P~.tNcrPLES AND. P~cmcE rN THE PHrLrPNNE CoNTEXf
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P~N(!IPL£5 AND P~errC£ rN THE PHtLtPPtNE CoNTEXT
ORVILLE L. BONDOC
The University of the Philippines Press "' -Diliman, Quezon City
THE UNIVERSITY OF THE PHILIPPINES PRESS E. de los Santos St., UP Campus, Dilirnan, Quezon City 1101 Tel. No.: (02)925-3243, (02)926-6642/Telefax No.: (02)928-2558 e-mail: [email protected]
© 2008 by Orville L. Bondoc All rights reserved. No copies can be made in part or in whole without prior written permission from the author and the publisher.
The National Library of the Philippines CIP Data
Recommended entry:
Bondoc, Orville L.
Animal breeding: principles and practice in the Philippine context I Orville L. Bondoc.-Quezon City: The University of the Philippines Press, c2008.
p.; ern.
1. Animal breeding-Philippines. 2. BreedingPhilippines. 3. Animal genetics-Techniques. I. Title.
SF105 636.082 2009 P091000060 ISBN 978-971-542-589-6
Book Design by Zenaida N. Ebalan
Printed in the Philippines by EC-tec Commercial
Contents
Foreword .......... .. .. .... .... .. ............................... ................. .............. xxi
Acknowledgements ............ ..................................... .................. ... . xxiii
Chapter 1: Introduction
Summary ............. .............. .. ..................................................... .. 1
A. Definition of Animal Breeding ............................ .. .......... .. !
B. Goals of Animal Breeding ................................................. 4
C. Short History of Animal Breeding ............................ ...... .. 5
D. Overview of Animal Breeding Industries .. ...... ........... .. .... 6
l. Value of improvement ................................................ 9
2. Role of the government .. ......................................... . 10
E. Research in Animal Breeding .......................................... 10
Chapter 2: Genetic Basis of Animal Differences
Summary ....... .... .. .. ... .............. ....................... ..... ... .. ................. 13
A. Transmission of Genetic Materials ................................ 14
l. Gametogenesis and fertilization .............................. 14
2. Discovery of the chromosomes .............. .. ............... 15
a. Chromosomes of domestic species ...... .. .... .. ..... 16
b. Chromosomes and sex determination .. .. .......... 16
3. Nature and functions of genes .............. .... ......... ...... 16
a. The gene ...... .. ..................................................... 16
b. Functions of the gene ............................. .. ......... 18
vi Animal Breeding
B. Principles of Mendelian Genetics ... ...... .......... ... ... .. ...... 19
l. Law of segregation ....... ... ... .......... .......... ... ........ .. ..... 20
2. Law of independent assortment.. ..... .. .... .... ........... ... 21
3 . Probability and tests of genetic hypothesis ....... ..... . 21
C. Gene Effects .... ........ ...... .. ...... ........ .. .. .. ... ... .. .... ..... ........... 21
l. Phenotypic expression of genes ........ ... ... .. .. ... ...... ... . 21
2. Types of gene action .... ... ... .. .... ..... .......... ... ....... ........ 22
a. Additive gene action ...................................... .. .. 24
b. Non-additive gene action ....... ......... .... ..... .. ........ 24
i. Dominance
ii. Overdominance
iii. Epistasis or interaction
3 . Variations in phenotypic ratios ... ....................... .... .. 2 7
a. Linkage (autosomal linkage) ................... ......... . 2 7
b. Sex-related traits .. ... ....... .. .. ... ..... .. ...... ....... ......... 29
i. Sex-linked traits
ii. Sex-influenced traits
iii. Sex-limited traits
c . Multiple alleles .......... .. ....... ...... .... ...... ...... ... .. ..... 32
d . Pleiotropy .... .......... .. .. ... ......... ........... ............. .. ... 33
e. Variable expressivity ..... .......................... .... .. ... .. 34
f. Incomplete penetrance ......... .... .......... .. .......... ... 34
g. Extranuclear (cytoplasmic) inheritance .. .. .. ..... 34
h. Maternal influence ...... .. .. ...... ... ... .. .. .. ... .............. 35
Chapter 3: Genetics of Animal Populations
Summary .. ..... .. ... ....... ... .... ... ... ................ ..... ... ..... .... ...... ..... ... ... 36
A. Genes in Populations ....... ........ ...... ..... ....... ... ...... .. .. .. .. .... 3 7
