2004 Across-Breed EPDs Unveiled

Dale Van Vleck provided an update of the across-breed EPDs established through the Germplasm Evaluation (GPE) project at the Roman L. Hruska U.S. Meat Animal Research Center.
This year there were relatively few changes to the across-breed expected progeny differences (AB-EPDs), reported Dale Van Vleck, University of Nebraska, Lincoln. The animal geneticist reported the 2004 adjustment factors for calculating AB-EPDs established through the Germplasm Evaluation (GPE) project at the Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Neb.

Van Vleck presented factors to adjust the EPDs of 17 breeds to a common birth year of 2002 for birth, weaning and yearling weight and EPDs of 15 breeds for the milk component of maternal weaning weight (see Table 1).

Birth Wt. Wean wt. Yrlg. wt. Milk
Hereford 3.4 -2.0 -13.7 -17.8
Angus 0.0 0.0 0.0 0.0
Shorthorn 7.8 31.4 44.5 12.1
South Devon 6.7 21.7 40.8 3.5
Brahman 13.0 34.8 -4.4 24.6
Simmental 6.4 22.4 21.9 10.0
Limousin 4.5 1.8 -19.9 -15.9
Charolais 10.5 38.4 53.4 2.6
Maine Anjou 6.7 17.6 5.5 7.6
Gelbvieh 5.4 7.1 -21.1 1.7
Pinzgauer 7.7 28.3 25.5 6.1
Tarentaise 3.6 30.1 13.4 17.8
Salers 4.9 30.7 46.1 9.0
Red Angus 3.6 -1.4 0.7 -7.8
Braunvieh 6.5 30.0 13.9 22.2
Brangus 5.7 20.0 20.4 —
Beefmaster 9.7 39.0 37.9 —
Cycle 7 of the Germplasm Evaluation (GPE) project was designed to re-evaluate what the seven most prominent beef breeds in North America, as determined by annual registrations. Included were Angus, Hereford, Charolais, Limousin, Simmental, Red Angus and Gelbvieh.
“Bulls of different breeds can be compared on a common EPD scale by adding the appropriate table factor to EPDs produced in the most recent genetic evaluations for each of the 17 breeds,” Van Vleck said.

Cycle 7 Insights
Cycle 7 of the GPE project reveals how much more rapidly improvement can be made when EPDs are available to help guide selection decisions, Larry Cundiff told the Genetics Prediction Committee.

“What we refer to as a cycle is like a separate experiment that involves a set of sire breeds, usually six or seven different sire breeds mated to cows of two or more breeds,” Cundiff explained while providing an overview of the project. Cyle 7 was designed to re-evaluate what had become the seven most prominent beef breeds in North America, as determined by annual registrations. Included were Angus, Hereford, Charolais, Limousin, Simmental, Red Angus and Gelbvieh.

“The differences today among the seven breeds are not as great as they were 30 years ago for weaning weight and most of the traits we evaluate,” Cundiff said, noting that the British breeds have closed the gap on the Continental breeds in terms of growth.

Conversely, for traits that have not been widely evaluated for long, little change in breed differences has occurred. He pointed out that differences in the carcass traits such as marbling and tenderness are about the same magnitude today as they were 30 years ago.

Revealing a few highlights of the study, Cundiff said that while Simmental had relatively high birth weights, calving ease scores for the breed were comparable to the British breeds. He also noted growth curve changes, using Angus as an example. Progeny sired by the light-birth-weight Angus cattle are going to have smaller mature weights, he said.

Cundiff said it’s too early to evaluate differences in reproduction traits, since the cows are just 2 years old. “We’ve never found significant reproduction differences in these breeds,” Cundiff reported, “probably because they are all managed to meet their nutrient requirements.”

Other noted differences for the Cycle 7 evaluation include the use of legacy sires in addition to young sires representative of the breeds, the mating of F1 cows to F1 bulls, multi-sire pasture-breeding using DNA parentage verification, and using Charolais- and Simmental-cross cows. Blood samples have been collected to provide DNA on all the calves produced in cycles 5, 6, 7 and 8.

These will require changing the model used to evaluate the data, Cundiff said. “We’re wanting to establish a design where we can do a multi-breed evaluation, estimate the breeding effects, estimate the heterosis effects, and at the same time estimate the quantitative trait loci (QTL) effects in an experiment where you can estimate one independent of the other.”


cutline

“As a data processor or EPD service provider, we have an obligation to ensure the EPDs are as reliable as possible given the pedigree and performance information that we have available,” said Colorado State University’s Dorian Garrick in expressing the importance of validation to the Genetic Prediction Committee. “We want these EPDs to be fit for their purpose.”


– by Shauna Rose Hermel