to pork producers and the University of Nebraska Agricultural Educators. Duringthis time he come in contact with over 23,000 people in Nebraska and the United States. He isnationally and internationally known for designing the LEVIS Swine Breeding facility and hiswork with artificial insemination (A.I.) of pigs. His educational information on breeding facilitydesign, A.I., and reproductive management of the breeding herd has gained state, national andinternational exposure through published articles and pork industry meetings. Dr. Levis hastraveled to many foreign countries to present seminars and conduct farm visits. He publishedmany extension articles on A.I. and reproductive management of pigs. He personally designednumerous swine breeding facilities for individual pork producers. During his tenure at Nebraskahe received the Distinguished Extension Specialist Award from the University of Nebraska in1988, the Dedicated Service to Pork Industry from the Nebraska Pork Producers Associationin 1988, the Livestock Service Award from the University of Nebraska in 1989, Excellence inTeam Programming from the University of Nebraska in 1991 and 1994, and in 1998 he receivedthe Extension Award from the American Society of Animal Science. He has published manyarticles in trade journals, proceedings and other extension publications.

Donald G. Levis


Thomas Long resigned his position as assistant professor/swineextension specialist in January 2000 to accept a position with National PigDevelopment (NPD) in North Carolina.

Dr. Long received his B.S. and M.S. degrees from the University ofIllinois in 1975 and 1985, respectively. His Ph.D. degree was from theUniversity of Nebraska in 1989. Prior to obtaining his M.S. degree, Dr.Long worked in the pork industry for seven years.

After receiving his Ph.D., he moved to Australia to work as coordinatorof the Pig Genetics Program at the Animal Genetics and Breeding Unit,University of New England, Armidale, New South Wales. His responsibili-ties there included maintenance and implementation of PIGBLUP, a soft-ware system used for genetic evaluation of pigs. He also conductedextension activities with the Australian Pig Industry on a national scale andserved as the genetic technical advisor to the pig branch of NSWAgriculture.

Dr. Long returned to the U.S. in 1994 to accept a position as assistant professor/swine specialistat the West Central Research and Extension Center at North Platte. His responsibilities includeddevelopment and implementation of a research program in sow and litter management with emphasison genetic x environmental interactions. He also provided leadership for swine management extensionprogramming in the West Central and Panhandle districts as well as statewide leadership for programsin swine breeding.

Dr. Long is currently the director of genetics and research at NPD. His responsibilities includeestablishing the direction of breeding and selection programs within NPD as well as guiding researchinitiatives within this organization.

Robert W. Wills resigned his extension swine veterinarian position atthe University of Nebraska in 2000 to accept a position in the College ofVeterinary Medicine at Mississippi State University. Dr. Wills received hisB.S. degree in 1978 from the University of Missouri, an M.S. degree in 1980from the University of Tennessee - Knoxville, and his DVM in 1984 fromthe University of Missouri. In 1996 he received his Ph.D. from Iowa StateUniversity. Prior to starting this Ph.D. program, Dr. Wills worked as aprivate veterinarian/partner at the Fayette Veterinary Clinic in Iowa.

Dr. Wills has written several articles for referred journals, most notablyregarding the transmission of the PRRSV to swine. He has conducted manyworkshops and seminars in the United States and other countries. Dr. Willsalso developed many educational aides and materials that are useful to porkproducers. He was instrumental in increasing the number of pork producersin Nebraska who were certified Level III in the NPPC Pork QualityAssurance Program and for helping many to make a decision whether or not to adopt composting asa method of mortality disposal.

In his current position as an associate professor of Epidemiology, Dr. Wills conducts researchprojects with swine and poultry. He also teaches veterinary students about epidemiology, swinediseases, and the pork industry. His extension efforts are focused on using epidemiology to improveanimal health and to promote food safety.

Thomas Long

Robert W. Wills


Larry Bitney , professor of agricultural economics, is retir-ing after 41 years of service to the University of Nebraska. Dr.Bitney is a native Nebraskan, born near Neligh. He received hisB.S. degree in 1958 and his M.S. in 1965, both in agriculturaleconomics from the University of Nebraska. He received hisPh.D. degree in agricultural economics from Oklahoma StateUniversity in 1969.

Dr. Bitney was hired as an assistant county extension agentin Dodge County in 1959 with primary responsibility for the Farmand Home Development Program, teaching families how toanalyze their farm records. He moved to Lincoln in 1963, as anassistant extension economist in the Department of AgriculturalEconomics. In 1965 he became leader of NEBFARM, an elec-tronic mail-in farm records and analysis program. After a two-year break at Oklahoma StateUniversity for his Ph.D. degree, he returned to the UNL Department of Agricultural Economicsin 1968 as associate professor with an extension-research appointment. He was promoted tofull professor in 1974. For two years beginning in 1982, Dr. Bitney held a 50 percentappointment with Extension Service-USDA in Washington D.C., providing national leadershipin farm financial management programming. After a sabbatical leave with the MIAC Moroccoproject in Settat, Morocco in 1990/91, he served for two years as the campus coordinator forthis USAID funded project.

Larry led or co-led the following educational programs: Managing for Tomorrow, Farm &Ranch Financial Counseling Service, Swine Enterprise Records and Analysis Program, andDecisions Now — Building Your Future. He supervises staff members who lead the Women inAgriculture programs, the UNL Beginning Farmer program, and the Returning to the Farmprogram. Dr. Bitney has been a member of the Pork Interest Group since its start in 1994. PorkCentral originated from efforts of this group and was started in 1996 as a cooperative effort ofNebraska Cooperative Extension and the Nebraska Pork Producers Association. He has servedas the fiscal manager of this program and as day-to-day supervisor of Al Prosch, the PorkCentral coordinator.

Dr. Bitney worked with a graduate student, James Friesen, in 1989 on an economic analysisof three pseudorabies eradication alternatives for Nebraska. Results from this project, fundedby the Nebraska Pork Producers Association, were used by state senators in drafting legislationfor the Nebraska pseudorabies eradication program. He has conducted economic analysis ofmany technologies related to the swine industry. Most of these efforts have been to helpproducers make decisions on the adoption of the technology or practice. Results have typicallyappeared as co-authored articles in the Nebraska Swine Report.

Among the awards that Dr. Bitney has received are the UNL Distinguished EducationService Award, USDA Superior Service Award, Distinguished Extension Specialist Award,IANR Team Effort Award, and Excellence in Team Programming awards.

Larry Bitney


Comparison of Swine Performance When FedDiets Containing Roundup Ready® Corn,

Parental Line Corn, or Two Commercial CornsRobert L. FischerAustin J. Lewis

Phillip S. Miller 1

Summary and Implications

This experiment was conducted toevaluate growth performance andcarcass quality measurements ingrowing-finishing pigs fed dietscontaining either Roundup Ready®corn expressing the CP4 EPSPSprotein, the parental control corn, ortwo commercial sources of non-genetically modified corn. The experi-ment used 72 barrows and 72 gilts withan initial body weight of 50 lb. Thepigs were allotted to a randomizedcomplete block design with a 2 × 4factorial arrangement of treatments(two sexes x four corn hybrids). Theexperiment continued until the aver-age body weight was 255 lb, at whichtime all pigs were slaughtered. Real-time ultrasound measurements weretaken on the final day of the experi-ment. Carcass quality measurementswere made 24 hours postmortem. Aver-age daily gain (ADG), average dailyfeed intake (ADFI), and feed efficiency(ADG/ADFI) were not affected by cornvariety, but there was an effect of sexfor all growth performance traits, withbarrows having greater (P < 0.001)ADG and ADFI than gilts and giltshaving better (P < 0.001) feed effi-ciency than barrows. Real-time ultra-sound measurements were similaramong corns, however a sex effect wasdetected for backfat (BF) depth, withgilts having less (P < 0.001) BF than

barrows. There were no differences incarcass midline BF measurementsamong corns, but there was a signifi-cant difference between barrows andgilts, with gilts having less (P < 0.05)BF than barrows. Total body electri-cal conductivity measurements werenot affected by corn, but hot carcassweight was greater (P < 0.001) inbarrows than gilts. Also, primal per-centage and percent carcass lean weregreater (P < 0.01) in gilts than bar-rows. Longissimus muscle quality scoreswere similar among corns and betweenbarrows and gilts, except for pH, whichwas greater (P < 0.05) in barrows thangilts. Analysis of longissimus musclecomposition revealed no main effect ofcorn variety (P > 0.05) or effect of sex(P > 0.05) for protein, fat, and waterpercentages. Roundup Ready® corn(2.99%) differed (P < 0.04) fromparental control corn (2.20%) but notcommercial corns (3.08 and 3.06%) inlongissimus fat content. In summary,there were no differences in growthperformance or carcass measurementsin growing-finishing pigs fed dietscontaining either Roundup Ready®corn, the parental control corn, or twocommercial sources of non-geneticallymodified corn. Roundup Ready® corncan replace traditional corn in dietsfor growing-finishing pigs.

Introduction

Genetically modified crops offerproducers a wide variety of agronomicbenefits. The use of Roundup Ready®corn provides flexible and broad-spec-trum, post-emergent weed control.

Glyphosate, which is the active ingredi-ent in the herbicide Roundup, is one ofthe most widely used herbicides in theworld. Therefore, Roundup Ready® cornwas developed to be tolerant toglyphosate. Previous experiments con-ducted with pigs and chickens havedemonstrated that genetically modifiedcorns are substantially equivalent tonontransgenic corn. Therefore, theobjective of this study was to comparegrowth performance and carcass qual-ity measurements in growing-finishingpigs fed diets containing either RoundupReady® corn (CRR 0633), the parentalcontrol corn (RX 670), or two commer-cial sources of non-genetically modi-fied corn (RX 760 and DK 647).

Procedures

Animals and Treatments

A total of 144 crossbred (PIC ×Duroc × Hampshire) barrows and giltswith an initial BW of 50 lb were used.The pigs were allotted to a randomizedcomplete block experiment with a 2 × 4factorial arrangement of treatments.Blocks were based on initial weightand pen location within the building.There were two sexes (barrows andgilts) and four genetic corn lines(RX 740, DK 647, RX 670, and CRR0633). Diets (Table 1) contained cornand soybean meal and were fortifiedwith vitamins and minerals to meet orexceed the NRC (1998) requirements for44- to 265-lb pigs. There were four dietphases during the experiment (Grower1, Grower 2, Finisher 1, and Finisher 2).

(Continued on next page)


0633). Also, the sex × corn line inter-action was included in the statisticalanalysis. Contrasts were performed tocompare the transgenic line with itsparental control (CRR 0633 vs RX 670)and with the two commercial referencelines (CRR 0633 vs RX 740 and DK 647).In all analyses pen was the experimentalunit.

Results

Growth Performance

Average daily gain, ADFI, and feedefficiency (ADG/ADFI) for the four dietphases and the entire experimentalperiod are shown in Table 2. During thefour diet phases, ADG, ADFI, and feedefficiency were not affected (P > 0.30)by corn variety. Average daily gain wasgreater (1.65, 2.27, 2.34, and 2.23 lbversus 1.57, 1.94, 2.12, and 2.07 lb;P < 0.05) in barrows than gilts duringthe four diet phases. Also, ADFI wasgreater (3.26, 5.42, 6.86, and 7.32 lbversus 3.09, 4.65, 5.84, and 6.42 lb;P < 0.05) in barrows than gilts duringthe four diet phases, respectively. Dur-ing the Finisher 1 and 2 periods, giltshad better (0.36 and 0.32 versus 0.34and 0.30; P < 0.01) feed efficiency thanbarrows, with no differences (P > 0.53)between barrows and gilts during theGrower 1 and 2 periods. Results of theoverall experimental period indicate nodifferences (P > 0.54) among corn vari-eties for ADG, ADFI, and feed effi-ciency. However, overall ADG (2.12versus 1.92 lb) and ADFI (5.58 versus4.87 lb) were greater (P > 0.001) in bar-rows than gilts, and overall feed effi-ciency was better (0.39 versus 0.38;P < 0.001) in gilts than barrows.

Carcass Characteristics

Real-time ultrasound, carcass, andTOBEC measurements are summarizedin Table 3. Ultrasound measurementsof tenth-rib BF and LMA did not differ(P > 0.38) among corns, but tenth-rib BFwas greater (P < 0.001) in barrows (0.91in) than gilts (0.72 in). Carcass BF (firstrib, tenth rib, last rib, and last lumbar)measurements were similar (P > 0.43)

Table 1.Ingredient and calculated composition of diets, as-fed basis.

Dietary Phases

Ingredients, % Grower 1 Grower 2 Finisher 1 Finisher 2

Corna 68.07 74.21 78.11 81.79Soybean meal (46.5% CP) 26.00 20.25 16.25 12.75Tallow 3.00 3.00 3.00 3.00Dicalcium phosphate 1.25 0.85 0.93 0.75Limestone 0.40 0.40 0.40 0.40Salt 0.30 0.30 0.30 0.30Vitamin premix

b0.70 0.70 0.70 0.70

Trace mineral premixc

0.10 0.10 0.10 0.10Antibiotic 0.13 0.13 0.13 0.13Lysine•HCl 0.05 0.06 0.08 0.08

Calculated nutrient content

Crude protein, % 18.10 15.80 14.30 12.10Lysine, % 1.00 0.85 0.75 0.65ME

d, Mcal/lb 1.56 1.57 1.57 1.57

Calcium, % 0.70 0.60 0.60 0.55Phosphorus, % 0.60 0.50 0.50 0.45

aThe only difference in the four diets within each dietary phase was the addition of the different

genetic corn lines.bSupplied per kilogram of diet: retinyl acetate, 3,088 IU; cholecalciferol, 386 IU; α-tocopherol

acetate, 15 IU; menadione sodium bisulfite, 2.3 mg; riboflavin, 3.9 mg; d-pantothenic acid, 15.4mg; niacin, 23.2 mg; choline, 77.2 mg; vitamin B

12, 15.4 µg.

cSupplied per kilogram of diet: Zn (as ZnO), 110 mg; Fe (as FeSO

4•H

2O), 110 mg; Mn (as MnO),

22 mg; Cu (as CuSO4•5 H

2O), 11 mg; I (as Ca(IO

3)•H

2O), .22 mg; Se (as Na

2SeO

3), .3 mg.

dMetabolizable energy.

Each diet phase was 28 days, exceptFinisher 2, which was 19 days. Thisresulted in a total experimental periodof 103 days.

The pigs were housed in a modi-fied-open-front building with 24 pens(pen dimensions 4.95 ft × 15.84 ft),and each pen contained six barrowsor gilts. Pigs had ad libitum access tofeed and water throughout the experi-mental period. Pigs remained on theexperiment until the average bodyweight of the pigs reached approxi-mately 255 lb, at which time all pigswere removed from the experiment.

Data and Sample Collection

Pigs were weighed and feed intakeswere measured biweekly to determineADG, ADFI, and feed efficiency (ADG/ADFI). Real-time ultrasound meas-urements were taken at the end of theexperiment by a certified technician,and tenth-rib backfat (BF) depth andlongissimus muscle area (LMA) wererecorded. At the termination of theexperiment, pigs were shipped toSiouxPreme Packing Co. in Sioux

Center, Iowa, where carcass charac-teristics were measured on individ-ually identified pigs using total bodyelectrical conductivity (TOBEC). At24 hours postmortem, midline BFmeasurements (first rib, tenth rib, lastrib, and last lumbar) and LMA traces atthe tenth rib were collected on all thecarcasses. Carcass quality tests werealso performed at 24 hours postmortem.These tests were on the longissimusmuscle at the tenth rib and included pH;firmness and marbling scores; andMinolta L*, a*, and b* values. A loinsample was collected from each carcassat the tenth rib and ten loin samples pertreatment (five barrows and five gilts)were used to determine longissimusmuscle chemical composition (pro-tein, fat, and water).

Statistical Analysis

Data were analyzed as a random-ized complete block design usingPROC MIXED of SAS. The main effectsin the statistical model were sex(barrows and gilts) and genetic cornline (RX 740, DK 647, RX 670, and CRR


among corns, but differences (1.80, 1.29,1.44, and .99 in versus 1.81, 1.09, 1.30,and .83 in; P < 0.05) between barrowsand gilts for all carcass BF measure-ments were detected with no differ-ences (P > 0.14) in LMA. Total bodyelectrical conductivity measurementsfor hot carcass weight (203 lb versus188 lb; P < 0.001), shoulder weight(27.52 lb versus 26.81 lb; P < 0.08),and total lean (99.36 lb versus 96.98 lb;P < 0.10) were greater for barrowsthan gilts. However, gilts had a greater(39.97% versus 37.77%; P < 0.0001)percentage of primal weight in rela-tion to hot carcass weight and a greater(51.50% versus 49.02%; P < 0.01)percentage of fat-free lean compared tobarrows. The TOBEC measurements didnot differ among corns (P > 0.30). Car-cass fat-free lean gain calculated fromTOBEC measurements was not affectedby either sex or corn variety (P > 0.14).

Longissimus Muscle Quality Scoresand Composition

Longissimus muscle quality scoresfor pH; marbling and firmness; andMinolta L*, a*, and b* values were notaffected (P > 0.32) by sex or corn line,except for pH which was greater(P < 0.05) in barrows (5.65) than gilts(5.60) (Table 4). Protein and waterpercentage of the longissimus musclewere similar (P > 0.21) between barrowsand gilts and among corns. The longis-simus muscle fat percentage wasinfluenced by sex (P = 0.07) and cornvariety (P = 0.07). The geneticallymodified corn (CRR 0633) vs parental(RX 670) comparison resulted in adifference (P < 0.04) in longissimusmuscle fat percentage with pigs fedthe parental corn (2.20%) having lessfat than pigs fed the geneticallymodified corn (2.99%).

Discussion

The results indicate no significantdifferences among the corns for ADG,ADFI, or feed efficiency. However, inthe present study, traditional sex differ-ences between gilts and barrows wereobserved in growth performance. Recentexperiments using barrows and giltsduring the finishing period have shownthat barrows have greater ADG andADFI than gilts. However, in these sameexperiments, gilts had superior feedefficiency compared to barrows.Results of the current experiment sup-port the results of previous experimentsand indicate the same differences inADG, ADFI, and feed efficiencybetween barrows and gilts.

Dietary treatment did not affectultrasound and carcass measure-ments, however a difference in backfat

Table 2. Growth performance of barrows and gilts.a

Genetic Line P-Value b

Item RX 740 DK 647 RX 670 CRR 0663 SEM T r t Sex Trt × Sex GMO vs Pc

GMO vs Convd

No. pens 6 6 6 6

Initial wt., lb 49.79 49.79 49.74 49.70 0.075 NS <0.001 NS NS NS

Final wt., lb 256.24 257.21 256.88 256.57 3.274 NS <0.001 NS NS NS

Grower 1ADG, lb 1.58 1.65 1.58 1.60 0.029 NS 0.008 NS NS NS

ADFI, lb 3.14 3.24 3.14 3.20 0.051 NS 0.007 NS NS NS

ADG/ADFI 0.50 0.51 0.50 0.50 0.009 NS NS NS NS NS

Grower 2ADG, lb 2.11 2.11 2.11 2.08 0.031 NS <0.001 NS NS NS

ADFI, lb 5.02 5.04 5.09 5.01 0.093 NS <0.001 NS NS NS

ADG/ADFI 0.42 0.42 0.41 0.42 0.007 NS NS NS NS NS

Finisher 1ADG, lb 2.24 2.20 2.25 2.23 0.047 NS 0.001 NS NS NS

ADFI, lb 6.31 6.27 6.43 6.39 0.146 NS <0.001 NS NS NS

ADG/ADFI 0.36 0.35 0.35 0.35 0.010 NS <0.001 NS NS NS

Finisher 2ADG, lb 2.13 2.15 2.15 2.17 0.053 NS 0.012 NS NS NS

ADFI, lb 6.75 6.86 6.82 7.03 0.147 NS <0.001 NS NS NS

ADG/ADFI 0.32 0.31 0.32 0.31 0.010 NS 0.001 NS NS NS

OverallADG, lb 2.00 2.01 2.01 2.01 0.030 NS <0.001 NS NS NS

ADFI, lb 5.18 5.22 5.24 5.27 0.094 NS <0.001 NS NS NS

ADG/ADFI 0.39 0.39 0.38 0.38 0.006 NS 0.001 NS NS NS

aTwo pigs removed from the data set.

bTrt = treatment; GMO = genetically modified organism; P = parental control line; Conv = conventional lines; and NS = nonsignificant effect,

P > 0.10.cTransgenic line (CRR 0633) comparison with parental control line (RX 670).

dTransgenic line (CRR 0633) comparison with conventional lines (RX 740 and DK 647).



Table 3.Ultrasound and carcass measurements.a

Genetic Line P-Valueb


GMO vs Convd

Ultrasound measurementsBackfat, in 0.82 0.81 0.82 0.83 0.031 NS <0.001 NS NS NSLMA e, in2 7.25 7.43 7.58 7.51 0.136 NS NS NS NS NS

Carcass measurementsf

First rib, in 1.88 1.89 1.87 1.87 0.060 NS 0.037 NS NS NSTenth rib, in 1.18 1.17 1.17 1.21 0.029 NS <0.001 NS NS NSLast rib, in 1.42 1.35 1.33 1.38 0.041 NS 0.006 NS NS NSLast lumbar, in 0.91 0.89 0.91 0.93 0.030 NS <0.001 NS NS NSLMA, in

28.57 8.77 9.08 8.77 0.313 NS NS NS NS NS

TOBEC measurementsHot carcass wt., lb 194.86 196.28 195.64 195.72 1.400 NS 0.001 NS NS NSHam wt., lb

h22.48 22.61 22.33 22.40 0.266 NS NS NS NS NS

Loin wt., lbh 25.87 26.76 26.18 26.35 0.322 NS NS NS NS NSShoulder wt., lb

h26.93 27.39 27.21 27.10 0.365 NS 0.077 NS NS NS

Primal percentagehi

38.68 39.04 38.87 38.88 0.372 NS <0.001 NS NS NSTotal lean, lb

g93.85 93.41 93.02 92.77 1.315 NS 0.092 NS NS NS

Percent leang

48.22 47.51 47.67 47.59 0.570 NS 0.001 NS NS NSLean gain, lb/dj 0.76 0.75 0.75 0.75 0.013 NS NS NS NS NS

aUltrasound data set contains 142 pigs and the carcass data set contains 141 pigs.

bTrt = treatment; GMO = genetically modified organism; P = parental control line; Conv = conventional lines; and NS = nonsignificant effect,

P > 0.10.cTransgenic line (CRR 0633) comparison with parental control line (RX 670).dTransgenic line (CRR 0633) comparison with conventional lines (RX 740 and DK 647).

eLongissimus muscle area.

fBackfat measurements were taken at the midline.

gFigured on a fat-free lean basis.

hContains 5% fat.iPrimal percentage was calculated by taking the total weight of the primals (ham, loin, and shoulder) divided by the hot carcass weight.

jLean gain calculation: Final fat-free lean – Initial fat-free lean

k

kInitial fat-free equation:

.95 * [-3.95 + (.418 * live weight, lb)]

103 d

Table 4.Longissimus muscle quality scores and composition.a

Genetic Line P-Valueb


GMO vs Convd

Longissimus muscle quality scores

Marbling 2.00 2.00 2.03 2.00 0.014 NS NS NS NS NS

Firmness 2.08 1.93 2.22 2.08 0.096 NS NS NS NS NS

pH 5.63 5.63 5.60 5.64 0.016 NS 0.015 NS NS NS

Minolta L* 49.75 50.78 50.59 50.69 0.623 NS NS NS NS NS

Minolta a* 7.20 6.71 7.17 7.40 0.262 NS NS NS NS NS

Minolta b* 2.11 2.39 2.51 2.58 0.294 NS NS NS NS NS

Longissimus muscle composition, %

Protein 23.74 23.48 23.78 23.51 0.216 NS NS NS NS NS

Fat 3.08 3.06 2.20 2.99 0.247 0.070 0.071 NS 0.039 NS

Water 72.31 72.40 72.71 72.53 0.262 NS NS NS NS NS

aData set includes 141 pigs, two pigs were not slaughtered and one loin was lost at the slaughter facility.

bTrt = treatment; GMO = genetically modified organism; P = parental control line; Conv. = conventional lines; and NS = nonsignificant effect,

P > 0.10.cTransgenic line (CRR 0633) comparison with parental control line (RX 670).dTransgenic line (CRR 0633) comparison with conventional lines (RX 740 and DK 647).


depth between barrows and gilts wasdetected, with no difference in longis-simus muscle area. The difference inbackfat depth between barrows andgilts is supported by the results ofprevious experiments, however inthese experiments gilts had greaterlongissimus muscle area than barrows,which is in contrast to the results of thepresent experiment. The similar longis-simus muscle area estimate for barrowsand gilts may be a result of feeding thebarrows and gilts the same lysine con-centration throughout the four-phasegrowing-finishing experiment. Previousresearch has shown that gilts requirehigher dietary concentrations of lysinecompared to barrows to maximize growthperformance and carcass leanness. Thesignificant effect of sex on hot carcassweight is a result of terminating theexperiment on a constant time basisresulting in a significant difference infinal weight between barrows and gilts.

Total body electrical conductivitymeasurements of the ham, loin, andshoulder weights were similar amongcorns, but the weight of the shoulderwas significantly different betweenbarrows and gilts. This increase inshoulder weight of the barrows is aresult of the greater slaughter weight ofbarrows (267 lb) versus gilts (247 lb).However, the TOBEC estimation ofprimal weights is similar to the whole-sale primal weights reported in previ-ous experiments. In the presentexperiment, the combined weight of theprimals (ham, loin, and shoulder) as apercentage of the hot carcass weightwas greater in gilts than barrows.Similarly, researchers have reportedthat when barrows and gilts are fed toa similar end weight, the primal percent-age is greater in gilts than in barrows.Previous studies have shown that giltsproduce carcasses with a greater per-centage of lean compared to barrows atsimilar end weights. The percentage offat-free lean was greater in gilts thanbarrows in the present experiment. Thisobservation is supported by thedecrease in backfat measurements anda greater primal percentage in gilts thanbarrows.

Longissimus muscle pH is stronglyrelated to pork quality. The pH value ishighly correlated to the quality traits ofcolor and water holding capacity aswell as various eating quality traits,such as tenderness. In the presentstudy, corn variety did not affect pH,but there was a significant effect of sexon the pH value with longissimus musclesfrom barrows having a greater pH valuethan those from gilts. Most previousstudies have indicated that 24-hourspostmortem pH measurements aresimilar between barrows and gilts.Although, a significant effect of sex onpH was detected, the pH values weresimilar to previous experiments and thepH is within the normal range formeasurements taken 24 hours post-mortem. The subjective measurementsof marbling and firmness of the longis-simus muscle were similar among cornsand between barrows and gilts. Themarbling and firmness values in thepresent study were numerically similarto those of previous experiments wherepigs were fed a corn-soybean meal diet.

The different corns and sexesresulted in minimal influence on long-issimus muscle color scores (MinoltaL*, a*, and b*). The Minolta L* values,which measure the lightness (0-100) ofthe sample, were within a normal rangeof 42 to 50 and were in agreement withother experiments. Although, Minoltaa* and b* values, which measure theamount of red (+a*) or green (-a*) andthe amount of yellow (+b*) or blue (-b*)in a meat sample, were not affected bycorn or sex, the numerical values of thepresent study were lower than thoseof previously reported experiments.

The percentages of protein andwater in longissimus muscle in thepresent experiment were not affectedby corn variety or sex (P > 0.05). Also,the percentages of protein, fat, andwater in longissimus muscle are similarto the percentages reported in otherexperiments. There was a trend towarddifferences in longissimus muscle fatpercentage due to sex (P = 0.07) andcorn variety (P = 0.07). Barrows (3.08%)had a greater fat percentage than gilts

(2.59%). This observation is consistentwith the greater backfat measurementsand lesser fat-free lean percentage inbarrows than gilts. Although the maineffect of corn on longissimus muscle fatwas not significant at the P < 0.05 level,individual contrasts indicated less fat(P < 0.04) in the parental control group(2.20%) than the Roundup Ready®group (2.99%). However, the RoundupReady® group did not differ (P < 0.80)from the two commercial varieties (3.08%and 3.06%).

Compositional analyses havebeen conducted to measure proximate(protein, fat, ash, carbohydrate, andmoisture), acid detergent fiber, neutraldetergent fiber, amino acid, fatty acid,calcium, and phosphorus contents ofRoundup Ready® corn line.

Results from the compositionalanalyses showed that the amounts ofproximate components, fiber, phos-phorus, amino acids, and fatty acids inthe Roundup Ready® corn were com-parable to those in the grain of thecontrol line and were within publishedliterature ranges. Because RoundupReady® corn has been shown to besimilar in composition to that of tra-ditional corn, it is not surprising thatin the present experiment no differ-ences were detected among corns forgrowth performance; ultrasound andcarcass measurements; and longissi-mus muscle quality measurements.

Conclusion

This experiment demonstrates thatthe feeding value of Roundup Ready®corn (CRR 0633) is equivalent to thatof conventional corns (RX 740 andDK 647). Therefore, Roundup Ready®corn can be used in swine diets with nodetrimental effects on growth per-formance or carcass characteristics.

1Robert L. Fischer is a research tech-nologist and graduate student, Austin J. Lewisis a professor, and Phillip S. Miller is anassociate professor in the Department ofAnimal Science.


Niacin and Vitamin B12 Requirements ofWeanling Pigs

Sara S. BlodgettPhillip S. MillerAustin J. Lewis

Robert L Fischer1


An experiment was conductedto assess the responsiveness ofweanling pigs to increased dietaryconcentrations of niacin and vita-min B

12. The purpose of the experi-

ment was to determine if the niacinand vitamin B

12 requirements of

nursery pigs are greater than theNRC (1998) recommendations for11 to 22 lb pigs. Pigs (initial weight9.4 lb) were fed one of four diets for atotal of 35 days: 1) Negative control,common nursery diet with no addedniacin or vitamin B

12; 2) Niacin, com-

mon nursery diet with 22.7 mg/lbadded niacin; 3) B

12, common nur-

sery diet with 36.3 µg/lb added vita-min B

12; and 4) Positive control,

common nursery diet with 22.7 mg/lbadded niacin and 36.3 µg/lb addedvitamin B

12. Pigs and feeders were

weighed weekly to determine aver-age daily gain (ADG), average dailyfeed intake (ADFI), and feed efficiency(ADG/ADFI). Pigs were visually scoredto assess any potential niacin andvitamin B

12 deficiencies on days 14,

21, 28, and 35. No niacin × vitaminB

12 interactions were observed. Dur-

ing Phase I, pigs fed supplementalniacin had a greater ADFI (P < 0.01)than pigs fed supplemental vitaminB

12. During Phase II, pigs fed supple-

mental vitamin B12

had the greatestADG (P < 0.001) and ADFI (P < 0.01).Overall, the pigs fed supplementalvitamin B

12 had greater ADG

(P < 0.001), ADFI (P < 0.01), andADG/ADFI (P < 0.05) than pigs fedsupplemental niacin. There were no

differences among groups for visualassessment of B vitamin deficiencies.Based on these results, the niacinrequirement of 10 to 40 lb pigs is notgreater than 4.5 µg/lb of diet and thevitamin B

12 requirement is greater than

3.1 µg/lb.

Introduction

The B-vitamins have received littleattention since the 1950s and 1960s. Inthe past 40 to 50 years, leaner pigs havebeen developed, which may increasetheir B-vitamin requirements due toincreased protein accretion. Vitaminsare important to consider when for-mulating diets, especially the water-soluble vitamins because the bodycannot synthesize these vitamins andthere is little storage in the body.

Niacin and vitamin B12

are the onlytwo B-vitamins that are significantlylimiting (below the NRC requirement) ina common nursery diet. There are con-flicting data regarding current niacinresearch. Research at Iowa State Uni-versity reported that niacin supple-mentation up to 13.6 mg/lb did not alteraverage daily gain (ADG), average dailyfeed intake (ADFI), feed efficiency(ADG/ADFI), protein accretion, or fataccretion of high-lean segregated earlyweaned pigs. Kansas State reportedthat adding niacin to nursery dietsimproved ADG and ADFI day 0 to 8after weaning with the greatest responseobserved at 25 mg/lb of diet.

Vitamin B12

functions include:purine and pyrimidine synthesis,transfer of methyl groups, formation ofproteins from amino acids, and carbo-hydrate and fat metabolism. The mostimportant function of B

12 is in the

metabolism of nucleic acids and pro-teins.

The major function of niacin isas a coenzyme, primarily as nicotina-

mide adenine dinucleotide (NAD) andnicotinamide adenine dinucleotidephosphate (NADP). Enzymes contain-ing NAD and NADP are important linksin a series of reactions associated withcarbohydrate, protein, and lipidmetabolism.

The objective of this study wasto determine the responsiveness ofweanling pigs to niacin and vitaminB

12 supplementation. Our hypothesis

was that pigs fed diets containingsupplemental niacin or vitamin B

12

would have greater ADG and improvedfeed efficiency than pigs fed a negativecontrol diet.

Materials and Methods

Pigs were weighed and allotted,based on initial weight and litter oforigin, to one of four treatments usinga randomized complete block design.Treatments were arranged in a 2 × 2factorial. Ninety-six pigs were allottedto 16 pens. There were four replicationsper treatment and six pigs per pen. Pigswere weaned at 14 to 16 days of age withan average initial weight of 9.4 lb. Theduration of the trial was 35 days (PhaseI was from day 0 to 14 and Phase II wasfrom day 15 to 35). The average finalweight was 38.2 lb.

Pigs and feeders were weighedevery seven days to determine ADG,ADFI, and ADG/ADFI. Pigs were scoredto determine whether there were anyvisual B-vitamin deficiencies. Twoindividuals examined the pigs on days14, 21, 28, and 35 using a scale of 1 to 5(1 having extensive deficiency signsand 5 having no deficiency signs). Thisassessment was based on physicalappearances, such as skin and haircoat characteristics.

The four diets (Table 1) were:1) Negative control, common nurserydiet with no added niacin or vitamin B

12;


Figure 1.The response of a) average daily gain (ADG), b) average daily feed intake (ADFI),and c) ADG/ADFI in weanling pigs. SEM = standard error of the mean.

AD

G,

lb

123456123456123456123456123456123456123456123456123456123456123456

123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456

123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456

123123123

1.6

1.2

0.8

0.4

0.0

a)

Phase I Phase II Overall

Feeding Phase

Negative Control Niacin B12

Positive Control

B12

, P<0.001SEM=0.0119

SEM=0.0150

B12

, P<0.001SEM=0.0154

123123123

123456123456123456123456123456123456123456123456123456123456123456123456

12345671234567123456712345671234567123456712345671234567123456712345671234567123456712345671234567123456712345671234567123456712345671234567123456712345671234567

123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456

b)

2.4

1.8

1.2

0.6

0.0

AD

FI,

lb


Feeding Phase


Positive Control

Niacin, P<0.01SEM=0.0128

B12

, P<0.01SEM=0.0309

B12

, P<0.01SEM=0.0218

123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456

123456123456123456123456123456123456123456123456123456

123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456123456

123123123


Feeding Phase


Positive Controlc)

1.0

0.8

0.6

0.4

0.2

0.0

AD

G/A

DF

I, l

b/lb

SEM=0.0114

SEM=0.0165

B12

, P<0.05

SEM=0.0251

2) Niacin, common nursery diet with22.7 mg/lb added niacin; 3) B

12, common

nursery diet with 36.3 µg/lb addedvitamin B

12; and 4) Positive control,

common nursery diet with 22.7 mg/lbadded niacin and 36.3 µg/lb addedvitamin B

12. All phase-I diets were for-

mulated to contain 22% CP, 1.5% totallysine, 0.31% total tryptophan, 0.9%Ca, and 0.78% P. Phase-II diets weresimilar to diets used in Phase I, exceptdiets were formulated to contain 21%CP, 1.4% total lysine, 0.29% total tryp-tophan, 0.86% Ca, and 0.74% P.

Pigs were housed in pens 6.3 ft ×3.4 ft that had plastic-coated wire floor-ing, one nipple waterer, and one four-hole stainless steel feeder. Pigs had adlibitum access to feed and water through-out the experiment. Heat lamps andcomfort boards were provided duringPhase I of the trial. The relative humid-ity (ranging between 50% and 60%) androom temperature (maintained at 78oF)were monitored continuously using atemperature and humidity recorder.

Results and Discussion

Average daily gain, ADFI, ADG/ADFI are shown in Figures 1a, b, and c,respectively. No niacin × vitamin B

12

interactions were observed. Averagedaily gain was greater (P < 0.001) duringPhase II and overall (P < 0.001) for thepigs fed supplemental vitamin B

12.