B. Genetic Specification of a Population ...... .. ... ... .. .... ... .... . 3 7
1. Gene frequency ...... ... .. .. ... ... ..... .. ... ..... ...... ....... ... ...... 38
2. Genotypic frequency .................. ..... .... .... ... .... ..... ..... 38
Contents vii
3 . Computation of gene and genotypic frequencies .... 38
a. When no dominance exists .. ..... ... ........ ..... .... ..... 38
b. With complete dominance .... ....... .. ..... .. ....... .. .... 40
c. Other variations ............ .... .......... .... .. .. .. .... .. ...... . 40
C. Population Dynamics .... ....... .. ...... .... .. .. .. .... .. ... .. ...... .. .. .. .41
l. Static population: Hardy-Weinberg equilibrium ..... 41
2. Dynamic population: Changes in gene frequency ... 43
a. Nonrandom mating .. .. .... ...... ....... ...... ... .. .... ........ 4 3
b. Migration ........... ....... .... .. .. ..................... ... ..... .. ... 44
c. Mutation .. .. .. .... .. .. .. ... ............ .... ..... .. ... .... .. .......... 45
d. Selection ..... ............. ..... ........... .... ... ..... ... ...... .. .. .. 46
e. Small population size ............................ .. .... .. .. .. .4 7
D. Applications of Population Genetks to
Quantitative Traits .. .......... ...... ... .... .... ... .... .. .. ..... ... .. .... .. .. 48
Chapter 4: Quantitative Effects of Genes in Populations
Summary .. ............................. ......... .... .. ...... ........ .... ... ............... 50
A. Values and Means ................................ .. ...... .. ....... .. .. .. .... 51
l. Quantitative traits of possible economic
importance ............ ....... .... .. ........ ... .. ........ .. ... ... .... ..... 51
2. Genetic and environmental effects ..... .... .... .. .. .. .. ..... 52
3. Population mean ....... .. .. .... .. ............. .. ........... ...... .... .. 53
4. Breeding values ............. .. .... .. ..... ..... .. .. .. ..... ..... ... ....... 54
5. Dominance and interaction deviations ........ .. .. .. .. .. .. 55
B. Variance .... ...... .. .. .. ....... .. ...... .. .. ...... .. ............ .. .. ..... .... .. ... . 55
l. Genotypic and environmental variance .. ..... ...... .. .... 55
2. Genetic components of variance ....... ..... .. .... .. ...... .. . 56
a. Additive variance (VA) .. .. ................ .... ........ .. .. ... 57
i. Based on records of a parent and its offspring
ii. Based on sib records
b. Dominance variance (V 0
) .. .. ...... .. ......... .. ........... 58
viii Animal Breeding
c. Interaction variance (V1) •• •••••••• ••• ••• ••• • •• •• • •••• • ••• •• 58
3. Environmental components of variance ..... .... .. ....... 59
C. Resemblance Between Relatives .. ..... ....... ........... ........... . 59
1. Phenotypic resemblance ....... ......... ...... .... ... ...... ... .. .. 59
2 . Genetic covariance ...... ... .... .... ..... .... ..... ... .. ... .. ....... ... 60
a . Offspring and parent ......... ....... ....... ... ..... ... ........ 60
i. Offspring and one parent
ii. Offspring and mid-parent
b. Half sibs .. ........ .... .... .......... ......... .. .. .............. .. .... . 62
c. Fullsibs .. ...... .. ........ ... .. .. .. .. ........... .. .. .. .......... .. .. .. 62
d. Twins .... .. ............. ... .. ... ...... ....... .. ........ .............. ... 63
e. Epistatic interaction .. ...... .............. .. .. ....... .... .... .. 63
3 . Environmental covariance ................................ .. ..... 63
D. Heritability and Repeatability .. .. .... .. ...... .. ...................... 64
l. Concept of heritability .. ..... .. .. ...... .... .. .. .... .... ........ .. .. 64
2. Estimation of heritability .......... ........ .... .... ...... .. .. .... . 65
a . Offspring-parent regression .. .. ........ .. ...... .. .. .. .... . 65
b. Sib analysis ....... .. .......... ...... .......... .. .............. .. .... 66
c. Intra-sire regression of offspring on dam ...... .. .. 6 7
3. Reliability of heritability estimates .. .... .................... 6 7
4 . Repeatability ............. ... .......... .. .. .. ............................. 68
E. Correlations and Interactions ........ .... ...... .. .. .. ...... .. .... .. .. 69
l. Genetic and environmental correlations ......... .. ...... 69
a. Causes of genetic correlation ...................... .... .. 71
b. Estimation of genetic correlation ... ... .. ...... .... .. .. 71
