|Van Tassell, Curtis - Curt|
Submitted to: Animal Breeding and Animal Genetic Resources Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/15/2001
Publication Date: N/A
Technical Abstract: The Holstein-Friesian dairy cow is undergoing rapid genetic change. Annual increase in genetic merit for protein yield is over 1% of the phenotypic mean in the United States. Those gains are achieved through intensive selection both within and across countries. Although selection goals vary somewhat among countries, the same top bulls have been used globally. The international popularity of a few bulls has led to increases in inbreeding and a rather small effective population size. This trend has been accelerated by recent improvements in international comparisons of bulls. Strategies to preserve genetic diversity and slow the rate of increase in inbreeding are being developed. Analysis of DNA provides an opportunity for more accurate selection decisions and parentage verification. New genes for the Holstein-Friesian population may be obtained through crossbreeding and, in some limited cases, through transgenics. However, mass selection will continue to be the most important method of change. In the future, genetic evaluation systems are expected to become more accurate through better modeling and inclusion of DNA marker information. Mating programs will be more widespread so that inbreeding can be minimized and dominance relationships used. Further consolidation of breeding companies may lead to a change in the structure of the genetic improvement program. Adoption of new reproductive technologies such as semen sexing, cloning, and improvements in oocyte recovery also may cause changes in the dairy cattle industry.