During Phase I, pigs receiving theniacin diet had a greater (P < 0.01)ADFI than pigs fed the vitamin B

12

diet. However, pigs fed the vitamin B12

diet had a greater ADFI during PhaseII (P < 0.01) and overall (P < 0.01). Therewere no differences in feed efficiencyexcept during the overall experimentalperiod, when the pigs fed vitamin B

12

had a greater ADG/ADFI (P < 0.05).Scores for each group are shown

in Figure 2. Essentially no B-vitamindeficiencies were observed through-out the five-week study, and there wereno differences among treatment groups.

The vitamin B12

content of the nega-tive control and vitamin B

12 supple-

mented diets were calculated to be 3.1and 39.4 µg/lb, respectively, and the



NRC requirement is 7.9 µg/lb. Thus, asexpected, supplementation with vita-min B

12 improved growth performance.

Almost all of the growth response wasobserved in Phase II with no responsein Phase I. Sows’ milk has a high con-tent of vitamin B

12 and perhaps the pigs

had sufficient stores of vitamin B12

atweaning to carry them through the firsttwo weeks post weaning without addi-tional supplementation.

The niacin content of the negative

Table 1.Composition of experimental diets, as fed basis.

Phase I Phase II

Ingredient, % NCa

Niacin Vitamin B12

PCa

NCa

Niacin Vitamin B12

PCa

Corn 31.81 31.81 31.81 31.81 43.07 43.07 43.07 43.07SBM, 46.5% CP 10.62 10.62 10.62 10.62 32.75 32.75 32.75 32.75Soy protein concentrate 6.25 6.25 6.25 6.25 ——- —— —— ——Whey 30.00 30.00 30.00 30.00 15.00 15.00 15.00 15.00Blood cells —— —— —— —— 2.00 2.00 2.00 2.00Animal plasma 8.00 8.00 8.00 8.00 —— —— —— ——Lactose 4.00 4.00 4.00 4.00 —— —— —— ——Corn oil 5.00 5.00 5.00 5.00 3.00 3.00 3.00 3.00Limestone 0.69 0.69 0.69 0.69 0.30 0.30 0.30 0.30Dicalcium phosphate 1.28 1.28 1.28 1.28 1.60 1.60 1.60 1.60Salt 0.30 0.30 0.30 0.30 0.53 0.53 0.53 0.53Vitamin mix

b0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25

Trace mineralc

0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15L-Lysine•HCl 0.15 0.15 0.15 0.15 —— —— —— ——DL-Methionine 0.11 0.11 0.11 0.11 0.06 0.06 0.06 0.06Mecadox 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00ZnO 0.40 0.40 0.40 0.40 0.30 0.30 0.30 0.30Vitamin B

12, µg/lb —— —— 36.30 36.30 —— —— 36.30 36.30

Niacin, mg/lb —— 22.70 —— 22.70 —— 22.70 —— 22.70aNC = Negative control and PC = Positive control

bSupplied per kilogram of diet: retinyl acetate, 3,088 IU; cholecalciferol, 386 IU; alpha-tocopherol acetate, 15 IU; menadione sodium bisulfite, 2.3mg; riboflavin, 3.9 mg; d-pantothenic acid, 15.4 mg; choline, 77.2 mg.cSupplied per kilogram of diet: Zn (as ZnO), 110 mg; Fe (as FeSO4•H2O), 110 mg; Mn (as MnO), 22 mg; Cu (as CuSO4•5 H2O), 11 mg; I (as Ca(IO3)•H2O),

0.22 mg; Se (as Na2SeO3), 0.3 mg.

response to added niacin. Coprophagymay have contributed to the availableniacin intakes because the negativecontrol pigs had access to feces ofpositive control or niacin-fed pigs inadjoining pens. The amount of avail-able niacin in corn was assumed negli-gible; however, true niacin availabilitymay be greater and the total niacincontributed by corn could be signifi-cantly greater than anticipated. Addi-tionally, tryptophan can be convertedto niacin (35 mg tryptophan to 1 mgniacin).

Conclusion

Based on these results, the niacinrequirement of 10 to 40 lb pigs is notgreater than 4.5 mg/lb of diet and thevitamin B

12 requirement is greater than

3.1 mg/lb. Further research is needed todefine more precisely and to describethe factors controlling the vitamin B

12

requirement of young pigs.

1Sara S. Blodgett is a graduate student,Phillip S. Miller is an associate professor,Austin J. Lewis is a professor, and Robert L.Fischer is a research technologist in theDepartment of Animal Science.

control and niacin-supplementeddiets were calculated to be 4.5 and27.2 mg/lb, respectively. This comparesto the NRC requirement of 6.8 mg/lb forpigs with an initial weight similar tothose used in this experiment. There-fore, we anticipated an improvementin growth performance when niacinwas supplemented.

Several factors may have affectedniacin intake and contributed to alack (except for ADFI in Phase I) of

Figure 2.Visual assessment of deficiency signs. Data based on a scale of 1 to 5, with 1having extensive deficiency signs and 5 having no deficiency signs. SEM =standard error of the mean.

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

Sco

re

SEM = 0.0834

Negative Niacin B12

Positivecontrol control

Treatment


Phytase Sources in Pelleted DietsMichael C. Brumm1


An experiment was conducted todetermine whether there were differ-ences in performance between twocommercial sources of phytase whenadded to corn and soybean meal-baseddiets prior to pelleting. Pelleted dietsinvestigated for growing-finishingbarrows of high-lean-gain-potentialincluded: 1) University of Nebraskarecommended formulations; 2) dietsformulated to contain 0.1% less avail-able phosphorus than recommended;3) diets formulated with 500 FYT/kgadded phytase from Ronozyme-P®;

4) diets formulated with 750 FYT/kgadded phytase from Ronozyme-P®;5) diets formulated with 500 FTU/kgadded phytase from Natuphos®; and6) diets formulated with 750 FTU/kgadded phytase from Natuphos®.Temperature of the pellets for all dietsas they exited the die ranged from150 to 160oF. Pigs fed diets formulatedto contain 0.1% less availablephosphorus than recommended hadslower (P < 0.05) growth, slower dailylean gain, poorer feed conversion, anddecreased bone ash and bone break-ing strength than pigs fed the Univer-sity recommended diets. Phytaserecovery following pelleting rangedfrom 74% to 100%. There was no effectof phytase level or source on daily

gain, daily feed, carcass lean, dailylean gain, bone ash or bone breakingstrength. Pigs fed diets formulated withRonozyme-P® had improved (P < 0.05)feed conversion compared with pigsfed Natuphos® as the phytase source.These results suggest that phytase isan effective replacement for dicalciumphosphate in swine diets, and thatunder the conditions of this experi-ment, phytase can be added to pelleteddiets prior to the pelleting process.

Introduction

The recent proposal by the UnitedStates Environmental Protection Agencyto regulate land application of animalmanures based on phosphorus has

Table 1. Experimental diet composition, 45 to 130 pound body weight

45 to 80 lb 80 to 130 lb

Item UNLa

NEGa

R500a

R750a

N500a

N750a

UNL NEG R500 R750 N500 N750

Ingredient, lb/tonCorn 1149 1153 1152.6 1152.4 1152.9 1152.85 1261 1265 1264.6 1264.4 1264.9 1264.85Soybean meal,

44% CP 550 550 550 550 550 550 445 445 445 445 445 445Wheat midds 200 200 200 200 200 200 200 200 200 200 200 200Choice white

grease 50 50 50 50 50 50 50 50 50 50 50 50Dicalcium

phosphate,18.5% P 19 8 8 8 8 8 12 1 1 1 1 1

Calcium carbonate 19 26 26 26 26 26 19 26 26 26 26 26L-lysine 3 3 3 3 3 3 3 3 3 3 3 3Salt 6 6 6 6 6 6 6 6 6 6 6 6Vit/TM mix 4 4 4 4 4 4 4 4 4 4 4 4Ronozyme-P

®b0.4 0.6 0.4 0.6

Natuphos®c 0.1 0.15 0.1 0.15Calculated composition

ME, kcal/lb 1521 1524 1524 1524 1524 1524 1531 1535 1535 1535 1535 1535Lysine, % 1.13 1.14 1.14 1.14 1.14 1.14 0.99 0.99 0.99 0.99 0.99 0.99Calcium, % 0.69 0.71 0.71 0.71 0.71 0.71 0.61 0.63 0.63 0.63 0.63 0.63Phosphorus, % 0.59 0.49 0.49 0.49 0.49 0.49 0.50 0.40 0.40 0.40 0.40 0.40Available

phosphorous, % 0.29 0.19 0.19 0.19 0.19 0.19 0.22 0.12 0.12 0.12 0.12 0.12Analyzed composition

Lysine, %d

1.24 1.22 1.20 1.20 1.22 1.19 1.09 1.05 1.05 1.06 1.03 0.97Calcium, %d 1.35 0.91 0.71 0.76 0.64 0.62 0.74 0.59 0.78 0.67 0.86 0.81Phosphorus, %

d0.58 0.56 0.53 0.53 0.48 0.46 0.55 0.48 0.46 0.50 0.42 0.41

Total phytase activity, units/kge

Prepelleting 289 311 920 1160 993 1315 232 273 851 1112 936 1282Postpelleting 172 209 683 838 787 1012 140 215 671 1113 772 1008

aUNL = University of Nebraska recommended; NEG = UNL formulated to 0.1% lower available P; R500 = 500 FYT/kg phytase from Ronozyme-P®;R750 = 750 FYT/kg phytase from Ronozyme-P®; N500 = 500 FTU/kg phytase from Natuphos®; N750 = 750 FTU/kg phytase from Natuphos®.bRonozyme-P® CT, Roche Vitamins, Inc., Parsippany, NJ 07054.

cNatuphos® 10000 G, BASF, Inc., Mt. Olive, NJ 07828.

dWard Laboratories, Kearney, NE 68848.

eRoche Vitamins, Inc. Parsippany, NJ 07054.



intensified the interest of pork pro-ducers in the use of phytase in swinediets. Phytase has reduced phospho-rus excretion by growing-finishing pigs25-35% when used in corn-soybeanmeal based swine diets as a replace-ment for inorganic phosphorus. A limitto the use of phytase has been theinability to include phytase in pelleteddiets prior to the pelleting process dueto losses in enzyme activity associatedwith the heat of pelleting. The onlymethod available to add phytase topelleted diets was to spray phytase onthe cooled pellet, involving expensiveequipment and time.

Recently, additional sources ofphytase have become available. Thishas renewed interest in the possibilityof adding phytase to pelleted diets priorto the pelleting process. The purposeof the following experiment was to com-

pare the effect of two commercial sourcesof phytase in pelleted diets on pigperformance.

Methods

The experiment was conducted atthe University of Nebraska’s HaskellAg Lab at Concord. At arrival, 288 cross-bred barrows (Thunderbird Genetics,Wecota, SD) were weighed, ear tagged,and assigned to the following treat-ments:

1) University of Nebraska rec-ommended diets (UNL );

2) UNL formulated to contain 0.1%less available phosphorus(NEG);

3) NEG formulated with 500FYT/kg Ronozyme-P® (R500);

4) NEG formulated with 750FYT/kg Ronozyme-P® (R750);

5) NEG formulated with 500FTU/kg Natuphos® (N500);and

6) NEG formulated with 750FTU/kg Natuphos® (N750).

Diets (Tables 1 and 2) were pelletedby a commercial feed mill. The phytaseproduct from both manufacturers waspreblended with ground corn beforemixing to assure a uniform mix. Tem-perature of the pellets as they exited thepellet die ranged from 150 to 160o F.Conditioning temperatures prior topelleting were 140 to 150o F. The pelletsize was 0.172 inch.

The lysine sequence was 1.13%from 45 to 80 lb body weight, 0.99% from80 to 130 lb, 0.78% from 130 to 190 lb,and 0.62% from 190 lb to slaughter.Diets were switched on the week theaverage weight of individual pens was

Table 2.Experimental diet composition, 130 pound bodyweight to slaughter.

130 to 190 lb 190 lb to slaughter

Item UNLa

NEGa

R500a

R750a

N500a

N750a

UNL NEG R500 R750 N500 N750

Ingredient, lb/tonCorn 1418 1425 1424.6 1424.4 1424.9 1424.85 1540 1544 1543.6 1543.4 1543.9 1543.85Soybean meal,

44% CP 290 287 287 287 287 287 171 170 170 170 170 170Wheat midds 200 200 200 200 200 200 200 200 200 200 200 200Choice white

grease 50 50 50 50 50 50 50 50 50 50 50 50Dicalcium

phosphate,18.5% P 10 0 0 0 0 0 8 0 0 0 0 0

Calcium carbonate 19 25 25 25 25 25 18 23 23 23 23 23L-lysine 3 3 3 3 3 3 3 3 3 3 3 3Salt 6 6 6 6 6 6 6 6 6 6 6 6Vit/TM mix 4 4 4 4 4 4 4 4 4 4 4 4Ronozyme-P®

b0.4 0.6 0.4 0.6

Natuphos®c 0.1 0.15 0.1 0.15Calculated composition

ME, kcal/lb 1541 1544 1544 1544 1544 1544 1549 1551 1551 1551 1551 1551Lysine, % 0.78 0.78 0.78 0.78 0.78 0.78 0.62 0.62 0.62 0.62 0.62 0.62Calcium, % 0.56 0.57 0.57 0.57 0.57 0.57 0.50 0.52 0.52 0.52 0.52 0.52Phosphorus, % 0.45 0.36 0.36 0.36 0.36 0.36 0.41 0.34 0.34 0.34 0.34 0.34Total available

phosphorous, % 0.19 0.10 0.10 0.10 0.10 0.10 0.16 0.09 0.09 0.09 0.09 0.09Analyzed composition

Lysine, %d

0.82 0.82 0.81 0.76 0.80 0.80 0.64 0.61 0.65 0.67 0.69 0.69Calcium, %d 0.64 0.63 0.64 0.71 0.70 0.70 0.74 0.60 0.69 0.65 0.59 0.56Phosphorus, %

d0.46 0.36 0.36 0.37 0.37 0.35 0.43 0.31 0.34 0.34 0.34 0.32

Phytase activity, FTU/kge

Prepelleting 227 303 817 1084 840 1185 255 280 802 1073 764 1152Postpelleting 155 184 640 912 719 918 222 216 758 840 754 938

aUNL = University of Nebraska recommended; NEG = UNL formulated to 0.1% lower available P; R500 = 500 FYT/kg phytase from Ronozyme-P®;R750 = 750 FYT/kg phytase from Ronozyme-P®; N500 = 500 FTU/kg phytase from Natuphos®; N750 = 750 FTU/kg phytase from Natuphos®.bRonozyme-P® CT, Roche Vitamins, Inc., Parsippany, NJ 07054.

cNatuphos® 10000 G, BASF, Inc., Mt. Olive, NJ 07828.

dWard Laboratories, Kearney, NE 68848.

eRoche Vitamins, Inc. Parsippany, NJ 07054.


at or above the target weight. The 1.13%lysine diets contained 100 g/ton Tylan.The remaining diets contained 40 g/tonTylan. All diets within a given lysinesequence were mixed on the same day.

Pigs were housed in two mechani-cally ventilated, partially slatted facili-ties. There were two replications ofeach treatment in each facility. Withineach facility, the pens measured 6 ft x 15ft and had 12 pigs/pen (7.5 ft2/pig).There was one three-hole stainless feederand one nipple drinker in each pen. Pensize was not adjusted in the event of pigdeath or removal.

At arrival, pigs were vaccinated forerysipelas, M. hyopneumonia, and Ssuis. All pigs that died during theexperiment were examined for cause ofdeath by a consulting veterinarian.

Pigs were weighed individuallyevery 14 days. Individual pigs wereremoved for slaughter on the week theyweighed 240 pounds or greater. Car-cass lean was determined by TOBECon individually identified pigs byemployees of SiouxPreme PackingCo., Sioux Center, Iowa.

At the time of first shipment toslaughter, the left front foot from thetwo heaviest pigs in each pen wascollected at the slaughter plant andfrozen. The frozen feet were sent to Dr.Merlin Lindeman at the University of

Kentucky for determination of metacar-pal bone breaking strength and boneash.

The pen of pigs was the experimen-tal unit. The following contrasts wereused to separate treatment means:

• UNL vs NEG - This examinedwhether a phosphorus deficiencywas created.

• UNL vs 500 - This examined ifthere was a response to 500 unitsof phytase/kg regardless ofphytase source.

• UNL vs 750 -This examined ifthere was a response to 750 unitsof phytase/kg regardless ofphytase source.

• 500 vs 750 - This examined whetherthe response to phytase variedwith the level added to the diet.

• R vs N - This examined whetherthere was a difference due tophytase source.


A phytase unit is defined as theamount of phytase which liberates onemicromole of inorganic phosphorus perminute from an excess of sodium phytateat 37o C and pH 5.5. Natuphos® phytaseunits are presented as FTU andRonozyme-P® as FYT. Both abbrevia-

Table 3.Main effects of experimental treatments on pig performance and carcass characteristics.

Treatmentsa

P Values

Ronozyme-UNL vs UNL vs UNL vs 500 vs P® vs

UNL NEG R500 R750 N500 N750 SEM NEG 500 750 750Natuphos®

No. pens 4 4 4 4 4 4

Pig wt., lbInitial 45.3 44.9 45.2 45.1 45.0 45.3 0.3 0.311 0.576 0.683 0.851 0.914Final 244.9 241.3 247.0 250.4 244.4 247.4 2.0 0.235 0.734 0.124 0.134 0.190

Daily gain, lb/d 1.95 1.78 1.93 1.96 1.91 1.95 0.03 0.005 0.469 0.930 0.326 0.617Daily feed, lb/d 5.42 5.13 5.38 5.44 5.43 5.52 0.09 0.039 0.872 0.584 0.391 0.453Feed/gain 2.78 2.89 2.78 2.78 2.85 2.83 0.04 0.013 0.275 0.436 0.684 0.037Dressing % 74.5 74.8 74.8 74.8 74.3 74.5 0.5 0.742 0.993 0.892 0.860 0.443Carcass % leanb 47.3 46.8 47.1 47.2 47.4 47.1 0.5 0.449 0.907 0.776 0.836 0.894Daily lean gain, lb/d

b0.696 0.614 0.688 0.703 0.687 0.683 0.017 0.014 0.720 0.888 0.789 0.569

Bone ash, %c

61.54 59.47 61.13 60.45 61.35 60.40 0.31 0.005 0.411 0.039 0.094 0.744Bone strength,

kg/cm2c

243.7 186.2 218.4 253.7 240.9 225.8 8.1 <0.001 0.117 0.523 0.227 0.380

aUNL = University of Nebraska recommended; NEG = UNL formulated to 0.1% lower available P; R500 = 500 FYT/kg phytase from Ronozyme-P®;R750 = 750 FYT/kg phytase from Ronozyme-P®; N500 = 500 FTU/kg phytase from Natuphos®; N750 = 750 FTU/kg phytase from Natuphos®.bContaining 5% fat.

cMetacarpal from front left foot of two pigs per pen.

tions are derived from fytase, the Dutchname for phytase. Different abbrevia-tions are used to define each sourcesince the two phytase sources origi-nate from different microorganisms.However, all laboratory assays arereported as FTU to simplify reporting.

The laboratory analysis of the dietsamples is given in Tables 1 and 2. The155-300 units/kg phytase activityreported for the UNL and NEG diets isthe result of the phytase activity con-tributed by the wheat midds. Theexperimental treatments of 500 and 750phytase units/kg were additions to thebasal diet and the phytase activity forthe phytase containing diets is withinnormal ranges when the activity con-tributed by wheat midds is accountedfor.

Phytase stability was defined asthe percentage of phytase in the pelletversus the phytase in the meal prior topelleting. The relatively cool pelletingtemperature of 150-160o F versus a morecustomary 180oF exit temperature,resulted in very good phytase stabilityfor both commercial sources of phytase.Averaged across all levels of lysine,stability ranged from 79% for the N750diets to 87% for the N500 diets. Stabilityfor the phytase associated with wheatmidds averaged 69% for the UNL diet



and 71% for the NEG diet.The main effects of the experimen-

tal diets on pig performance are inTable 3. Decreasing the available phos-phorus from the recommended levels(NEG vs UNL) resulted in a reduction(P < 0.05) in daily gain, daily feed intake,and daily lean gain. It also resulted in apoorer feed conversion efficiency.

The addition of phytase at 500 and750 units/kg to the NEG diet resulted inperformance that was similar to pigs fedthe UNL diets. There were no differ-ences in performance or carcass char-acteristics between sources of phytasein this study except for feed conversionefficiency. Pigs fed Ronozyme-P® asthe phytase source had a better feedconversion efficiency than pigs fedNatuphos® (2.78 vs 2.84; P = 0.037).

Bone strength and bone ash werelower (P < 0.01) for pigs fed a diet 0.1%lower in available P than the Universityof Nebraska recommendation (NEG vsUNL). While bone ash decreased slightlyfor the 750 versus 500 phytase units/kgtreatment for both sources of phytase,there was no effect of phytase level onbone breaking strength, a more sensi-tive indicator of dietary adequacy.

Conclusion

These results are in agreementwith the large body of data supportingthe effectiveness of phytase in swinediets as a replacement for inorganicphosphorus sources such as dicalciumphosphate. They also suggest that atrelatively cool pelleting temperatures,

phytase losses are not as great as pre-viously thought, meaning phytase useto reduce phosphorus in swine manuremay be another economic option forproducers who use pelleted feeds.Finally, both sources of phytase wereeffective in improving performancecompared to the negative treatment.However, Ronozyme-P® fed pigs hadbetter feed conversion, regardless oflevel of addition. In this study, therewas no benefit from adding 750 FTU/kgversus the lower level of 500 FTU/kg.

1Michael C. Brumm is a professor ofAnimal Science located at the University ofNebraska Haskell Agricultural Laboratory,Concord, Neb.

Managing Swine Dietary Phosphorus to MeetManure Management Goals

Michael C. BrummCharles A. ShapiroWilliam L. Kranz 1


A demonstration was carried outfor 15 months at a 1,200-head grow-ing-finishing facility in Holt County,Neb. The purpose was to document theimpact of diet formulation on phos-phorus excretion and the associatedland area needed to utilize the phos-phorus in the accumulated manure.The demonstration facility had four300-head rooms. Prior to the demon-stration, pigs in all rooms were feddiets formulated to contain 0.55-0.57%total phosphorus for all phases ofgrowth. For the demonstration, tworooms were fed diets formulated to theUniversity of Nebraska recommendedlevels for available phosphorus. Theother two rooms were fed diets formu-lated to have the same amounts of allnutrients except phosphorus as theUniversity of Nebraska diets using

reduced amounts of dicalcium phos-phate and phytase. Analysis of fecessamples taken twice per month for thefirst 11 months, and monthly there-after, indicated a 34% reduction inphosphate in the excreted feces ofgrowing-finishing pigs fed diets con-taining phytase. Based on the phos-phorus needs for 180 bu/acre corn, theswitch from the previous diets con-taining 0.55 to 0.57% total phospho-rus to diets formulated with decreasingamounts of phosphorus according tothe University of Nebraska recom-mendations resulted in 49 feweracres needed per year for land appli-cation of the manure. Formulating thediets according to the University ofNebraska recommendations and uti-lizing phytase and reduced amounts ofdicalcium phosphate resulted in anadditional reduction of 65 acres peryear. In this demonstration, phytasewas effective in reducing phosphorusexcretion by growing-finishing pigs,even in diets formulated according tothe University of Nebraska recommen-dations. Phytase use, combined with

the reduction in estimated phospho-rus excretion when switching from theprevious nutrition program of 0.55 to0.57% total phosphorus to decreasingamounts of phosphorus according tothe University of Nebraska recommen-dations, resulted in an estimated 114fewer acres needed per year for appli-cation of the accumulated manure atagronomic rates.

Introduction

Nitrate contamination of ground-water was first detected in Holt County,Neb. in the mid-1960s. From 1976 to1990, nitrate-N concentrations increasedin 90 percent of the wells sampled bythe Natural Resource Districts (NRD) inthe county. As a consequence of theconcerns associated with this increase,the Holt County Groundwater Educa-tion Project was initiated in 1995.

The Holt County Manure Man-agement Education Project, a spin-offfrom the Groundwater Education Pro-ject, is a three-year effort funded by anEPA-319 grant with cooperation among


UNL Cooperative Extension, UNL Con-servation and Survey Division, USDA-NRCS, the Lower Niobrara NRD, andthe Upper Elkhorn NRD. The goal of theproject is to educate producers on crop-ping and manure best management prac-tices to protect water resources fromcontamination. The project centersaround demonstrating best manage-ment practices that are cost effectiveand that can be used in existing produc-tion facilities.

Best management practices includewhole-farm nutrient planning whenanimal manures are spread on irrigatedcrop land. Whereas nitrogen manage-ment was the primary goal of the fundeddemonstration effort, large amounts ofphosphorus are also present in beefand swine manures. A typical analysisof swine slurry has a phosphorus con-tent, expressed as P

2O

5, that is as high

or higher than the available nitrogencontent, expressed as ammonium-N(Table 1).

Table 2 lists the average nutrientremoval by crops. Applying high ratesof swine slurry to meet the nitrogenneeds of crops such as corn results inthe over-application of phosphorus andpotassium relative to the crop needs.With the US Environmental ProtectionAgency proposing to regulate AnimalFeeding Operations based in part onthe phosphorus content of the col-lected and land applied manures, a dem-onstration site was identified to examinethe role of dietary manipulation of phos-phorus on the phosphorus content ofswine manure.

Methods

The demonstration site was a 1,200-head, 4-room, fully slatted finishingfacility with pull-plug gutters to anoutside concrete manure storage tank.Pigs typically enter the facility at 45-55lb and are sold for slaughter weighing255-265 lb. The finishing facility is lo-cated on a corner of an irrigated quartersection (160 acres) in Holt County. Themanure management goal of the pro-ducer is to use the center pivot irrigatedportion of the quarter section (132 acres)for manure utilization by a cropping

Table 1.Typical nutrient content of liquid swine manure.a

% Dry matter NH4-N Organic-N P

2O

5K

2O

- - - - - - - - - - - - - lb/1000 gal - - - - - - - - - - - - -

Deep pit 5 17 10 19 15

- - - - - - - - - - - - - lb/acre-inch - - - - - - - - - - - - -

Anaerobic lagoon 0.25 50 29 17 86aUSDA-SCS Agricultural Waste Management Field Book (1992). Due to extreme variability, manure

analysis is recommended for each situation.

Table 2.Average nutrient removal by crops.a

Crop N content P2O

5 content K

2O content

- - - - - - - - - - - - - - - - lb/bu grain - - - - - - - - - - - - - - - - -

Corn grain 0.90 0.39 0.22Soybean 3.76 0.82 1.20Grain sorghum 0.90 0.38 0.21Oats 0.38 0.24 0.15Wheat 1.36 0.50 0.27

- - - - - - - - - - - - - - - - - lb/ton forage - - - - - - - - - - - - - - - -

Alfalfa hay 57.2 11.8 55.1Corn silage 8.6 3.2 7.7

aUniversity of Nebraska NebGuide 97-1334.

Table 3.University of Nebraska dietary recommendations for total and availablephosphorus in corn-soybean meal diets.

a

Pig body wt., lb: 45-80 80-130 130-190 190-market

Total P, %b 0.58 0.51 0.47 0.43

Available P,% 0.29 0.22 0.19 0.16aNebraska and South Dakota Swine Nutrition Guide EC95-273.

bAssumes corn and soybean meal based diet formulations.

system of continuous corn.Prior to the demonstration, the pro-

ducer was feeding diets formulated usingcorn, soybean meal and a base mixcontaining 7.8% phosphorus. Whenthe base mix was added to the corn-soybean meal diets at the recommendedrate of 55 lbs/ton, the complete diets forpigs from 45 pounds to market weightcontained 0.55% to 0.57% total phos-phorus and 0.27% to 0.28% availablephosphorus.

This type of dietary formulation isquite common in the pork industry.Based on an estimated 1.5 gal of manureper pig space per day and the values inTables 1 and 2, the producer needed an

estimated 300 acres each year to utilizethe phosphorus in the manure whenharvesting 180 bu/acre in a continuousirrigated corn cropping system.

In contrast to the phosphorus con-tent of the diets formulated with thebase mix, the current University of Ne-braska recommendations for total andavailable phosphorus in corn-soybeanmeal diets are given in Table 3. Includ-ing 55 lb of the base mix in the diet metthe phosphorus needs of 45-lb pigs,but provided excess phosphorus for allother stages of growth.

Because the goal of the demon-stration was to reduce the amount of



demonstration period compared todiets formulated to the University ofNebraska recommendations withoutphytase.

To calculate the impact of the di-etary changes implemented at the dem-onstration site, a two-step analysis wasconducted. For the analysis, it was as-sumed there was no difference in per-formance between the producer’sprevious base mix formulated diets, theUniversity of Nebraska recommendeddiets and the recommended diets for-mulated with phytase. Assuming a 2.98feed:gain ratio, 2.7 turns or groups ofpigs per year, and 1,200 pigs per turn,changing from diets formulated withthe 55 lb base mix to diets formulatedaccording to the University of Nebraskarecommendations resulted in a totalestimated reduction in phosphorusentering the facility in the feed of 1,484pounds per year. Adding phytase tothe University of Nebraska recom-mended diets resulted in a further esti-mated reduction in phosphorus in thefeed of 1,976 lb per year.

If it is assumed that all diets met thegrowing pigs requirements for digest-ible phosphorus, the reductions in phos-phorus in the feed translate directlyinto reductions in the amount of phos-phorus excreted in the manure. Thus,changing from formulating diets with a55 lb inclusion of a base mix containing7.8% phosphorus to formulating dietsaccording to the University of Nebraska

Table 4. Holt County demonstration diets.

Pig body wt., lb: 45-80 80-130 130-190 190-market

Ingredient, lb Phytase: No Yes No Yes No Yes No Yes

Corn 1338 1347 1415 1424 1528 1537 1680 1689Soybean meal (46.5% CP) 590 590 520 520 410 410 260 260Fat 20 20 20 20 20 20 20 20Dicalcium phosphate 22 9 16 3 14 1 13 0Limestone 18 20 17 19 16 18 15 17Salt 6 6 6 6 6 6 6 6Vitamin/trace mineral mix 5 5 5 5 5 5 5 5L-lysine 1 1 1 1 1 1 1 1Phytase

a0 2 0 2 0 2 0 2

2000 2000 2000 2000 2000 2000 2000 2000

Calculated compositionLysine, % 1.07 1.07 0.98 0.98 0.83 0.83 0.64 0.64Ca, % 0.72 0.60 0.62 0.50 0.56 0.44 0.51 0.39Total P, % 0.59 0.48 0.53 0.41 0.48 0.37 0.45 0.33Avail P, % 0.29 0.17 0.23 0.11 0.20 0.08 0.18 0.06

aNatuphos, BASF Corp, Mt Olive, NJ 07828. According to the manufactures recommendations, when added at 500 FTU/kg, the product provided.12% available P and Ca in cereal grain based diets.

Figure 1. Impact of phytase on fecal phosphate, Holt County Demonstration Project.

9%

8%

7%

6%

5%

4%

3%

2%

1%

0%University of Nebraska University + phytase

Jun

-00

Jul-

00

Au

g-0

0

Se

p-0

0

Oc

t-0

0

No

v-0

0

De

c-0

0

Jan

-01

Fe

b-0

1

Ma

r-0

1

Ap

r-0

1

Ma

y-0

1

Jun

-01

Jul-

01

Au

g-0

1

Se

p-0

1

Sample Date

Fec

al p

hosp

hate

, %

DM

bas

is

total phosphorus in the manure, pigs intwo of the four rooms were fed dietsformulated with limestone, dicalciumphosphate, salt and a vitamin-tracemineral premix according to the Uni-versity of Nebraska recommenda-tions (Table 4). Pigs in the other tworooms were fed diets formulated to theavailable phosphorus requirementutilizing phytase. In this demonstra-tion, phytase was added at 500 FTU/kgof diet and replaced up to 13 lb ofdicalcium phosphate per ton of diet.

Phytase increases the availabilityof phytate-phosphorus in corn andsoybean meal so lesser amounts ofinorganic phosphorus are needed in

diets. This results in a decrease in theamount of phosphorus excreted in themanure.

Results and discussion

Manure was sampled by takinggrab samples of feces on top of the slatstwice per month in each of the fourrooms from mid-June 2000 through mid-May 2001, and monthly thereafter.Samples were sent to a commerciallaboratory for analysis. Results ofthe manure sampling are shown inFigure 1. The inclusion of phytase inthe diets reduced fecal phosphorusexcretion an average of 34% for the


recommendations and using phytaseto enhance phosphorus availabilityresulted in 3,460 fewer pounds of phos-phorus in the manure yearly. Using aconversion factor of 2.3 to convert el-emental phosphorus to P

2O

5, the change

in diet formulations results in a totalreduction of 7,958 lb of phosphate peryear.

If the long term phosphate need forirrigated corn at this site is 70 lb/acre(180 bu/acre x 0.39 lb P

2O

5/bu), the change

from the 55 lb inclusion product to theUniversity of Nebraska recommendeddiets represented 49 fewer acres neededper year for utilization of the phospho-rus in the manure. Adding phytase tothe University of Nebraska recom-mended diets represented an additional65 fewer acres. In summary, convertingfrom a nutrition program using a 55 lbinclusion rate base mix containing 7.8%phosphorus to a program using the

University of Nebraska recommenda-tions and phytase resulted in 114 feweracres needed per year for proper utiliza-tion of the phosphorus in the manure atthis site.

Conclusion

While the producer was unable toachieve the goal of applying all themanure from the demonstration facilityon land under one center pivot system(132 acres), altering the phosphorussources in growing-finishing diets froma 55 lb inclusion rate of a base mixcontaining 7.8% phosphorus to dietsformulated for decreasing amounts ofphosphorus using dicalcium phosphateand phytase resulted in a major reduc-tion in the amount of crop land neededto properly utilize the phosphorus inthe manure. Based on the estimatedoriginal cropping acres needed for

continuous irrigated corn and thereductions in phosphorus associatedwith the dietary changes demonstrated,the new land base needed is estimatedto be 186 acres if the phytase contain-ing diets are fed to all pigs in the facility,down considerably from the original300 acre estimate. The 34% reduction inphosphorus content in the feces for thephytase fed pigs versus pigs fedUniversity of Nebraska recommendeddiets formulated with dicalciumphosphate is similar to reductionsreported in the scientific literature.

1Michael C. Brumm is a professor andextension swine specialist, Charles A. Shapirois an associate professor and extension soilsspecialist and William L. Kranz is an asso-ciate professor and extension irrigationspecialist at the Haskell Ag Lab, Concord,Neb.

Update on the Economics of FeedingRactopamine (PayleanTM) to Finishing Pigs

Duane E. ReeseLarry L. Bitney 1


Ractopamine is a feed additivethat improves feed efficiency, daily gain,and carcass merit in finishing pigs. Aneconomic feasibility analysis on thefeeding of 4.5 and 9.0 g/ton ractopamineto finishing pigs fed a 1% lysine, corn-soybean meal diet for an average of 29days before slaughter was conducted.The analysis was performed in twostages: 1) an economic benefit forractopamine was calculated fromrevenues due to improved feed effi-ciency, daily gain and carcass yield(dressing percent), and 2) the amountof a carcass lean premium needed perpig to recover the added cost of feedingractopamine was calculated for eachdietary level of ractopamine. One poundof PayleanTM, containing 9 grams of

ractopamine per pound, cost $28and live slaughter pig prices were$34, $42, and $50/cwt. In 10/12 ofour evaluations, the cost of feedingractopamine cannot be justified eco-nomically through improved feed effi-ciency, daily gain, and carcass yieldalone (corn =$2.00/bu; soybean meal= $200/ton). A producer would needto earn carcass lean premiumsranging from $0.23 to $1.78/pig inorder to recover the cost of feedingractopamine. However, we projected apotential profit of $0.55 and $1.50/pigfrom feeding 9 g/ton ractopaminewhen live slaughter price was $42 and$50/cwt, respectively, and whenractopamine-fed pigs were allowedto reach a heavier body weight atslaughter. We conclude that a con-sistent carcass lean premium is neces-sary sometimes to justify feedingractopamine economically and that itcan improve profitability of porkproduction.

Introduction

Ractopamine (PayleanTM; ElancoAnimal Health) was approved by theFood & Drug Administration (FDA) in1999 for increased rate of gain, improvedfeed efficiency, and increased carcassleanness in finishing pigs fed a com-plete diet containing at least 16% crudeprotein (0.82% lysine) from 150 to 240lb. The additive can be included in afinisher diet at 4.5 to 18.0 g/ton.