2. Genotype by environment interactions .......... .. .. .... . 7l
a. Definition and examples .. .. ........ .. .... .... .... .. ........ 71
b. Effects on selection ...... .. ...... .. ........ ........ .. .... .. .... 73
F. Statistical Methods to Estimate Genetic Parameters .... 73
Contents ix
Chapter 5: Selection in Farm Animals
Summary .. ..... ........ ........... .. .... .. ...... ... ................... .... .. .... ...... ... . 75
A. Principles of Selection ..... .... ............ .. .... .. ...... ..... ..... ... .... 76
1. Natural and artificial selection ........ ........ ... ... .. .... .. .. 7 6
2. Genetic effects of selection .... ........ .. .... ...... .. ...... ... ... 76
B. Methods of Selection ..... ...... ...... .. .... .... .. ..... .......... ... ... .... 78
1. Individual selection ... ........ .. ...... ....... ... ....... ... ... .... .. .. 79
2. Use of information from relatives .. .... ... .. ... .... ... ... .... 79
a. Selection on the basis of pedigree ... ..... .... ... .. .. .. 79
b. Selection on the basis of progeny tests .... ... ...... 80
c. Selection on the basis of sib information ...... .. .. 81
3. Use of measurements on several traits ... .... ..... ...... .. 82
a. Tandem method ... ... ........ ... .......... .. ... ...... .... ...... . 82
b. Independent culling levels .... .. ..... ............ ..... .... . 82
c. Selection index .......... .. ... .. .. ...... ....... .. .... .. ........ ... 83
C. Selection Index Theory ....... .. .... ..... ....... ..... ... ....... .. .. ... ... 84
1. Genetic and phenotypic variances and
covariances ..... .. .... .... .. ... .... .. .. .... ... ..... ..... .. .. ........... .. . 84
2. Economic values ........ ... ......... ...... .... .... ........ .. .. ......... 85
D. Evaluating Animals by BLUP .. ... ....... .... ..... ... .... .. ... .... ..... 87
l. BLUP animal model .... .. ..... .. ... .. ... .. .... ... ..... ... ...... ... ... 88
2. BLUP versus selection index ... .. .. .. ..... ... ... .. ~ .... ... ... ... 90
3. Comparison of BLUP with other methods
of predicting breeding values .. ....... .... ........ .... ......... . 91
4 . Applications to the local livestock industry ... ........ . 92
E. Estimation of Genetic Progress ..... ... ..... ..... .............. ...... 94
1. Prediction of genetic improvement per year .. ....... .. 94
a. Basic formula ........ ... ............. .... ..... ... ... .... ...... ..... 94
b. Correlated response .... .. ..... ..... ..... .... ... ............ 100
X Animal Breeding
c. Theoretical response possible by current selection methods .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 10 1
2. Measurement of realized genetic improvement ... 101
a. Methods to monitor genetic improvement .. .. 102
b. Realized genetic improvement in farm
animals ........................ .... .. ............ ... .... .... .... ... 103
c. Long-term effects of selection .......... .. .... ........ 103
d. New developments in statistics and
computing ... ............................................. .... .. . 104
Chapter 6: Systems of Mating
Summary .... .... ... ......... .. .. ........................................ .... ............ 105
A. Inbreeding .............. ............ .. ................ .. ...................... 107
1. Relationship coefficients ....................................... 107
a. Additive relationship ............... .... .. .............. .. .. 108
b. Dominance relationship ......................... .. ..... .. 109
2. Inbreeding coefficient ....................... .................... 110
3. Rate of inbreeding .. ............ .......... ......................... 111
4. Change in genotypic frequency and genetic
variance due to inbreeding .. ........ ........ .... .. .... .. ..... 112
5. How to measure relationships and inbreeding .... 113
a. Tabular method ............................................... 114
b. Path coefficient method .. ................................ 120
6. Consequences of inbreeding .. .. .. .. .. .. .. .. .. . .. .. .. .. . .. .. . 123
a. Exposure of undesirable recessive gene
combinations ............ .. ... .. .. .............................. 123
b. Inbreeding depression ............ .. .. .... ................ 124
7. Practical uses of inbreeding .... ............. ...... .. .... ..... 125
a. Increased prepotency ..................................... 125
