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Title: DIRECT SELECTION FOR GENETIC IMPROVEMENT OF HEALTH AND FITNESS TRAITS IN THE UNITED STATES DAIRY POPULATION

Author
item Norman, H
item Vanraden, Paul
item Van Tassell, Curtis - Curt

Submitted to: Beltsville Agricultural Research Center Symposium
Publication Type: Proceedings
Publication Acceptance Date: 9/10/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Increases in the efficiency of dairy animals help to provide the world's needed food supply. To improve production efficiency, a strong genetic improvement program must be maintained. This is achieved in the U.S. through a cooperative relationship between several organizations and the Animal Improvement Programs Laboratory (AIPL). AIPL is responsible for maintaining a national database that contains information on pedigree, milk and component yields, and a number of health and fitness traits related to economic merit. The database is used for international research by AIPL personnel and cooperating research organizations throughout the world. An objective is to determine the economic values of a number of health traits and develop measures of overall merit. This research allows more accurate characterization of dairy animals with useful germplasm for increased productive life and improved disease resistance. Selection for overall merit has resulted in some shifts in trait emphasis to improve or prevent deterioration in some fitness traits since implementation. The economic index used between 1994 and 2000 gave emphasis to the yield traits, to productive life, and to low milk somatic cell scores. The annual genetic improvement for productive life .3 to .9 months for the breeds. There has been little genetic change in somatic cell score over the last five years. AIPL calculates genetic evaluations for calving ease in cooperation with the National Association of Animal Breeders. Much of the effort is directed toward using high calving ease bulls on heifers. Phenotypic and genetic trends in calving difficulty are increasing. Phenotypic measures of reproductive performance have been deteriorating over the last two decades.