Technical Keynote Session 1

Genomic Evaluation Prevalent
in the Dairy Industry

By Troy Smith

During the 2009 Beef Improvement Federation (BIF) committee presentations addressing emerging technologies and advancements in selection decisions, University of Melbourne (Australia) veterinarian and geneticist Mike Goddard explained that practical application of genomic evaluation is more advanced in the dairy industry, compared to the beef cattle industry. Goddard explained that all major dairy countries are applying selection based on a panel of genetic markers to estimate breeding value (EBV) or expected progeny difference (EPD) among animals.

This requires a reference population that has been genotyped for markers associated with economically important traits. In dairy cattle, Goddard said, this has usually consisted of progeny-tested bulls. However, Goddard says future reference populations will also include females.

The reference population is used to estimate a prediction equation for breeding value from marker genotypes. The prediction equation can then be applied to genotyped bulls and heifers that do not have individual records or progeny. With increased size of reference population, Goddard said, comes increased accuracy of the prediction equation. It is possible to predict an animals breeding value for milk yield, for example, almost as accurately using markers as with a progeny test.

“Applying intense selection for high-accuracy bulls and selection for the best females promises to double the rate of genetic improvement,” Goddard said.

A potential consequence of whole-genome-based selection is an eventual decline in the use of artificial insemination (AI), he said. “Improvement in bulls raised for use naturally, might reduce the previous AI advantage.”

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The 41st BIF Research Symposium and Annual Meeting was hosted by the California Beef Cattle Improvement Association and the California Cattlemen's Association. For more information, visit www.bifconference.com or www.calcattlemen.org/bif2009.html.