b. Detection of lethal genes ............... .... ............. 126
Contents xi
c. Concentrated use of a genetically superior
animal .. .. ... ...... ... ......... ... .. ..... .. ....... ....... ....... .... 126
d. Formation of inbred lines .... .. ... ... ... .... .. .......... 126
B. Outbreeding ..... .. ... .. ..... .... ..... .... ..... .. ......... ...... ..... ........ 128
1. What is heterosis? .......... ..... ...... .. ......... ..... .. .. .. ...... 128
2. Genetic bases for heterosis .. .. .. ...... .... .. .. ...... .... .... . 130
3. How to estimate heterosis ........ .... .......... ......... .. .. . 132
4. Forms of outbreeding .......... .. ... .. .. ...... .. .... .. .... .... .. 136
a. Outcrossing ...................... ......... .. ............. .. .. .. . 136
b. Linecrossing .............. ... .. .. ......................... .. .... 137
c. Crossbreeding .. .. .... .. .. .. .. .. .......... ...... .......... .. ... 138
i. Two-breed crossing (Single crosses)
ii. Backcrossing
iii. Three-breed crossing (Three-breed terminal cross)
iv. Four-breed terminal cross (Topcrossing)
v. Crisscrossing
vi. Three-breed rotation
vii. Four-breed rotation
viii. New breed development
ix. Combining inbreeding, crossbreeding, and selection
d. Grading up .............. .... ...... .. .... ... .... .... .. .. .. ....... 150
e. Species hybridization ................ .. .. .. .......... ...... 151
Chapter 7: Biotechnology Applications for Animal Improvement
Summary ................ ........ .. .... .... .... .... .. .......... ... .. .. ... ... ......... .. .. 153
A. Techniques in Biochemical and Physiological
Genetics ....... ... ...... ... .. ...... ... .. .... ...... ... .. .. ....... ............... 154
B. Techniques in Molecular Genetics (Modern Genetic Engineering) ..... ... .... ........ ..... .... ........... ... ..... .. ..... ..... .... 156
xii Animal Breeding
1. Identification of individuals or genetic groups
and verification of parentage .. .. .. ...... .. ........ .. .... .. .. 156
2. Removal or blocking of undesirable genes .. ......... 158
3. Alteration of structural genes to change product quality ... .. ..... ... .. .. ........ .. ....... ...... ....... ........ ...... .. ..... 158
4. Evaluation of candidates for selection .. .... ........ .. .. 158
5. Transfer of genes .... .. .. ...... .. .. .... ...... .. .. ...... .. ...... ..... 159
C. Techniques in Reproduction or Artificial Breeding .. .. 160
l. Artificial insemination and related technologies .. 161
2. MOET and embryo transfer-based technologies .. 162
a. Pre-pubertal and juvenile MOET .. .... .. .... ...... .. 163
b. Embryo production in vitro ........ .... .......... .. .. .. 164
c. Embryo splitting and cloning ...... .... .... .. .. .... .... 164
d. Predetermining the sex of offspring .......... .. ... 165
e. Induced twinning .. .. .................. .. .... .. .... .. .... .. .. 165
f. Chimeras .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 166
g. Cryopreservation .. .. .. ........ .. .... .. ...... .. .. .. ........ .. 166
Chapter 8: Animal Breeding Strategies for Livestock and Poultry Genetic Improvement in the Philippines
Summary ...... ........................... .. ........ .. ......... .. ......... .. ... ......... . 167
A. Systematic Approach to the Design of Animal Genetic Improvement Programs .. ........ .. .. .. ...... .... ...... ....... ....... . 16 7
1. Future environments (production and marketing systems) .......... .. ........................ ...... ...... ..... .... .. .. ... . 168
2. Breeding objectives and selection criteria ........ .... 169
3 . Testing and selection program ............ .. ...... .... ...... 170
a. Data collection .............. .... .. .... ...... ........ .... ...... 171
b. Animal performance recording .... .... .. ...... .. .... 171
c. Prediction and reporting of breeding values .. 172
d. Organizing a local selection program .. .... .... .. 173
Contents xiii
e . Importation strategy .......... .... .... .. ...... ........ .... . 174
4 . Crossbreeding systems ........ .. ........ ...... .. .. ............ .. 17 6
5 . Dissemination (dispersal and distribution) of improved breeding stock .. ........ .. .. .. .. .. ...... ...... .. .... 177
6 . Problems and future prospects ........ ...... .... ...... ..... 178
B. Carabao (Water Buffalo) Breeding ........ .. .. ...... .. .. .. .. .. .. 180
1. Industry profile ............ .. ............ .... .. .. .. .... .......... .. .. 180
