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item Powell, Rex

Submitted to: International Conference for Dairy Producers
Publication Type: Review Article
Publication Acceptance Date: 5/3/2004
Publication Date: 7/14/2004
Citation: Powell, R.L. 2004. Programas geneticos para el ganado lechero en Estados Unidos [Genetic programs for dairy cattle in the United States]. Proceedings of the Conferencia Internacional sobre Ganado Lechero [International Conference on Dairy Cattle], July 14-16, 2004, Guadalajara, Mexico. p. 123-132.

Interpretive Summary:

Technical Abstract: Milk production in the United States was at an all-time high in 2003 and was relatively higher for cows on official Dairy Herd Improvement (DHI) testing. Although testing programs are more flexible, most tested cows have milk from one milking per month sampled by a DHI supervisor. Collected data are processed by one of five centers (DRPC), and management reports returned to farms. Once strictly regional, centers now compete to provide these services. Through cooperative agreement, the DRPC also send production data to USDA for use in computing genetic evaluations. Breed registry organizations maintain herdbooks, provide registry certificates, classify animals, and promote breed improvement. In 2003, artificial insemination (AI) organizations progeny tested over 1800 bulls in the United States. To obtain adequate records for reliable evaluation of young sires, they provide monetary incentives for use of this semen and participation in DHI testing services. Among Holsteins, only about 1 in 13 progeny tested bulls is returned to active service. About 70% of all U.S. milking cows are likely produced by AI; 96% of cows with DHI records including sire identification are by AI. The U.S. dairy industry is decentralized, with independent organizations carrying out production testing, breed registry, artificial insemination, and genetic evaluation, but these groups cooperate through the Council on Dairy Cattle Breeding. Genetic evaluations for yield of milk, fat, and protein; somatic cell score; productive life (longevity); calving ease (daughter and service sire); daughter pregnancy rate (female fertility); and conformation are computed quarterly. Three indexes are calculated to assist sire selection for the general (NM$), cheese (CY$), and fluid (FM$) markets. The emphasis given to traits in these indexes reflects the increasing proportion of milk used for manufactured products and the decline in fluid consumption, and the increased interest in reducing costs by improving fitness traits. Since 1995, U.S. evaluations have also been included in international sire evaluation calculated by Interbull. Although evaluations among countries are not perfectly correlated, evaluations including the additional data from foreign daughters and relatives are generally more accurate, and in most cases, Interbull evaluations are considered official in the United States. Genetic mapping of dairy animals continues to progress, and it is hoped that genetic evaluation procedures will account for genes that impact traits of economic value.