In the 2001 Nebraska Swine reportwe estimated the value of feedingractopamine to finishing pigs. We con-cluded that a consistent carcass pre-mium was necessary to justify feedingractopamine economically. That con-clusion was reached based on pig per-formance data generated during thelate 1980’s and early 1990’s. Improve-ments have been made in the geneticmerit of pigs since then that couldaffect the response to ractopamine. In



Method for Estimating Value

Costs

Corn-soybean meal diets contain-ing 0.72 and 1.03% lysine were formu-lated. We assumed a 0.72% lysine dietwould be fed to finishing pigs providedno ractopamine; that allowed us to cal-culate the cost of additional aminoacids provided to pigs fed ractopamine.Because ractopamine reduces feedintake and increases lean gain, dietaryamino acid level should be increased.All the diets contained 44% crude pro-tein soybean meal as the sole source ofsupplemental protein and the same levelof energy, amino acids, vitamins andminerals. Diets were formulated to con-tain 0, 4.5 and 9.0 g/ton of ractopamine.Ractopamine ($28/lb of premix or$3.11/g of active ingredient) replacedcorn in the diet. Corn and soybean mealwere priced at $2.00/bu and $200/ton,respectively. Feed efficiency and dailygain would not be expected to improveby feeding a diet containing more than0.72% lysine to finishing pigs used inthe studies summarized for this report,thus all the additional ingredientexpense for providing ractopamine fedpigs a higher lysine diet was assignedto them.

Some producers have reported ahigher death loss among pigs fedractopamine while they are transportedto market. However, no transport deathshave been reported in the scientificliterature. We included a transport deathcost of $0.45/pig in our analysis, afigure estimated by researchers fromCape Fear Consulting in Warsaw, NCbased on field trials where 4.5 and 9.0g/ton ractopamine was evaluated.

Revenues

The responses for feed efficiencyshown in Tables 1 and were applied tothe diet containing ractopamine toestimate revenue from improved feedefficiency. The revenue realized fromimproved feed conversion was attrib-uted to ractopamine. (Note: The controldiet for calculating the revenue con-tained 0.72% lysine.)

We modeled two scenarios toestimate revenue from improved daily

Table 1. Effect of ractopamine (4.5 g/ton) on finisher pig performance.a,b

Ractopamine, g/ton

Item 0 4.5

No. pens 33 61No. pigs 300 331Daily gain, lb 2.17 2.35Daily feed, lb 6.36 6.19Feed/gain 2.97 2.65Hot carcass weight, lb 200 202Yield, % 74.7 74.5Lean, % 56.4 56.8aMeans from Cook et al., 2001; Herr et al., 2001; and Main et al. 2001 weighted according to the

number of pens/treatment.b1.04% lysine diet; 29.2-day feeding period.

Table 2. Effect of ractopamine (9.0 g/ton) on finisher pig performance.a,b

Ractopamine, g/ton

Item 0 9.0

No. pens 39 97No. pigs 357 668Daily gain, lb 2.24 2.49Daily feed, lb 6.59 6.34Feed/gain 2.96 2.55Hot carcass wt., lb 200 207Yield, % 74.3 75.4Lean, % 54.9 55.8aMeans from Cook et al., 2001; Herr et al., 2001; Main et al., 2001; and Boyd et al., 2001 weighted

according to the number of pens/treatment.b1.02% lysine diet; 28.8-day feeding period.

addition, researchers have recentlyinvestigated the response of racto-pamine in diets containing more than16% crude protein and when it is fed forless time before slaughter than in previ-ous trials. Therefore, we believe a re-evaluation of the economic feasibilityof feeding ractopamine to finishing pigsis warranted.

Performance Results

Pig performance results wereobtained from 4 abstracts given at theAmerican Society of Animal Sciencemeetings in 2001. Data from the 4abstracts were combined to produceone data set for pigs fed 4.5 or 9.0 g/tonractopamine (Tables 1 and 2). Meansfor each response variable wereweighted according to the number ofpens of pigs per treatment.

Total dietary lysine provided topigs fed ractopamine ranged from 0.9to 1.14%. The average level of lysineprovided to pigs fed ractopaminewas 1.03%. Slaughter weight for pigsfed ractopamine ranged from 245 to

288 lb. The duration of ractopaminefeeding varied between 21 and 32 daysbefore slaughter and all carcass datawere collected at commercial slaughterplants. Fat-O-Meater® technology wasused to collect carcass measurementson 80% of the pigs represented in Tables1 and 2 while the AutoFOM® was usedto access 20% of the pigs.

Daily gain and feed efficiencyincreased by 8 and 11 %, respectively,when pigs were fed diets containing4.5 g/ton ractopamine (Table 1). Hotcarcass weight for pigs fed 4.5 g/tonractopamine was 2 lb heavier, yield(dressing percent) was unchanged,and lean percent was improved by0.4% units compared to the control.Providing 9 g/ton ractopamineimproved daily gain and feed efficiencyby 11 and 14%, respectively (Table 2).Hot carcass weight was increasedby 7 lb, yield by 1.1% units, and leanpercent by 0.9% units. These obser-vations support previous data show-ing that pigs fed 9.0 g/ton ractopamineperform better than those fed 4.5 g/ton.


gain by feeding ractopamine. In thefirst scenario we assumed pens wouldbe “topped out” (TO) twice then theentire facility would be emptied. There-fore, pig slaughter weight would remainconstant after ractopamine was intro-duced, except for pigs in the last ship-ment to market. They would weigh morewhen fed ractopamine, but we did notconsider that in our analysis. Insteadwe assumed the faster growth rate dueto feeding ractopamine would be mani-fest in fewer days to market. That couldresult in some savings in interest, utili-ties, and repair costs. This was creditedat the rate of $0.05 per pig per day. TheTO scenario is meant for producerswho believe they are producing theheaviest market hogs their packer willaccept given the time they have to feedthem.

In the second scenario, we assumedpigs provided ractopamine were fed ona time constant basis (TC), i.e., theywere fed for the same number of daysbefore going to market as beforeractopamine was introduced. Faster dailygain would be manifest in heavier pigssold. The extra live weight sold wasvalued at $42/cwt. The TC scenario ismeant for producers who are short onfeeding days and can market heavierpigs without additional sort loss.

Revenue from increased carcassyield was calculated assuming a car-cass price of $56.75/cwt of carcass.

Because of the large variation ingenetics, production systems, anddifferences in packer buying gridsand how carcasses are evaluated, it isdifficult to develop estimates of thebenefit a producer would receive incarcass lean premiums. The approachwe have taken is presented in Tables 3and 4. Costs and revenues for feedingractopamine are itemized for feeding 4.5(Table 3) and 9.0 g/ton ractopamine(Table 4) for TO and TC productionscenarios. In the event that the addi-tional costs exceeded the additionalrevenues, we calculated the amount ofa carcass lean premium required tobreakeven.


Feeding 4.5 g/ton ractopamine in aTO production scenario would require

a carcass lean premium of $1.78/pig tobreakeven (Table 3). In contrast, feed-ing 9.0 g/ton ractopamine in a TC pro-duction scenario did not require a carcasslean premium to breakeven (Table 4).Instead we projected a net profit of$0.64/pig; any lean premium earnedwould further increase net profit. Leanpremiums were required to breakevenfeeding 4.5 g/ton ractopamine in a TCproduction scenario ($0.67/pig) and9.0 g/ton in a TO scenario ($0.86/pig).Our results indicate that a producerusing a TO production scenario is moredependent on his/her pigs earning alean premium than one who uses a TCscenario. In the TC scenario, theimprovement in daily gain is valuedmore than it is in the TO scenario.

Considering that the methodwe used to calculate revenues fromimproved daily gain significantly

affected the requirement for a lean pre-mium, we also modeled the economicsof feeding ractopamine at slaughter pricesof $34 and $50/cwt (Figures 1 and 2).The amount of a lean premium requiredwhen feeding 4.5 g/ton ractopamine ina TO production scenario was notaffected by slaughter price (Figure 1),because slaughter weight is constantand carcass yield was not affected byractopamine. However, in a TC pro-duction situation, the amount of leanpremium required to break evendecreased as slaughter price increased.Feeding 9.0 g/ton ractopamine, resultedin a smaller lean premium required forthe TO production scenario as slaugh-ter price increased, because of increas-ing revenues from carcass yield. Incontrast, no lean premium was requiredwhen feeding 9.0 g/ton ractopamine in

Table 3. Costs (-) and revenues (+) from feeding ractopamine (4.5 g/ton) in differentproduction scenarios.

a

Top out Time constant

$/pig $/pig

Item Amount Cumulative Amount Cumulative

Ractopamine -1.17 -1.17 -1.26 -1.26Extra amino acids -1.44 -2.61 -1.44 -2.70Transport deaths -0.45 -3.06 -0.45 -3.15Gain +0.11 -2.95 +2.06 -1.09Yield +0.00 -2.95 +0.00 -1.09Feed/gain +1.17 -1.78 +0.42 -0.67Required lean premium

b+1.78 0.00 +0.67 0.00

Net 0.00 0.00

aTop out = pens are topped out twice then facility emptied; Time constant = pigs are fed ractopaminefor the same number of days before going to market as before it was introduced.bPremium required to cover costs of feeding ractopamine after considering revenues from gain,

carcass yield, and feed efficiency.

Table 4. Costs (-) and revenues (+) from feeding ractopamine (9.0 g/ton) in differentproduction scenarios.

a


$/pig $/pig

Item Amount Cumulative Amount Cumulative

Ractopamine -2.30 -2.30 -2.54 -2.54Extra amino acids -1.47 -3.77 -1.47 -4.01Transport deaths -0.45 -4.22 -0.45 -4.46Gain +0.14 -4.08 +2.85 -1.61Yield +1.68 -2.40 +1.72 +0.11Feed/gain +1.54 -0.86 +0.53 +0.64Required lean premium

b+0.86 0.00 0.00

Net 0.00 +0.64aTop out = pens are topped out twice then facility emptied; Time constant = pigs are fed ractopamine

for the same number of days before going to market as before it was introduced.bPremium required to cover costs of feeding ractopamine after considering revenues from gain,

carcass yield, and feed efficiency.



Summary and Conclusions

Ractopamine generally improvesgrowth performance, carcass leannessand yield, especially at the 9 g/ton level.No lean premium was required tobreakeven in 2/12 economic evalua-tions conducted. Lean premiumsbetween $0.23 and $1.78/pig wererequired in 10/12 evaluations we con-ducted. In most of the situations wemodeled, growth performance and car-cass yield did not cover the costs offeeding ractopamine. In those situa-tions, ractopamine must improve car-cass traits that your packer is capableof measuring and paying for. If earninga carcass premium is in doubt, considerfeeding 9g/ton ractopamine in a TCproduction scenario when slaughterprice is greater than about $42/cwt.

Practical experience with feedingractopamine in today’s pork industry isincreasing, but it is still limited. There-fore, it is important that producerscalculate the costs and benefits ofractopamine for themselves and supple-ment that with published research data.

It may be very useful for producersto collect data from their own pigs fedractopamine. One would obtain spe-cific information from the packer whichwould help in deciding if the lean premi-ums we calculated are likely to be ob-tained. Also, you can determine howwell you can effectively manage feed-ing ractopamine to achieve optimumresults. For example, can you ensurethe majority of pigs receive ractopaminefor about 28 days before slaughter? Inaddition, can you ensure that pigs fedractopamine will receive the extra carethey need during handling and trans-port? Guidelines for conductingon-farm feed research trials are avail-able in the University of Nebraskapublication, Conducting Pig FeedTrials on the Farm (EC 92-270) avail-able at county extension offices inNebraska or on the Internet at http://www. ianr .un l .edu /pubs /sw ine /ec270.htm.

1Duane E. Reese is extension swinespecialist in the Department of AnimalSciences and Larry L. Bitney is extensionfarm management specialist in the Depart-ment of Agricultural Economics.

Figure 1. Estimated carcass lean premiums required to cover cost of feeding 4.5 g/tonractopamine at various slaughter pig prices and production scenarios. Top out= pens are topped out twice then facility emptied; Time constant = pigs are fedractopamine for the same number of days before going to market as before itwas introduced.

21.8

1.61.41.2

10.8

0.60.40.2

0

Le

an

pre

miu

m,

$/p

ig


34 42 50

$/cwt live

Figure 2. Estimated carcass lean premiums required to cover cost of feeding 9.0 g/tonractopamine at various slaughter pig prices and production scenarios. Negativevalues indicate amount of potential profit, not including any lean premiumthat may be obtained, from feeding ractopamine. Top out = pens are topped outtwice then facility emptied; Time constant = pigs are fed ractopamine for thesame number of days before going to market as before it was introduced.

1.5

1

0.5

0

-0.5

-1

-1.5

-2

Le

an

pre

miu

m,

$/p

ig


34 42 50

$/cwt live

a TC production situation when liveprice was $42/cwt or more; our resultsindicate net earnings between $0.55and $1.50/pig not including any leanpremium that may be obtained.

If a producer considers it highlylikely to obtain a larger average leanpremium than that shown in Figures 1and 2, it would be profitable to feedractopamine. When considering pos-sible premiums for carcass leanness,note that it is likely that not all car-casses from a group of pigs fedractopamine will be shifted into a higher

carcass pricing category and earn alean premium. Thus, carcasses frompigs that earned a lean premium mustpay for the ractopamine consumed bypigs that did not earn a premium.

The price of PayleanTM will alsoaffect the size of the carcass lean pre-mium needed per pig. For each $2/lbchange in the price of PayleanTM, thelean premium required changes byapproximately $0.15, and $0.30 per pigfor the 4.5 and 9.0 g/ton levels,respectively.


Defining the Optimal Feed Budget System forTerminal-Crossed, Growing-Finishing Barrows

Robert L. FischerPhillip S. MillerAustin J. Lewis

Darren J. Critser1


This experiment was conducted toevaluate growth performance andcarcass quality measurements ingrowing-finishing barrows assignedto different feed budget systems.Forty-eight barrows with an initialbody weight of 47.3 lb were randomlyallotted to one of three different feedbudget systems. The experiment wascontinued until the average bodyweight was 270 lb, at which time allpigs were slaughtered. Growth per-formance and real-time ultrasoundmeasurements were taken biweekly,except for the final period, which was24 days. Carcass tenth-rib backfatand longissimus muscle area measure-ments were made 24 hours postmortem.Overall, average daily feed intake(ADFI) was affected (P < 0.05) by feedbudget with barrows assigned toBudget 2 having the greatest ADFIcompared to barrows fed Budget 1(P < 0.05) and 3 (P < 0.10). There wasa trend (P = 0.106) toward an effect offeed budget on average daily gain(ADG). Barrows allotted to Budget 2had greater overall ADG than bar-rows allocated to Budget 1 (P < 0.10)and 3 (P < 0.10). Feed efficiency forthe overall experimental period wasnot affected (P > 0.10) by feed budget;however, the comparison of Budget 1and 2 resulted in a difference in feedefficiency with barrows from Budget 1having better (P < 0.10) feed efficiencythan barrows from Budget 2. Ultra-sound and carcass measurementswere similar for pigs fed the three

feed budget systems. The main effect offeed budget on total body electricalconductivity measurements was onlysignificantly different (P < 0.10) forhot carcass weight. Returns above feedcost and feed cost per pound of gainfrom 50 lb to market weight were notaffected by feed budget. Barrows allot-ted to Budget 2 had the greatest ADGand hot carcass weight; however, thisgroup also had the greatest ADFI, whichresulted in no difference in the returnabove feed costs or feed cost per poundof live weight gain. In summary, therewere no major differences in overallgrowth performance, carcass charac-teristics, or return above feed costs ingrowing-finishing barrows fed differ-ent feed budgets.

Introduction

An important question that occursin the feeding of growing-finishing pigsis when to change diets. A feed budgetis a mechanism that can be used toensure that the correct amount of eachdiet is delivered to a given group ofpigs. Feed budgets are designed toprovide pigs the correct amount of feedto gain a predetermined amount of bodyweight. In traditional systems in whichpigs are fed on a time basis instead of afeed budget, pigs with poor feed intakeand therefore slow growth may notreach the predetermined weight beforebeing switched to the next diet. In a feedbudget system, the manager of the fin-ishing barn does not have to guess theweight of the pigs to determine whichdiet to order because the diet to bedelivered to the group of pigs is auto-matically determined by the feed bud-get. The use of feed budgeting willresult in more accurate phase feedingby not over- or under-delivering dietsfor each phase. Because environmental

and management factors are majordeterminants affecting pig performance,the greatest challenge to using a feedbudget system is customizing the feedbudget for a specific production sys-tem. Therefore, the objective of thisexperiment was to compare three differ-ent feed budget systems when fed toterminal-crossed, growing-finishingbarrows.

Procedures

Forty-eight crossbred (Danbred;Sire - Line 771 × Dam - 75% Line 200 or400 × 25% NE White Line) barrows withan initial body weight of 47.3 lb wereused in a growing-finishing experiment.Pigs were allotted to one of 24 pens(5 ft × 7.1 ft) which included fourlocation blocks (six pens/block) in anenvironmentally control room. Theaverage weight within each locationblock was similar and each treatmentwas replicated twice within each loca-tion block. Treatments consisted of threedifferent feed budget systems (Table1). Each feed budget offered the sametotal pounds of feed throughout thegrowing-finishing period, but the feedbudgets differed in the amounts of eachdiet fed during the experimental period.Therefore, diets were changed on a penbasis when a pen of pigs had consumedthe allotted amount of diet. Diets (Table2) contained corn and soybean mealand were fortified with vitamins andminerals to meet or exceed the NRC(1998) requirements for 44- to 265-lbpigs. Pigs had ad libitum access to feedand water throughout the experimentalperiod. Pigs remained on the experi-ment until the average body weight ofthe pigs reached approximately 270 lb,at which time all pigs were removedfrom the experiment.



Pairwise comparisons between feedbudgets were conducted only whenthe main effect of treatment was signifi-cant (P < 0.10). Ham, loin, shoulder, andtotal lean weights were analyzed withhot carcass weight as a covariate. In allanalyses pen was the experimental unit.


Growth Performance

Average daily gain, ADFI, and feedefficiency (ADG/ADFI) for the sevendata collection periods and the entireexperimental period are shown in Table3. During Period I, ADG and feed effi-ciency were affected (P < 0.01) by feedbudget. Average daily gain and feedefficiency were greater (P < 0.007) inbarrows fed diets from Budgets 1 and 2compared to Budget 3. During Period II,barrows fed diets from Budget 1 hadgreater ADG (P < 0.06) and feed effi-ciency (P < 0.01) than barrows con-suming diets from Budgets 2 and 3.An effect of feed budget on ADG andADFI was detected during PeriodVII, with barrows consuming dietsfrom Budgets 2 and 3 having thegreatest body weight gain (P < 0.02)and pigs consuming diets from Bud-get 2 having the greatest (P < 0.07)feed intake. Results for the overallexperimental period indicated a trend(P = 0.106) toward an effect of feedbudget on ADG and a significant effect(P < 0.05) on ADFI, with barrows con-suming diets from Budget 2 havingthe greatest ADG and ADFI.

Carcass Characteristics

Real-time ultrasound, carcass, andTOBEC measurements are provided inTable 4. Ultrasound measurements oftenth-rib BF and LMA did not differ(P > 0.10) among feed budgets. Also,tenth-rib BF and LMA carcass mea-surements were similar (P > 0.10) amongfeed budgets. Although a large differ-ence in ultrasound and carcass tenth-rib LMA measurements was detected(ex. Budget 1 ultrasound LMA = 6.34 in2

versus carcass LMA = 9.58 in2; seeTable 4), there was no effect of feedbudget on ultrasound or carcass

Table 1.Lysine concentration and amount of each diet fed per pig for each feed budget.

Dietary phases

Diet 1 Diet 2 Diet 3 Diet 4 Diet 5

Lysine, % 1.15 0.90 0.75 0.65 0.60

Pounds of each diet, per pig Total

Budget 1 105 110 152 135 118 620

Budget 2 54 108 135 111 212 620

Budget 3 — 210 — 410 — 620

Table 2.Ingredient and calculated composition of diets, as-fed basis.

Dietary phases

Ingredients, % Diet 1 Diet 2 Diet 3 Diet 4 Diet 5

Corn 61.48 71.85 78.13 82.95 84.93Soybean meal (46.5% CP) 32.25 22.40 16.25 12.50 10.75Tallow 3.00 3.00 3.00 2.00 2.00Dicalcium phosphate 1.65 1.08 0.93 1.00 0.75Limestone 0.38 0.40 0.40 0.25 0.28Salt 0.30 0.30 0.30 0.30 0.30Vitamin premix

a0.70 0.70 0.70 0.70 0.70

Trace mineral premixb

0.10 0.10 0.10 0.10 0.10Antibiotic 0.125 0.125 0.125 0.125 0.125Lysine•HCl 0.025 0.05 0.075 0.075 0.075

Calculated nutrient contentCrude protein, % 20.40 16.70 14.30 12.90 12.20Lysine, % 1.15 0.90 0.75 0.65 0.60ME

c, Mcal/lb 1.56 1.57 1.57 1.55 1.55

Calcium, % 0.80 0.65 0.60 0.55 0.50Phosphorus, % 0.70 0.55 0.50 0.50 0.45

Analyzed nutrient contentCrude protein, % 20.80 16.50 15.20 12.90 12.40Lysine, % 1.07 0.85 0.74 0.61 0.57Gross energy, Mcal/lb 1.85 1.85 1.84 1.81 1.83Calcium, % 0.81 0.69 0.53 0.53 0.51Phosphorus, % 0.72 0.60 0.43 0.48 0.48Fat, % 4.90 5.14 4.67 4.81 5.12Dry matter, % 91.73 92.05 90.27 90.83 91.49Ash, % 5.75 4.72 3.95 3.70 3.65

aSupplied per kilogram of diet: retinyl acetate, 3,088 IU; cholecalciferol, 386 IU; α-tocopherol

acetate, 15 IU; menadione sodium bisulfite, 2.3 mg; riboflavin, 3.9 mg; d-pantothenic acid, 15.4mg; nicacin, 23.2 mg; choline, 77.2 mg; vitamin B

12, 15.4 µg.

bSupplied per kilogram of diet: Zn (as ZnO), 110 mg; Fe (as FeSO

4•H

2O), 110 mg; Mn (as MnO),

22 mg; Cu (as CuSO4•5 H

2O), 11 mg; I (as Ca(IO

3)•H

2O), .22 mg; Se (as Na

2SeO

3), 0.3 mg.

cMetabolizable energy.

Pigs and feeders were weighedbiweekly (denoted as periods), exceptfor Period VII which was 24 days, todetermine average daily gain (ADG),average daily feed intake (ADFI), andfeed efficiency (ADG/ADFI). Real-timeultrasound measurements (tenth-ribbackfat (BF) depth and longissimusmuscle area (LMA)) were recorded atthe beginning of each period. Theexperiment period was 108 days. At thetermination of the experiment, pigs were

shipped to SiouxPreme Packing Co. inSioux Center, Iowa, where carcasscharacteristics were measured onindividually identified pigs using totalbody electrical conductivity (TOBEC).At 24 hours postmortem, tenth-rib BFmeasurements and LMA traces at thetenth rib were recorded for all carcasses.

Data were analyzed as a random-ized complete block design using PROCMIXED of SAS. The main effect of thestatistical model was feed budget.


Table 3. Effect of feed budget on growth performance.

Feed budget P-Valuea

Item 1 2 3 SEM T R T 1 vs 2 1 vs 3 2 vs 3

No. pens 8 8 8

Initial wt., lb 47.61 47.78 46.68 0.992 NS NS NS NSFinal wt., lb 268.06 280.71 267.60 4.778 0.1135 0.076 NS 0.066

Period I (day 0-14)ADG

b, lb 1.65 1.70 1.38 0.062 0.004 NS 0.007 0.002

ADFI c, lb 2.76 2.83 2.70 0.085 NS NS NS NSADG/ADFI, lb/lb 0.60 0.60 0.51 0.006 <0.001 NS <0.001 <0.001

Period II (day 15-28)ADG, lb 2.22 2.11 2.05 0.049 0.056 0.099 0.020 NSADFI, lb 4.01 4.10 4.03 0.102 NS NS NS NSADG/ADFI, lb/lb 0.56 0.51 0.51 0.010 0.006 0.007 0.003 NS

Period III (day 29-42)ADG, lb 2.18 2.26 2.24 0.066 NS NS NS NSADFI, lb 4.76 5.05 4.84 0.135 NS NS NS NSADG/ADFI, lb/lb 0.46 0.45 0.46 0.012 NS NS NS NS

Period IV (day 43-56)ADG, lb 2.28 2.29 2.17 0.079 NS NS NS NSADFI, lb 5.63 6.05 5.59 0.197 NS NS NS NSADG/ADFI, lb/lb 0.41 0.38 0.39 0.009 NS 0.058 NS NS

Period V (day 57-70)ADG, lb 2.15 2.24 2.25 0.053 NS NS NS NSADFI, lb 6.00 6.45 6.24 0.176 NS 0.084 NS NSADG/ADFI, lb/lb 0.36 0.35 0.36 0.008 NS NS NS NS

Period VI (day 71-84)ADG, lb 2.06 2.20 2.04 0.093 NS NS NS NSADFI, lb 6.44 6.94 6.32 0.233 NS NS NS 0.076ADG/ADFI, lb/lb 0.32 0.32 0.32 0.009 NS NS NS NS

Period VII (day 85-105)ADG, lb 1.87 2.25 2.13 0.068 0.003 0.001 0.016 NSADFI, lb 6.45 7.56 6.94 0.223 0.008 0.002 NS 0.064ADG/ADFI, lb/lb 0.29 0.30 0.31 0.007 NS NS NS NS

Overall (day 0-108)ADG, lb 2.04 2.16 2.05 0.042 0.106 0.062 NS 0.071ADFI, lb 5.27 5.75 5.40 0.133 0.047 0.018 NS 0.072ADG/ADFI, lb/lb 0.39 0.38 0.38 0.005 NS 0.096 NS NS

aTRT = treatment; NS = nonsignificant effect, P > 0.10.bADG = average daily gain.

cADFI = average daily feed intake.

measurements. Total body electricalconductivity measurement of hotcarcass weight was greater (P < 0.10) forbarrows fed diets from Budget 2 thanfor barrows fed diets from Budgets 1and 3. Although barrows allocated toBudget 2 had greater hot carcass weights,the increase in ADFI of pigs in thisgroup resulted in a greater (P < 0.10)feed cost per pig (Table 5), whichresulted in a similar return above feedcost and feed cost per pound of liveweight gain (17 cents per pound, from50 lb to market weight).

Conclusions

These results indicate that bar-rows fed under optimal growing condi-

tions (2 pigs/pen and an environ-mentally controlled room) do notexhibit major differences in growthperformance or carcass characteristicswhen assigned to different feed bud-gets throughout the growing-finishingperiod. Although hot carcass weightwas greater in barrows allotted toBudget 2, they also had the greatestADFI, which resulted in a similar feedefficiency and return above feed costswhen compared to the other feedbudgets. The greatest effect of the dif-ferent feed budgets on ADG occurredduring Periods 1 and 2 of the growing-finishing period. This suggests that thebody weight gain of barrows is the mostsensitive to dietary lysine concentra-tion during the first 28 days of the

growing-finishing period (initial bodyweight 50 lb). Although no major dif-ferences in the feed budget systemswere observed in the current experi-ment, a much different outcome ispossible if this experiment was con-ducted on a commercial swine opera-tion. Therefore, further research isneeded to explore the effects of com-mercial swine production (i.e., stockingrate, disease, management) on feedbudget systems.

1Robert L. Fischer is a research tech-nologist and graduate student, Phillip S. Milleris an associate professor, and Austin J. Lewisis a professor in the Department of AnimalScience. Darren J. Critser is a swine nutrition-ist for Danbred USA.


Table 4.Effect of feed budget on ultrasound and carcass measurements.

Feed budget P-Valuea


Ultrasound measurementsTenth-rib backfat, in 0.83 0.87 0.87 0.031 NS NS NS NSLMA b, in2 6.34 6.19 6.09 0.129 NS NS NS NS

Carcass measurementsTenth-rib backfat, in

c,d0.96 0.94 0.98 0.046 NS NS NS NS

LMA, in2

9.58 9.64 9.05 0.304 NS NS NS NS

TOBEC measurementsHot carcass wt., lb 200.57 212.69 200.13 4.347 0.091 0.062 NS 0.054Ham wt., lb

e,i23.05 23.13 22.63 0.492 NS NS NS NS

Loin wt., lbe,i

27.55 27.06 27.24 0.335 NS NS NS NSShoulder wt., lbe,i 27.94 28.13 27.67 0.405 NS NS NS NSPrimal percentage

e,f38.46 37.78 38.40 0.633 NS NS NS NS

Total lean, lbe,i

100.34 99.17 98.80 1.832 NS NS NS NSPercent lean

d46.21 46.21 45.89 0.841 NS NS NS NS

Lean gain, lb/dayd,g

0.72 0.77 0.71 0.025 NS NS NS NS

aTRT = treatment; NS = nonsignificant effect P > 0.10.

bLongissimus muscle area.

cBackfat measurements were taken at 3/4 the distance along the loin muscle.

dCalculated on a fat-free lean basis.

eContains 5% fat.fPrimal percentage was calculated by taking the total weight of the primal cuts (ham, loin, and shoulder) divided by the hot carcass weight.

gLean gain calculation: Final fat-free lean – Initial fat-free lean

h

108 dhInitial fat-free equation: .95 * [ -3.95 + (.418 * live weight, lb)]

iHot carcass weight used as a covariate in the statistical analysis.

Table 5. Effect of feed budget on revenue and feed costs.

Feed budgeta

P-Valueb


Economics, 50 lb to 260 lbc,d

Average feed cost/pig, $ 36.06 35.65 36.14 0.294 NS NS NS NS

Feed cost/lb of gain, $ 0.17 0.17 0.17 0.002 NS NS NS NS

Economics, 50 lb to marketd,e

Gross income, $/pig 130.54 136.70 130.32 2.327 0.114 0.076 NS 0.066

Average feed cost/pig, $ 37.68 39.92 37.30 0.501 0.094 0.082 NS 0.045

Return above feed, $/pig 92.87 96.78 93.02 1.634 NS NS NS NS

Feed cost/lb of gain, $ 0.17 0.17 0.17 0.001 NS NS NS NS

aDiet costs/lb, $ : Diet 1 = 0.075; Diet 2 = 0.069; Diet 3 = 0.065; Diet 4 = 0.061; Diet 5 = 0.060; diet costs only included cost of the ingredients.bTRT = treatment; NS = nonsignificant effect P > 0.10.

cFeed cost per pig and feed cost per pound of live weight gain were calculated from a starting weight of 50 lb to a constant ending weight of 260 lb.

dA live weight price of $48.70 per hundred pounds of live weight was used in the economic analysis.

eFeed cost per pig and feed cost per pound of live weight gain were calculated from a starting weight of 50 lb to market weight for all pigs.


Effects of Glutamine onGrowth Performance and Small Intestine

Villus Height in Weanling Pigs

Steven J. KittPhillip S. MillerAustin J. Lewis

Robert L. Fischer1


The pig’s small intestinal struc-ture and function is altered during thedays that follow weaning. As a conse-quence, the digestive and absorptivecapacity of weanling pigs may decreaseduring this period, and this may bepartially responsible for the postwean-ing growth lag. Additionally, healthbenefits may be associated with animproved small intestinal structure andfunction during the early postwean-ing period. This experiment was con-ducted to evaluate the effects ofcrystalline glutamine and (or) dietcomplexity on small intestine villusheight and growth performance of18-day-old pigs. During the 21-daytrial, no differences in villus heightwere observed between pigs fed dietswith or without supplemental glutamineor between pigs fed a complex diet ora simple diet. Pigs fed the complex diethad improved (P < 0.01) average dailygain during days 0 to 4, 7 to 14, and 14to 21. The majority of improvementin average daily gain of pigs fed thecomplex diet was likely due to theimprovement in average daily feedintake; in as much as average dailyfeed intake was improved (P < 0.05)during days 0 to 4, 4 to 7, 7 to 14, and

14 to 21. Pigs fed the simple diet hadimproved (P < 0.05) feed efficiencyduring days 7 to 14 and 14 to 21.Although supplemental glutamine didnot improve villus height, it didimprove (P < 0.05) feed efficiency dur-ing days 14 to 21, regardless of dietcomplexity. The glutamine-inducedimprovement in feed efficiency may havebeen related to other improvements inintestinal structure and function thatwere not measured in this experiment.

Background and Introduction

Villus atrophy (degeneration ofthe absorptive organelles) and crypthyperplasia (increased cellular growthof the cells that replace villus epithelialcells) is observed in the small intestineof the weanling pig. During this time, itis thought that a temporary decrease indigestive and absorptive capacityensues for several days. Additionally,it has been estimated that the majorityof the immune response of a weanlingpig is mediated in the small intestine.

Glutamine is an amino acid that isconsidered nonessential for swine.However, in humans glutamine pro-motes gastrointestinal growth duringintravenous feeding and after traumaticevents such as gastrointestinal sur-gery. Rapidly dividing cells, includingthe absorptive and immune cells of thesmall intestine, use glutamine (in pref-erence to glucose) as an energy source.Additionally, free (unbound to protein)glutamine is the most abundant amino

acid in sow milk, particularly in latelactation. The addition of 1% crystal-line glutamine to a corn-soybean mealdiet has been reported to reduce villousatrophy in the jejunum (mid portion ofthe small intestine) on the seventh dayafter weaning. Other studies have dem-onstrated improvements in intestinallamina propria depth (region associ-ated with immune cell synthesis) andincreased crypt depth. Cell cultureexperiments have shown that glut-amine decreased intestinal permeabil-ity after an endotoxin (toxin synthe-sized by E. coli) challenge and E. colichallenge suggesting that glutaminedecreases the ability of enteric path-ogens and their toxins to enter theportal blood circulation. Animal experi-ments have confirmed an improvedimmune response, with elevated IgG(a indicator of immune system activa-tion) after an E. coli challenge.

The goal of this study was to deter-mine the effect of crystalline glutamineon villus height and growth perfor-mance in nursery pigs fed simple orcomplex Phase-I diets.

Procedures

A total of 115, 18-day-old (+ 2)weanling pigs were used in this experi-ment. On day 0, four pigs were killed todetermine initial villus height. Theremaining 111 pigs were blocked (n = 4)by weight and randomly assigned topen (n = 16; 7 pigs/pen). Treatments(Table 1) were arranged in a 2 × 2



factorial with the main effects beingglutamine concentration (0% or 1%)and diet (simple or complex). Pigs andfeeders were weighed and four pigs pertreatment were killed on days 4, 7, 14,and 21. Pigs that were used for villusheight determination were fully anes-thetized, and an incision was made nearthe naval. The intact small intestinewas removed from the body cavity andplaced in physiologic saline solution,and the pig was then killed before itregained consciousness. Duodenumsamples were taken at 5 cm from thebeginning of the small intestine andjejunum samples were taken from thecentral point between the beginningand end of the small intestine. Sampleswere immediately fixed in a formalinsolution and transferred to an ethanolsolution. The duodenum and jejunumsamples were imbedded in paraffin,sliced, mounted on a slide, and stained.A total of fifteen representative villiwere measured from three sites of eachsample using a microscope with a powerof 25 times that of normal vision. Datawere analyzed as a randomized com-plete block design with initial weight asthe block, pen as the experimental unit,and individual pigs as the sampling unitfor villus height determination. Dataare reported as least squares means.


Pigs fed the complex diet hadincreased average daily gain (ADG)during days 0 to 4 (P < 0.01), 7 to 14(P < 0.05), and 14 to 21 (P < 0.10) com-pared to pigs fed the simple diet(Figure 1). Average daily feed intake(ADFI) of pigs fed the complex diet wasincreased during days 0 to 4 (P < 0.05),4 to 7 (P < 0.001), 7 to 14 (P < 0.001), and14 to 21 (P < 0.05) (Figure 2). Pigs fed thesimple diet had greater (P < 0.05) feedefficiency (ADG/ADFI) during days 7to 14 and 14 to 21 (Figure 3). Greater(P < 0.05) ADG/ADFI was observedduring days 14 to 21 in pigs fed sup-plemental glutamine compared to pigsfed the diets without supplementalglutamine.

Table 1. Composition of diets, % (as fed).