a . Stock importations .... ............ .. .. ...... ................ 181
b. Philippine Carabao Center (PCC) .. .. .............. 181
2 . Water buffalo breeds .... ................ .......... ...... .. .. .... . 182
a. Swamp buffaloes .. .... .. ................ .. .. ...... .. .......... 182
b. River buffaloes ........ .. .. .... .... ...... ........ .. .... ...... .. . 183
3 . Quantitative traits of economic importance
in water buffaloes .... .... .... .. .. .............. .................. .. 187
4. Selection within purebreds ........ .... .. .. .. ...... ........... 187
5. Crosses between river x swamp buffaloes .. ...... ... 190
a . Heterosis estimates .. ........ .. .. .... .............. .. .... .. . 191
b. Karyotype analysis .... ............ .... .... .. ...... .......... 191
6. Applications of artificial insemination (AI) and embryo transfer (ET) technologies in water buffaloes .. .. .. .. .. .. .. .. .................... ... .. .... ... .. .. .. ..... ..... 192
C. Dairy Cattle Breeding .. .. ...... .... .. .... .. .... .. .. .. ............ .. .... 193
1. Industry profile ............ ........ ................ .. .... .... ........ 193
2. Stock importations and dairy cattle breeds .... ..... 194
3 . Quantitative traits of economic importance
in dairy cattle .. .... .. .. .. ............... ........ ... .... .. .. .. .... ... 196
4. Selection programs .... .. .... .. ................ .. .... .. .... .. .. .... 198
a . AI progeny testing .... ...... .. .. ...................... .... .. . 198
i. Importance of artificial insemination
ii. Test of young bulls program
iii. Sire evaluation
xiv Animal Breeding
b. MOET breeding schemes ................................ 200
c. Open nucleus breeding scheme ...................... 201
i. Foundation selection program
ii. Continuation selection program
d. Response to selection ..................................... 203
5. Crossbreeding of dairy cattle ................................ 203
a. Average genetic difference between Bos
taurus and Bos indicus .. ..................................... 204
b. Heterosis estimates ......................................... 205
c. Genotype (heterosis) x environment
interaction ...... ................... ..... ................... ...... 206
D. Beef Cattle Breeding ......... .... ....................... ...... .......... 207
1. Industry profile ...................................................... 207
2. Stock importations and beef cattle breeds in the Philippines ..... ................................................ ........ 207
3. Quantitative traits of economic importance
in beef cattle .......................................................... 215
4. Selection programs ................................................ 216
a. Improvement within a breed .......................... 217
i. Performance testing
ii. Progeny testing
iii. Pedigree testing
b. Improvement in a commercial herd ............... 219
i. Sire selection
ii. Selection of female replacements
iii. Cow culling
c. Local genetic evaluations ................................ 221
d. Response to selection ..................................... 223
5. Crossbreeding of beef cattle ................................. 223
a. Upgrading ........................................................ 224
Contents XV
b. Commercial crossbreeding .... .. ........ .... .......... . 225
i. Rotational crossbreeding
ii. Terminal crossbreeding
6. Applications of reproductive biotechnologies
in beef cattle .......... .. .................. .. ...... .. .... .. ............ 227
a. Artificial insemination and estrus synchronization ........ .. ................. .... ................ 227
b. Multiple ovulation and embryo transfer .. .. .. .. 229
E. Goat Breeding ........... .. .......... .. .... ...... ................ ... .. ... .. . 229
l. Industry profile ....................... .... .. .. ........ .. ............ . 229
2. Stock importations and goat breeds in the Philippines ... .. ........ .. ................ ... ....... ...... .... .. .. .. ... . 230
a. Performance standards for various goat
breeds .... .. .. .. .......... ................. .. ............. .. .... ... . 232
b. Diversity of goat genetic resources ... .. .. .... .. ... 234
i. Blood protein polymorphisms in native goats
ii. Association between blood protein polymorphisms and mature body weight and external body measurements
