“USMARC’s Germplasm Evaluation Program serves as a long-standing resource for current differences among U.S. beef breeds and enables annual updates to across-breed EPD (expected progeny difference) adjustment factors and breed of sire differences for growth and carcass traits,” said Dr. Larry Kuehn, Research Leader at the U.S. Meat Animal Research Center in Clay Center, Nebraska. Kuehn gave his presentation “Quantifiable Differences to Inform Breed Selection and Use” during the Beef Improvement Federation (BIF) Symposium July 4 in Calgary, Alberta, Canada.
Breed differences for new traits
In addition to sharing updates to across-breed EPD adjustment factors and breed of sire means for routine growth (birth, weaning, milk, yearling) and carcass (fat, marbling, ribeye area, hot carcass weight) traits, Kuehn shared results from more recent analyses for traits that are not included in these annual updates.
He shared breed differences for color stability of beef including chroma change and myoglobin concentration and breed differences for feed intake and feed efficiency. Additionally, he shared results of a study that estimated breed differences for mature cow weight, both adjusted and unadjusted for body condition scores. He also showed results from an analysis of cow lifetime productivity defined as cumulative weight weaned as a cow and depicted breed representation in quadrants of high mature weight/high weight weaned, high mature weight/low weight weaned, low mature weight/high weight weaned, and low mature weight/low weight weaned.
On the horizon
USMARC is working to provide EPDs for traits that are not part of routine genetic evaluations for bulls that contribute to the Germplasm Evaluation Program to the owners of the bulls and to the beef industry. These EPDs will be multi-breed and genomically enhanced and the target release date is at the end of 2024. Examples of traits include feed intake, fertility, disease resistance, tenderness and color stability.
Kuehn said, “We’ve long known that differences among breeds may not be consistent in all environments for all traits.” With that in mind, he shared high-level details relative to the ARS Grand Challenge that seeks to quantify genotype by environment by management (GxExM) interactions at the breed level given massive amounts of data would be needed to quantify this at a sire level. As an initial step towards this goal, the USMARC sent females and bulls to Beeville, Texas, and El Reno, Oklahoma.
The “2023 Across-Breed EPD Table and Improvements” information is posted to the BIF Website at beefimprovement.org/23acrossbreedepd.
To watch Kuehn’s full presentation, visit https://youtu.be/WguzojmHOjg. For more information about this year’s Symposium and the Beef Improvement Federation, including additional presentations and award winners, visit BIFSymposium.com.