Simple Complex

Ingredient Control Glutamine Control Glutamine

Corn 46.65 45.65 33.79 32.79Dried whey 0 0 35.75 35.75Soybean meal, 46.5% CP 45.78 45.78 13.45 13.45Spray-dried plasma 0 0 6.00 6.00Menhaden fish meal 0 0 6.00 6.00Corn oil 3.00 3.00 3.00 3.00Dicalcium phosphate 2.54 2.54 0.06 0.06Limestone 0 0 0.20 0.20Salt 0.74 0.74 0.35 0.35L-Lysine•HCl 0.13 0.13 0.09 0.09DL-Methionine 0.10 0.10 0.11 0.11L-Threonine 0.08 0.08 0 0Vitamin premixa 1.00 1.00 1.00 1.00Mineral premix

b0.20 0.20 0.20 0.20

L-Glutamine 0 1.00 0 1.00

Calculated composition:

MEc, kcal/lb 1,539 1,559

Lactose, % 0 25.0CP, % 25.5 22.0Lysine, % 1.60 1.60Ca, % 0.90 0.90P, % 0.92 0.73P avail., % 0.55 0.55Na, % 0.30 0.70

aSupplied per lb of diet: retinyl acetate, 2,000 IU/lb; cholecalciferol, 250 IU; α-tocopherol acetate,10 IU; menadione sodium bisulfite, 1.50 mg; riboflavin, 2.50 mg; d-pantothenic acid, 10.0 mg;niacin, 15.0 mg; choline, 50 mg; vitamin B

12, 10.0 µg.

bSupplied per lb of diet: Zn (as ZnO), 100 mg; Fe (as FeSO

4•H

2O), 100 mg; Mn (as MnO), 20 mg;

Cu (as CuSO4•5 H2O), 10 mg; I (as Ca(IO

3)•H

2O, 0.14 mg; Se (as Na

2SeO

3), 0.27 mg.

cMetabolizable energy.

123123123

123451234512345123451234512345

123451234512345123451234512345123451234512345123451234512345

123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345

12345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345

Figure 1. Average daily gain of pigs fed diets differing in complexity and crystallineglutamine concentration. Gln = glutamine.

1.2

1.0

0.8

0.6

0.4

0.2

0.0

-0.2

AD

G,

lb/d

ay

Day 0-4 Day 4-7 Day 7-14 Day 14-21

Simple Diet Simple Diet + Gn Complex Diet Complex Diet + Gln

Diet, P < 0.01 Diet, P < 0.05 Diet, P < 0.10SEM = 0.06 SEM = 0.06 SEM = 0.05 SEM = 0.05


Table 2.Effects of diet complexity and crystalline glutamine supplementation on weanling pig villus height and small intestinelength.

Diet Glutamine Diet × GlutamineSimple Complex

Control Glutamine Control Glutamine Pd < SEM

Day 4a

Duodenum VHb, mm 0.438 0.493 0.488 0.512 NS NS NS 0.032

Jejunum VH, mm 0.338 0.327 0.324 0.334 NS NS NS 0.015Day 7

Duodenum VH, mm 0.162 0.160 0.221 0.162 0.05 0.05 0.05 0.012Jejunum VH, mm 0.131 0.121 0.141 0.126 NS 0.20 NS 0.009

Day 14Duodenum VH, mm 0.232 0.204 0.232 0.226 NS 0.18 NS 0.012Jejunum VH, mm 0.161 0.176 0.159 0.157 NS NS NS 0.010

Day 21Duodenum VH, mm 0.257 0.252 0.220 0.253 NS NS NS 0.022Jejunum VH, mm 0.191 0.195 0.184 0.182 NS NS NS 0.014SI

c length, m 10.533 10.970 10.980 11.138 NS NS NS 0.459

aDay 0 duodenum = 0.475 mm; Day 0 jejunum = 0.420 mm.

bVH = villus height.cSI = small intestine.

dNS = P > 0.20.

123451234512345123451234512345

12345123451234512345123451234512345123451234512345123451234512345123451234512345

123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345

1234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345123451234512345

123123123

Figure 2.Average daily feed intake of pigs fed diets differing in complexity andcrystalline glutamine concentration. Gln = glutamine.

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

AD

FI,

lb

/da

y

Day 0-4 Day 4-7 Day 7-14 Day 14-21

Simple Diet Simple Diet + Gln Complex Diet Complex Diet + Gln

Diet, P < 0.05 Diet, P < 0.001 Diet, P < 0.001 Diet, P < 0.05SEM = 0.03 SEM = 0.03 SEM = 0.04 SEM = 0.09

Villus height (Table 2) on day 7 wasreduced by 37% and 31% of day 0 villusheight in the duodenum and jejunum,respectively. Villus height increasedprogressively after day 7, but by day 21was still only 52% and 45% of day 0duodenum and jejunum villus height,respectively. Surprisingly, diet com-plexity had little effect on villus heightwith the exception that the control-complex diet had greater duodenumvillus height on day 7, resulting in aninteraction of diet complexity andglutamine concentration (P < 0.05).Duodenum villus height seemed tobe greater on day 4 in pigs offered thecomplex diet and glutamine supple-mentation, but was not different(P > 0.27) from pigs fed the simple ornon-glutamine supplemented diet. Nodifference (P > 0.52) in total small intes-tine length was observed among treat-ments on day 21.

The results from this trial confirmedthat ADFI was increased when pigswere offered a complex diet comparedto a simple diet. This increase in ADFIsupported an improved ADG. How-ever, pigs fed the simple diet had agreater ADG/ADFI. No improvement invillus height was attributed to dietcomplexity or glutamine supplemen-tation; however, the variability in

villus height measurements appearedto be high. The improvement in ADG/ADFI in pigs offered the diet with sup-plemental glutamine coupled withknown properties of glutamine on in-testine metabolism suggests an improve-ment in intestine function or morphology.

Future research will attempt toexamine the effects of glutamine onsmall intestine growth using moredirect measurements. For example,

indices of protein and DNA concentra-tions may provide a more definitiveanswer to how glutamine is influenc-ing intestinal growth. Also, it may beimportant to study the effects ofglutamine during a pathogen challenge.Presently, we are working on an assayto quantify glutamine in feedstuffs tohelp objectively assess dietary gluta-mine concentration in a practicalmanner.



Conclusions

Data from this trial suggest thatdiet complexity had a significant effecton growth, but little to no effect onintestine villus height. Supplementalglutamine did not improve villus heightbut did improve feed efficiency in thethird week of this 21-day growth study.Additional research is needed toexamine the effects of glutamine onintestine metabolism and function toascertain whether glutamine may bebeneficial in practical situations.

1Steven J. Kitt is a graduate student,Phillip S. Miller is an associate professor,Austin J. Lewis is a professor, and Robert L.Fischer is a graduate student and researchtechnologist in the Department of AnimalScience.

1234512345123451234512345123451234512345123451234512345

1234512345123451234512345123451234512345

12345123451234512345123451234512345123451234512345

12345123451234512345123451234512345123451234512345

123123123

Figure 3.Feed efficiency of pigs fed diets differing in complexity and crystallineglutamine concentration. Gln = glutamine.

1.0

0.7

0.4

0.1

-0.2

-0.5

-0.8

-1.1

-1.4

-1.7

-2.0

-2.3

AD

G/A

DF

I

Day 0-4 Day 4-7 Day 7-14 Day 14-21

Simple Diet Simple Diet + Gln Complex Diet Complet Diet + Gln

Diet, P < 0.05Diet, P < 0.18 Diet, P < 0.12 Diet, P < 0.05 Glutamine, P < 0.05

SEM = 1.25 SEM = 0.11 SEM = 0.02 SEM = 0.03

Influence of Linoleic Acid Isomers on Body Fat

Kim HargraveKristin NolletteMerlyn Nielsen

Jess Miner1


In two studies, mice were feddiets containing either individualconjugated linoleic acid (CLA) iso-mers or a mixture of isomers in thepresence or absence of dietary essen-tial fatty acids. Mice fed the C18:2∆10,12 CLA isomer lost as much bodyfat as mice fed a mixture of isomers.This effect was not observed when themice were fed the C18:2 ∆9,11 isomeror when feed intake was restricted. Theloss of body fat was much greater inmice consuming an essential fatty aciddeficient diet versus a control diet.This supports our hypothesis that forCLA to deplete body fat, it must first bemetabolized in a manner similar tolinoleic acid. Furthermore, we sug-

gest that the loss of body fat may bemediated by metabolism of CLA to anisomer of arachidonic acid. Under-standing the mechanism by which CLAcauses body fat loss, in pigs as well asmice, will allow for greater regulationof body fat content.

Introduction

Conjugated linoleic acid (CLA)is a group of isomers of linoleic acid(C18:2 ∆9,12), which, when consumed,produce health benefits such as reduc-ing the incidence of cancer and cardio-vascular disease and reducing bodyfat content. Furthermore, in swine,dietary CLA has resulted in firmerbellies, reduced backfat, and improvedfeed efficiency. Our group previouslyreported (Nebraska Swine Report 2001,pg 27 – 28) that not only did dietaryCLA supplementation cause a loss ofbody fat in mice, but that it also resultedin programmed cell death, or apoptosis,of fat cells. The basis for the following

two studies was to further determinethe mechanism by which CLA is caus-ing both the body fat loss as well as theapoptosis. The predominant naturallyoccurring isomer is C18:2 ∆9,11 (CLA9/11), whereas commercially synthe-sized CLA products usually containapproximately equal amounts ofC18:2 ∆10,12 (CLA 10/12) and CLA 9/11as well as smaller quantities of otherisomers. The diverse benefits of CLAmay depend on different isomers. There-fore our first objective was to determinewhich isomer(s) are responsible for theloss of body fat in mice.

Arachidonic acid (C20:4 ∆5,8,11,14)is synthesized in animals from dietarylinoleic acid. Similarly, CLA 10/12 canbe metabolized to C20:4 ∆5,8,12,14. Thisproduct of CLA metabolism couldantagonize the normal production ofprostaglandins from arachidonic acid.Therefore, mice fed a diet deficient inlinoleic acid, and thus arachidonic acid,may be especially sensitive to the anti-


obesity effect of dietary CLA. Our sec-ond objective was to compare the effectof CLA in dietary essential fatty acid-adequate and -deficient diets.

Procedures

Experiment 1

Seventy-two mixed sex mice wereallotted to one of five diets (each 7%fat) and allowed to consume ad libitum,except the Pair-Fed group, for 5 days:

Control purified diet with 7% soyoil

Pair-Fed control diet at intake of CLAMix

CLA Mix 2% CLA mixture and 5%soy oil

CLA 9/11 0.82% CLA 9/11 and 6.18%soy oil

CLA 10/12 0.88% CLA 10/12 and 6.12%soy oil

Individual isomers were includedthe concentrations they were found atin the CLA Mix diet. Feed intake andbody weight were measured daily.After 5 days, the mice were killed andretroperitoneal (RP) fat pads wereremoved and weighed. Body fat wasdetermined on carcasses by etherextraction.

Experiment 2

Eighty, newly weaned male micewere fed either a control diet (7% soyoil) or essential fatty acid deficient(EFAD) diet (7% coconut oil) for 6weeks. Next, half of the mice in eachgroup were supplemented with 0.5%CLA mixture, replacing either soy orcoconut oil, for 2 weeks. Then the micewere killed and RP fat pads, epididymal(Epi) fat pads, and livers were removedand weighed. Body fat was determinedby ether extraction.

Results

Experiment 1

Feed intake was reduced (P < 0.001)in mice fed CLA Mix and CLA 10/12 as

Figure 1.Effect of CLA Mix or individual isomers on feed intake (Experiment 1). *CLA10/12, CLA Mix, and Pair-Fed differ from Control ( P < 0.001).

6

5

4

3

2

Fe

ed

in

take

, g

/da

y

0 1 2 3 4 5

Days of CLA supplementation

S.E. = 0.15 Control

CLA 9/11

CLA 10/12CLA Mix

Pair-Fed

Figure 2.Effect of CLA Mix or individual isomers on body weight (Experiment 1). Noeffect of dietary treatment on body weight was detected.

35

34

33

32

Bod

y w

eigh

t, g

S.E. = 0.9

1 2 3 4 5

Days of CLA supplementation

CLA 9/11

ControlCLA 10/12

CLA MixPair-Fed

Table 1. Effect of dietary treatment on feed intake, body weight change, and fat padweights (Experiment 2).

Dietary Treatmentsd

Control CLA EFAD EFAD +CLA SEM

Feed intake, g/dBefore CLA

e3.79 3.79 3.82 3.82 0.12

After CLAe 4.45a 3.95b 4.50a 3.85b 0.08Body wt. change, g

f

Before CLAe

16.66 16.66 16.94 16.94 0.47After CLA

e2.75

a1.55

b2.55

a-0.46

c0.30

RP wt., gg

0.37a

0.19b

0.34a

0.09c

0.03Epi wt., gh 0.61a 0.45b 0.55a 0.21c 0.04

abcDifferent letters in a row indicate differences, P < 0.05.

dDietary treatments are as follows: Control – 7% soy oil diet for 8 weeks; CLA – 7% soy oil diet

for 6 weeks, 0.5% CLA mix + 6.5% soy oil diet for 2 weeks; EFAD – 7% coconut oil diet for 8 weeks;and EFAD + CLA – 7% coconut oil diet for 6 weeks, 0.5% CLA + 6.5% coconut oil diet for 2 weeks.eFeed intake and body weight change before CLA is the first six weeks of the study; after CLA is

the final 2 weeks of the study.fBody weight change is calculated as the weight at the final week of the feeding period minus theinitial weight of that feeding period.gRP = retroperitoneal fat pads.hEpi = epididymal fat pads.



on feed intake, body weight, or bodyfat. However, when CLA was fed tomice deficient in essential fatty acids itseffects were greatly amplified (P < 0.001);a reduction of 73% in RP, 57% in Epi,and 66% in total body fat (Figure 4).

Discussion

Our results indicate that CLA 10/12is responsible for the loss of body fatobserved when mice are fed a mixture ofCLA isomers. This loss of body fat maybe mediated through metabolism of CLAto an isomer of arachidonic acid. Thiswas the basis for the design of Study 2.Arachidonic acid is a precursor to theseries 2 prostaglandins, some of whichappear to protect against cell death.Therefore, CLA-mediated inhibition ofthe conversion of arachidonic acid toprostaglandin could explain the fat celldeath caused by feeding CLA. Essen-tial fatty acids (linoleic and linolenic)protect against the full effect of CLA,which may indicate that CLA and thesefatty acids are metabolized via a com-mon metabolic path.

The knowledge that CLA 10/12 isresponsible for the full fat-reducing-effect of CLA will allow both research-ers, as well as swine producers to moreaccurately formulate diets on the activeCLA isomer (CLA 10/12), instead of onthe total CLA content. This becomesespecially important when differentsources of CLA are used as differentmanufacturing procedures produce dif-ferent ratios of isomers. In addition,recognizing the metabolic pathwaythrough which CLA acts should facili-tate development of better methods tomanipulate body fat in the future.

1Kim Hargrave is a graduate stu-dent, Kristin Nollette is an under-graduate student, Merlyn Nielsen is aprofessor, and Jess Miner is an assis-tant professor in the Department ofAnimal Science.

Figure 3.Effect of CLA Mix or individual isomers on body fat (Experiment 1). abcBars withdifferent superscripts differ (P < 0.10).

20

15

10

5

0

Bo

dy

fat,

%

Dietary treatment

a

ab

c

a

bc

Co

ntr

ol

Pa

ir-F

ed

CLA

Mix

CL

A 9

/11

CL

A 1

0/1

2

Figure 4. Effect of essential fatty acid deficiency (EFAD) and CLA supplementation onbody fat (Experiment 2). abcBars with different superscripts differ (P < 0.001).

25

20

15

10

5

0

Bo

dy

fat,

%

a

b

a

c

Dietary treatment

Co

ntr

ol

CL

A

EF

AD

EF

AD

-C

LA

well as the Pair-Fed mice, starting onday 2 (Figure 1). However, there wereno significant differences in body weightamong dietary treatment groups in thisshort time period (Figure 2). After 5days of CLA supplementation, bodyfat content of mice fed the CLA Mix andthe CLA 10/12 isomer was 20% less(P < 0.10) than that of mice fed theControl diet (Figure 3).

Experiment 2

Supplementation of CLA reduced(P < 0.05) both feed intake and bodyweight change in the final 2 weeks ofthe study (Table 1). CLA reduced(P < 0.001) RP (49%) and Epi (19%) fatpad weights when added to the controldiet (Table 1). Furthermore, CLAreduced total body fat by 27% (Figure4). The EFAD diet alone had no effect


Dietary Amino Acid Utilization for Body ProteinDeposition — Current and Future Research

Janeth J. ColinaAustin J. Lewis

Phillip S. Miller 1


In modern pork production it isimportant to maximize the animal’spotential for daily lean gain byincreasing the body protein deposi-tion with as little wastage of theingested amino acids as possible.Therefore, it is important to maxi-mize the efficiency with which diet-ary amino acids are used for proteindeposition or lean gain. This effi-ciency is measured by using nitro-gen balance studies or comparativeslaughter procedures. Supplementingswine diets with crystalline aminoacids and replacing part of the diet-ary protein can reduce diet cost andwill also reduce the amount of nitro-gen excreted in manure. However, ithas been demonstrated that the effi-ciency of utilization of crystallineamino acids may be lower than thatof amino acids bound in protein.Although the reasons for this areunclear, it may be associated withthe frequency of feeding and differ-ences in the rate of absorptionbetween the two sources of aminoacids. Research in progress isdesigned to investigate the effi-ciency with which crystalline lysineis utilized for protein deposition innursery pigs. This research will obtainadditional information about therelative utilization of crystallineand protein-bound amino acids.

Amino Acid Utilization for BodyProtein Deposition

Body proteins are continuouslybeing formed (protein synthesis) andbroken down (protein degradation). Inan adult animal, synthesis and degra-dation are equal and body protein isneither gained or lost. However, in agrowing animal, synthesis exceedsdegradation and this results in proteindeposition or accretion. Dietary indis-pensable amino acids are used for avariety of metabolic processes in thebody and are precursors for a widerange of biologically active compounds,but it is protein deposition thataccounts for the greatest amino acidsuse. The efficiency with which absorbedamino acids are used for protein depo-sition depends on several factorsincluding genetic differences andwhether the amino acid intake is limit-ing or in excess of the requirement. Ingrowing-finishing pigs consumingdiets that are limiting in protein, themost limiting acid will be used moreefficiently than other amino acids, andit is the efficiency of utilization of thisamino acid that will affect how well theoverall dietary protein is used.

Nitrogen Balance andComparative Slaughter Trials

The efficiency of amino acid utili-zation is typically measured usingeither N (nitrogen) balance studies orcomparative slaughter trials (bodycomposition is measured). The twomethods yield different results. Esti-mates of N retention are higher whenmeasured by the N balance techniquethan when measured by the compara-

tive slaughter technique. Some studieshave estimated values of 8.96 and 7.51g of protein retained per g of lysineintake by using nitrogen balance andslaughter trials, respectively. The dif-ferences are larger at low than at highrates of protein deposition. The mainexplanation for the discrepancy betweenthe two methods is that N losses infeces and urine are usually underesti-mated in N balance studies, with a con-sequent overestimation of N retention.

Crystalline Amino Acids vs Protein-bound Amino Acids

Recent evidence has indicatedthat the efficiency of utilization ofcrystalline amino acids may be lowerthan the efficiency of amino acid utiliza-tion from intact protein. One studyreported that the efficiency for tryp-tophan was 54% for protein-boundtryptophan but only 14% for crystal-line tryptophan. Others have foundthat the efficiency of utilization of crys-talline tryptophan may be only 50% ofprotein-bound tryptophan.

The reasons for the poor efficiencyof crystalline tryptophan are unknown,but in one study pigs were fed threetimes daily and it is possible that infre-quent feeding may have contributed tothe lower efficiency. Similar resultshave been observed when feedingdietary lysine infrequently. Crystallinelysine in diets fed once daily is used50% less efficiently than crystallinelysine in similar diets fed more frequently(i.e., twice or more per day).

The reduced efficiency of crystal-line amino acid utilization has beenattributed to the rapid absorption of



Figure 1.Feed efficiency (lb/lb) of nursery pigs fed four concentrations of dietary lysine.

1.75

1.50

1.25

1.00

AD

G/A

DF

I, l

b/lb

1.05 1.20 1.35 1.50

Lysine (%)

crystalline amino acids relative to aminoacids derived from intact protein suchas soybean meal. Free amino acids areabsorbed more rapidly than those boundin protein, which probably provides anunbalanced pattern of amino acids tomuscle and affects growth performancein pigs by decreasing protein synthe-sis. If crystalline amino acids areabsorbed too quickly the temporaryexcess of absorbed amino acids at thetissue level may result in oxidation lossesof the free amino acids and degradationin the liver. Studies indicate improve-ments in growth performance in pigsfed soybean meal supplements (pro-tein-bound lysine) diets in comparisonto pigs fed lysine-supplemented diets.However, these differences were attrib-uted to gut fill because no differencesin carcass weight were detected. There-fore, the strategy is to balance thearrival of the protein-bound aminoacids and free amino acids at the site ofabsorption.

Reduced efficiency of amino acidutilization resulting from differences inthe time course of absorption betweenprotein-bound and crystalline lysinehas not been observed under ad libitumfeeding conditions. It is unlikely thatdifferences in absorption rate explaindifferences in utilization of the lysineunder ad libitum feeding conditionsbecause of the continual supply of aminoacids that are absorbed. However, fur-ther research is needed to examine the

relationship between feeding level andcrystalline amino acid utilization.

Current ResearchWe are currently investigating the

efficiency with which crystalline lysineis utilized for protein deposition innursery pigs. A preliminary 28-day studywas conducted to develop a lysine-deficient diet using 96 nursery pigs (11lb initial body weight and 15 day old).The dietary treatments consisted of thebasal diet (1.05% lysine) and three con-centrations of total lysine: 1.20%, 1.35%,and 1.50%. These concentrations wereachieved by adding crystalline lysineto the basal diet. Pigs were grouped onthe basis of initial weight and allotted atrandom to 16 pens within a nurseryfacility. There were six pigs per pen(three barrows and three gilts). Pigswere allotted to four dietary treatmentswith four replications (weight blocks)per treatment (24 pigs per treatment).Average daily gain (ADG), average dailyfeed intake (ADFI), and feed efficiency(ADG/ADFI) were measured weekly.At the end of the study all pigs werebled to determine plasma urea concen-tration. As expected, lysine was limit-ing in the basal diet and supplementationwith crystalline lysine increased ADG(P = 0.05) and ADG/ADFI (P < 0.001).However, no differences were observedfor ADFI. A linear response (P < 0.001)for ADG/ADFI indicated that diets with1.05 and 1.20% lysine were limiting and

the requirement was approximately1.35% (Figure 1). Plasma urea nitrogen(PUN) decreased as the lysine concen-tration in the diet increased. A higherconcentration of PUN was estimated inpigs fed the diet with 1.05% lysine incomparison with pigs fed diets 1.20 and1.35% lysine (P < 0.05) and 1.50% lysine(P < 0.01). These results indicate thatnitrogen retention improved when thehigher concentration of lysine was fed.

Future Research

We are now studying the efficiencywith which crystalline lysine and thelysine present in soybean meal are usedfor body protein deposition in nurserypigs. Studying the efficiency of aminoacid utilization under ad libitum feedingconditions will be important to deter-mine whether crystalline amino acidsare used less efficiently than aminoacids in intact protein. If it is true, futurestudies must be focused on looking atalternatives to improve the amino acidutilization from crystalline sources,taking into account that the use ofcrystalline amino acids can provideenvironmental and economical advan-tages.

Take Home Points

1) Supplementing low-protein dietswith crystalline amino acids at ade-quate concentrations can offerenvironmental and economicalbenefits. Several factors can affectthe utilization of dietary aminoacids and differences in the rate ofabsorption probably occur betweencrystalline and protein-bound aminoacids. This may affect growth per-formance in pigs.

2) During certain situations, crystal-line amino acids may be used lessefficiently than the amino acids inintact protein. Therefore, carefuluse of crystalline amino acids mustbe made to ensure that they areutilized as efficiently as possible.

1Janeth J. Colina is a graduate student,Austin J. Lewis is a professor, and Phillip S.Miller is an associate professor in theDepartment of Animal Science.


Reproductive Responses in the NE Index LineEstimated in Pure-line and Crossbred Litters

D. B. PetryR.K. Johnson1


The NE Index Line (Line I) hasbeen selected since 1981 only for littersize and as a pure-line has 3.5 to 4more pigs per litter than its randomlyselected control (Line C). Line I hasbeen released to the industry where itis being used in crossbreeding appli-cations, but whether the responserealized in the pure-line is expressedin crossbreeding applications is notknown. The objective of this experi-ment was to estimate responses inreproduction in Line I in pure-linesows, in pure-line sows mated to pro-duce F

1 litters and in F

1 sows mated to

produce three-way cross litters. Atotal of 850 litters were producedover six-year seasons. There were 224pure-line I and C litters, 393 F

1 litters

produced from I and C females matedwith Danbred® USA Landrace (L) orDH (T) boars, and 233 litters by IxLand CxL females mated with T boars.Contrasts of means were used to esti-mate the genetic difference between Iand C and interactions of line differ-ences with mating type. Farrowingrate of Lines I and C (93.3 vs 91.8%)did not differ. Averaged across allgroups, mean number born alive perlitter and number and weight of pigsweaned per litter, both adjusted fornumber nursed and weaning age of12 days, were 10.1 pigs, 9.7 pigs, and75.9 lb, respectively. Direct geneticeffects of I were greater (P < 0.05) thanC for total born (3.53 pigs), number

born alive (2.53 pigs), number ofmummified pigs (0.22 pigs), and litterbirth weight (4.72 lb). Line I was lessthan C (P < 0.05) for litter weaningweight (–4.15 lb). However, inter-actions of line effects with crossingsystem were significant. In pure-linelitters, I exceeded C by 4.18 total pigsand 1.76 stillborn pigs per litter;whereas in F

1 litters the difference

between I and C was 2.74 total pigsand 0.78 stillborn pigs per litter. Thecontrast between I and C for numberweaned and litter weaning weight inpure-line litters was 0.32 pigs and-0.62 lb, respectively, compared with0.25 pigs and -4.72 lb in F

1 litters.

Reproductive performance of Line Isubstantially exceeds that of the con-trol line. Although the responserealized in crossbreeding applicationswas somewhat less than in the pure-line, crossbreeding is an effective wayto utilize the enhanced reproductiveefficiency of the Index line.

Background

Population

The populations studied were theNE Index line that has been selected forincreased litter size and its control line.The base population of Large Whiteand Landrace was formed by recipro-cally crossing boars and sows of thetwo breeds in 1979. Random mating ofthe F

1 and F

2 was used to produce F

3

litters that were born in 1981. Theselitters, designated Generation 0, wererandomly assigned to the Control line(C), that was randomly selected, or theIndex line (I), that was selected for an

index of ovulation rate and embryonicsurvival. Selection during Generations12 through 14 in I was on number offully formed pigs per litter at birth. DuringGenerations 15 and 16, I was selectedfor number born alive and birth weight.

Mating Design

The experiment reported hereinused pigs from eight different geneticbackgrounds that included pure Line Iand C pigs and pigs produced bycrossing lines I and C with Danbred®USA Landrace (L) and the 3/4 Duroc x1/4 Hampshire terminal sire (T). PureLine-I and Line-C Generation 16 giltswere randomly assigned to be matednaturally to boars of their own line or tobe inseminated with semen of L toproduce Generation 17 I x I, L x I, C x C,and L x C litters. Artificial inseminationwas used to produce crossbred littersbecause the biosecurity policy at theexperimental farm prohibited intro-duction of live boars. Lines I and C weremaintained throughout the selectionexperiment with 15 boars per genera-tion and a 3:1 sow-to-boar ratio. Laborwas not available to train and collectsemen from pure-line I and C boars sonatural service was used to producepure-line litters. A random sample of Iand C sows was retained after weaningtheir litters and inseminated with semenof T to produce T x I and T x C litters attheir second parity. Sows were culledafter weaning their second litter.

Pure-line and F1 gilts from the first

litters were retained for breeding toproduce Generation 18 progeny. Pure-line females were again randomly



assigned to be mated naturally to boarsof their own line or to be inseminatedwith semen of L boars. F

1 females were

inseminated with semen from T boars.Genetic types produced in Generation18 were I x I, L x I, C x C, L x C, T(L x I),and T(L x C). A random sample of bothpure-line and F

1 sows was retained after

weaning their litters and inseminatedwith semen of T boars to produce T x I,T x C, T(L x I), and T(L x C) litters at theirsecond parity. No pigs in these litterswere retained for breeding and all sowswere culled after weaning their secondlitter.

Pure-line and F1 gilts from Genera-

tion 18 were retained and mated accord-ing to the same design as used to produceGeneration 18 litters. After weaningthese litters, a random sample of sowswas retained for a second litter. Pure-line I and C sows were inseminated withsemen of L boars, and F

1 gilts were

inseminated with semen of T boars. Themating design by generation and par-ity, and the number of litters producedare illustrated in Table 1.

Selection

Selection of pure Line-I gilts andboars was done by ranking litters onnumber born alive. Line-I boars wereselected from the 15 largest litters. Thetwo boars with the greatest birth weightwere selected from each litter. One

was designated a breeder and the otheran alternate. Gilts were selected simi-larly; however because more gilts wereneeded, they were selected from theupper 50% of the litters for number bornalive. Within these litters, gilts withlow birth weight were culled and amaximum of four gilts per litter wasselected. Replacements in C were selectedrandomly within paternal half sib fam-ily (boars) and litters (gilts) to give 15breeding boars and the necessary num-ber of gilts each generation.

Data

A total of 850 litters over six sea-sons, consisting of 224 pure-line, 393F

1, and 233 3-way crosses, was studied.

Farrowing rate (FR) was calculated asthe percentage of females designated

for breeding that farrowed a litter.Number of fully formed pigs (FF),number born alive (BA), numbers ofstillborn (SB) and mummified piglets(MUM), and litter birth weight (LBW)were recorded at birth of litters. Numberweaned (NW) and weight of the litter(LWW) were recorded at weaning.


Farrowing rate was analyzed with achi-square test. Birth and litter traitswere analyzed with general linear mod-els that included year/season/geneticgroup. Litter weight was recorded as atrait of the dam. Because crossfosteringof pigs among different genetic groupsoccurred, procedures were used to ac-count for genetic makeup of pigs nursedby dams, age when pigs were weaned,

Table 1. Number of litters of each group produced per year/season

Genetic groupa Year/season

Sire Dam Litter 1998/1 1998/2 1999/1 1999/2 2000/1 2000/2

C C C 36 39 35I I I 44 35 35L C L x C 45 35 26 24L I L x I 49 27 25 20T C T x C 47 32T I T x I 43 20T L x C T (L x C) 43 18 37 22T L x I T (L x I) 43 17 33 20

aC = Control, I = Index, L = Danbred® USA Landrace Sire, T = Danbred® Duroc-Hampshire TerminalSire.

Table 2. Estimates of contrasts among means for traits measured at birth and for traits measured at weaning.

Traits measured at birthb

Weaning traitsc

Contrasta

FF NBA SB MUM LBW (lb) LWW (lb) NW (pigs)

I – C 3.53** + .30 2.53** + .30 0.99** +0.18 0.22** + 0.06 4.72** + 0.77 -4.15* + 1.61 -0.26 + 0.16

R:P – F1

-1.21* + 0.57 NS -.75** + 0.33 NS NS 12.52** + 3.90 1.80** + 0.39(I – C)

P4.18** + 0.39 1.76** + 0.22 -0.62 + 1.10 0.32** + 0.11

(I – C)F1

2.75** + 0.30 0.78** + 0.18 -4.72** + 1.81 -0.56** + 0.18F

1 – P -0.83** + 0.28 -0.52 + 0.28 -0.30 + 0.16 -0.05 + 0.06 1.08 + 0.73 12.24** + 1.19 0.25* + 0.12

T – F1

1.71** + .29 1.51** + 0.29 0.21 + 0.17 -0.03 + 0.06 7.65** + 0.73

aI – C estimates the overall effect of the index line vs the control.

R: P – F1

tests the interaction of selection response between I and C in pure-line dams with pure-line litters vs pure line dams with F1 litters.

(I – C)P

estimates the difference between index and control when measured in pure-line litters produced from pure-line dams.(I – C)

F1 estimates the difference between index and control and when measured in F

1 pigs produced from pure-line dams.

F1 – P is the difference between averages of F

1 litters by pure-line dams and pure-line line litters by pure-line dams.

T – F1 is the difference between averages of 3-way cross litters produced from F

1 dams and F

1 litters produced by pure-line dams.

bFF = Number of fully formed pigs, NBA = Number of pigs born alive, SB = Number of stillborn pigs, MUM = Number of mummified pigs, LBW = Litter

birth weight.cLWW = Litter weaning weight, NW = Number weaned.

se = Standard error.** P < 0.01, *P < 0.05, NS = Not significant (P > 0.05).


and number of pigs in the litter aftercrossfostering was completed. There-fore, number weaned and litter weaningweight are traits of the sow as if theywere nursing the same number of pigsof the same genetic makeup. Contrastswere used to estimate differences in theoverall effect of I vs C and to testwhether the response was different inpure line, F

1 and three-way cross litters.

Also, the effect of crossing was esti-mated as the average differencebetween pure-line, F

1 and three-way

cross litters.


Line I and C did not differ in farrow-ing rate. Thus, no correlated responsein fertility from selection for litter size inLine I was detected. The overall meanfarrowing rate was 90.8%. A slightreduction in farrowing rate occurredwhen pure-line females were mated to Lboars. The average difference in far-rowing rate between pure-line femalesmated pure and those mated AI to Lboars was 10.6%. This reduction is notlikely a genetic effect of line of service

sire, but could have been caused by AItechniques. Pure-line dams artificiallyinseminated to produce F

1 litters had

8.6% lower farrowing rate than F1 dams

producing three-way cross progeny.Contrasts were designed to esti-

mate effects due to genetic makeup ofthe dam. Season and line of pig the damproduced were confounded (see Table1), so differences could not be aver-aged across all subclasses. Differencesbetween I and C within interaction sub-classes (pure-line, F1 and 3-way) wereestimated only if an interaction wasdetected (P < 0.05). Table 2 containscontrasts among means for traits mea-sured at birth.

Responses to selection for increasedlitter size were 3.53 + .30 (P < 0.0001)fully formed pigs, 2.53 + 0.30 (P < 0.0001)live pigs, 0.99 + 0.18 (P < 0.0001) still-born pigs, and 0.22 + 0.06 (P < 0.01)mummified piglets per litter. The differ-ence in litter birth weight between I andC was estimated to be 4.72 + 0.77 lb(P < 0.0001).

An interaction of selection response(I minus C) with mating group occurred(P < 0.05). The response in I for fullyformed pigs when measured in pure-line dams producing pure-line pigswas 4.18 + 0.39 (P < 0.0001) pigs andwhen measured in pure-line dams pro-ducing F

1 pigs response was 2.75 + 0.30

(P < 0.0001) pigs. The differencebetween I and C in number of stillbornpigs per litter measured in pure-linedams producing pure-line pigs was 1.76+ 0.22 (P < 0.0001) pigs, whereas thedifference in pure-line dams producingF

1 pigs was 0.78 + 0.18 (P < 0.0001) pigs.

Figures 1 and 2 illustrate these inter-actions.

Interactions were not significantfor litter birth weight, which may explainthe interactions for numbers of pigs. Ifuterine capacity allows only a certainweight of pigs to be carried to term, thenpure-line pigs with F

1 litters, for which

each individual pig was heavier, couldproduce that same weight with fewerpigs than pure-line dams with pure line


Figure 1.Number of fully formed pigs per litter for pure-line Control and Index damswith pure-line litters (P) and pure-line dams with F1 litters (F1).

13.5

12.5

11.5

10.5

9.5

8.5

7.5

Num

ber

of p

igs

P

F1

Control Index

Genetic makeup of dam

8.92 8.7

13.1

11.67

Figure 2.Number of stillborn pigs per litter for pure-line Control and Index dams withpure-line litters (P) and pure line dams with F1 litters (F1).

2

1.5

1

0.5

0

Num

ber

of p

igs

0.430.51

2.19

1.51

P

F1

Control Index



pigs. It is also possible that bettertiming of insemination with ovulationoccurred with natural matings used inpure-line production and that fewer eggswere fertilized when artificial insemi-nation in F

1production was used.

The average I and C F1 litters pro-

duced from pure-line dams had fewerfully formed pigs (-0.83 + 0.28; P < 0.01)than the average of pure-line I and Clitters. A possible explanation is thatpure-line dams producing F

1 progeny

were inseminated artificially whereaspure-line progeny were produced withnatural matings. Alternatively, uterinecapacity may limit total weight of thelitter so that litter birth weight is similarfor pure-line dams with F

1 litters and

pure-line dams with pure-line litters. F1

dams with three-way cross pigs pro-duced 1.71 + 0.29 more fully formedpigs, 1.51 + 0.29 live pigs and 7.65 + 0.73lb more litter birth weight than pure-linesows with F

1 litters (P < 0.001). These

increases are due to heterosis as three-way cross pigs produced from an F

1

dam express 100% individual and ma-ternal heterosis whereas F

1 pigs pro-

duced from pure line dams express only100% individual heterosis.