iii. Analysis of albumin and transferrin electrophoretic band patterns in different sib families of goats
iv. Geographical distribution of goat blood proteins among Anglo Nubian, native goats and their F
1 crosses
3. Quantitative traits of economic importance
in goats ....... .. ............ .. ... .. ... .. ........ .... .... ...... .. .. ... .... 236
4 . Selection program .. .. .. .. .. .. .. .. .. .. .. .. . .. .. . .. . .. .. .. .. .. .. .. .. 23 7
a . The Philippine Goat Breed Registry .. ... .. ........ 238
b. Local genetic evaluations ..... .... ..... ......... ........ . 238
c. Response to selection .. .. ........ .. .. .... .. ...... ......... 239
xvi Animal Breeding
5. Crossbreeding in goats ... .... ... ... .... ..... ... ...... .... ... .... 239
a . Upgrading ... ...... .... ... ..... ..... .. .. .... .... .. ...... ......... . 239
i. Mature weight and external body measurements
ii. Carcass characteristics
b. Heterosis estimates ......... .. ..... .. ...... .... ... ......... . 241
6. Applications of reproductive biotechnologies
in goats ... .... ... .......... ... .. .. .. .......... ... .. .... .. ........... ..... 242
a. Artificial insemination ..... ..... .. .. ... ........ .. .... .. ... 24 2
b . Multiple ovulation and embryo transfer ....... . 243
F. Swine Breeding ... .. ... ........ ........ .... .. ...... ... .......... ........... 244
1. Industry profile ...... ...... ...... ..... ....... .. ....... ... ..... ....... 244
2. Stock importations ........... .... ....... .... ... .... ......... .... .. 245
3. Swine breeds in the Philippines ..... ... .. ........ ... ... .. .. 246
4. Quantitative traits of economic importance
in swine .. ..... ..... .......... ...... .... .. ... .. ... .......... .... ....... ... 250
5. Selection program ..... .. ...... ......... ..... ... .. ... ..... ......... 252
a . The pyramid structure .. ... ..... ... .. .. ...... .... .. ..... .. 253
b. Home test versus station test ...... ... ................ 253
c. The National Swine Performance Testing Program (NSPTP) ........ ........ ...... ... ..... .. ........... 253
d. Local genetic evaluations ..... ... .... ... .... .. ...... .. .. . 254
e. Locally-derived selection indices .... ........ .... ... . 255
f. Response to selection .. ........ ..... ...... .. ... ...... .. ... 256
i. Results of selection experiments
ii. Recent developments
iii. Other strategies to improve quality of pork
6. Crossbreeding of swine .. ........ ..... .. ...... ...... .. .... ..... . 257
a. Crossbreeding systems ........ ...... ... ........... .. ..... 258
b. Heterosis estimates ..... ... ...... .... ........ ..... .. ... ..... 258
Contents xvii
7. Applications of reproductive biotechnologies
in pigs ............. .... ............ .. ............ .... ......... ..... ....... 260
a. Artificial insemination ...... .... .. .... .... .. .... ...... .... 260
b. Multiple ovulation and embryo transfer ........ 260
G. Poultry (Chicken) Breeding ...... .... .. .. .. .. .. ...... .. .... ...... .. 261
l. Industry profile .. ...... .... .. .. ............ .. ................ .... .. .. 261
a. Production of native chickens .... .. .. .. .. .. ...... .. .. 261
b. Broiler industry .. .. .................. .. ............ .. .. .... .. . 262
c. Layer industry ...... ........ ........ .. .... .. ...... .. .. .... .. ... 262
2. Poultry breeding industry and stock
importation .. .... .. .... ................ ..... ... .... ... .. .. ......... ... . 263
3 . Chicken breeds in the Philippines .............. .. ........ 264
a. Philippine native chickens .... .. .......... .... .. .... .. .. 264
b. Modern chicken breeds .. .. .... .. .... .. ........ .. .. .. .. .. 267
4 . Broiler breeding .. .. .. .. .. .. .. .... ........ .... .... .. .... ...... .... .. . 268
a. Quantitative traits of economic importance
in broilers ... ........... .. ... ............. .... .... .... ..... .. .. ... 268
b. Broiler improvement program ...... ...... .... .... .... 270
i. Testing and selection program
ii. Crossbreeding systems
5. Layer breeding .... .......... .... .................. .... ...... ...... .. . 2 72
a. Quantitative traits of economic importance
in layers ............................... ...... .. ........ .. .......... 2 72
b. Layer improvement program .. .... .... ...... ...... .... 274
i. Multiple-trait selection
ii. Crossing strains or breeds
iii. Elimination of poorer lines, strains, and commercial stocks
