Challenges to dairy cattle management: genetic considerations.
Several new technologies will be used to produce continued genetic change in dairy cattle. These technologies are categorized broadly as 1) improved modeling, selection, and evaluation methods; 2) use of new and improved reproductive technologies; 3) new developments in molecular genetics; and 4) new developments in immunogenetics. Improvements in evaluation will continue as computers become faster and have more storage capabilities. Improved mathematical models that more nearly describe the biology of lactation will maximize estimation of genetic differences and reduce residuals. New reproductive technology could allow reduction of generation intervals two- to fivefold compared with present generation intervals and, combined with genetic markers, could markedly accelerate progress. Health problems in dairy cattle are expected to increase as production increases. Thus, selection for decreased incidences of health disorders will be needed, probably by selection of sires with improved general immunocompetence. Research is in the early stages of application of techniques of molecular genetics to animal breeding. Early uses will allow detection and alleviation of genetic defects. Eventually, marker genes that directly affect production and metabolic pathways that also affect production will be subjected to selection. The ability to foresee new and potentially useful techniques will be determined by scientific advancement of areas in which researchers are engaged; thus, accurate prediction far into the future cannot be expected.
Freeman
A E
AE
Department of Animal Science, Iowa State University, Ames 50011.
Lindberg
G L
GL
D000818:Animals; D002417:Cattle / Q000235:genetics* / Q000276:immunology; D003612:Dairying; D005819:Genetic Markers; D007121:Immunocompetence; D008957:Models, Genetic; D008967:Molecular Biology; D012099:Reproductive Techniques / Q000662:veterinary
D005819:Genetic Markers