The availability of expected progeny differences, selection indexes and genomic ratings for a wide range of traits, genetic decisions can become complex and intimidating. The process can be simplified though, as Kansas State University cow-calf Extension specialist Bob Weaber, PhD., explained during last week’s Beef Improvement Federation conference.
A first step for commercial producers, Weaber says, is to set breeding objectives for the herd, targeting areas of emphasis such as fertility, calving ease, temperament or calf value. A ranch’s production system should help guide the breeding objectives. A ranch, for example, that sells calves at weaning and purchases crossbred replacement heifers can use terminal sires selected for moderate calving ease and high growth. Ranches that retain heifers from their own herd need to focus more on maternal traits in their bull selection, balanced with growth traits such as weaning weight. Producers who retain ownership through the feedyard need to consider yearling weights and carcass merit along with maternal or reproduction traits. For most producers in an integrated production system, Weaber says selection priorities should put about twice as much emphasis on reproduction as on growth and end product. For producers who sell calves at weaning, emphasis on growth and carcass traits should be even less.
Multiple-trait selection can be complicated by the number of EPDs available and the fact that some EPDs measure indicator traits, such as birth weight, instead of economically relevant traits such as calving ease. Use of selection indexes can help simplify the process, Weaber says, as the index combines EPDs into an objective measure of an animal’s relative merit for a group of traits.
Breed associations and seedstock producers have developed indexes to address specific breeding objectives, based on whether a producer sells calves at weaning or retains ownership. So the first step for the commercial producer, Weaber says, is to use market endpoints to guide them to the appropriate index. Once using the index, limit the use of other individual EPDs in selection.
Weaber says he would like to see more seedstock producers eliminate unnecessary EPDs, for adjusted weights and indicator traits from their catalogs, and use more selection indexes to help simplify bull selection.
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