Correlated response in litter wean-ing weight to selection for increasedlitter size was –4.15 + 1.61 lb (P < 0.05);however, no response in number weanedwas detected. Both of these traits wereadjusted for number of pigs after fos-tering. Litter weaning weight measuresboth weight and number of pigs; whereasnumber weaned measures survival rate.These results indicate better milkingability for C than for I sows, but survivalrate of pigs was not affected.

An interaction on both number andweight of litters weaned in the expres-sion of the selection response (I – C)when measured in pure-line dams vs F

1

dams occurred (P < 0.05). The responsein F

1 dams was –4.72 + 1.81 lb (P < 0.01)

and response in pure-line dams was-0.62 + 1.10 lb (P > 0.05). The responsein number weaned in F

1 dams was -0.56

+ 0.18 pigs (P < 0.01) and in pure-line

dams it was 0.32 + 0.11 (P < 0.01) pigs.Figure 3 and 4 illustrate these inter-actions. Overall, F

1 dams had litters that

weighed 12.23 + 1.19 lb (P < 0.0001) morewith 0.25 + 0.12 (P < 0.05) more pigsthan pure-line dams.

Conclusion

Responses for litter size in purelines were consistent with estimatesobtained after 14 generations of selec-tion. Responses in included increasedtotal number of pigs and number of live

pigs at birth, but also increased inci-dence of stillborn and mummified pigsand decreased litter weaning weight.Crossbreeding reduced the incidencesof stillborn and mummified piglets andlitter weaning weight increased greatlyin F

1 sows. Sow productivity of Line I at

birth and weaning was improved withcrossbreeding.

1D. Petry is a graduate student andtechnician and R. Johnson is professorin the Department of Animal Science.

95

85

75

65

55

45

35

25

Figure 3.Weight of pigs weaned in standardized litters of pure-line Control and Indexdams (P) and F1 dams (F1).

Po

un

ds

71.77

87.91

74.86

83.19 P

F1

Control Index


Figure 4.Number of pigs weaned per litter for pure-line Control and Index dams (P) andF1 dams (F1).

10.4

10.2

10.0

9.8

9.6

9.4

9.2

9.0

Num

ber

of p

igs

9.28

10.16

9.97

9.58

P

F1

Control Index



Growth and Carcass Responses in theNE Index Line Estimated in Pure-line

and Crossbred LittersD. B. PetryJ. W. Holl

R. K. Johnson1


The objective was to estimateresponses in growth and carcass traitsin the NE Index line (I) that wasselected 19 generations for increasedlitter size. Responses in pure-line, F

1

and 3-way cross litters were compared.In Exp 1, 694 gilts that were retainedfor breeding, including 448 I andcontrol (C) and 246 F

1 I and C by

DanbredTM Landrace (L), were evalu-ated. Direct genetic effects of I and Cdid not differ for backfat or days to 230lb; however, I had 0.24 in2 smallerlongissimus muscle area (LMA) thanC (P < 0.05). F

1 gilts had -0.13 in less

backfat, 0.67 in2 greater LMA and –31d less to 230 lb than pure-line gilts(P < 0.05). Exp 2 used individually-penned barrows and gilts including43 I and C, 77 F

1 produced from

pure-line females mated to (L) orDanbred® USA DH boars (T), and 763-way crosses produced from F

1

females mated to T boars. Directgenetic effects of I did not differ from Cfor average daily feed intake (ADFI),average daily gain (ADG), feedconversion (FC), days to 250 lb, backfat(BF), LMA, ultimate pH of the longis-simus, longissimus Minolta l* score,and % lean estimated by TOBEC.Responses (I minus C) in growth andcarcass merit did not differ whenmeasured in pure-line and crossbredpigs. Interactions between responsesin F

1 and pure lines were not signifi-

cant except for pH. F1 and 3-way cross

pigs averaged 0.51 lb/d greater ADFI,-0.53 less feed/gain and 0.44 lb/d moreADG than pure-line pigs (P < 0.01). F

1

and 3-way crosses had -0.35 in less BF,0.89 in2 greater LMA, 6.2 % greaterlean, and 5.3 higher Minolta l* scorethan pure lines (P < 0.05). No cor-related responses to selection forincreased litter size in overall growthor carcass traits occurred. MatingLine I to leaner, faster growing sireswill increase ADFI, ADG, LMA, andpercentage lean , decrease feed/gainratio, decrease backfat, and lightenmeat color.


The mating design and selectionof parents are described in the preced-ing paper and are not repeated here.Data for this paper were collected intwo experiments on pure-line I and Cpigs and F

1 and three-way cross pigs

produced by crossing I and C withDanbred Landrace and terminal Duroc-Hampshire sires as described in thepreceding paper. The experiment wasconducted during three year/seasonenvironments.

Experiment 1

A total of 694 gilts that wereretained for breeding, including 538pure-line (I and C) and 156 F1 (L x I andL x C) were evaluated. Backfat (BF) andlongissimus muscle area (LMA) at thetenth rib measured with an Aloka 500instrument and adjusted to weight of194.5 lb and days to 230 lb wererecorded in these gilts.

Experiment 2

A total of 196 barrows and giltswere individually penned. The geneticmakeup of these pigs included 21 I, 22C, 22 L x I, 22 L x C, 17 T x I, 16 T x C, 39Tx(LxI) and 38 Tx(LxC). Pigs were

selected at random from the availablelitters except for pure line pigs, whichwere selected at random after replace-ment gilts and boars were selected. Onepig was sampled from as many differentlitters as possible in order to broadlyrepresent the populations. Pigs weremoved from the nursery to the indi-vidual feeding unit at approximately65 days of age. After a 7-day acclima-tion period, they were placed on test.Pigs were weighed and scanned for BFand LMA at 3-week intervals, and weigh-backs on feeders were taken. A dietformulated to contain 16% crude pro-tein, 0.81% lysine, 0.65% calcium, 0.55%phosphorus, and 1,502 kcal/lb ME wasfed throughout the trial. Temperaturewas maintained at a range of 65 to 80oFdepending on season. Pigs were ontest until they weighed a minimum of236 lb when they were transported toSiouxPreme Packing Co. in Sioux Center, Iowa, for processing and evalu-ation.

Average daily feed intake (ADFI),average daily gain (ADG), feed conver-sion ratio (feed/gain), BF, and LMAwere recorded on pigs at three-weekintervals. Percentage carcass leanestimated by TOBEC, ultimate longis-simus pH 24 hours after slaughter, andMinolta l* color score on loins werecollected at SiouxPreme.


Data for group-fed gilts, and pen-fed barrows and gilts were analyzedseparately. Weight at final age(approximately 170 days), BF, and LMAwere recorded for group-fed gilts withgenetic group and year/season fittedas fixed effects and with weight at finalage as a covariate.

Data for individually-fed pigs were(Continued on next page)


collected during consecutive 3-weekintervals from when pigs were placedon test at 72 days (mean weight = 60.0lb) until they were removed from test atapproximately 250 lb. Data for each periodand data for the entire test period wereanalyzed separately. Data recorded wereweight at beginning of the test and atthe end of each 3-week period, feedintake during each period, BF, and LMAat the end of each period. From the feedintake and weight data, ADG, ADFI,and feed/gain ratio (FC) were calcu-lated. These three traits were analyzed

with a general linear model thatincluded genetic group x year x seasoncombination, sex of the animal andgroup x year x season by sex inter-action.

Carcass traits were fitted to thesame model with final live weightincluded as a covariate. The combinedeffect of season x genetic group wasfitted together because all geneticgroups did not occur in each seasonand appropriate linear contrasts ofeffects were used to estimate line dif-ferences and interactions with matingsystem.


Experiment 1

Table 1 contains contrasts amongmeans for growth traits recorded ingilts retained for breeding. Differencesbetween I and C within interactionsubclasses (pure line and F

1) were esti-

mated only if the interaction was sig-nificant.

There was a correlated responsein LMA to selection for increased littersize. Line I gilts had 0.24 + 0.09 in2

(P < 0.05) smaller LMA than Line C gilts.Differences between I and C gilts inBF and Days were not significant.

An interaction in responses(I minus C) in BF and LMA in pure linegilts vs F

1 gilts occurred. Pure-line I

gilts had -0.05 + 0.01in less BF (P < 0.01)than pure-line C gilts. The difference inBF when measured in F

1 gilts was 0.03

+ 0.02 in (P > 0.05). Pure-line I gilts had-0.10 + 0.20 in2 (P > 0.05) less LMA thanpure-line C gilts; whereas, the differ-ence when measured in F

1 gilts was

-0.67 + 0.26 in2 (P < 0.05). One possibleexplanation for this interaction isthat higher levels of inbreeding (esti-mated to be 22% in Line I and 15% inLine C at Generation 19) caused Line Ipigs to grow slower and eat less feed aspurebreds, but this difference was elimi-nated in F

1 pigs that expressed 100%

heterosis.Overall F

1 gilts had less BF (-0.13 +

0.02 in), larger LMA (0.66 + 0.07 in2), andreached 230 lb in fewer days (-31.3 +4.34 d) than pure-line gilts (P < 0.0001).These differences are due to the jointeffects of 100% heterosis in F

1 gilts and

to the effect of the 50% genetic makeupof the F

1 gilts from the Danbred USATM

Landrace sires.

Experiment 2

Sex was significant for ADFI, ADGand Days to 250 lb and season/parity/line was significant for ADFI, ADG, FCand Days to 250 lb. Table 2 containsestimates of contrasts among means.Lines I and C did not differ for any of thetraits measured (P > 0.05). Overall, LineI pigs ate 0.08 + 0.04 lb more feed per

Table 1.Contrasts among means for traits measured on gilts retained for breeding(Exp. 1).

Traits measuredb

Contrasta

BF (in) SE LMA (in2) SE Days to 230 lb SE

I – C -0.003 0.02 -0.24* 0.09 3.52 3.77R: P – F

10.10* 0.04 -1.24* 0.56 NS

(I – C)P

-0.05** 0.01 -0.10 0.20(I – C)

F10.03 0.02 -0.67* 0.26

F1 – P -0.13** 0.02 0.66** 0.07 -31.32** 4.34

aI – C is the contrast of the overall effect of the index line vs. the control.R: P – F

1L tests the selection response between I and C in pure-line pigs vs. F

1L pigs.

(I – C)P

tests the difference between pure-line I and C pigs.(I – C)

F1 tests the difference between F

1 I and C pigs.

F1 – P tests the average difference of F

1 pigs vs the average difference of pure-line pigs.

T – F1 tests the average difference of 3-way cross pigs vs the average difference of F

1 pigs.

bBF = Backfat, LM = Longissimus muscle area.

SE = Standard error.**P < 0.01.*P < 0.05.NS = Not significant (P > 0.05).

Table 2.Contrast among means on growth traits measured on individually-pennedpigs (Exp. 2).

Traits measuredb

Days toContrast

aADFI (lb) SE ADG (lb) SE FC (lb/lb) SE 250 lb SE

I – C 0.08 0.04 0.02 0.01 0.05 0.10 -4.40 5.25R: P-F

1LNS NS NS -17.98* 8.85

(I – C)P

4.58 4.00(I – C)

F1L-6.70 3.95

F1L

- P 0.12** 0.02 0.09** 0.01 -0.47** 0.06 -27.65** 2.81T – F

1L-0.03 0.02 0.005 0.01 -0.12* 0.06 -3.33 2.82

T – F1T

0.03 0.03 0.01 0.01 -0.05 0.06 -2.87 3.22

aI – C is the contrast of the overall effect of the index line vs the control.

R: P – F1L

tests the selection response between I and C in pure-line pigs vs F1L

pigs.(I – C)

P tests the difference between pure-line I and C pigs.

(I – C)F1L

tests the difference between F1L

I and C pigs.F

1L – P tests the difference between average F

1L pigs and pure-line pigs.

T – F1L

tests the difference between average 3-way cross pigs and F1L

pigs.T – F

1T tests the difference between the average of 3-way cross pigs and F

1T pigs.

bADFI = Average daily feed intake, ADG = Average daily gain, FC = Feed conversion.

SE = Standard error.**P < 0.01, *P < 0.05, NS = Not significant (P > 0.05).


day, gained 0.02 + 0.01 lb more weightper day, had 0.05 + 0.10 greater food/gain ratio, and reached 250 lb 4.40 + 5.25days sooner than C pigs.

An interaction for days to 250 lb inselection response (I minus C) esti-mated in pure-line pigs vs F

1L pigs

occurred. The response in pure-linepigs was 4.58 + 4.00 d (P > 0.20) whereasthe response in F

1L pigs was 6.70 + 3.95

d (P > 0.05). The biological explanationis that pure line I pigs ate less feed thanC pigs, which caused them to gain lessrapidly, but L x I pigs ate more feed thanL x C pigs. It is possible that the greaterlevel of inbreeding in line I than Ccaused them to grow slower and eatless feed as purebreds, but this differ-ence was eliminated in F

1 pigs. Overall

F1L

pigs had higher ADFI (0.12 + 0.02lb), ADG (0.09 + 0.01 lb/d), lower FC(-0.47 + 0.06), and reached 250 lb infewer days (27.7 + 2.81 d) than pure-linepigs (P < 0.001). Overall three-way crosspigs had lower FC (-0.12 + 0.06) thanF

1L pigs (P = 0.05). Other differences

between three-way cross pigs andF

1T pigs were not significant.Responses estimated in the dif-

ferent crosses differ because F1 pigs

express 100% individual heterosis,

whereas pure line pigs express noheterosis, and 50% of the genetic makeupof the F

1L pigs were from the Danbred®

USA Landrace sire. The enhanced per-formance of 3-way crosses over F

1L

pigs was due to the effect of the Danbred®USA Terminal sire and the expressionof 100% individual and maternal het-erosis.

Carcass Traits

Sex was significant for BF andpercentage carcass lean and season/parity/line was significant for BF,LMA, percentage lean, and Minolta l*color score. Interactions between theseeffects were not significant. Traits werestandardized to a live weight at slaugh-ter of 248.2 lb. Table 3 contains esti-mates of contrasts among means.

Lines I and C did not differ (P > 0.05)for any of the traits measured. Overall,I had 0 .10 + .06 in more BF, 0.16 + 0.26in2 less LMA, 0.40 + 1.56 less % lean,0.04 + .08 lower pH, and 1.01 + 2.52greater Minolta l* color score (palermeat).

Interactions of line differences andgenetic background where measuredwere not significant. When pigs are

standardized to a live weight of 248.2 lbthe conclusion is that responses in Iand C did not differ in carcass meritwhen measured in pure-line and cross-bred pigs.

Overall F1L

pigs had less BF (-0.32+ 0.04 in), more LMA (0.81 + 0.15 in2),greater percentage carcass lean (5.52 +0.96 %), and higher Minolta l* colorscore (4.54 + 1.49 score) than pure-linepigs (P < 0.01). Differences betweenthree-way cross pigs and F

1L pigs and

between three-way cross pigs and F1T

pigs were not significant.

Conclusion

There were no correlated responsesin growth and carcass traits to selec-tion for increased litter size. Line differ-ences were expressed equally in pureline and crossbred pigs. Carcass andgrowth traits were greatly improved bycrossing both Lines I and C withDanbred’s Landrace and Terminal sires.

1D. B. Petry is a graduate student andresearch technician in the Department ofAnimal Science, J. W. Holl is a graduatestudent at North Carolina State University,and R. K. Johnson is a professor in theAnimal Science Department.

Table 3.Contrast among means for carcass traits measured on individually-penned pigs (Exp. 2).

Traits measuredb

Contrasta

BF (in) SE LMA (in2) SE % Lean SE pH SE l* SE

I – C 0.10 0.06 -0.16 0.26 -0.40 1.56 -0.04 0.08 1.01 2.52F

1L- P -0.32** 0.04 0.81** 0.15 5.52** 0.96 -0.09 0.05 4.54** 1.49

T – F1L

-0.02 0.04 0.16 0.14 1.39 0.83 -0.01 0.04 1.45 1.36T – F

1T-0.02 0.04 0.46** 0.16 0.08 0.96 -0.03 0.05 1.04 1.56

aI – C is the overall effect of the index line vs the control.

F1L

– P tests the difference between the average of F1L

pigs and pure-line pigs.T – F

1L tests the difference between the average of 3-way cross pigs and F

1L pigs.

T – F1T

tests the difference between the average of 3-way cross pigs and F1T

pigs.bBF = Backfat, LMA = Longissimus muscle area, Lean = % carcass lean measured with TOBEC, pH = Muscle pH at 24 h after slaughter, l* = Minolta

l* color score.SE = Standard error.**P < 0 .01, *P < 0.05, NS = Not Significant (P > 0.05).


Economic Analysis of the Selection Response inthe NE Index line

D. B. PetryB. P. McAllisterR. K. Johnson1


The objective was to estimateeconomic effects of 19 generations ofselection for increased litter size inthe NE Index line. Using realized bio-logical data, 1,250-sow enterprisesbased on Index line and Control linefemales were simulated. Each systemwas closed to introduction of femalesand included pureline females matedto produce replacement pureline andF

1 gilts, and F

1 females mated to termi-

nal cross boars to produce marketprogeny. Costs of production andincome statements were producedusing the reproductive, growth andcarcass data from the NE Index (I) andControl (C) lines reported in the twopreceding papers. Gross revenues wereestimated using the SiouxPremePacking Co. grid payment matrix. Theproduction system based on Index sowsproduced 24,417 pigs per year withnet income of $23.76 per pig. The out-put for the system based on Controlsows was 20,166 pigs with net incomeof $16.73 per pig. Within each matinggroup, net revenue for pureline I pigswas $2.05 per pig more than for Line Cpigs and net revenue for three-waycross pigs with 25% Line I genes was$2.89 per pig more than for terminalcross pigs with 25% Line C genes.However, net revenue for F

1 pigs with

50% Line C genes was $2.50 per pigmore than for those with 50% Line Igenes. Highly prolific lines such asLine I have a large effect on reducingproduction costs and increasingincome. Crossbreeding is an effectiveway to utilize the enhanced reproduc-tive efficiency of the Index line.

Background

The NE Index Line (Line I) wasdeveloped with selection only forincreased litter size. It excels in repro-duction. Its commercial value wasdemonstrated in the National PorkProducers Council Maternal Eval-uation Project (MLE) that includedGPK347 females, a cross of the Indexline with a maternal line of DeKalbChoice Genetics. Return on equity for asystem using GPK347 was 21.1% com-pared with 16.5% for the average ofother lines in the MLE. Although thisexperiment produced economic data thatled to increased use of the Index linein commercial production, it did notproduce data to calculate the economicreturn from selection for litter size. Toestimate the economic response, totalproduction systems based on eitherIndex or Control sows must be com-pared.

In this analysis data from the littersand pigs described in the previouspapers were used to simulate a 1,250-sow farrow-to-finish enterprise to com-pare economic returns for breedingsystems using either Line I or Line Cfemales. The production system wasclosed to introduction of females andused artificial insemination to produce

F1 replacement gilts and terminally-sired

market pigs.


Table 1 contains the number oflitters per year along with mean repro-ductive performance for 1,250-sow unitsbased on Line C and Line I females. Ineach case, it was assumed that the pureline was propagated within the systemand semen from Danbred® USALandrace or terminal sires was used toproduce F

1 gilts and market pigs,

respectively. The number of purelinefemales was set at 50 with 15 boarsretained for breeding each generationto maintain rate of inbreeding in thepure line at approximately 1% pergeneration. The number of matingsof I or C sows to produce F

1 gilts was

determined by experimental estimatesof farrowing rates and litter sizes, andimposed gilt selection rate and sowculling rates described below.

Production Assumptions

Annual sow and boar replacementrates were set at 30% and 33%, respec-tively. Female replacement rate corre-sponded with a policy of culling allopen females and all females that hadeight litters. A confinement production

Table 1. Reproductive statistics and estimated number of I and C sows necessary tomaintain a 1,250-breeding sow operation.

% oF MarketGenetic Groupa % FRb NBAc DLd Litterse total Replacements pigs

C 98.2 8.49 0.20 116 4 41 733L x C 81.5 8.27 0.20 160 5.5 339 524T(L x C) 86.5 10.37 0.20 2,635 90.5 - 18,909Total 2,912 100 380 20,166I 93.5 10.90 0.20 116 4 37 909L x I 84.3 10.28 0.20 131 4.5 345 564T(L x I) 88.9 12.11 0.20 2,664 91.5 - 22,944Total 2,912 100 382 24,417aC = Control, I = Index, L x C = Landrace x Control, L x I = Landrace x Index, T (L x C) = Terminal

DH x (Landrace x Control) three-way cross, T (L x I) = Terminal DH x (Landrace x Index) three-way cross.bFR = Farrowing Rate of gilts and sows designated for breeding.

cNBA = Number born alive per litter.

dDL = Death loss.

eLitters = Number of litters per year.


system including breeding and gesta-tion facilities, farrowing facilities, nurs-ery, and finishing facilities was modeled.The production system modeled mim-icked the one used at the University ofNebraska Experimental Swine Farm inwhich pigs are weaned at 12 days of ageand raised in a nursery until approxi-mately 55 to 60 days when they aretransferred to a finishing building. Oncemarket weight was reached (250 lb) valuewas calculated based on the SiouxPremePacking Co. payment matrix.

Breeding gilts and pureline boarswere selected at approximately 180 daysand transferred to the breeding andgestation building. Number of selectedfemales and matings varied with fertil-ity of the lines to produce 56 litters perweek.

Income Statements

Costs of production were based onestimates of new construction/equip-ment costs that were depreciated over15 years for buildings, 10 years formajor equipment, and five years forminor equipment. These costs and thosefor additional fixed and variable inputsdescribed in Table 2 were charged backto pigs on a per pig marketed basis.

New housing costs were set at$130 per pig space for the nursery, $175per pig space for finishing, and $1,100per breeding female space for breeding,gestation and farrowing. Other costswere obtained from a variety of sourcesincluding the 1999 Iowa State Univer-sity Swine Report, the Maternal LineGenetic Evaluation Program EconomicAnalysis, and a local Nebraska pro-ducer.

Gross income was calculated onthe SiouxPreme Packing Co. matrix thattakes into account weight of the car-cass and percentage lean estimated byTOBEC. Average market death loss wasassumed to be equal for both Line I andLine C systems. Variable costs werethen calculated and subtracted fromnet income to calculate an economicvalue known as contribution marginper pig marketed. Contribution marginis defined as net revenue per pig mar-keted minus variable cost per pig mar-keted. Fixed costs were calculated andsubtracted from the contribution mar-gin to give net return per pig marketed.


Net Revenue Per Pig Marketed

Income statements for productionsystems are in Table 2. Net revenue per


Table 2.Income statement for integrated breeding system based on Control and Index line females.a

Control line Index line

Line C L x C T(L x C) Line I L x I T (L x I)

Gross revenue/pig sold, $ 102.42 125.12 124.60 105.47 122.62 127.49Less death loss cost/pig sold, $ 1.62 1.62 1.62 1.62 1.62 1.62Net revenue/pig sold, $ 100.80 123.50 122.98 103.85 121.00 125.87

Variable costs/pig sold, $Feed costs, $ 61.14 45.95 40.87 61.00 45.10 41.31Labor costs, $ 14.12 14.12 14.12 13.10 13.10 13.10Veterinary, drugs and supplies, $ 1.64 1.64 1.64 1.60 1.60 1.60Utilities, $ 2.28 2.28 2.28 2.22 2.22 2.22Fuel and oil, $ 0.41 0.41 0.41 0.40 0.40 0.40Water costs, $ 2.03 2.03 2.03 1.98 1.98 1.98Building and equipment repairs, $ 2.59 2.59 2.59 2.52 2.52 2.52Transportation costs, $ 1.39 1.39 1.39 1.35 1.35 1.35Semen cost, $ — 17.38 1.58 — 13.10 1.32Waste management, $ 1.54 1.54 1.54 1.50 1.50 1.50Marketing, $ 4.10 4.10 4.10 4.00 4.00 4.00Interest on variable costs, $ 2.93 2.93 2.93 2.85 2.85 2.85Total variable costs/pig , $ 94.17 96.36 75.48 92.52 89.72 74.15

Contribution margin/pig, $ 6.63 27.14 47.50 11.33 31.28 51.72

Fixed cost/pig sold, $Depreciation on buildings (15 yr), $ 8.94 8.94 8.94 8.43 8.43 8.43Depreciation on major equipment (10 yr), $ 0.79 0.79 0.79 0.65 0.65 0.65Depreciation on minor equipment (5 yr), $ 0.20 0.20 0.20 0.16 0.16 0.16Interest on buildings and major equipment 5.09 5.09 5.09 4.76 4.76 4.76Insurance and taxes on buildings and

major equipment, $ 3.03 3.03 3.03 2.80 2.80 2.80Professional fees, $ 1.00 1.00 1.00 1.00 1.00 1.00Maintenance cost (breeding stock), $ 9.91 9.91 9.91 8.18 8.18 8.18Total fixed costs/pig sold, $ 28.96 28.96 28.96 25.98 25.98 25.98

Net return per/sold, $ -22.33 -1.82 18.54 -14.65 5.30 25.74Number of pigs sold 733 524 18,909 909 564 22,944Net return on total number of pigs sold, $ -16,367.89 -953.68 350,572.86 -13,313.47 2,991.30 590,663.91Total net return, $ 333,251.29 580,341.74Rate of return on investment, % 12 18Cash return/pig sold, $

b-12.40 8.11 28.47 -5.41 14.54 34.98

aL x C = Danbred® USA Landrace x Control, T (L x X) = Danbred® USA terminal Duroc-Hampshire x (L x C), L x I = Landrace x Index, and T

(L x I) = Duroc-Hampshire (L x I).bCash return/pig sold = net return/pig sold plus all depreciation costs.


pig marketed varied by line and cross,ranging from $100.80 per pig for Line Ito $125.49 per pig for T (L x I). PurelineI and C pigs were predicted to havecarcass value of 93% of the base priceon the Sioux Preme matrix, F

1 L x I and L

x C were predicted to have value of102% of the base price, and three-wayterminal crosses 103% of the base price.In the system based on Line I, netrevenue was greater for three-way crossthan for F

1 pigs ($125.87 vs $121.00 per

pig). However, in the system based onLine C, net revenue per pig was greatestfor F

1 pigs ($123.50) because their car-

cass weight was greater. Overall, three-way terminal cross Line I pigs had themost net revenue per pig.

Averaged across Line I and Csystems, the increase in net revenuefrom pureline pigs to F

1 pigs was $19.93

per pig. There was a small additionalincrease of $2.18 from F

1 to three-way

cross pigs. The terminal crossing sys-tems that realized 100% heterosis andused the Danbred® USA lines selectedfor increased growth rate and percent-age carcass lean had a large, positiveeffect on gross revenue per pig.

Variable Costs

Feed costs made up more than 50%of the total variable costs and thereforeefficiency of feed use greatly affectedvariable costs per pig. Three-way crosspigs were the most efficient and reachedmarket weight sooner than F

1 or pureline

pigs. Pureline pigs took 31 days longerto reach market weight and had feed/gain ratios 0.59 units higher than three-way crosses. Line I pigs had an advan-tage of $0.55 per pig over Line C in feedcosts.

Labor costs for breeding/gestation/farrowing/nursery were fixed for thesize of the production unit and thustotal costs for this labor was the samefor systems using both Line I and LineC females. Labor costs for finishingpigs were calculated assuming a con-stant pig/worker ratio. Because morepigs were produced in the Line I system(Table 1), it needed one more employeefor finishing, but produced 4,251 morepigs than the Line C system. As a result

labor costs per pig were greater in theLine C system ($14.12 per pig) than forthe Line I system ($13.10 per pig).

Semen costs differed among crossesand between Line I and C systems.There was no semen cost for pureline Iand C production because these pigswere produced with natural service.Breeding costs for boars in purelineproduction were considered to be partof breeding herd maintenance costsincluded in fixed costs as describedbelow. The cost of semen for L and Twas set at $30 and $6 per dose, respec-tively, which made semen costs greaterfor production of F

1 pigs ($13.10 per pig

for Line I system vs $17.38 per pig forLine C system) than three-way crosspigs. Semen costs were $1.32 per pigand $1.58 per pig for three-way crossLine I and C pigs, respectively. Semencosts were less for I than C becauseboth farrowing rate and litter size werehigher for I than C sows. In addition,waste management costs per pig mar-keted were less for Line I than C ($1.50vs $1.54) because both required thesame number of gestation/farrowingspaces, but Line I produced more pigs.The remaining variable costs expressedper pig marketed were also less in LineI because of its greater litter size.

Contribution margin per pig washigher in all three crosses for the sys-tem with Line I than the one with Line C.Averaged across the I and C systems,contribution margin for three-way crosspigs was $20.40 per pig more than for F

1

pigs, and the margin for F1 pigs was

$20.23 higher than for pureline pigs.

Fixed Costs

Depreciation costs were consid-ered a fixed cost and were lower in thesystem with Line I because of theincreased number of pigs marketed.However, the major difference in fixedcosts between Line I and C systemswas due to maintenance cost ofbreeding stock that included costs tomaintain breeding boars, gilts and sows.This cost was $8.18 per pig for theLine-I system and $9.91 per pig for theLine-C system.

Net Return

Crossbreeding had a large effecton net return. Averaged across sys-tems net return for F

1 pigs was $20.23

per pig more than for pureline pigs andreturn for three-way cross pigs was$20.40 per pig more than for F

1 pigs.

Profitability for each group within thesystem and for the entire system wasgreater for the Line-I system than theLine-C system. The return for purelineI and C pigs was negative, $-14.65 perpig and $-22.33 per pig, respectively,because they grew slow, had poor feedconversion, and had substandard car-casses. Net return for F

1 L x I and L x C

pigs was $5.30 per pig and $1.82 per pig,respectively. Net return for three-waycross T(L x I) pigs was $25.74 per pig vs$18.54 for three-way cross T(L x C) pigs.

Rate of Return on Investment

Net income for the system wascalculated as the sum of the product ofnumber of pigs times net return per pigfor each of the three crosses within theLine I and Line C system divided by thetotal number of pigs within the system.The production system based on Indexsows produced 24,417 pigs per yearwith average net income of $23.76 perpig. Output for the system based onControl sows was 20,166 pigs with netincome of $16.73 per pig. There was anadvantage of 6% in rate of return oninvestment for the system with Line Isows.

Conclusion

The system with Line I femalesmarketed 3.4 pigs more per sow per yearthan the Line C system for an annualresponse to 18 generations of selection(the study used pigs from Generations17, 18, and 19) of 0.19 pigs marketed persow per year. The total difference in netreturn was $7.03 per pig. The annualresponse in net return from selectionfor increased litter size was $0.39 perpig marketed.

D. B. Petry is a graduate student/tech-nician in animal science, B. P. McAllister isa Ph.D. student in accounting, and R. K.Johnson is a professor in the Department ofAnimal Science.


PAYLEAN® Improves Growth and CarcassMerit of Pigs with 25% and 50% Nebraska

Index Line Genes

R. K. JohnsonD. Petry

P. S. MillerR. Fisher1


The Nebraska Index Line excels inreproduction and is being used inindustry breeding programs. How-ever, because it has been selectedonly for litter size since 1981, growthand carcass merit of pure-line pigsare below industry standards. Theobjectives of this experiment were1) to compare growth and carcasstraits of Index cross pigs with either50% or 25% Line I genes in a cross-breeding system typical of how theline is used in the industry and 2) todetermine the effects of feeding 18 gPAYLEAN® per ton during the last28 days of the feeding period on Indexcross pigs. Line I was crossed withDanbred® USA Landrace (L) boarsand Duroc-Hampshire terminal boarsto produce F

1 pigs with 50% Line I

genes and terminal cross pigs with25% Line I genes. Pigs with 25% LineI genes grew faster (2.03 vs. 1.97 lb/d)from 65 days of age to approximately240 lb than pigs with 50% Line I genes(P < 0.05). They also ate more feed perday although the difference was notsignificant (5.82 vs 5.76 lb per d).Thus, the difference between groups infeed conversion was small and notsignificant. Terminal cross pigs with25% Line I genes had only 0.02 in lessbackfat at the end of the experimentthan F

1 pigs with 50% Line I genes, but

they had significantly larger longissi-mus muscle area (6.42 vs 6.10 in2) andgreater percentage carcass lean (52.4vs 51 %). Pigs of both genetic groupsand both barrows and gilts respond-ed similarly to a diet with 18 gPAYLEAN® per ton. FeedingPAYLEAN® at 18 g/ton for 28 dayssignificantly increased growth rate(2.19 vs. 1.80 lb/d), reduced feedintake (6.49 vs. 6.81 lb/d) improvedefficiency of growth (0.33 vs 0.26 gain/feed ratio, corresponding with 3.03and 3.85 feed/gain ratios), increasedcarcass weight (185.4 vs 177.2 lb),increased dressing percentage (75.2vs 74.3%), and increased carcasslean (53.6 vs 49.9%). Performance andcarcass merit of pigs with 25% Line Igenes were greater than for F

1 pigs

with 50% Line I genes, and feedingPAYLEAN® at the rate of 18 g per tonproduced similar increases in per-formance and carcass merit of bothgroups.

Introduction

The Nebraska Index Line (Line I)was established in 1981 and has beenselected only for increased litter size.Line I sows produce approximately 3.5more pigs per litter than a randomlyselected control that was derived fromthe same base population. A cross knownas GPK347 of Line I with a maternal lineof DeKalb Choice Genetics was enteredinto the National Pork ProducersCouncil Maternal Line Evaluation andevaluated along with five other indus-try lines. Total productivity through

four parities per replacement gilt forGPK347 females was 33% to 51% greaterthan for the other lines. Females of allsix lines were mated to the same termi-nal sires, and growth of progeny andpercentage carcass lean of progeny ofGPK347 sows were 94% and 98%,respectively, of the average of othercrosses.

Even with slower and less efficientgrowth and fatter carcasses in prog-eny, net return on investment was esti-mated to be as great or greater for theGPK347 sows than for all other lines. Asa result, pork producers are usingcrosses of Line I in breeding programsand future use of these crosses isexpected to increase. In these systems,F

1 Index cross gilts are produced and

crossbred gilts and sows are mated toterminal sires to produce three-way crosspigs. Two kinds of market pigs – thosewith 50% Line I genes, the F

1 barrows

and cull gilts from F1 gilt production,

and those with 25% Line I genes, thethree-way cross terminal pigs – are pro-duced. Faster, more efficient growthand leaner carcasses in both of thesegroups would enhance the value ofLine I cross females to commercialproducers.

Ractopamine HCl is a feed ingredi-ent that directs nutrients to increasegrowth, improve efficiency and increaseamount of carcass lean. PAYLEAN® isa trademark of Elanco’s brand ofractopamine. The objective of thisexperiment was to 1) determine the dif-ference in growth and carcass traits ofF

1 pigs that were 50% Line I and terminal

cross pigs that were 25% Line I, and(Continued on next page)


2) to determine the response in growthand carcass traits and the economicreturn in barrows and gilts of both ofthese groups to a diet with 18 g per tonof PAYLEAN® fed the last 28 daysbefore slaughter.

Methods

A total of 306 pigs from 56 litterswere used. Pigs with 50% Line I genes(designated F

1) were an F

1 cross pro-

duced by artificially inseminating LineI females with semen of Danbred® USALandrace (L) boars. Pigs with 25% LineI genes (designated T) were terminalcross pigs produced by inseminating Lx I females with semen of Danbred®USA Duroc-Hampshire terminal sires.The litters were a random sample ofapproximately 35 litters of each groupand pigs were a random sample fromwithin these litters. Equal numbers ofbarrows and gilts were sampled.

Pigs were moved from a nursery tofinishing facilities at approximately 56days of age. A random sample of 66pigs, an equal number of each sex andgenetic group, were placed in an envi-ronmentally controlled building withindividual feeding pens (IFU), theremainder were placed in 24 pens of anaturally ventilated building (MOF)with 10 pigs of the same sex and geneticgroup in each pen. A corn-soybeanmeal based diet formulated to contain18% crude protein, 0.95% lysine, and1,506 kcal ME per lb was fed to all pigsthroughout the experiment. A randomone-half of the pigs received this dietwith PAYLEAN® at the rate of 18 g perton during the last 28 days beforeslaughter.

After a one-week adjustmentperiod, each pig was weighed and indi-vidual feed intake recording of pigs inthe IFU and pen feed intake recordingof pigs in the MOF commenced. Onepig in the MOF died during the adjust-ment period leaving a total of 305 pigsin the trial. At the beginning of the trial,one-half of the pigs in the IFU and one-half of the pens in the MOF wererandomly assigned within each sex-genetic group subclass to receive thediet containing PAYLEAN®.

Traits

The objective was to feed pigs inthe IFU to a final weight between 240and 260 lb and to feed pens of pigs in theMOF to final average weights between240 and 250 lb with all pigs in the penweighing at least 215 lb. To accomplishthese objectives, each pig was weighedat 21, 42 and 63 days after being placedon test. Slaughter date was designatedfor each pig or pen of pigs based onprevious growth rate and 63-day weight.The final 28-day period for each pigbegan either 63, 70, or 77 days afterbeing placed on test. Pigs were weighedagain 14 days before designated slaugh-ter date.

