The Angus Journal is a monthly magazine known for in-depth coverage of American Angus Association programs and services; the Angus business; herd management techniques; and advertising reflecting genetics herd philosophies.
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136 n ANGUSJournal n January 2015 T he best criterion for genetic selection is the genomically enhanced expected progeny difference (GE-EPD), Dan Moser told a standing-room-only crowd in Kansas City, Mo., Nov. 4. The president of Angus Genetics Inc. (AGI) and director of performance programs for the American Angus Association addressed the group during the breed improvement breakout session at the Angus Means Business National Convention & Trade Show hosted Nov. 4-6 at the KCI Expo Center in Kansas City. DNA testing provides opportunity to characterize animals at a younger age, which reduces the risk involved in using a young animal if you are seeking to make directional change in a trait, Moser said. "It doesn't totally take away the risk, but it lessens the risk, because of what we know about an animal that's too young to be progeny tested." Even though it might be tempting to focus on the DNA information only, Moser encouraged cattlemen to focus on the GE- EPD, which includes all the information. While DNA is the new, exciting technology, birth-weight scales are good technology, too, he noted. "That tells us some things that the DNA by itself doesn't tell us." Moser explained how GE-EPDs are calculated and why they are recalibrated. Calculating traditional EPDs, he explained, involves combining (1) pedigree information, (2) performance information on the individual of interest and (3) progeny performance (see Fig. 1). Each of the three inputs is weighted in the equation according to how much information it contributes. As more performance information is available on the animal, it plays a greater role in the calculation than pedigree, and as progeny data accumulate, they are weighted more heavily than pedigree or individual performance. "It gets the most weight because it's the most refective of the animal's merit," Moser explained, "and the rest of these things stay in the background on the most proven sires." The only difference between traditional EPDs and GE-EPDs is the addition of genomic testing as a fourth source of information, he noted, emphasizing that pedigree, performance and progeny performance are still important (see Fig. 2). While addition of information from pedigree, individual performance and progeny information happens in a sequence, information from genomic testing can happen at any time, Moser pointed out. "It could happen on a baby calf." When the genomic information is added doesn't matter, he added. Weighting of the factors is determined by how much information it provides to that particular evaluation so "we have the optimal number that does the best job of describing the animal." @ "The database that the American Angus Association has, combined with genomic samples, is unrivaled throughout the industry. The rate at which this technology is being adopted is really making a difference in our population and gives us even more powerful tools to move forward," said Dan Moser. GE-EPD Best Measure Fig. 1: Traditional EPDs Fig. 2: GE-EPDs Combining all the information that's known on an animal for a particular trait, the genomically enhanced expected progeny difference provides most comprehensive look at an animal's genetic merit. by Shauna Rose Hermel, editor PHOTO BY SHAUNA ROSE HERMEL