H. Duck Breeding ................................ .. ...... ...... .... .... .. .... . 276
l. Industry profile .......... .. .............................. .... ........ 2 7 6
xviii Animal Breeding
2. Stock importation ......... , ........... .. .......................... 277
3. Duck breeds in the Philippines ............................. 278
a . Meat-type breeds ............................................ 278
b. Egg-type breeds ............................................... 2 79
4 . Quantitative traits of economic importance
in ducks ................................................................. 280
5. Selection program ................................................. 281
6. Crossbreeding of ducks ......................................... 283
Chapter 9: Conservation and Use of Domestic Animal Genetic Resources
Summary .. ..................... .... ..... ... ..... ................ .... ... ...... ... ... ..... 284
A. Importance of Biodiversity of Livestock and Poultry Genetic Resources ....... ......................... .... .... ...... ......... 285
l. Present applications .... ....... ........ .... ....................... 285
2. Scientific research ................................................. 287
3. Public sentiment .. .. .. ...... ..... ........ .................. .. .. .. .. . 287
4. Future insurance ................................................... 287
B. Priorities for Conserving Animal Genetic Resources ... 287
C. Kinds of Conservation Schemes ...... .... ... .. ................... 289
l. In situ conservation ............................................... 289
2. Ex situ conservation ..................... ... ...................... 290
3. Recommended conservation methods .................. 292
D. Applied Breeding Schemes for Conservation .............. 293
l. Maintaining genetic diversity ............ .... ........ ........ 296
2. Avoiding/minimizing hazards and genetic loss ..... 296
3. Multiplying the conserved stocks .... ..................... 297
Appendices
2.1. Some notes on probability ......................................... 299
2.2. Test of genetic hypotheses ..... .. ............ ........ ............... 302
Contents xix
4.1. Statistical formulas useful in the study of
quantitative genetics .. .. .......... .. ........ .... ........ .... .. .. ...... 306
4.2. Milestones in quantitative genetics .. .. .......... ...... ...... .. 310
4.3 . Local applications/practice of quantitative
genetics ........ .. ... ........ .... .......... .. .................. ... .... ......... 310
4.4. Milestones in statistical methodology .. ........ .... ... ...... 314
4.5 . Local applications/practice of statistical
methodology ... ...... ..... ............ ............. ........ .. ... .......... 314
5.1. Milestones in selection ........ .. .......... .... ........ ... ........ .. .. 317
5.2. Local applications/practice of selection .. .... .. .. .......... . 318
6.1. Milestones in mating designs .. .. ...... .... ......... .... ...... ... . 322
6.2. Local applications/practice of mating designs ........ ... 322
Practice Questions/Problems
Mendelian inheritance ..... .. ...................... ............ ..... ....... .. 325
Linkage and sex-related traits .. ... .. .................. ........ .... .. .... 328
Laws of probability ....... ..... .... ..... ... .... ..... .... .. ..... ..... .... .... ... 331
Chi-square (X2) test .. .... .. ..... ..... ... .... ....... .. ....... .. .. ..... .. ....... 333
Gene and genotypic frequency ..... .... ...... .. .. .. ...... ....... .. .... .. 334
Effects of selection on gene frequency ...... ........ ...... .. ...... .. 335
Values and means ... ...... .... ............... ..... ....... ...... ...... ...... .... 336
Mean, variance, correlation, and regression .. .. ... .. .. .. .... .. . 33 7
Estimation of heritability .. .. .......... .. ........ ..... ..... .... ... .. ..... .. . 338
Methods of selection for more than one trait.. .... ......... .. .. 341
Prediction and measurement of response to selection ... .. 34 2
Inbreeding ... ......... ............. .. .................. ..... .... ...... ..... ........ . 344
Outbreeding ... .... .... ...... .... .. ...... ........ .... ............... ... .. ... ...... . 345
Operations manual of a livestock breeding
station/center .. .... ... .... ... ...... ........ .... ... .... ...... ... ... .. ........ 348