Individual feed intake for pigs inthe IFU and pen feed intake for pigs inthe MOF were recorded. Feed intakewas recorded for Period 1, the first 21days on test, Period 2, the second 21 d,Period 3, the variable period from 42days after being placed on test to 28days before designated slaughter date,Period 4, the first 14 days whenPAYLEAN® was fed, and Period 5, thelast 14 days when PAYLEAN® was fed.Feeding periods 1 and 2 were each 21days, Period 3 averaged 22.9 days, andPeriods 4 and 5 were each 14 days.Performance was recorded in each pe-riod to determine the growth pattern ofpigs of each line and to determinewhether the pattern was different whenpigs were eating diets with and withoutPAYLEAN®.

Each pig was scanned for tenth ribbackfat thickness and longissimusmuscle area with an Aloka 500 instru-ment at the end of each period. Backfatand longissimus muscle area were notrecorded at day 0.

After final weights and scan datawere collected pigs were transported toSiouxPreme Packing Co., Sioux Center,Iowa where they were slaughtered thenext morning. Carcass traits recordedwere hot carcass weight, percentagecarcass lean estimated by TOBEC, and24-hour post slaughter longissimusmuscle pH and Minolta l* color score.

Statistics

Average daily feed intake for eachpen of pigs in the MOF was calculatedfor each period and this average wasassigned to each pig in the pen. Feedefficiency was calculated for each pigas the ratio of its weight change duringthe period to actual feed intake (IFU) orpen average feed intake (MOF). Growthtraits analyzed were weight at thebeginning of the trial, weight, backfatand longissimus muscle area at the endof Period 3, and at the end of the trial,and average daily gain, average dailyfeed intake, and gain/feed ratio duringeach period of growth. Carcass traitsanalyzed were hot carcass weight, dress-ing percentage, percentage lean, pH,and Minolta l* score.

All traits including feed intake andgain/feed were analyzed as a trait of thepig and data for pigs in the IFU andMOF were analyzed together. A mixed-model that accounted for the randomeffects of litter and pig within pen andthe fixed effects of building, geneticline, sex, diet (with or withoutPAYLEAN®) period of growth, two-factor interactions of line, sex, and dietwith period, and the 3-order interac-tions of line by sex by period, line bydiet by period, and sex by diet by periodwas fitted to data collected during thegrowing period. Period was omitted frommodels of carcass traits.

Results

Growth

The number of pigs, average weightat the beginning of the trial and averageweight, backfat thickness, and longis-simus muscle area at the end of Period3, and at the end of the trial for pigs ineach group are in Table 1. Pigs with 25%and 50% Line I genes did not differsignificantly in weight or backfat thick-ness, but T pigs had 0.25 + 0.093 in2

larger longissimus muscle area after 63days on test and 0.32 + 0.093 in2 largermuscle area at the end of the trial thanF

1 pigs. At the end of the trial barrows

were heavier than gilts and had greaterbackfat thickness and smaller longissi-


mus muscle area (P < 0.05). Pigs desig-nated to be fed PAYLEAN® did notdiffer from controls in weight, backfat,or longissimus muscle area at the end ofPeriod 3, before PAYLEAN® was fed.After 28 days of eating a diet with 18 gPAYLEAN® per ton, pigs weighed more(8.4 + 2.12 lb), had less backfat (-0.08 +0.021 in), and had larger longissimusmuscle area (0.68 + 0.07 in2) than con-trols (P < 0.01).

Average daily feed intake, averagedaily gain, and gain/feed ratios duringeach period are in Table 2. Interactionsof line and sex with period of growthand with PAYLEAN® treatment gener-ally were not significant. Terminal crosspigs gained faster than F

1 pigs in each

period, although the difference wassignificant only in Period 5. Averagedover the test period, pigs with 25%Line I genes gained 0.068 lb/d more thanpigs with 25% Line I genes (P = 0.05).Terminal cross and F

1 pigs had very

similar feed intake in each period anddid not differ significantly in gain/feedratio. Barrows ate more feed and gainedmore rapidly in each period than gilts(P < 0.01), but the sexes did not differsignificantly in gain/feed ratio.

PAYLEAN® had a dramatic effecton average daily gain during the first 14days it was fed when pigs fedPAYLEAN® gained 0.56 + 0.044 lb/dmore than controls. Although not sig-nificant, daily feed intake was -0.20 +0.121 lb less; consequently gain/feedratio exceeded that of controls by 0.09+ .044 units during the first 14 d. Theincrease in daily gain for pigs fedPAYLEAN® during the second 14 dayswas less (0.24 + 0.04 lb/d) becausePAYLEAN® reduced daily feed intakemore (-0.44 + 0.121 lb) than during thefirst 14 days that it was fed. Gain/feedratio for pigs fed PAYLEAN® was stillsignificantly better during the last 14days than for pigs fed the control diet(0.05 + 0.007 units). These results areconsistent with reports in the literaturethat the greatest benefit from feedingPAYLEAN® occurs during the firsttwo weeks. Pigs can become refractoryto PAYLEAN® as the length of thefeeding period increases. The gain/feedratios for pigs fed PAYLEAN® corre-

Table 1.Least-squares means and contrasts for weight, backfat and longissimusmuscle area

Lineb Sexc Payleand

Feedinginterval

aT F

1P

eB G P

e+ - P

e

Number of pigs151 154 152 153 153 152

Weight at beginning of test (day 0), lb57.8 55.1 56.0 56.9 56.4 56.4

Days during each interval1 65.1 66.2 63.9 67.4 64.9 66.32 28 28 28 28 28 28

Weight at end of period, lb1 185.9 184.1 0.57 185.9 183.9 0.39 183.5 186.5 0.132 241.7 237.5 0.18 241.9 237.3 0.05 243.7 235.3 < 0.01

SED

f3.00 2.36 2.12

10th rib backfat at end of period, in1 0.55 0.57 0.29 0.60 0.52 < 0.01 0.55 0.57 0.112 0.69 0.71 0.16 0.76 0.65 < 0.01 0.66 0.74 < 0.01

SED

0.021 0.021 0.021

Longissimus muscle area at end of period, in2

1 5.16 4.91 < 0.01 4.94 5.15 < 0.1 5.04 5.04 0.872 6.42 6.10 < 0.01 6.18 6.34 0.03 6.60 5.92 < 0.01

SED

0.093 0.076 0.070

aFeeding interval 1 includes Periods 1, 2, and 3 (see text) when PAYLEAN® was not fed and varied

in length, Feeding interval 2 was the last 28 days of the trial when PAYLEAN® (18g/ton) was fedto half of the pigs.bF

1 = Index x Landrace F

1 cross, T = Duroc-Hampshire (I x L) cross.

cG = gilt, B = barrow.

d- = PAYLEAN® not fed, + = PAYLEAN® fed last 28 days.

eP = the probability associated with tests of differences between lines, sexes, or diets.fSE

D = standard error of differences between means.

spond with ratios of 3.03 lb feed per lbgain during the 28 days that PAYLEAN®was fed, whereas ratios for control pigscorrespond with 3.85 lb feed per lb gainduring this period.

Daily feed intake increased as pigsincreased in age and weight. However,average daily gain was greater duringPeriods 2 and 3 ( days 22 to 63 of thefeeding period) than during all otherperiods. Sharp reductions in daily gainand efficiency of growth occurred dur-ing the last 28 days of the feedingperiod.

Carcass Traits

Pigs with 25% Line I genes hadheavier carcass weights (5.1 + 2.6 lb, P= 0.06; Table 3) due in part to greater liveweight (Table 1) and in part to greaterdressing percentage (0.5 + 0.3 %) than

pigs with 50% Line I genes. They alsohad 1.4 + 0.6 % more carcass lean andpaler muscle as Minolta l* values were1.8 + 0.8 units greater (P < 0.05). The twogenetic groups did not differ in longis-simus muscle pH.

Barrows had 2.8 + 2.1 lb heaviercarcasses than gilts (P = 0.20), due totheir greater weight at the end of thetest; however, some of the difference inlive weight was offset by the 0.7 + 0.2 %(P < 0.01) greater dressing percentagefor gilts than barrows. Gilts also hadcarcasses with 1.2 + 0.5 % more leanthan barrows (P < 0.01), but carcassesof the sexes did not differ significantlyin muscle pH or Minolta l* color score.

Pigs fed PAYLEAN® had heaviercarcasses (8.2 + 1.9 lb, P < 0.01) due toboth greater live weight (Table 1) and toan increase of 0.9 + 0.2% in dressing



Table 2.Least-squares means and contrasts for average daily feed intake, average dailygain, and gain/feed ratio during each of five periods of growth.

Lineb Sexc Payleand

Feedinginterval

aF

1T P

eG B P

e- + P

e

Avg. daily gain, lb1 1.81 1.85 0.55 1.76 1.90 < 0.01 1.83 1.83 0.672 2.03 2.12 0.06 1.96 2.18 < 0.01 2.07 2.07 0.723 2.07 2.12 0.48 2.01 2.18 < 0.01 2.12 2.07 0.304 2.12 2.18 0.09 2.09 2.23 < 0.01 1.87 2.43 < 0.015 1.79 1.90 0.03 1.79 1.92 < 0.01 1.72 1.96 < 0.01

SED

f 0.044 0.044 0.044

Avg. daily feed intake, lb1 4.63 4.63 0.90 4.52 4.74 0.08 4.67 4.59 0.492 5.34 5.49 0.22 5.23 5.62 < 0.01 5.40 5.42 0.813 6.17 6.15 0.98 5.84 6.48 < 0.01 6.20 6.11 0.464 6.62 6.77 0.10 6.46 6.88 < 0.01 6.77 6.57 0.095 6.59 6.68 0.45 6.42 6.86 < 0.01 6.86 6.42 < 0.01

SED

0.121 0.121 0.121

Gain/feed ratio, lb/lb1 0.40 0.42 0.09 0.41 0.41 0.99 0.41 0.41 0.842 0.38 0.39 0.40 0.38 0.39 0.16 0.38 0.38 0.813 0.34 0.34 0.34 0.34 0.34 0.31 0.34 0.34 0.484 0.31 0.32 0.32 0.32 0.32 0.87 0.27 0.36 < 0.015 0.27 0.28 0.10 0.27 0.27 0.65 0.25 0.30 < 0.01

SED

0.008 0.007 0.007

aPeriods 1 and 2 were each 21 d, Period 3 was 22.9 d, and periods 4 & 5 were each 14 d.

bF

1 = Index x Landrace F

1 cross, 3-way = Duroc-Hampshire (I x L) cross.

cG = Gilt, B = barrowd- = PAYLEAN® not fed, + = PAYLEAN® (18g/ton) fed last 28 d, during Periods 4 and 5.

eP = the probability associated with tests of differences between lines, sexes, or diets.

fSE

D = standard error of differences between means.

percentage (P < 0.01). Pigs fedPAYLEAN® had 3.7 + 0.5% more leanin carcasses than control pigs (P <0.01). Pigs fed PAYLEAN® and con-trols did not differ significantly in long-issimus muscle pH or Minolta l* score.

Conclusions

Pigs with 25% Line I genes and75% genes from Danbred ® USA linesgrew more rapidly, had greater carcasslean, and paler longissimus muscle thanpigs with 50% of their genes from eachsource. Pigs of both genetic groupsresponded similarly to a diet with 18 gper ton PAYLEAN®. Feeding pigs adiet with 18 g per ton PAYLEAN® for 28days before slaughter increased growthrate 22%, improved feed conversionratio 27%, and increased carcass lean7.4% over control pigs; however, theeffect of feeding PAYLEAN® wasapproximately twice as great during thefirst 14 days that it was fed comparedwith the last 14 days.

1R. K. Johnson is professor of animalscience, P. S. Miller is associate professor ofanimal science, and D. Petry and R. Fisherare graduate student/research technicians inthe Department of Animal Science.

Table 3. Least-squares means and contrasts + SE for carcass traits.a

HCW, lb Dress % % Lean pH Minolta 1

Item Mean Pe

Mean Pe

Mean Pe

Mean Pe

Mean Pe

Lineb

T 183.8 75.0 52.4 5.72 50.4F

1178.8 74.5 51.0 5.79 48.6

5.1 + 2.6 0.06 0.5 + .3 0.07 1.4 + .6 0.03 -.07 +.06 0.24 1.8 +0 .8 0.04

Sexc

G 179.9 75.2 52.3 5.75 49.2B 182.7 74.4 51.4 5.76 49.8

-2.8 + 2.1 0.20 0.7 + 0.2 < 0.01 1.2 + .5 < 0.01 .01 + .06 0.92 0.6 + 0.8 0.44

Payleand

+ 185.4 75.2 53.6 5.80 48.7- 177.2 74.3 49.9 5.75 50.2

8.2 + 1.9 <0.01 0.9 + 0.2 < .01 3.7 + 0.5 < 0.01 .08 + .06 0.16 -1.5 + 0.8 0.07

aHCW = hot carcass weight, Dress % = hot carcass weight/off-test live weight; % lean = percentage of carcass lean estimated by total body electricalconductivity at SiouxPreme Packing Co.; pH = ultimate 24 h longissimus muscle pH; and Minolta 1 = Minolta 1 color score.bT = DH (I x L) cross, F

1 = I x L cross.

cG = gilt, B = barrow

d+ = pigs fed PAYLEAN® (18 g/ton) during last 28 days before slaughter; - = pigs not fed PAYLEAN®.

eP = the probability associated with tests of differences between lines, sexes, or diets.


Economic Analyses of Feeding 18 g per tonPAYLEAN® to Crosses of the NE Index Line

R. K. JohnsonD. B. PetryP. S. MillerR. F. Fisher1


Economic returns per pig for F1

and terminal cross barrows and giltsof the NE Index line when fed a dietwith or without PAYLEAN® at 18 gper ton for 28 d before slaughter werecompared. Although not significant,terminal cross pigs with 25% Line Igenes were more profitable than F

1

pigs with 50% Line I genes and giltswere more profitable than barrows.Several scenarios were modeled toevaluate the economic returns fromfeeding PAYLEAN®. Increased profitswere similar across lines and sexesbut varied depending on whether in-transit death losses were consideredtreatment effects. The best estimates ofthe increased income per pig fromfeeding PAYLEAN® were $5.33 + 1.56for the scenario with no in-transit lossesand $1.54 + 4.83 when in-transit losseswere assumed to be related to feedingPAYLEAN®.

Introduction

As a result of the superiority of theNE Index line in reproduction docu-mented in the NPPC Maternal Line Evalu-ation project it is now being used broadlyin industry breeding programs. Its valuewould be further enhanced from im-provements in growth, food conver-sion and carcass value. In the previousreport we show that feeding a diet withPAYLEAN® at 18 g per ton during thelast 28 days before slaughter signifi-cantly improved growth and carcassmerit of Line I cross pigs. PAYLEAN®is a relatively expensive product and

these improvements must more thanoffset its cost to justify feeding it. Thepurpose of this report is to estimate theeconomic effects of differences in growth,feed conversion, and carcass value inpigs with 25% and 50% Line I genes andto determine the economic value offeeding these pigs a diet with 18 g/tonPAYLEAN®.


Details of the experiment are de-scribed in the preceding paper. Briefly,a growth test of 305 pigs with averagebeginning age of 68.6 days and weightof 56.4 lb and final weight of approxi-mately 240 lb was conducted. A corn-soybean meal diet formulated to contain18% crude protein, 0.95% lysine, and1,506 kcal/lb ME was fed to all pigsthroughout the experiment. One-half ofthe pigs were randomly assigned toreceive this diet with PAYLEAN® atthe rate of 18 g per ton during the last 28days before slaughter. Two crossbredtypes of pigs were studied, an F

1 of

Danbred™ USA Landrace and Line I,pigs with 50% Line I genes, and a termi-nal cross (T) from L x I females matedwith Danbred™ USA Duroc-Hampshiresires, pigs with 25% Line I genes.

Sixty-six pigs were housed and fedin a building (IFU) with individual feed-ing pens and half were fed PAYLEAN®.The rest were in another building (MOF)penned according to genetic line, sex,and diet treatment (with or withoutPAYLEAN®) with 10 pigs per pen. Bodyweight of each pig was recorded at thebeginning of the test, 28 days beforeslaughter when half the pigs began toreceive the diet with PAYLEAN®, andat the end of the test. Feed intake foreach pig in the IFU and each pen in theMOF was recorded for the intervalsfrom the beginning of the test to 28days before slaughter and the last 28

days before slaughter. Pen-fed pigswere assigned the average feed intakeof the pen. Each pig was scanned 28days before slaughter and at final weightwith an Aloka 500 instrument to esti-mate tenth rib backfat thickness andlongissimus muscle area.

The objective was to feed pigs inthe IFU to a final weight between 240and 260 lb and pens of pigs in the MOFto final average weights between 240and 250 lb with all pigs in the penweighing at least 215 lb. Each pig wasweighed at 21, 42 and 63 days afterbeing placed on test. Slaughter datewas designated for each pig or pen ofpigs based on previous growth rate andweight on day 63 of the test. The final28-day period for each pig began 63, 70or 77 days after being placed on test.Because of the goal to market all pigs ina pen on the same day, five pigs in theMOF projected to not weigh 215 lb afteranother 28 days were removed fromtest. In addition, four pigs were re-moved from test earlier, two that werecrippled and two with hernias. One pigdied between day 0 and 63 of the test.Pigs were transported to SiouxPremePacking Co. the day they were removedfrom test and slaughtered the next morn-ing. Percentage carcass lean was esti-mated with TOBEC and pigs were valuedon the SiouxPreme payment matrix. Fourpigs died in-transit. The distribution ofpigs across genetic line/sex/treatmentis shown in Table 1.

Production Costs and Pig Value

Costs of production from whenpigs were placed on test to delivery tothe packing plant were calculated foreach pig. Initial cost of pigs was set at$.814 per lb based on local feeder pigprices during February and March, 2001.Cost of the 18%-protein diet was set at



$.0586 per lb, the actual cost of the dietdelivered to the bin at the experimentalswine farm. The amount of PAYLEAN®consumed by pigs receiving it was cal-culated from their feed intake duringthe last 28 days of the trial and aPAYLEAN® cost per pig was assignedassuming it cost $3.11 per g. A fixedcost of $12.36 was assigned to each pigbeginning the test as if this was a costper pig space. Costs in this amountwere derived from production costsassigned to lines in the NPPC MLP(Dhuyvetter K. and T. Schroeder, 2000,Maternal Line Genetic Evaluation Pro-gram (MLP) Economic Analysis; inMaternal Line National Genetic Evalu-ation Program Results, April, 2000) andincluded professional fees ($.53), inter-est on the sum of one-half the variablecost per pig plus the cost of the feederpig ($2.46), depreciation on buildingsand equipment ($4.52), interest on build-ings and equipment ($3.78), and insur-ance/taxes on buildings and equipment($1.07). A variable cost for each pig wascalculated from the number of days itwas on test at a rate of $.0512 per day.This cost was calculated from the re-port cited above and included the sumof average costs per pig for buildingand equipment repairs ($1.28), utilities,fuel and oil ($.33), veterinary supplies($1.00), and labor ($2.99), divided by109.4, the average number of days in thefinisher for MLP pigs. A marketing costof $4.00 was assigned to each pig mar-keted. All costs were summed to obtaintotal production costs for each pig.

A value was assigned to eachpig based on its hot carcass weight andpercentage lean estimated by TOBECat SiouxPreme Packing Co. The basecarcass price of $.67/lb received forthese pigs was used. Profit for each pigwas calculated as market value minustotal costs.

Economic Analyses

Economic analyses were conductedin a 2x2x2 factorial arrangement thatincluded two assumptions about in-transit death losses, two alternativesfor calculating feed costs, and twoassumptions about causes for death/removal of pigs before slaughter.

Table 1.Distribution of pigs across genetic line, sex, and diet, and number removed ordied during the experiment or in-transit to slaughter.

DiedRemoved during experiment in-transit

Linea

Sexb

PAYLEAN® Day 0 Cripple Hernia Died Smallc

F1

G - 39 1F

1B + 38 1

F1

G - 38 1 1F

1B + 39 1

T G - 38 1 1 1T B + 38 1T G - 37 2 1T B + 38 1 1

aF1 = Landrace x Index, 50% Line I genes; T = Duroc-Hampshire sires x (L x I), 25% Line I genes.

bG = gilt, B = barrow.

cPigs removed during the experiment because their projected weight at slaughter date was less than

215 lb.

In-transit Death Losses

Pigs that died in-transit could betreatment effects or these losses couldbe independent of treatments. Analy-ses were completed making both as-sumptions. In analyses assuming thatpigs that died in–transit were randomand not related to genetic line, sex orPAYLEAN®, value of pigs that died in-transit was assigned based on predictedhot carcass weight and percentage car-cass lean. Hot carcass weight was as-signed based on live weight on the daypigs were marketed and the averagedressing percentage for their line/sex/diet subclass. Percentage lean was pre-dicted from final scan backfat and long-issimus muscle area and regressioncoefficients of percentage lean on backfatand longissimus muscle area calculatedfrom the complete data set.

Analyses assuming that in-transitlosses were related to genetic line/treat-ment effects were performed assumingthese pigs incurred all production costsbut had value of $0 when marketed.

Feed Costs

Feed costs were calculated in twoways: 1) as the trial was conducted inwhich all pigs received an 18%-proteindiet throughout the trial with feed costsof $0.0586/lb, and 2) an assumption thatcorn was substituted for soybean mealto reduce protein to 16% in the diet fedthe last 28 days to pigs not receivingPAYLEAN® without affecting growth

or carcass traits. Feed consumed dur-ing this period by these pigs was set at$0.0551/lb, the actual cost of this feedbeing fed concurrently to other pigs atthe experimental farm.

Pigs Died or Removed During theTrial

Economic returns for each of thefour combinations of assumptions aboutin-transit losses and feed costs werecalculated based on 1) all 305 pigs thatentered the trial, and 2) only those pigsthat reached market weight. The first ofthese assumes that causes of pigs notcompleting the test, those that died orwere removed early, were related togenetic line, sex and diet. Full costsuntil the day a pig was removed fromtest or until it died were included andthese pigs were assigned market valueof $0. Pigs that were removed from testand those that died during the test werenot included in analyses of only thosepigs that reached market weight.

In each of the eight combinations,value of pigs marketed, total produc-tion costs, profit, and carcass lean pre-mium as a percentage of base price foreach pig were fitted to a model thataccounted for random effects of penand litter, fixed effects of building, line,sex, and PAYLEAN® treatment, andtwo-factor interactions among fixedeffects. Two-factor interactions amongline, sex and PAYLEAN® treatmentwere not significant in any analysis. Pigvalue, production costs, profit, and


Table 2.Income, production costs, net profit, and carcass premium (+ SEa) for different scenarios of feeding PAYLEAN® at 18 g/ton

28 days before slaughter to crosses of the NE Index line.

All pigs beginning the trial (n = 305) Final pigs marketed only (n = 295)

No mkt lossb Mkt lossb No mkt loss Mkt loss

Groupc 18Pb 18-16Pb 18P 18-16P 18P 18-16P 18P 18-16P

Pig value, $/pigT-cross 121.64 121.64 120.15 120.15 126.80 126.80 124.59 124.59F

1120.17 120.17 118.43 118.43 123.07 123.07 116.67 116.67

Difference 1.47 + 2.97 1.47 + 2.97 1.72 + 3.45 1.72 + 3.45 3.73 + 2.19 3.73 + 2.19 7.93 + 5.41 7.93 + 5.41

Barrow 119.72 119.72 117.14 117.14 124.64 124.64 118.65 118.65Gilt 122.09 122.09 121.44 121.44 125.23 125.23 122.61 122.61Difference -2.37 + 2.97 -2.37 + 2.97 -4.30 + 3.45 -4.30 + 3.45 -0.59 + 1.53 -0.59 + 1.53 -3.95 + 4.78 -3.95 + 4.78

Paylean 127.06 127.06 125.24 125.24 130.46 130.45 123.67 123.67No Paylean 114.75 114.75 113.35 113.35 119.41 119.41 117.59 117.59Difference 12.3 + 2.97*** 12.3 + 2.97*** 11.88 + 3.45*** 11.88 + 3.45*** 11.05 + 1.49*** 11.05 + 1.49*** 6.09 + 4.46 6.09 + 4.46

Total cost, $/pigT-cross 99.07 98.75 99.07 98.75 100.08 99.75 100.08 99.75F

198.34 98.03 98.34 98.03 98.93 98.62 98.86 98.55

Difference 0.73 + 1.59 0.73 + 1.55 0.73 + 1.59 0.73 + 1.55 1.15 + 1.50 1.13 + 1.50 1.22 + 1.49 1.21 + 1.49

Barrow 98.73 98.41 98.73 98.41 100.04 99.71 100.02 99.69Gilt 98.67 98.37 98.67 98.37 98.98 98.66 98.93 98.61Difference 0.06 + 1.17 0.05 + 1.16 0.06 + 1.17 0.05 + 1.16 1.07 + 0.75 1.05 + 0.74 1.09 + 0.74 1.07 + 0.74

Paylean 101.10 101.10 101.10 101.10 101.77 101.77 101.78 101.78No Paylean 96.30 95.68 96.30 95.68 97.24 96.6 97.17 96.52Difference 4.80 + 1.13*** 5.42 + 1.12*** 4.80 + 1.13*** 5.42 + 1.12*** 4.53 + 0.71*** 5.18 + 0.71*** 4.61 + 0.70*** 5.25 + 0.70***

Profit, $/pigT-cross 22.96 23.27 21.48 21.79 26.67 27.00 23.30 23.63F

121.54 21.85 19.43 19.74 23.34 23.66 17.47 17.80

Difference 1.42 + 2.21 1.42 + 2.21 2.05 + 3.05 2.05 + 3.05 3.33 + 1.77 3.34 + 1.77 5.82 + 5.16 5.83 + 5.16


Paylean 25.96 25.96 23.71 23.71 27.99 27.99 21.48 21.48No Paylean 18.54 19.16 17.21 17.83 22.02 22.67 19.30 19.95Difference 7.41 + 2.21*** 6.79 + 2.21*** 6.50 + 3.05** 5.88 + 3.05* 5.97 + 1.56*** 5.33 + 1.56 *** 2.19 + 4.83 1.54 + 4.83

Carcass premium,% of base valueT-cross 99.16 99.16 97.90 97.90 103.50 103.50 101.01 101.01F

199.6 99.6 98.16 98.16 102.06 102.06 97.35 97.35

Difference -0.44 + 2.16 -0.44 + 2.16 -0.27 + 2.66 -0.27 + 2.66 1.24 + 0.68 1.24 + 0.68 3.66 + 3.96 3.66 + 3.96


Paylean 101.96 101.96 100.48 100.48 104.65 104.65 99.37 99.37No Paylean 96.80 96.80 95.58 95.58 100.71 100.71 98.99 98.88Difference 5.16 + 2.16** 5.16 + 2.16** 4.89 + 2.66* 4.89 + 2.66* 3.95 + 0.49*** 3.95 + 0.49*** 0.38 + 3.79 0.38 + 3.79

aSE = SE of difference between means.bNo mkt. Loss. full value was assigned to pigs that died in-transit; Mkt. loss, pigs that died in-transit were assigned value of zero.c18 P = feeding 18% protein diet to all pigs throughout the trial; 18-16 P = feeding control pigs 18% protein diet until 28 days before slaughter and 16% protein thereafter.cF

1 = Landrace x Index, 50% Line I genes; T = D-H sires x (L x I), 25% Line I genes.

* P < .10, ** P < .05, *** P < .01.

carcass premium for all combinations ofeconomic scenarios are in Table 2.

Results

T-cross vs F1 Pigs

Although not significant (P > 0.10),value of T-cross pigs with 25% Line I

genes was greater than for F1 pigs in all

scenarios, ranging from $1.47 + 2.97 forall pigs with no market losses to $7.93 +5.41 for only those pigs marketed andwith market losses. The difference isbecause 7 T-cross pigs were removedfrom the trial compared with only 3 F

1

pigs (Table 1). Increased value of T-cross pigs was due mostly to increased

carcass weight due to more rapid growthand, in the scenario using only thosepigs marketed, to greater premium abovethe base. Neither total production costsnor profit per pig differed significantlybetween T-cross and F1 pigs, but in allscenarios both were greatest for T-crosses. Increased profit per pig from



pigs with 25% compared with 50% LineI genes ranged from $1.42 + 2.21 to $5.83+ 5.16 per pig.

Barrows vs Gilts

Gilts had greater value than bar-rows in all economic scenarios becausethey were leaner and received a greaterpremium, although none of the differ-ences were significant. Differences incosts between barrows and gilts weresmall and not significant. Although dif-ferences were not significant, gilts weremore profitable than barrows.

PAYLEAN®

Feeding PAYLEAN® significantlyincreased value of pigs in all scenariosexcept the ones based only on pigs thatwere marketed and with zero value forpigs that died in-transit. Pigs fed a dietwith 18 g PAYLEAN® per ton wereleaner and heavier when marketed andreceived greater carcass premium.They had increased value over controlpigs that ranged from $11.05 + 1.49 to$12.30 + 2.97 per pig. In the scenarios inwhich only the pigs marketed wereconsidered, pigs fed PAYLEAN® hadgreater value, but the differencebetween treated and non-treated pigsdeclined greatly and was not signifi-cant. The reduction in the differencewas because the two pigs on thePAYLEAN® treatment that died in-transit were heavy, lean pigs with pre-dicted average hot carcass weight of190.5 lb, lean percentage of 54%, andcarcass premium of 107%, whereaspredicted averages for the two controlpigs that died were 165 lb carcassweight, 51.9% lean, and premium of100.5%. Although in this scenario dif-ferences in average value betweentreated and control pigs was $6.09 +4.46 it was not significant because in-cluding values of $0 for pigs thatdied in-transit greatly increased varia-tion and increased standard errors ofdifferences.

Total costs were significantlygreater ($4.61 + 0.70 to 5.42 + 1.12 per

pig) for pigs fed PAYLEAN® than forcontrol pigs. Costs were reduced be-tween $0.62 to $0.89 per pig for thescenario in which control pigs were feda 16% protein diet the last 28 daysbefore slaughter. Average daily feedintake for pigs fed PAYLEAN® was6.42 lb per day. During the last 28 daysthey consumed 181.9 lb feed and 1.64 gPAYLEAN®. Feeding PAYLEAN® in-creased costs an average of $5.09 perpig.

Profit for pigs fed PAYLEAN® wassignificantly greater than for controls($5.33 + 1.56 to 7.41 + 2.21 per pig) in allscenarios except the ones includingonly marketed pigs and with zero valuefor pigs lost in-transit. In this last sce-nario, increased profit from feedingPAYLEAN® was only $1.54 + 4.83 whencontrols were fed a 16% protein dietduring the last 28 days before slaugh-ter. Because losses before thePAYLEAN® treatment period occurredrandomly across lines, sexes, and treat-ments, including costs for these pigsdid not affect differences among ef-fects.

Discussion and Conclusions

Results for the scenario that in-cluded all pigs fed an 18% protein dietand zero market value for pigs lost in-transit compare lines, sexes, andPAYLEAN® treatment as the experi-ment was conducted. In this scenario,profit per pig was not significantly greaterfor pigs with 25% Line I genes than forthose with 50% Line I genes ($2.05 +3.05), was not significantly greater forgilts than barrows ($4.32 + 3.05), butwas greater for pigs fed 18 g per tonPAYLEAN® than controls ($6.50 + 3.05).A more realistic comparison is the onethat included all pigs with control pigsbeing fed a 16%-protein diet the last 28days. Then, differences between linesand sexes were similar to other sce-narios, but increased profit from feed-ing PAYLEAN® decreased to $5.88 +3.05 per pig. In these analyses, deathsand conditions that led to removal ofpigs were assumed to be due to the

effects studied (line, sex, and treat-ment).

For the assumption that all losseswere random and not related to line, sex,or diet, the appropriate scenarios arethe ones including only the pigs mar-keted and with predicted market valuesfor those pigs lost in-transit. In thesecases, the added profits from feeding 18g PAYLEAN® per ton were $5.97 + 1.56when all pigs were fed an 18%-proteindiet, and $5.33 + 1.56 when control pigswere fed a 16%-protein diet for 28 days.The last scenario including only thepigs marketed and assigning a value of$0 to those that died in-transit uses theassumption that losses up to 28 daysbefore slaughter are completely ran-dom and not related to line and sexeffects, but that in-transit deaths arerelated to treatments. Under these as-sumptions, feeding 18 g PAYLEAN®per ton increased profit by only $1.54 +4.83 and $2.19 + 4.83 per pig for 18 and18-16% protein regimens for controlpigs.

The experiment was too small todetermine whether deaths and condi-tions for removal of pigs were due tolines, sexes, or treatment. Causes ofdeaths and conditions causing pigs tobe removed before the last 28 daysbefore slaughter were not related toPAYLEAN® treatment. Ten pigs diedor were removed before the last 28 daysof the trial and seven of these wereassigned to the control diet. Includingthem with value of $0 greatly affectedestimates of profit from feedingPAYLEAN®. Therefore, the two bestestimates of the increased profit fromfeeding PAYLEAN® are $5.33 + 1.56 forthe scenario with no in-transit lossesand $1.54 + 4.83 when in-transit losseswere assumed to be related to treat-ment.

1R. K. Johnson is professor of animalscience, P. S. Miller is an associate professorof animal science, D. B. Petry and R. F. Fisherare graduate students/technicians in the De-partment of Animal Science.


Applicability of High-Rise TM Hog Housing forFinishing Operations

Richard R. Stowell1


The design of High-RiseTM swinefacilities allows the generation of asolid, manure-laden material fromhogs raised in confinement housingwith slatted floors. The volume ofmanure that must be handled annuallycan be reduced through continuousmoisture loss that takes place withinthe system’s drying bed and recyclingof bed material. Recycling typicallyinvolves mixing material twice a year— at the end of finishing periods.Moisture contents of twice-recycledmanure-laden bed material rangedbetween 55-65% with continuousaeration for three years of produc-tion. This moisture range makes thematerial acceptable directly as feed-stock for composting. Ammonia emis-sions should be similar to those fromdeep-pit facilities. However, the levelsof other problematically odorous gasesshould be reduced most of the time dueto the generally aerobic nature of thedrying bed. Hydrogen sulfide wasseldom detected within the buildingusing readily available sensingequipment (i.e. H

2S < 0.3 ppm) even

during handling of the manure-ladenbed material, and was never measuredat more than 4 ppm, which is promisingfrom a safety standpoint. Data col-lected from six production groups in-dicated that average daily gain andfeed efficiency of finishing pigs in theHigh-RiseTM facility were equal to orpossibly better than that of those pro-duced simultaneously in 11 nearbyconventional facilities with an iden-tical source of pigs and the samecontract-feeding arrangement. Con-struction of such a facility incursadditional costs associated with

purchasing, installing and operatingthe aeration system and paying someproprietary fees. With these addedcosts (+15-20% initial), this system isprojected to be a viable alternativemainly for those operations having acombination of special criteria/constraints, including: relatively highrisk of polluting local waterways orwater supply; long manure-haulingdistances to fields; access to marketsfor solid manure or compost feedstock;some, but not tremendous, pressure tolimit odor generation; and/or limitedwater availability.

Introduction

Environmental, neighbor andeconomic pressures have encouragedpork producers to investigate optionsthat are available for housing their pigs,especially growing-finishing pigs. Onerecent development in swine housingis the High-RiseTM concept. This hous-ing system was designed to solidifyhog manure within a slatted-floor pro-duction facility. A second goal was toimprove the quality of air inside andaround the building — with the expectedresults being improved pig performanceand less potential for neighbor com-plaints about odor.

Water Quality

Liquid manure systems have beentargeted as environmental pollutersbased upon some real evidence andconsiderable amounts of negative per-ception. Handling manure as a soliddoes not eliminate the potential forpollution or neighbor concerns, but insome circumstances, it can reduce thesepressures substantially. When apply-ing dilute manures, especially effluentfrom lagoons, onto land, over-applica-tion of water can be a problem. Soils

may be brought close to or beyondsaturation, which increases the likeli-hood of surface runoff and tile outflow,both of which can pollute surfacewaters. Light soils are prone to rapidpercolation and potential groundwatercontamination. Solid manures can beapplied at rates that meet soil nutrientneeds without greatly affecting soilmoisture levels.

A second advantage of handlingsolid manure is that the manurebecomes more transportable. Systemsfor handling liquid manure achievedwide acceptance because manure couldbe handled with pumps with minimallabor input. Liquid manure is easilytransported and applied onto land thatis adjacent to the primary farmstead.However, requirements for pumping andconveying liquid manure can quicklybecome unwieldy if the material must bemoved longer distances, waterways orother natural features must be crossed,or public roadways must be used ortraversed. Solid manure can be readilyloaded onto trucks at much higher drymatter and nutrient densities, whichgives it greater hauling value.

