Cream of the Crop: Breeding Better Dairy Cattle

ARS scientists at Beltsville played a vital role in designing the BeadChip and are using it in genomics-based studies on dairy cattle. Beltsville geneticist Curt Van Tassell is leading development of a new genomic method to identify bulls that produce daughters with optimum milk production, calving ease, and other traits.

"Progeny testing," the method now used to determine a bull's genetic merit, is time-consuming and costly. At ARS's Bovine Functional Genomics Research Unit, Van Tassell, with ARS geneticists Tad Sonstegard and George Wiggans, is working to whittle down the cost of progeny testing to about $500 a bull.

Their approach is called "genome-enhanced improvement." It combines computer-aided statistical analysis with more than four decades' worth of records on dairy performance and conformation to help locate desirable genes.

Collaborating with the Beltsville team are professors Jerry Taylor and Robert Schnabel with the University of Missouri-Columbia; and Illumina, the San Diego firm that manufactures the BeadChip.

The researchers plan to examine a total of 53,000 SNPs from 12,000 cows and bulls representing several commercial dairy breeds and an ARS research population at Beltsville. Then they'll correlate SNP data to traits of interest, such as milk, fat, and protein production.

Eventually, information derived from the markers will help dairy producers streamline their identification and breeding efforts. And, Van Tassell says, cutting test costs while increasing the rate of genetic improvement in dairy cattle will help make the U.S. germplasm industry more competitive globally.

Agricultural Reasearch magazine, August 2008 Complete Article