Technical Keynote Session 4

Across-Breed EPD Tables Adjusted

By Troy Smith

Since genetic evaluation of breeding animals is based on breed-specific data, the resulting expected progeny difference (EPD) values are not comparable across breeds. This can be frustrating to commercial cow-calf producers whose breeding programs involve more than one breed. However, for most of two decades, animal scientists at the U.S. Meat Animal Research Center (USMARC), Clay Center, Neb., have calculated adjustment factors which allow comparison of the genetic merit of individuals representing different breeds.

During the 2009 Beef Improvement Federation (BIF) symposium, USMARC scientist Larry Kuehn reported that the latest adjustments to across-breed EPD (AB-EPD) tables have been completed. Kuehn said EPD tables have been adjusted to breed difference for birth year 2007.

“Factors are derived by adjusting estimates of breed differences from data at USMARC, to the average EPD of bulls sampled in the Germplasm Evaluation Program,” Kuehn explained. “To use the factors, a producer simply adds the factor to the EPD calculated by each breed association in individual analysis.”

Kuehn said adjustment factors are calculated for birth, weaning and yearling weight, maternal milk, and carcass traits (marbling ribeye area and fat depth) for 18 different breeds. That includes this year’s addition of Chiangus and Santa Gertrudis. More phenotypic data also has been added to a model offering improved estimates of breeding differences.

“I think we’re making a better model that uses information better,” Kuehn stated.

To see the adjustment factors, click here.

Editor’s Note: This summary was written under contract or by staff of Angus Productions Inc. (API). To request reprint rights contact Shauna Rose Hermel, editor, at 816-383-5270. PowerPoints are posted with permission of the presenter and may not be reproduced in whole or in part without the express permission of the presenter.

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.