Nonfarm people usually associatesolid manure as being a more desirablemanure product than liquid manure.From the perspective of those who mightbe in the market to purchase manure,more nutrients and organic matter canbe obtained from solid manure withoutthe mess that is associated with liquidmanure.

Air Quality

Farm neighbors and other publiccitizens have raised concerns overodors from animal production, espe-cially from larger swine facilities. Fewproducers can ignore this issue andexpect to be readily accepted by their



Air quality inside productionfacilities is important for achievinggood pig performance and associatedprofit potential. The health and safetyof operators/employees also areimpacted by indoor air quality. Numer-ous studies have associated highammonia levels with respiratory dys-function and reduced performance.Hydrogen sulfide is characterized as apoisonous gas that is known for itspresence in confined manure storageareas.


System Design and Description.

4-M Farms built the first High-RiseTM hog facility (Figure 1) in DarkeCounty, Ohio in 1997-98 with a capital-

improvements (construction) grant fromthe Ohio Department of AdministrativeServices. This demonstration/researchbuilding was built to test the concept ofthe facility’s design, in which manure at90% moisture would be partially stabi-lized and dried in place on a bed ofbulking agents (wood shavings, saw-dust ground pallets, paper, straw, corn-stalks, corncobs, etc.;). The first batchof pigs was placed in the facility in July1998.

Although labor efficiency, pigperformance, and construction costswere considered to be important, theydid not drive the design. The intendedresult was a unique design that wouldbe competitive with other facilities whenanalyzed on a total system basis, butwould be more desirable from an envi-ronmental standpoint.

The design of this facility incor-porated several significant variationson design concepts of high-rise layer(poultry) facilities, one of the mostsignificant being a patented aerationsystem or plenum, which is used toaerate, dry, and solidify the manure.Pigs are housed in the upper story onslats (Figure 2). A layer of bulkingmaterial is placed in the lower storybefore pigs are brought into the facility.Manure falls through the slatted floor,into the lower story, and onto the dry-ing bed. The bulking material adsorbsfree liquids, contains the manure, andallows air to flow through the bed. Air-flow is directed into the bed from below,drying the material and supplying oxy-gen to the system. Once moistened airleaves the bed, it combines with venti-lation air supplied to the pigs and isexhausted by fans located in sidewallsof the lower story.

The most visible difference betweena High-RiseTM facility and conventionalswine production facilities is that thestructure is taller. The floor of the lowerstory can be constructed at groundlevel. No pit is constructed into theground meaning excavation require-ments are reduced. Large access doorsare included to allow implementsaccess into the lower story. A rampmust be constructed to facilitate load-ing and unloading pigs. Construction

Figure 2. Cross-section view of commercial version of High-RiseTM finishing facility.

Figure 1. High-RiseTM Hog Building – 4-M Farms research/demonstration facility.

local communities in the future. Giventhe pace of changes in the rural land-scape, the greater mobility of the citi-zenry, and increased ideologicalseparation of those from farm and non-farm backgrounds, the attention givento odors can only be expected to in-crease.

Aeration of manure is an odor-control strategy that has been imple-mented in a number of different systems.The premise is that the products ofaerobic decomposition should containsignificantly lower levels of odoroushydrogen sulfide and volatile organiccompounds than would be producedby anaerobic bacteria. Therefore, theexhaust air from a facility that utilizesaeration should be less odorous thanthat from production facilities storingliquid manure.

Air intake

Air intake

Exhaust fan

Pig space

Drying bed


must provide for the installation of theaeration system, especially the in-floorplenum (system of air ducts). Otherconstruction features are similar to thosefor conventionally designed slatted-floor facilities. Wet-dry feeders mustbe used in a High-RiseTM facility to limitwater wastage.

The ventilation systems in thesefacilities are distinctly different fromthose of facilities with conventionalmechanical ventilation systems in thatall of the exhaust fans are located in thelower story of the building. Air is drawninto the building through openings inthe attic. Tempered air is pulled from theattic into the pig space in the upperstory through baffled ceiling inlets. Thereis typically one inlet on each side thatruns almost the length of the produc-tion room. This design directs jets of airoutward from the room inlets along theceiling of the room. Fresh air mixes withroom air prior to being drawn throughthe slatted flooring into the lower story.Since the upper story is nearly airtightother than the ceiling inlets and slattedflooring, the bulk movement of air isdownward, with ventilation air movinginto the lower story before beingexhausted from the building.

Data Collection

Modern monitoring and controlsystems for maintaining desired tem-peratures within the pig space werebuilt into the research/demonstrationfacility. Indoor (upper story) and out-door dry-bulb air temperatures, dry-bulb air temperatures at eight locationsdistributed evenly around the pig space,and fan operation data were collectedon a nearly continuous basis. Ammo-nia, hydrogen sulfide and carbon diox-ide concentrations were measured atthree locations within each story andfrom the exhaust fans located aroundthe building perimeter using Dräger tubes(w/hand pump). These measurementswere taken roughly every other weekduring the first six growouts. Grabsamples of mixed manure-laden bedmaterial were collected during severalbuilding cleanouts.

Pig performance from this facilitywas compared to that of pigs within 11

Figure 3.Growth rate (a) and feed efficiency (b) of pigs raised in the High-RiseTM facilitycompared to pigs raised in conventional facilities.

a)2.0

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.0

Ave

rage

dai

ly g

ain

(lb/d

ay)

#1 #2 #3 #4 #5 #6 Ave.

Production group

Conventional High-Rise

#1 #2 #3 #4 #5 #6 Ave.

Production group

b) Conventional High-Rise

3.0

2.9

2.8

2.7

2.6

2.5

2.4

2.3

2.2

2.1

2.0

Fee

d co

nver

sion

rat

io (

lb/lb

)

nearby conventionally designed fin-ishing facilities. All of the conventionalfacilities had fully slatted floors, wereeither tunnel-ventilated or naturallyventilated, and had deep pits. All 12facilities were stocked with contractpigs from the same source and were onthe same feeding program. Productionschedules were pre-set by the contrac-tor to meet packer schedules, whichresulted in growout periods being setinitially for the same number of days.The growout periods overlapped, butbegan at different times over about a3-week period to accommodate pro-duction schedules. The contractor

recorded feed delivery and pig weights,along with producer records of deathlosses and culls.


Manure/Bed Material

Wood shavings and corn stoverperformed well as bulking materials,especially in terms of maintaining theirporosity. Sawdust and shredded news-paper have not performed well in spottrials (where they were used under onlyone or two pens) because the surfaces



of both materials matted over quickly,resulting in poor flow of manure down-ward and air upward. Chopped strawwas acceptable as a bulking agent.

Bed material could be recycled twice,meaning it was used for three growoutsor for more than a year. After the pigswere removed, the material was mixedand allowed to heat for a few days.After being used for three growouts,about 2.5-3 ft of material remained. Ona volume basis, about 65% less materialhad to be transported and utilized ascompared to liquid manure in a deep pit.The manure-laden bed material is handledas a solid using front-end loaders andtrucks.

Although considerable drying ofthe bed material took place, compostingdid not occur without mixing. The ma-nure-laden material quickly heated af-ter it was mixed. The microbial inactivitybefore and activity following mixingwere documented using temperatureprobes. Most of the manure-laden bedmaterial has been composted on site fordistribution by a manure brokerage.Other nearby producers with commer-cial High-RiseTM buildings planned toapply their material to land and incor-porate it without composting thematerial.

The characteristics of the manure-laden bed material varied with theextent of recycling done, the choice ofbed material used, and the location thatwas sampled. In general, however, thenutrient density of the bed material wasmuch higher than that of liquid manurefrom conventional facilities. While thenutrient density was increased, nochange in the total amounts of phos-phorus and potassium (or other miner-als) present in the material was foundnor was any change expected. Nutrientanalyses indicated that nitrogen lossesfrom the material (on a total mass basis)were on the same scale as losses frommanure stored in deep pits. Much ofthis nitrogen loss occurs through vola-tilization as ammonia and emission fromthe building in the exhaust air.

Thermal Conditions

Average air temperatures withinthe upper story were maintained within

a fairly narrow band around the desiredindoor temperature during cool and coldweather, +2oF during 20oF swings inoutdoor temperature. Individual tem-peratures throughout the pig space werealso quite stable. During the summer,all fans were operated at full capacity,which resulted in excellent air qualitywithin the pig space. During very hotweather, mist was evaporated in theinlet air streams to provide supplemen-tal cooling. Sprinkling is not compat-ible with this housing system sincewater wastage needs to be minimized.

Gas Levels

Measured concentrations of ammo-nia within the pig space were consis-tently below 20 ppm which is theeight-hour exposure threshold limitestablished (by OSHA) for buildingoccupants. Over the two years in whichgas measurements were made, the aver-age concentration was 4.3 ppm andreadings ranged from undetectable to19 ppm. Ammonia concentrations inthe pig space of conventional finishingfacilities have been reported to rangefrom about 5 ppm during summer to 10-20 ppm during winter. Concentrationsof ammonia within the lower storyregularly exceeded this limit and onereading exceeded 120 ppm. The aver-age concentration downstairs was 23.3ppm. Exhaust air concentrations had anoverall mean of 17.9 ppm.

The pronounced trend was forammonia levels to increase during coldweather when ventilation rates were ata minimum. The increased rate of ammo-nia generation under slightly warmerconditions was more than offset byhighly elevated rates of ventilation.The ammonia levels within the lowerstory could be irritating during winter,causing watery eyes, odor, and slightrespiratory distress when the area wasoccupied for several minutes.

Hydrogen sulfide was not found inmeasurable quantities within the pigspace. Additionally, no odor or othersign of its presence was noted upstairs.Occasionally, hydrogen sulfide wasdetected at concentrations notexceeding 0.5 ppm downstairs. Hydro-gen sulfide is an odorous gas (rotten-

egg smell) and is lethal at high concen-trations. Low concentrations of hydro-gen sulfide in the exhaust air bode wellfor addressing concerns about odor.

Gas measurements were also takenduring consecutive cleanouts duringthe summer and fall of 2000. Ammoniaconcentrations during cleanout weresimilar to those during the last weekswith pigs in the building and emissionswere about the same as that duringproduction in the summer. Hydrogensulfide was detected more frequentlyduring cleanout than during produc-tion, but average levels were still wellbelow 1 ppm and only one reading wasabove that level (3.6 ppm).

Pig Performance

Growth rate of swine raised in theHigh-RiseTM appeared to exceed theaverage rate for the 11 comparisonfacilities for the first six growouts(Figure 3) based upon contractor data(Cooper Farms, Inc.). Overall averagedaily gain was 1.84 vs 1.73 lb/day andpigs were marketed at 115 vs 119 daysin the High-RiseTM and conventionalfacility, respectively. Feed efficiency inthe High-RiseTM facility was similar tothat of the comparable conventionalfacilities (2.64 vs. 2.62). Pigs within theHigh-RiseTM facility grew rapidly andhad reasonable feed conversion ratios.The fairly stellar performance can prob-ably be attributed to a combination ofgood management, a good source ofpigs, new facilities, and reasonably goodair quality. Other than using wet/dryfeeders, there is little difference inmanaging pigs in a High-RiseTM facilitythan in conventional, fully slattedfacilities. Any effects of feeder typewere not evaluated in this investiga-tion.

Death losses exceeded those ofthe comparable production facilities(4.2% vs 3.2%), largely due to twoenteric disease outbreaks. Since thefacility was available for tours anddemonstration purposes, it was diffi-cult to maintain tight biosecurity on thepremises even though access to the pigspace was restricted. Respiratory ail-ments were not evident in the pigs.


Systems Perspective

The High-RiseTM concept forraising pigs shows potential foraddressing some important environ-mental concerns. There are additionalinitial and operating costs associatedwith the facility, however. Extra initialcosts include proprietary fees and thecost of the aeration fans and installingthe in-floor aeration system. Operationof the aeration fans consumes electricalenergy at a rate that is about thatrequired to operate the minimum-ventilation system. Therefore, the eco-nomics of utilizing such a facility designneeds to be evaluated as part of a totalsystems analysis. Such an analysis wouldinclude social and environmental costs,to the extent to which they are known orcan be estimated.

Conclusions

After monitoring the operation of aHigh-RiseTM hog finishing facility fornearly three years, it is evident thatsuch facilities can produce a solidmanure product. With recycling of thedrying bed material, substantially lessmaterial volume needs to be handledand moisture contents near 60% may beexpected. Additionally, the followingconclusions were made concerning theperformance of this type of facility forraising pigs:

• Air quality for the pigs, in termsof the thermal and gaseous envi-ronments, should be as good orbetter than that of conventionaldeep-pit facilities, but gas levelswill probably exceed thosepresent within facilities with flush

systems since the manureremains within the facility;

• There appear to be benefits forodor control and safety due tothe aerobic conditions that aremaintained within the drying bed,but considerable ammonia willstill be emitted and common safetymeasures should still be prac-ticed when handling manure-ladenbed material within the facility;and

• Pig performance should notdiffer from conventional fullyslatted facilities given reason-able management.

1Richard Stowell is an assistant profes-sor in the Biological Systems EngineeringDepartment. He worked in this topic areawhile at, and with support from, The OhioState University, Columbus, Ohio.

Sorting and Mixing Effects in aWean-to-Finish Facility

Michael C. Brumm1


An experiment was conducted toevaluate whether removing and mix-ing lightweight pigs in a wean-to-finishfacility resulted in improved pig per-formance to slaughter compared tonever removing pigs from a pen fromweaning to slaughter. Two popu-lations of pigs were compared. Theremoved and mixed population con-sisted of pens comprised of 1) 20 pigsper pen with the five lightest pigsremoved three weeks after weaningand 2) 15 pigs per pen with the pencomprised of the five lightest pigs fromthree of the 20 pig pens. The unsortedpopulation consisted of 15 pigs perpen from weaning to slaughter. Therewas no effect of treatment when com-paring populations on daily gain, dailylean gain, carcass lean percentage,daily feed intake or feed conversionefficiency. On day 158 following wean-ing when the heaviest pigs from both

populations were removed for slaugh-ter, pigs in the removed and mixedpopulation were represented in bothends of the pig weight distributioncurve, while no pigs from the unsortedpopulation were present in the light-est weight category. Results of thisexperiment do not support the recom-mendation that removing and remix-ing lightweight pigs in a wean-to-finishfacility improves performance anddecreases variation in pig weight attime of slaughter.

Introduction

Managing variation in pig weighthas major consequences for pig flowand price received for producers usingwean-to-finish facilities. Many produc-ers using wean-to-finish managementroutinely overstock pens at weaning,sorting off the lightest weighing pigsand remixing the pigs at some pointduring the first three to five weeksfollowing weaning. They follow thismanagement practice in the belief thatremoving the lightest pigs from a pen

and remixing with other lightweight pigsresults in better overall pig performancefor the population of pigs placed in thefacility at weaning. The purpose of thefollowing experiment was to evaluatewhether removing and mixing lightweightpigs in a wean-to-finish facility resultsin improved pig performance comparedto never removing pigs from a pen fromweaning to slaughter.

Methods

The experiment was conducted atthe University of Nebraska’s HaskellAg Lab at Concord. Pigs were housedfrom weaning until slaughter in a fullyslatted, curtain-sided facility with freshwater, under-slat flushing for dailymanure removal. Pens measured 8 ft x 14ft and contained one, two-hole wean-to-finish feeder and one wean-to-finishcup drinker. At weaning, each pen hada rubber mat and heat lamp for pigcomfort.

Following weaning at an averageage of 17 days, barrows were trans-



On day 21 following weaning, thefive lightest pigs in three of the 20/15pens were removed and mixed to createthe treatment pen labeled 15M. Fromday 21 to slaughter, all pens had 15pigs/pen, unless death loss or poorperformance resulted in removal of apig. Pen size was not adjusted in theevent of death or removal.

At arrival, pigs were fed two poundsof a commercial pelleted diet per pig.Following this, diets were in meal formand formulated to contain the followinglysine levels: 1.44% from 13 to 18 lb,1.37% from 18 to 25 lb, 1.31 % from 25 to40 lb, 1.20% from 40 to 60 lb, 1.10% from60 to 90 lb, 1.00% from 90 to 135 lb,0.80% from 135 to 190 lb, and 0.62% from190 lb to slaughter.

On day 158 following weaning, allpigs that weighed 255 lb or greater wereindividually identified and removed forslaughter. All remaining pigs were indi-vidually identified and sent to slaugh-ter on day 172 following weaning. Pigswere slaughtered at IBP Inc., Madison,Neb. Carcass lean was reported on theindividually identified pigs for calcula-tion of daily lean gain from day 61. Day61 post-weaning corresponded mostclosely with typical arrival weights forpurchased feeder pigs and initial weightsfor calculation of daily lean gain.

The orthogonal contrast of 20/15 +15M versus 15S was examined to testwhether population differences existedfor the two management schemes.

Results

There was an effect of group sizefor the first 21 days following weaning(Table 1). Pigs in the 15S treatmentweighed more (P < 0.05) because of agreater daily gain (P < 0.05) and dailyfeed intake (P = 0.06) compared with the20/15 treatment. There was no effect oftreatment on feed conversion efficiencyor within pen weight variation. Theseresults are in agreement with publisheddata suggesting group size effects aremost dramatic during the early post-weaned period.

As expected, within-pen weightvariation expressed as the coefficientof variation decreased for the 20/15 and15M population following removal of

Table 1. Effect of experimental treatments on pig performance for first 21 days post-weaning, least square means.

Treatmenta

Item 20/15 15S P values

No. pens 9 3

Pig wt, lbWeaning 10.7 10.6 0.43621 d 19.7 20.9 0.046

Coefficient of variation of within pen weight, %Weaning 15.7 17.2 0.13221 d 19.5 17.0 0.140

Daily gain, lb 0.43 0.49 0.028

Daily feed, lb 0.61 0.67 0.063

Feed:gain 1.42 1.36 0.880a20/15 = 20 pigs per pen for 21 days followed by removal of 5 lightest; 15S = 15 pigs/pen neversorted or moved.

Table 2.Effect of experimental treatments on pig performance, least square means.

Treatmenta

P values

Sorted/Mixed Unmixed 20/15 + 15MItem 20/15 15M 15S Treatment vs 15S

No. of pens 9 3 3

Pig wt, lb21 d post-sort 21.4 15.3 21.0 0.001 0.00161 d 65.6 56.2 63.4 0.001 0.110158 d 257.8 243.7 253.7 0.001 0.234Slaughter 271.2 261.0 267.3 0.027 0.715

Coefficient of variation of within pen weight, %21 d post-sort 13.7 11.3 17.0 0.009 0.003158 d 7.6 7.9 6.9 0.732 0.443

Daily gain, lb21-61 d 1.11 1.02 1.07 0.047 0.90961 d-slaughter 1.98 1.90 1.96 0.051 0.37821 d-slaughter 1.65 1.59 1.64 0.007 0.347

Daily feed, lb21-61 d 2.01 1.61 1.92 0.003 0.25861 d-slaughter 5.63 5.39 5.46 0.027 0.57221 d-slaughter 4.41 4.17 4.39 0.008 0.157

Feed:gain21-61 d 1.81 1.58 1.79 0.001 0.06361 d-slaughter 2.85 2.83 2.78 0.203 0.12921 d-slaughter 2.67 2.62 2.68 0.252 0.291

Carcass lean, % 54.4 54.1 54.5 0.242 0.276

Daily lean gain, lb 0.76 0.72 0.74 0.026 0.832a20/15 = 20 pigs per pen for 21 days followed by removal of the 5 lightest pigs/pen; 15M = 5 lightest

pigs from each of the 3 20/15 pens; 15S = 15 pigs/pen never sorted or moved.

ported 225 miles from a southwestMinnesota farrowing facility to theresearch site. Immediately after arrival,the pigs were ear tagged, weighed, andassigned to the experimental treatments.Weight blocks were not used in order toincrease within-pen weight variation atthe beginning of the study. There werethree replicates of the experimentaltreatments with five pens per replicate

for a total of 15 pens.Experimental treatments were:

1) Fifteen pigs/pen from weaning toslaughter (15S)

2) Three pens of 20 pigs/pen for threeweeks following weaning, reducedto 15 pigs/pen (20/15)

3) Fifteen pigs/pen comprised of thefive lightest pigs from the threepens of the 20/15 treatment (15M).


the lightest five pigs from the 20/15treatment pens (Table 2). Because the15M pen contained the lightest pigs onday 21, the pen average weight was alsothe lightest on day 61 and day 158. Finalweight for this treatment was also low-est due to the method used to removepigs for slaughter.

When comparing the populationof 20/15 + 15M versus the 15S popula-tion, there was no effect of treatment onwithin-pen weight variation, daily gain,daily lean gain, carcass lean percent-age, or daily feed intake. For the 21 to 61day period, the 15S population had animproved (P = 0.06) feed:gain ratio com-pared with the 20/15 + 15M population.There was no difference between thepopulations for the time period of 61days to slaughter or from 21 days toslaughter.

Figure 1 displays the variation inpig weight of each population on day158 when the heaviest pigs in thefacility, regardless of population, wereremoved for slaughter. The sorted andmixed population is represented in bothends of the population weight curve,while the unsorted population is notrepresented in either the two lowestweight groupings or the heaviest weightgrouping. Further evidence that theremoval and remixing of the lightestpigs on day 21 post-weaning did not

25%

20%

15%

10%

5%

0%

% o

f p

op

ula

tion

Unsorted

Light pigs sorted and mixed

Figure 1.Effect of sorting and mixing vs no sorting on distribution of pig weight on day158 post-weaning.

<200 201-210 211-220 221-230 231-240 241-250 251-260 261-270 271-280 280-290 291-300 301-310

Weight category, lb

improve overall performance is pro-vided by the fact that on day 158, 51%of the 15S population were removed forslaughter, while only 43% of the 20/15+ 15M population were removed.

Conclusion

Results of this experiment do notsupport the recommendation thatremoving and remixing light weight pigs

21 days after weaning in a wean-to-finish facility improves performance ofa population of pigs and decreasesweight variation at time of slaughtercompared to maintaining pen integrityfrom weaning to slaughter.

1Michael C. Brumm is professor ofanimal science at the Haskell Ag. Lab, Con-cord, Neb.

Competition — It’s Not Just“Cost” of Production

Allen Prosch1


Pork producers are faced withnumerous competitive challenges.Having a higher cost of productionthan other pork producers has alwaysbeen a reason to exit the pork industry.Even when their cost of production iscompetitive, producers still choose toexit the industry. Hog prices, corn pricesand the hog/corn ratio from 1970 to2000 were examined in relation to the

change in the number of pork produc-ers in Nebraska to identify the degreeof influence that each had on producer’sdecisions to enter or exit pork produc-tion. The annual average price of mar-ket hogs per cwt and the price of cornhad little relationship to the number ofpork producers in the state. (r2 <0.1).The hog/corn ratio (the average mar-ket price of hogs per annum divided bythe average market price of corn perannum) had a slightly stronger rela-tionship (r2 = 0.16). The data werefurther divided into five, six-year groups

and analyzed. The relationship be-tween hog/corn ratio and number ofpork producers in the state was muchstronger in the 1970s and early 1980s(r2 = 0 .63 to 0.68). The relationshipweakened dramatically in the late1980s and the 1990s (r2 = 0.08 to0.0005). This suggests factors otherthan profitability as defined by thehog/corn ratio, are exerting moreinfluence on the decision to remain inpork production now than in the past.New challenges in the industry, suchas labor relations, contract negotia-



tions and dealing with regulatoryagencies all require a degree of peopleskills not previously required to besuccessful in pork production. The newchallenges often require different skillsand carry different risk. A competitivecost of production is necessary toremain in business, but it has areduced influence on the decision tocontinue in production.

Introduction

Pork producers have control overthe cost of such inputs as feed, medi-cines, and facilities. Successful porkproducers have exercised control overthese items for many years. Tradition-ally, being a low cost producer has keptthem competitive with each other andsubsequently kept them in business. Inrecent years other factors, such asenvironmental regulations, marketaccess and labor relationships havebecome prominent in competitiveness.This paper examines the issue ofprofitability and its impact on the deci-sion to remain in pork production.

Methods

Three relationships were analyzedusing a regression analysis. The aver-age annual price per cwt of market hogs,the average annual price per bushel ofcorn and the ratio of the average annualprice per cwt of market hogs divided bythe average annual price per bushel ofcorn (hog/corn ratio) were compared tothe change and the percent of changein the number of pork producers inNebraska. Nebraska Agricultural Sta-tistics Service data from 1970 thru 2000were used for all analyses. Market hogprice, corn price and the hog/corn ratiowere independent variables. The changeor percent of change in the number ofNebraska pork producers was thedependent variable. The relationshipswere analyzed on a same year and on aone-year lagged basis. Data for thethirty-year period, beginning in 1970,were aggregated in five periods of sixyears each.


Cost of Production

When comparing cost of produc-tion, Midwest producers of all sizes are

competitive with domestic and foreignpork producers. While size enables someoperations to improve in selected costof production items where economiesof scale apply, this same scale createsactivities and costs in other items that,at some point, limits how low cost ofproduction can be driven. Differencesin cost of production between pro-ducers remain. Minnesota, Iowa andNebraska data for the year 2000 indicatethat, on average, small (250 to 300 sowfarrow to finish — or 4,000 to 6,000annual market hog sales) producershad a cost per cwt of pork produced of$38 to $39. Small producers in the upperrange for profitability (top 40%) hadcosts per cwt of $34 to $36. Similarly,Lawrence and Grimes (2000) surveyedproducers and found that with a bushelof corn valued at $2.50 and a market hogprice of $39.00 per cwt, 39% of theproducers whose annual marketingswere less than 10, 000 head annuallysaid they planned to stay in pork pro-duction.

Current corn prices are not as highas the $2.50/bushel used in the Lawrenceand Grimes survey. Mid-Septemberprices for corn based on the Omahamarket ($1.88/bushel) and for markethogs based on the Western Cornbeltcarcass market ($61.45/cwt) are givingproducers with a $39 per cwt cost ofproduction over $16 profit per hogmarketed; producers with $34 per cwtcost would profit over $29 per hogmarketed. However, at a market hogprice of $39 per cwt, the profit per hogdrops to $0 for the average group and$12.50 for the low cost group. A pro-ducer may be competitive based oncost of production, but the total dollarsreturned, due to low margin on lownumbers sold, may not be worth theeffort, especially in a diversified cropand livestock operation.

Hog Price

Do producers exit the industry inlarger numbers during or immediatelyafter years of low prices? When exam-ining the relationship of hog price andthe number of producers exiting orentering the industry on same year orone-year lagged basis, the price of hogsdoes not appear to be the decisivefactor for Nebraska producers (Figure1). Comparing the strength of the rela-

tionship on a same year basis the r2=0.04. With a one-year lag of the depen-dent variable, the strength of the rela-tionship decreased, r2= 0.028. Producersexited the industry despite rising pricesfrom 1971 to 1973, 1974 to 1975, 1980 to1982, and again from 1983 to 1984. From1985 to 1991 there was a period of “calm”in the number of Nebraska pork pro-ducers entering or exiting the industry,with three years showing modestdeclines in the number of producers,three years showing no change in thenumber of producers and one yearshowing an increase. Since 1992, thenumber of pork producers remaining inproduction has decreased every year.This was in spite of the fact that markethog prices from 1992 thru 1997 weresimilar to prices from 1975 to 1991 withvalues near or above $42 per cwt.

The percentage change in the num-ber of pork producers each year vs hogmarket price was plotted (Figure 2).From 1980 thru 1982 and again from1994 thru 1997 the year-to- year per-centage of producers exiting the indus-try increased. Producers left the industrydespite increases in hog prices duringthese periods.

Corn Price

Hog price is only half the equation.A period with a high cost of productionmay negate the value of high hog prices.The value of corn, especially for diver-sified crop and livestock producers whohave excess corn to sell, may impact thedecision to exit pork production. Com-paring corn price to the number of pro-ducers in pork production on same yearor one-year lagged basis indicates thatcorn price was not a decisive factor(Figure 3). The strength of this relation-ship on a same year basis was r2 = 0.003.With a one-year lag of the dependentvariable, the strength of the relation-ship increased slightly, r2 = 0.07. From1974 thru 1977, with steadily decliningcorn prices, Nebraska producers choseto exit the industry during two of thefour years, with a large decline in porkproducer numbers in 1975. In the 1980sproducers chose to exit and enter porkproduction during years of both risingand falling corn prices. In the 1990srising or falling corn price had littleimpact as producers exited the industryin every year following 1991.


‘70

‘71

‘72

‘73

‘74

‘75

‘76

‘77

‘78

‘79

‘80

‘81

‘82

‘83

‘84

‘85

‘86

‘87

‘88

‘89

‘90

‘91

‘92

‘93

‘94

‘95

‘96

‘97

‘98

‘99

‘00

Hog/Corn Ratio

The hog/corn ratio is the computedratio of the market hog price per cwtdivided by the corn price per bushel.The ratio may be a good proxy forprofitability, with higher ratios, 25 to 1,

being considered more profitable andlower ratios, 15 to 1, being consideredless profitable. In their survey, Lawrenceand Grimes (2000) priced corn at $2.50per bushel which, when combined witha $39 per cwt cash hog price, results ina hog corn/ratio of 15.6 to 1. Since 1970,when comparing the percentage change

in the number of Nebraska pork produc-ers compared to the hog/corn ratio, inthe same year, we find that producersboth exited and entered pork produc-tion during periods of both a high anda low ratio (Figure 4).

A low hog/corn ratio, an indicator

10

5

0

-5

-10

-15

-20

-25

No. of Producers Price

Figure 2. The annual average market hog price/cwt vs the annual percent of change in the number of Nebraska pork producers.

Per

cent

age

chan

ge i

n nu

mbe

r of

pro

duce

rs

60

50

40

30

20

10

0

Ma

rke

t h

og

pri

ce,

$/c

wt

‘70

‘71

‘72

‘73

‘74

‘75

‘76

‘77

‘78

‘79

‘80

‘81

‘82

‘83

‘84

‘85

‘86

‘87

‘88

‘89

‘90

‘91

‘92

‘93

‘94

‘95

‘96

‘97

‘98

‘99

‘00

Year

Figure 1. Average annual market hog price/cwt vs the annual change in the number of Nebraska pork producers.

2000

1000

0

-1000

-2000

-3000

-4000

Cha

nge

in n

umbe

r of

pro

duce

rs

60

50

40

30

20

10

0

Ma

rke

t h

og

pri

ce,

$/c

wt

Year




of poor profitability, may impact adecision to quit production in yearsfollowing the low ratio. For the one-year time lag, the results suggest pro-ducers do tend to exit the industry oneyear after an unprofitable period.

Comparing the strength of the rela-

tionship between the hog/corn ratio asthe independent variable and the per-cent change in the number of Nebraskaproducers as the dependent variable,with a one-year time lag, suggests thisrelationship was much stronger in the1970s and decreased dramatically in the

80s and 90s (Figure 5). The strength ofthe relationship (r2) indicates that 63%of the change in the number of produc-ers during the 1970 to 1975 period isexplained by the hog/corn ratio. How-ever, during the 1994 to 1999 periodonly 0.05% of the change in the number

Figure 3. The average annual corn price/bushel vs the annual change in the number of Nebraska pork producers.

2000

1000

0

-1000

-2000

-3000

-4000

Cha

nge

in n

umbe

r of

pro

duce

rs

3.50

3.00

2.50

2.00

1.50

1.00

0.50

0.00

Cor

n pr

ice,

$/b

u

Year


‘70

‘71

‘72

‘73

‘74

‘75

‘76

‘77

‘78

‘79

‘80

‘81

‘82

‘83

‘84

‘85

‘86

‘87

‘88

‘89

‘90

‘91

‘92

‘93

‘94

‘95

‘96

‘97

‘98

‘99

‘00

‘70

‘71

‘72

‘73

‘74

‘75

‘76

‘77

‘78

‘79

‘80

‘81

‘82

‘83

‘84

‘85

‘86

‘87

‘88

‘89

‘90

‘91

‘92

‘93

‘94

‘95

‘96

‘97

‘98

‘99

‘00

Year


Figure 4.The computed ratio of the Nebraska average annual market hog price per cwt divided by the Nebraska average annual cornprice per bushel compared to the percent of change in the number of Nebraska pork producers using a one-year time lag.

10

5

0

-5

-10

-15

-20

-25

Per

cent

age

chan

ge i

n nu

mbe

r of

pro

duce

rs

38

33

28

23

18

13

Ho

g/c

orn

ra

tio


of producers could be explained by thehog corn ratio. These results suggestinfluencers other than the hog/cornratio prompted pork producers to leavethe industry — especially from 1982 to1999 — even if they were profitable andhad a competitive cost of production.

Other Influencers

If the hog/corn ratio doesn’t havethe impact that it had in the past on aproducer’s decision to remain in porkproduction, what new factors are influ-encing producers to exit pork produc-tion? In 1997 Lawrence reported onmore than 14,000 Iowa pork producerswho had decided to exit the industrybetween December 1992 and December1996. While 80% of these producerscited issues of profitability, many otheritems also impacted their decision. Alack of competitive markets, environ-mental regulation and future laborresources were important to over 50%of producers who answered the sur-vey.

In their 2000 study, Lawrence andGrimes reported on the factors that pro-ducers said would limit future expan-sion. Lack of market outlets was importantto smaller producers and environmen-tal regulation was important to bothsmall and large producers. Owners oflarger units also noted the difficulty inhiring good employees as an issue lim-iting growth.

Labor

Labor is one of the new influencersof competitiveness in the pork indus-try. At some point either a facility orlabor (or both) becomes a limiting fac-tor in expanding pork production inresponse to smaller margins. Traditionalproducers, who have little if anynonfamily labor, find themselves con-sidering the use of hired labor. Smallerproducers are then faced with the prob-lem of having a large enough unit toafford full-time help. While row cropfarmers may be able to compensatethrough the use of seasonal help, smallswine operations likely do not havethat option. The swine unit is managedto produce pork year round, and whenjustifying full-time help, production

needs to improve or increase.

Market Access

Market access is also one of thenew influencers in the decision pro-cess. In 1997, Lawrence reported that60% of producers surveyed cited mar-ket access as important to very impor-tant in their decision to leave production.In 2000, Grimes and Lawrence reported71% of all hogs were marketed on someform of contract or packer agreement.However, producers marketing less than2,000 market hogs per year marketed77% of their production on the cashmarket. Only 10% of the producersmarketing 10,000 to 50,000 market hogsper year used the cash market. Negoti-ating contract or packer arrangementsrequires different skills than pork pro-duction. It also requires additional time,which many small producers may nothave.

Smaller producers may consider aniche or specialty market as an alter-nate approach to market access issues.However, to reach consumers directly,or to supply retail outlets requires deal-ing face-to-face with potential custom-ers. Building such relationships maytake even more time and skill than nego-tiating contracts or packer arrangements.

Environmental Regulations

Environmental issues are becom-ing increasingly important. For anyoperation, meeting regulatory require-ments involving lengthily processeswith regulators, consultants and thepublic, can be an overwhelming task.Also, new regulations being developedat state and federal agencies willrequire producers to seek additionalpermits and keep additional records.This creates a great deal of uncertaintyfor many traditional producers.

Conclusion

Input cost has less impact onNebraska pork producers’ decision toremain in pork production than it hadin the past. Producers express itemssuch as labor, environmental regula-tion, and market access as more impor-tant influencers now. The ability to dealwith new challenges in pork productionmay become the critical competitiveadvantage in the future.

1Allen Prosch is the Pork Centralcoordinator at the University of Nebraska.References are available by request from theauthor.

Figure 5.R-square values generated from a regression analysis using the hog/corn ratioas the independent and leading variable and the percentage change in thenumber of Nebraska pork producers as the lagged dependent variable for eachsix-year period between 1970 and 1999.

