10/06/1991

Across-Breed EPDS Could Make Comparison of Sires Easier for Commercial Cattle Producers

AUBURN, Ala.— In the future, accurate adjustment factors to form across-breed Expected Progeny Differences (EPD) could be available to commercial cattle producers, if regional differences and lack of structured crossbreeding data can be overcome, according to Lisa Kriese, assistant professor of animal and dairy sciences in Auburn University's College of Agriculture.

EPD values are currently only useful for comparisons within breeds of cattle due to genetic differences between beef breeds, but across-breed EPDs would be more useful to commercial producers because this would allow them to compare sires of different breeds and aid in bull selection.

Across-breed EPD concepts were first proposed by Larry Cundiff of the U.S. Department of Agriculture Meat and Animal Research Center, with Dave Notter of Virginia Tech, at the Clay Center in Nebraska, in 1989. They used data from a study designed to look at sire breed differences and came up with adjustment factors that could be used to compare EPDs among different breeds.

In 1990, John Hough, an assistant professor of animal and dairy sciences at the time, initiated a study at Auburn University that would mimic the Clay Center study, to see if adjustment factors found in the Southeast would be comparable to current adjustment factors.

The research was done at the Alabama Agricultural Experiment Station's Black Belt Substation in Marion Junction using Angus x Simmental cows bred to three lines of sires: (1) Hereford -- the control or base line for comparison, (2) Beefmaster alternated with Limousin and then Charolais and (3) Brahman alternated with Gelbvieh.

The first group of calves was born in 1991, and since then, data on birth weight, weaning weight and yearling weight for each year's calf crop has been collected and analyzed using models like those used at the Clay Center.

"We take measurements from the time they're born until they are ready for slaughter," Kriese said.

What Kriese has found from this research is that adjustment factors for the Southeast are not the same as those found in Nebraska, due to regional environmental differences.

"I truly believe it's going to be difficult to come up with across-breed adjustment factors that are going to work for all parts of the U.S.," she said. "Although it's something we need in the industry, right now we're at a stand still."

The problem is not the lack of knowledge on how to collect and use the data that could make across-breed EPDs possible, but the lack of sufficient data that would eliminate regional differences.

"We've got the methodology, but we must get people and organizations excited about keeping the records, analyzing data and educating producers," Kriese said.

Another problem is that group would be in control of collecting and analyzing the vast amount of data needed to make this possible, she said.

This study on across-breed EPDs at Auburn University will end in two years, and then Kriese may tackle another similar area of EPD research -- crossbred EPDs, which would allow for comparison between purebred cattle and crossbred cattle.

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By:
Anna M. Lee