chapter 9 
Page 
Background 167 
The Scientific Era in Livestock Production 167 
Controlled Breeding 168 
Scientific Production 170 
Resistance to Change 171 
Some Future Trends 172 
Technologies 173 
Technologies That Are Presently Useful 174 
Sperm Storage 174 
Artificial Insemination 174 
Estrus Synchronization 176 
Superovulation 176 
Embryo Recovery 176 
Embryo Transfer 177 
Embryo Storage 177 
Sex Selection 177 
Twinning 177 
More Speculative Technologies 178 
In Vitro Fertilization 178 
Parthenogenesis 178 
Cloning 178 
Cell Fusion 179 
Chimeras 179 
Recombinant DNA and Gene Transfer 179 
Genetics and Animal Breeding 179 
The National Cooperative Dairy Herd 
Improvement Program 180 
Other Species 181 
Conclusion 183 
Impacts on Breeding 183 
Dairy Cattle 183 
Beef Cattle 185 
Page 
Other Species 187 
Other Technologies 188 
Aquaculture 189 
Poultry Breeding 189 
Issue and Options for Agriculture— Animals .... 190 
Tables 
Table No. ' Page 
30. Heritability Estimates of Some Economically 
Important Traits 169 
31. Results of Superovulation in Farm Animals .174 
32. Experimental Production of Identical 
Offspring 178 
33. National Cow Year and Averages for All 
Official Herd Records, by Breed May 1 , 1978- 
Apr. 30, 1979 ” ^ 181 
34. Predicted Difference of Milk Yield of Acti\ e 
A1 Bulls 184 
Figures 
Figure No. Page 
30. Eras in U.S. Beef Production 168 
31. Milk Yield/Cow and Cow Population, United 
States, 1875-1975. . . . ! 170 
32. Milk Production per Cow in 1958-78 170 
33. The Way the Reproductive Technologies 
Interrelate 175 
34. Change in the Potential Numher of Progein 
per Sire From 1939 to 1979 176 