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

r2

0.63

0.68

0.08

0.004 0.0005

70-75 76-81 82-87 88-93 94-99

Year


Factors Affecting Bacon Color and CompositionJ.E. Mann

R.W. MandigoD.E. BursonR. Garza1


The objective of this study was todetermine the effects of genetic line,diet, sex, slaughter weight and loca-tion within the slab on the proximatecomposition and color of bacon leanand fat. Bacon slabs manufacturedfrom bellies of 756 barrows and giltsof six different genetic lines equallydistributed among four feeding regimes,with differing lysine levels, and threeweight groups and processed into slicedretail bacon (nine slices/inch) wereused. Sliced bacon slabs were dividedinto five equally sized sections and twobacon slices were taken from theanterior end of each for machinevision and proximate analyses. Alltreatments were found to have an effecton fat color, lean color and proximatecomposition of bacon (P<0.05). Gene-tic line had the greatest effect onbacon composition. Bacon withincreased fat tended to have whitercolored fat, suggesting a link betweenthe two attributes. Decreased dietarylysine and increased slaughter weightsboth led to fatter bacon slabs withwhiter colored fat. Bacon producedfrom barrows, in comparison to gilts,and from fatter genetic lines also hadlighter colored fat. Fat cell hyper-trophy in fatter animals may lead toincreased fat cell volume and a subse-quent decrease in the concentrationsof intracellular organelles and cellwall components, per unit of tissue,resulting in whiter colored fat. Itappears that a number of factors com-bine to affect lean color as each animalproduction parameter in this studyaffected lean color in a different way.While values were statistically dif-ferent between treatments (P <0.05),results from this study show bacon

lean and fat color to be relativelyconsistent across treatments. Meansfor each were classified toward “paler”and “whiter” ends of the color scaleused in this study. Understandingquality attributes of the very valuablesliced bacon market is crucial toproducer understanding of the value-added component bacon contributesto the value of the pig in the market-place.

Introduction

During the late 1980s many con-sumers used the nutritional merit offoods as a major food purchasing crite-ria; however, these same consumersare now increasingly choosing foodsbased on their flavor. Because of thischange in consumer attitudes, bacon isenjoying a resurgence in popularity.Increasing bacon sales, primarily in thefood service sector, have led to anincrease in the value of raw bellies andbacon.

The increase in belly value has ledto an increased interest in the effects ofmodem pork production methods onthe belly and subsequently on baconproduced from the belly. Previous con-sumer preference studies have shownthat lean-to-fat ratio and lean and fatcolor are the most important attributesin bacon purchasing decisions. Thepresent study determined the effects ofvarious current production methodson these factors.

Procedures

This research was just one portionof the National Pork Producers CouncilQuality Lean Growth Modeling (QLGM)project, which was comprised of 1,588pigs in three test groups. The meatquality portion of the project evaluatedthe yield and processing characteris-tics of the bellies, loins and hams fromthese animals. Variables of interestincluded genetic line, target slaughterweight, actual slaughter weight, diet,

sex and in the bacon portion of thestudy the type of bacon produced,either food service or retail, and loca-tion within the bacon slab. Because ofproblems with background colors bleed-ing through the thin sliced food servicebacon, this report deals specificallywith the thicker sliced retail portion ofthe bacon, consisting of 756 baconslabs. Animal finishing, slaughter andfabrication were completed at NPPCowned and contracted facilities in Min-nesota. Animals in the QLGM studywere of six genetic lines, including Berk-shire, Danbred, Duroc, Hampshire,Newsham hybrids and DeKalb. Thesegenetic lines were selected to assure afull range of performance for growth,carcass composition and meat quality.The sampling methods used in the projectdo not allow these results to representa valid genetic evaluation. Therefore,genetic lines are identified as numbers(1-6) with no particular order.

Animals were randomly assignedto three slaughter weight groups (250,290 and 330 lb). Pens of animals wererandomly assigned one of four diets(1-4). The four diets were developedwith constant energy, mineral andvitamin contents but differed in protein(lysine) levels (1—high lysine, 2—intermediate high, 3—intermediate lowand 4—low lysine). Intermediate dietscontained lysine levels within NationalResearch Council (NRC) 1988 guide-lines while diets 1 and 4, respectively,exceeded and failed to meet theseguidelines. Diets were adjusted at pre-specified intervals (90, 140, 190, 240and 290 lb) for metabolizable energy,added fat and lysine levels.

Following slaughter, bellies wereremoved from one side of each carcassand cut to common industry specifica-tions. Bellies were then individuallyvacuum packaged, frozen and shippedto the Loeffel Meat Laboratory at theUniversity of Nebraska where they wereheld in frozen storage to await furtherprocessing.


Using industrial equipment andcommon industry procedures and for-mulations, raw bellies were processedinto cooked bacon slabs, which werethen held in frozen storage. Slabs weretransported in a refrigerated truck to acooperating commercial bacon proces-sor in Omaha where they were pressedand sliced. Retail-style bacon slabs weresliced to approximately nine slices perinch. Sliced bacon slabs were placed oncardboard sheets, placed in plastic bagsand boxed for transfer, by refrigeratedtruck, to the University of NebraskaMeat Laboratory. Sliced slabs were heldin frozen storage until evaluation.

Upon evaluation, damaged andpartial bacon slices were removed fromboth ends of the slab. The slab was thenmeasured and divided into five equalsegments. The first two slices of theanterior end of each section wereremoved for machine vision analysis.These sample slices were packaged inpaper to exclude light, which could causecolor changes, and stored in a refriger-ated area until machine vision analysis.A machine vision system consisting ofa digital RGB camera housed in a woodenchamber with a fixed light source con-nected to a computer with the neces-sary hardware and software was used.The system was equipped withSAMPLEX® software to classify andanalyze digital images.

Bacon samples were prepared anddigital images were captured by themachine vision system. The color clas-sification system used in this projectwas previously developed at the Uni-versity of Nebraska specifically for theclassification of bacon color. Datareported by SAMPLEX® were in theform of pixel counts for each of the nineprogrammed classes: one for backgroundcolor, five for lean color, and three forfat color.

Bacon color was divided into twogroups: overall fat color (FatScore) andoverall lean color (LeanScore). Eachwas a composite color score repre-senting an average value obtained bycombining the color classes recognizedby the machine vision system. FatScorewas the average value of the three curedfat color classes (white, beige and dark)

and LeanScore was the average valueof the five cured meat color classes(very pale, pale, medium, medium darkand very dark). FatScore values of 1, 0and -1 were assigned, respectively, tothe white, beige and dark fat color classes.LeanScore values of 2, 1, 0, -1 and 2,were assigned, respectively, to the verypale, pale, medium, medium dark andvery dark lean color classes. Equationsused to determine FatScore andLeanScore were as follows:

FatScore = [((white pixel # x 1) + (beigepixel # x 0) + (dark pixel # x -1)) / total pixel#] LeanScore = [((very pale pixel # x 2)+ (pale pixel # x 1) + (medium pixel # x 0)+ (dark pixel # x -1) + (very dark pixel #x -2)) / total pixel #]

Proximate composition for protein,moisture, fat and ash was determinedfor the vision samples of each baconslab.


All treatments affected color andproximate composition of bacon(P < 0.05). Genetic line had the greatesteffect on bacon composition with anapproximately 13% difference in fatcontent between the fattest and leanestgenetic lines. Dietary lysine level alsohad a major effect. Diets with lysinelevels below NRC guidelines resultedin bacon with significantly (P <0.05)higher fat contents (Table 1) thanthose containing lysine levels withinor exceeding the guidelines agreeingwith previous research showingincreased daily gain of adipose tissuewith decreased dietary lysine levels.Bacon from barrows was found to havea higher fat (P<0.05) content than thatfrom gilts. Bacon derived from heavierweight animals was found to be have ahigher fat content.

Table 1.Bacon proximate composition as affected by genetic line, diet, sex, targetslaughter weight group and sampling location as main effects.

abc

Effect Fat (%) S.E. Moisture (%) S.E. Ash (%) S.E. Protein (%) S.E.

Line*1 54.74

a0.83 34.34

a0.65 1.79

a0.06 9.14

a0.26

2 42.65b

0.81 43.38b

0.63 2.18b

0.06 11.79bd

0.253 45.95

c0.81 40.69

cd0.63 2.06

ce0.06 11.31

be0.25

4 47.76d

0.80 39.57c

0.63 1.98d

0.06 10.69ce

0.255 41.95b 0.81 43.91b 0.64 2.15b 0.06 11.99d 0.256 45.79

c0.81 41.04

d0.63 2.13

be0.06 11.04

e0.25

Diet*1 45.06

a0.74 41.61

a0.58 2.11

a0.06 11.22

a0.22

2 44.93a

0.74 41.61a

0.58 2.10a

0.06 11.36a

0.223 46.14a 0.74 40.60b 0.59 2.01b 0.06 11.24a 0.234 49.76

b0.74 38.12

c0.58 1.97

b0.06 10.15

b0.22

Sex*Barrow 48.26

a0.66 39.09

a0.53 2.04

a0.06 10.62

a0.19

Gilt 44.69b

0.66 41.89b

0.53 2.04a

0.06 11.37b

0.19

Weight, lb*250 43.02

a0.74 43.01

a0.58 2.11

a0.06 11.86

a0.22

290 46.46b

0.69 40.48b

0.56 2.07a

0.06 10.98b

0.21330 49.93

c0.71 37.97

c0.57 1.96

b0.06 10.14

c0.21

Location**1 43.48a 0.40 42.21a 0.33 2.24a 0.05 12.07a 0.122 47.71

b0.40 39.85

b0.33 2.02

b0.05 10.43

b0.12

3 51.03c

0.40 37.45c

0.33 1.88c

0.05 9.64c

0.124 48.93

d0.40 38.78

d0.33 2.00

b0.05 10.29

b0.12

5 44.66e

0.40 41.78e

0.33 2.12d

0.05 11.44d

0.12

abcMeans with the same superscript within the same column and main effect were not significantly

different (P < 0.05).*Proximate composition values derived from all bacon slabs studied (individual and composite).**Proximate composition values derived from bacon slabs of animals fed diets 1 and 4 only(individual).



For all treatments except samplinglocation, increased fat content resultedin whiter fat color in bacon, suggestinga link between the two criteria. A num-ber of different factors could contrib-ute to this link. One possibility is thatfat cell size and/or density influencesfat color. Previous research has shownthat increased fat content after five orsix months age in the pig is causedprimarily by hypertrophy (an increasein size) of existing fat cells rather thanhyperplasia (increase in number offat cells). Following this logic, leanerbellies would have a higher density offat cells per unit of tissue. This couldlead to a darkening of fat color causedby increased concentrations of intra-cellular organelles and cell wall com-ponents. Increased cellular lipid contentof fatter bellies would lead to a lowerdensity of fat cells per unit of tissue.This could dilute the effect of intracel-

lular organelles and cell walls on fatcolor.

Sampling location was the onlytreatment that deviates from the abovetrend. Sampling location interacted(P < 0.05) with weight group for fatcolor, with the general trend in fat coloracross locations being the same foreach weight group. While fat contentincreased similarly from either endtowards the middle of the slab, fat colordid not follow the same trend. For allweight groups (Table 2), sampling loca-tions 1, 2 and 3 each had significantlywhiter colored fat than the two poste-rior-most locations (4 and 5). When thegeneral makeup of locations I through3 are considered it is seen that theselocations each contain the Pectoralisprofundi and the Latissimus dorsimuscles, which are found at no otherlocations. Perhaps either the way inwhich these muscles respond to pro-

cessing condition or their intramuscu-lar fat content affects overall fat color atthese locations.

In comparison to all other treat-ments, sampling location had the larg-est effect on lean color of bacon. Forlocation, lean color and fat contentfollowed similar trends, with the excep-tion of location 1 where increasing fat-ness resulted in a paler lean color. Baconfrom location 1, closest to the anteriorend, had a light colored lean, compa-rable to bacon from the fattest location(3). Of all locations, bacon from loca-tion 1 tended to have the least super-ficial muscle area on the medial surfaceof the slice. The majority of muscle areaat location 1 consisted of the Pectoralisprofundi and the Latissimus dorsi, whichare situated deep in the slab. Thesemuscles tended to be lighter in colorthan those located superficially. Onepossible explanation, for the light leancolor at location 1, is that muscles situ-ated deep within the slab may have anincreased moisture content, comparedto superficial muscles. Superficialmuscles would be exposed to moresevere conditions during heat pro-cessing, which could lead to a reducedmoisture content and a darker color.Additionally, intermuscular fat may actas a hydrophobic barrier preventingthe escape of moisture from musclelocated deep within the slab.

While it appeared that fat colorand fat content were related, therewere no obvious linkages in regardsto lean color. This research suggeststhat a number of factors combine toinfluence lean color, as each produc-tion parameter seemed to affect leancolor in a different way.

In this study, reduced dietary lysinelevels in the diet led to lower fat con-tents and darker lean colors agreeingwith previous research finding thatdecreased fat deposition resulting in adarker colored lean. This could be aconsequence of decreased intramus-cular fat deposition. However, we foundopposite results for slaughter weight,with darker colored lean found in baconproduced from fatter, heavier weightanimals.

Table 2.Bacon lean and fat color as affected by genetic line, diet, sex, target slaughterweight group and sampling location as main effects.

abc

Effect FatScored

S.E. LeanScoree

S.E.

Line1 0.37* 0.14 0.37* 0.042 0.26* 0.14 0.41* 0.043 0.31* 0.14 0.36* 0.044 0.34* 0.14 0.44* 0.045 0.24* 0.14 0.38* 0.046 0.26* 0.14 0.47* 0.04

Dietc

1 0.29a

0.14 0.39* 0.042 0.25

b0.14 0.39* 0.04

3 0.28ab 0.14 0.39* 0.044 0.36

c0.14 0.4* 0.04

S e xBarrow 0.32

a0.14 0.42

a0.03

Gilt 0.27b

0.14 0.38b

0.03

Weight, lb250 0.23* 0.14 0.43* 0.04290 0.30* 0.14 0.40* 0.04330 0.35* 0.14 0.38* 0.04

Location1 0.32* 0.14 0.48* 0.032 0.35* 0.14 0.36* 0.033 0.34* 0.14 0.50* 0.034 0.25* 0.14 0.37* 0.035 0.22* 0.14 0.30* 0.03

*Because of significant interactions the significance of main effects were not analyzed.abc

Means with the same superscript within the same column and main effect were not significantlydifferent (P < 0.05).dFatScore is the average value of three fat color classes recognized by the machine vision system.

eLeanScore is the average value of five lean color classes recognized by the machine vision system.


Divergent results suggest that anumber of factors combine to effectmuscle color. Color has been found tobe affected by genetic differences withinand between breeds as well as bychanges in animal production practices.Factors such as muscle fiber type andpigment concentrations have been foundto influence lean color. Prior researchhas found a significant variation in themetabolic profiles of muscles betweenbreeds. Differences in sensory proper-ties of meat have been attributed todifferences in the enzymatic activitiesof muscles. Additionally, differenceshave been found in the concentrationof heme pigments in muscles of differ-ent breeds.

Conclusions

Lean-to-fat ratio and lean and fatcolors have been reported to be themost important attributes in consumerpurchasing of bacon. Bacon with a leancontent of 40% or more, when com-pared to bacon of higher fat contents,has been found to be more desirable toconsumers. However, increased lean-ness can lead to a decrease in bellythickness, which could affect consumerpreference. Furthermore, it has beendemonstrated that leaner bacon gener-ally contains a higher percentage ofunsaturated fatty acids than fatterbacon. This is of concern becauseunsaturated fat has a greater suscepti-bility to the development of oxidativerancidity than saturated fat, which coulddecrease bacon shelf-life. Of all designcriteria considered in this study, noindividual treatment or combination oftreatments resulted in bacon with anaverage fat content of more than 55%.Only animals of genetic line 1 producedbacon that, on average, exceeded 50%fat.

While fat and lean color differedsignificantly across treatments, the datashows color to be relatively consistent.Average color values for fat and leanfell within a relatively narrow range ofthe color scales used. Fat colors tendedto fall within the “white fat” categorywhile lean colors tended to fall within

the “pale lean” category. The “pale-ness” of the overall lean scores isprobably due to the contribution ofmuscles deep within the slab as thesemuscles tended to be lighter in colorthan those located superficially.

Like most products, there are nouniversal standards for “perfect”bacon. However, pork processors canuse data from this project to help selectraw materials that best fit the demands

of their customers. Research on theconsumer acceptance of differences incolor of bacon lean and fat should beconsidered as it would allow a morecomplete use of this data set.

1J. E. Mann is in graduate school atTexas Tech. Univ., Lubbock, Tex., R. W.Mandigo and D. E. Burson are faculty at theUniversity of Nebraska, R. Garza is withExcel Corp. Wichita, Kan.

Figure 1. Orientation of belly muscles at each sampling location (Garza, 2001).

Bacon Slab Locations

1

2

3

4

5

1

23

4

1

3

2

4

56

1

23

46

7

2

3

4

68

5 6

4

Muscles

1 - Serratus ventralia2 - Pectoralis profundi3 - Latissimus dorsi4 - Cutaneus trunci5 - Rectus abdominia6 - Obliquus externus abdominus7 - Intercostalis exteri8 - Serratus dorsalis caudalis

Figure 2.Bacon sampling diagram.

1 2

Slice

1 2 3 4 5

Sampling Location

An

teri

or P

oste

rior


Effectiveness of Pork Quality AssuranceTraining for Youth

Rosie Nold1


Over 3,500 youth in Nebraska weretrained and certified in Pork QualityAssurance (PQA) in 1999. Qualityassurance training had an impact onthe youths’ opinions about qualityassurance and consumers and on theyouths’ knowledge of quality assur-ance practices. Emphasis on charac-ter development and decision-makingskills translated into positive responsesabout the responsibilities of a live-stock producer to animals and con-sumers. While most youth understoodat least some of their responsibilitiesprior to completing the training, thequality assurance training served toreinforce the understanding of thoseyouth and also to help all youthrecognize the breadth of the respon-sibilities that they have as livestockproducers. Educating youth aboutquality assurance will also benefitthe livestock industry. The youths’knowledge of quality assurance prac-tices will strengthen the livestockindustry’s standards for producing safeand wholesome food products, bothcurrently and in the future. While thelivestock produced by these youth maynot represent a large proportion oftoday’s livestock industry, the youththemselves represent the future of thelivestock industry. Only a small pro-portion may be directly involved in

production and use their skills in thatmanner, but all will be consumers.Food safety has been and will con-tinue to be an issue to consumers.These youth will be consumers andshould have a better appreciationand understanding of the meas-ures that livestock producers taketo ensure a safe, high quality, andwholesome food supply.

Background

When young people begin a projectwhere the final product is food, theyalso assume a legal and moral obliga-tion to produce a quality, wholesome,and safe product for consumers. It iscritical that young producers are con-sciously aware of these responsibili-ties and understand the implications.Only with such an understanding willthey deliberately adopt practices andprocedures that allow them to fulfilltheir obligations to consumers. Becauseof a desire to instill this understandingin youth, quality assurance educationhas become a major focus of theNebraska 4-H livestock program. Asyouth learn to implement quality assur-ance practices, they will develop anawareness and skills that will affecttheir current projects. In addition, theywill develop an appreciation for foodsafety and responsibility that will formthe foundation for their future contri-butions as producers, consumers, orboth.

Quality assurance programs and

training materials exist for adult audi-ences; however, these materials have astrong emphasis on technical knowl-edge, with little discussion of responsi-bilities. In addition, these materials weredesigned for adult audiences and con-sist of lengthy manuals and lectureprograms. These characteristics makethe existing materials difficult to usewith youth audiences. Hence, the goalof this project was to develop a moreage appropriate quality assurance train-ing program for youth.


Materials

Existing adult materials weremodified to be more relevant and inter-active. In order to accommodate theentire span of ages in 4-H (from 8 to 18years) the materials were designed toappeal to characteristics of 9 to 11 yearolds, as well as to some of the charac-teristics of older youth. Researchidentifying the needs for each agegroup was used in developing programcontent and design. For example, char-acteristics of 9- to 11-year-old youththat were considered included: 1) Aremore interested when actively involvedin making or doing something, 2) Enjoyworking in groups, and 3) Are begin-ning to accept responsibility for theirown actions. The characteristics ofolder youth that were considered were:1) Can take responsibility in evaluatingtheir own work, 2) Are beginning to


develop a community consciousness,3) Are developing a growing concernfor the well-being of others (Karns andMyers-Walls, 1996).

Considering these characteristics,the materials included numerous hands-on activities and interactive discus-sions where younger and older youthworked together. Furthermore, usingthe Character Counts! (JosephsonInstitute of Ethics, 1992) model as aframework, hypothetical situationsapplicable to quality assurance andlivestock projects were developed. Thesituations emphasized responsibilitiesinvolved in producing food and exhib-iting animals, including the ultimateresponsibility of producing safe foodfor consumers.

For ease of use, all materials werecombined into a “kit” that was utilizedby county extension staff. Items inthe kit included a reference manualof technical knowledge, teachingmethods, posters, stuffed pigs for usein practicing quality assurance proce-dures, hypothetical drug labels, andsyringes with various needle sizes.

To provide continuity amongcounty programs across the state,inservice sessions were delivered toextension educators and assistants. Oncetrained, these staff delivered programsacross the state, often with the assis-tance of local veterinarians. Over 3,500youth were trained and certified in PorkQuality Assurance (PQA) during thefive month period of March 1999 to July1999.

Testing Procedure

To determine the impact of the train-ing on youths’ opinions about andknowledge of quality assurance prac-tices, pre- and post-tests were com-pleted by youth who attended the trainingsessions. The instrument for youth ages12 years and over included five state-ments to evaluate their opinionstoward quality assurance and consum-ers of pork or meat products, and fivequestions to test their knowledge ofquality assurance practices. The testfor youth ages 8 to 11 years included


Table 1.Summary of quality assurance knowledge questions and answers.

Possible answers for Possible answers for 128 to 11 age group and over age group

Question topic (* indicates correct answer) (* indicates correct answer)

Proper injection sites A.Neck* A. Neck*B. Loin B. Elbow*C. Rump C. LoinD. Ham D. Ham

Needle usage A. 16 gauge, 1 1/2 inches Same as 8 to 11 age groupB. 18 gauge, 1/2 inch*C. BurredD. 18 gauge, 1 inch, bent

Records information A.Pig ear notch* Same as 8 to 11 age groupB. Amount of drug*C. Withdrawal time*D. Date given*

Drug misuse consequences A.Monetary* Same as 8 to 11 age groupB. Livestock show reputation*C. 4-H’er reputation*D. Consumer confidence*

Proper handling A. Sorting panels* Not askedB. Electric prodsC. Slapping hamD. Working with before show*

Responsibilities as exhibitor A. Feed & water* Same as 8 to 11 age groupB. Proper handling*C. ProfitD. Safe product for consumers*E. Purple ribbon showmanship

Table 2. Change in opinions from pre- to post-training, %.

Question Strongly Strongly Chinumber Statement Agree Agree Disagree DisagreeSquare

1 “Consumers have a Pre-test 91.7 7.4 0.6 0.3 <0.001right to expect thepork they eat is safeand wholesome.” Post-test 97.0 2.4 0.4 0.2

2 “Most consumers Pre-test 5.2 28.1 29.3 37.4 <0.001don’t care abouthow pigs are treated Post-test 4.2 12.5 19.0 64.3and handled.”

3 “It is the responsibility Pre-test 86.5 11.4 1.5 0.6 <0.001of every hog producerand exhibitor to producePost-test 94.5 4.0 1.1 0.4a safe and wholesomeproduct.”

4 “If a 4-H member Pre-test 50.7 36.1 10.0 3.2 <0.001forgets to record adrug injection....drug Post-test 79.7 15.4 2.4 2.5residue....4-H memberviewed as irresponsible.”

5 “Using a tranquilizer Pre-test 13.2 29.1 24.2 33.5 <0.001...calm wild steer...is responsible because Post-test 9.3 15.4 17.0 58.3protecting public.”


parental consent forms signed beforeyouth could respond to the pre- andpost-tests.


Opinions

Chi-square analyses showedchanges (P < 0.001) in opinions for allstatements. For questions 1, 3 and 4,the most desirable opinion, based onquality assurance principles, would be“Strongly Agree.” The percentage ofindividuals who slightly or stronglyagreed with statements 1, 3, and 4 in thepre-test was high, but a shift towardeven stronger agreement was seen inthe post-test. Similarly, for questions 2and 4, for which the most desirableanswer would be “Strongly Disagree,”from pre- to post-test there was shifttoward more “Slightly Disagree” and“Strongly Disagree” opinions. Resultsare shown in Table 2.

Quality Assurance Knowledge

Between pre- and post-tests, therewere significant increases (P<0.05) incorrect answers for every knowledgebased question for the 12 and overgroup (Table 3). For all except one of thequestions that also had distinctlyincorrect answers, there were signifi-cant decreases (P<0.05) in the percent-age of incorrect answers. For questionswhere all possible answers were cor-rect, there were increases in the per-centage of correct responses for allpossible responses. Especially obvi-ous differences were seen in recogni-tion of the ham as an incorrect place forinjections and the elbow pocket as anappropriate place for injections (ques-tion 1), and recognition of information,particularly withdrawal times, that shouldbe included in records (question 2).

Correct responses from nearly 90%or more of the youth for injection siteplacement (question 1), informationnecessary in records (question 2), properneedle usage (question 3), and respon-sibilities of a producer (question 5)indicate a good overall understanding

Table 3.Change in knowledge from pre- to post-training, of quality assurance practices,12 and over age group.

Question Question topic % Response Difference

number & answers Pre-test Post-test (+ Std. Err.)

1 Injection sites:A. Neck* 84.7 96.7 + 12.0 + 2.5%B. Elbow* 30.7 79.4 + 48.7 + 3.7%C. Loin 4.8 0.6 - 4.2 + 1.4%D. Ham 37.3 5.3 - 32.0 + 3.3%

2 Records Information:A. Pig ear notch* 63.2 86.5 + 24.3 + 3.6%B. Amount of drug* 74.7 93.9 + 19.2 + 3.0%C. Withdrawal time* 42.9 91.8 + 48.9 + 3.4%D. Date given* 86.6 93.9 + 7.3 + 2.5%

3 Needle usage:A. 16 gauge, 1 1/2 inches 28.9 14.3 - 14.6 + 3.4%B. 18 gauge, 1/2 inch* 71.5 89.9 + 18.4 + 3.3%C. Burred 1.6 0.5 - 1.2 + .9%D. 18 gauge, 1 inch, bent 3.3 2.2 - 1.1 + 1.4%

4 Drug misuse consequences:A. Monetary* 45.2 67.3 + 22.1 + 4.2%B. Livestock show reputation* 56.8 80.3 + 23.5 + 3.9%C. 4-H’er reputation* 63.1 82.6 + 19.5 + 3.7%D. Consumer confidence* 73.3 82.3 + 9.0 + 3.6%

5 Responsibil it ies:A. Feed & water* 89.2 95.8 + 6.6 + 2.2%B. Proper handling* 77.2 90.8 + 13.6 + 2.1%C. Profit 20.6 29.4 + 8.8 + 3.7%D. Safe product for consumers* 78.3 89.6 + 11.3 + 3.1%E. Purple ribbon showmanship 14.1 20.9 + 6.8 + 3.3%

*Indicates correct answer.

only questions designed to test theirknowledge of quality assurance prac-tices and responsibilities.

To evaluate the knowledge of qualityassurance practices, multiple choicetests were used. The test for the 8 to 11age group included six questions, withmultiple correct answers per question.Youth were instructed that multipleanswers were possible. Questionsregarding injection sites and needleusage used pictures, rather than wordsas choices. The test for the 12 and overage group included only five ques-tions, but also with multiple correctanswers per question. A summary ofquestion topics and possible answersis presented in Table 1.

To determine opinions towardquality assurance and consumers ofmeat products, participants were askedto circle one of the following: “Stronglyagree,” “Slightly agree,” “Slightly dis-agree,” or “Strongly disagree,” for eachof the five statements listed in Table 2.

Statistical Analyses

Chi-square analyses were used todetermine if there was a difference inthe outcomes between pre- and post-tests in the opinions of youth partici-pating in the training. Because the qualityassurance knowledge questions hadmore than one possible correct answer,the percentage of responses was calcu-lated for each possible answer. Thedifference in the probability of havinga response on the pre-test versus theprobability of having the same responseon the post test was calculated andcompared using a 95% confidenceinterval. The sample consisted of 1,054pre-tests and 1,040 post-tests for the 12and over age group and 584 pre-testsand 612 post-tests for the 8 to 11 agegroup. The sample sizes for statisticalanalyses were lower than the actualnumber of youth participating in thetraining because of the need to have


of quality assurance by this group ofyouth.

The only question for which therewas an increase in incorrect responseswas question 5. This may be due anoverall increase in knowledge aboutpork production and the accompany-ing responsibilities. An increase inoverall awareness of pork productioncould lead the youth to view the an-swers about profit and ribbons as cor-rect answers. Furthermore, the low hogprices of 1999 led to discussions aboutprofit in many different situations. Thepresence of these discussions by adultsduring or near the time of the PQAsessions may have influenced theyouths’ answers. In addition, theprogram’s emphasis on responsibilitymay have led the youth to believe thatincreased responsibilities should alsobring increased rewards, such as profitand ribbons at a fair.

Results (Table 4) for the 8 to 11 agegroup also showed significant increases(P<0.05) in correct answers for all ques-tions. Of special note are differencesseen in recognition of the ham as anincorrect place for injections (question1), the recognition of information, par-ticularly withdrawal times, that shouldbe included in records (question 3), andrecognition of the possible conse-quences of drug misuse (question 4).Following training, nearly 100% of theyouth recognized the neck as the propersite for injections (question 1), over95% correctly answered questions aboutneedle usage (question 2), and over85% recognized at least three items thatshould be included in records (ques-tion 3), proper pig handling techniques(question 5) and the responsibilities ofa swine producer (question 6). We specu-late that the 8 to 11 age group likelyused the same reasoning as did theother age group in answering thesequestions.

1Rosie Nold is the extension youthspecialist, Department of Animal Science.References are available upon request fromauthor.

Table 4.Change in knowledge from pre- to post-training, of quality assurance practices,8 to 11 age group.

Question Question topic % Response Difference

number & answers Pre-test Post-test (+ Std. Err.)

1 Injection sites:A. Neck* 81.8 99.8 + 18.0 + 3.1%B. Loin 9.6 2.8 - 6.8 + 2.7%C. Rump 13.4 3.0 - 10.4 + 3.1%D. Ham 41.8 14.8 - 27.0 + 4.9%

2 Needle usage:A. 16 gauge, 1 1/2 inches 30.5 26.8 - 3.7 + 5.1%B. 18 gauge, 1/2 inch* 88.7 95.6 + 6.9 + 3.0%C. Burred 1.9 0.5 - 1.4 + 1.2%D. 18 gauge, 1 inch, bent 4.4 0.2 - 4.2 + 1.7%

3 Records information:A. Pig ear notch* 68.7 80.8 + 12.1 + 4.9%B. Amount of drug* 71.6 88.0 + 16.4 + 4.5%C. Withdrawal time* 36.0 78.9 + 42.9 + 5.0%D. Date given* 83.9 91.0 + 7.1 + 3.7%

4 Drug misuse consequences:A. Monetary* 40.9 59.6 + 18.7 + 5.6%B. Livestock show reputation* 41.2 64.4 + 23.2 + 5.5%C. 4-H’er reputation* 45.0 66.4 + 21.4 + 5.5%D. Consumer confidence* 54.6 77.6 + 23.0 + 5.2%

5 Pig handling:A. Sorting panels* 68.9 86.5 + 17.6 + 4.7%B. Electric prods 4.2 3.5 - 0.7 + 2.2%C. Slapping ham 21.3 11.3 - 10.0 + 4.2%D. Working with before show * 90.3 94.0 + 3.7 + 3.1%

6 Responsibil it ies:A. Feed and water* 96.2 87.8 + 1.6 + 2.0%B. Proper handling* 87.1 94.3 + 7.2 + 3.3%C. Profit 22.1 31.8 + 9.7 + 5.0%D. Safe product for consumers* 74.6 89.4 + 14.8 + 4.3%E. Purple ribbon showmanship 20.2 24.3 + 4.1 + 4.7%

* Indicates correct answer.


Explanation of Statistics Usedin This Report

Pigs treated alike vary inperformance due to their differentgenetic makeup and to environmentaleffect we cannot completely control.When a group of pigs is randomlyallotted to treatments it is nearlyimpossible to get an “equal” group ofpigs on each treatment. The naturalvariability among pigs and the numberof pigs per treatment determine theexpected variation among treatmentgroups due to random sampling.

At the end of an experiment, theexperimenter must decide whetherobserved treatment differences are dueto “real” effects of the treatments or torandom differences due to the sampleof pigs assigned to each treatment.Statistics are a tool used to aid in thisdecision. They are used to calculatethe probability that observeddifferences between treatments werecaused by the luck of the draw whenpigs were assigned to treatments.The lower this probability, thegreater confidence we have that“real” treatment effects exist. In factwhen this probability is less than.05 (denoted P < .05 in the articles),there is less than a 5% chance (lessthan 1 in 20) that observed treatmentdifferences were due to randomsampling. The conclusion then is thatthe treatment effects are “real” andcaused different performance forpigs on each treatment. But bear inmind that if the experimenter obtainedthis result in each of 100 experiments,five differences would be declared tobe “real” when they were really due tochance. Sometimes the probabilityvalue calculated from a statisticalanalysis is P < .01. Now the chance that

random sampling of pigs causedobserved treatment differences isless than 1 in 100. Evidence for realtreatment differences is very strong.

It is commonplace to saydifferences are significant whenP <.05, and highly significant whenP < .01. However, P values can rangeanywhere between 0 and 1. Someresearchers say that there is a tendencythat real treatment differences existwhen the value of P is between .05and .10. Tendency is used because weare not as confident that differencesare real. The chance that randomsampling caused the observeddifferences is between 1 in 10 and 1in 20.

Sometimes researchers reportstandard errors of means (SEM) orstandard errors (SE). These arecalculated from the measure of

variability and the number of pigs inthe treatment. A treatment mean maybe given as 11 ± .8. The 11 is the meanand the .8 is the SEM. The SEM orSE is added and subtracted fromthe treatment mean to give a range. Ifthe same treatments were appliedto an unlimited number of animalsthe probability is .68 ( 1 = completecertainty) that their mean would be inthis range. In the example the rangeis 10.2 to 11.8.

Some researchers report linear(L) and quadratic (Q) responses totreatments. These effects are testedwhen the experimenter usedincreasing increments of a factor astreatments. Examples are increasingamounts of dietary lysine or energy,or increasing ages or weights whenmeasurements are made. The L andQ terms describe the shape of a linedrawn to describe treatment means.A straight line is linear and a curvedline is quadratic. For example, iffinishing pigs were fed dietscontaining .6, .7, and .8% lysine gained1.6, 1.8 and 2.0 lb/day, respectivelywe would describe the response tolysine as linear. In contrast, if thedaily gains were 1.6, 1.8, and 1.8 lb/daythe response to increasing dietarylysine would be quadratic. Probabilitiesfor tests of these effects have the sameinterpretation as described above.Probabilities always measure thechance that random sampling causedthe observed response. Therefore, ifP < .01 for the Q effect was found,there is less than a 1 % chance thatrandom differences between pigs onthe treatments caused the observedresponse.


MajorsAGRICULTURAL SCIENCES M AJOR

AgribusinessAgricultural EconomicsAgricultural EducationAgricultural JournalismAgronomyAnimal ScienceBiochemistryCrop ProtectionDiversified Agricultural StudiesFood Science and TechnologyHorticultureMechanized Systems ManagementVeterinary ScienceVeterinary Technologist

NATURAL RESOURCES MAJORS

Environmental StudiesFisheries and WildlifeNatural Resources & EnvironmentalEconomicsRange ScienceWater Science

PREPROFESSIONAL PROGRAMS

PreforestryPreveterinary Medicine

RELATED MAJORS

Agricultural EngineeringBiological Systems Engineering

Transfer Students• 2 + 2 Transfer agreements with several

community colleges and universities• Transfer scholarships available

Benefits of CASNR• 12:1 Teacher to student ratio• 15:1 Computer to student ratio

Scholarships• CASNR awards over $300,000 in

scholarships annually• $400,000 Plummer & Haskell Loan

program available for enrolled students

Educational Opportunities• World class faculty dedicated to teaching

and advising students• Travel abroad opportunities• Grants for foreign study programs for

credit• Veterinary school - agreement with Kansas

State allows students to apply through theNebraska applicant pool and attend forresident tuition

Career Opportunities• Outstanding opportunities for internships

and after-graduation employment• Career Day held each fall• East Campus Career Services office is staffed

by a CASNR Career

Minority Opportunities• Academic and personal counseling• MANRRS - Minorities in Agriculture,

Natural Resources and Related SciencesA national organization for internships,employment and graduate school andscholarship opportunitiesSpecial minority scholarships available

IMPORTANT

CONTACTS

* Sue VossRecruitment & Retention(402) [email protected]

* Student Ambassadors(402) [email protected]

RED-Y-Line(800) 742-8800 ext.2541

www.ianr.unl.edu/casnr/index.htm

We can helpyou discover

a collegefilled with

possibilities!

College of Agricultural Sciencesand Natural Resources

A college that’s more thanjust black

and white...

Documents

University of Nebraska Cooperative Extension EC 02-219-A ...University of Nebraska Cooperative Extension EC 02-219-A NEBRASKA SWINE REPORT lNutrition lGenetics lReproduction lEconomics