How to Analyze Beef EPDs

Analyzing EPDs on beef cattle requires study, planning and concentration. "EPD" is the abbreviation for expected progeny differences that measure the genetic potential of an animal. Most breed associations provide EPDs in an annual sire summary. The breed association collects performance data such as birth weights on an animal and its ancestors and other relatives including parents, grandparents, brothers and sisters. The performance data is used by breed associations to calculate EPDs using complex statistical equations and models. Performance data used to calculate EPDs must be from purebred cattle of the same breed to be reliable. EPDs are commonly used by cow/calf producers to select herd sires.

Things You'll Need

  • Current sire summary for your breed of cows
  • Red pencil
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Instructions

    • 1

      Determine which EPDs are the most important to produce the desired characteristics in your cattle. The most popular EPDs are calving ease, birth weights, weaning weights, maternal milk production and yearling weights. Write a breeding plan that encompasses the use of desired EPDs.

    • 2

      Obtain a current sire summary from your breed association and compare EPDs from the bulls that fit your breeding plan. Scott Greiner of Virginia Cooperative Extension explains how to compare EPDs. He uses the example that Bull A has a +5 birth weight EPD and Bull B has a +1. Based on these numbers, Bull A would be expected to sire calves that average 4 pounds heavier at birth than calves sired by Bull B.

    • 3

      Circle all the listed bulls with a red pencil, that have EPDs matching your breeding plan. Then check the percentile ranking of each EPD for the bulls you circled. Percentile ranking tables are published in sire summaries and are used to determine where a bull ranks in his breed for certain traits. For example, a bull may be ranked in the top 10 percent of his breed for calving ease and in the bottom 20 percent for weaning weights. Percentile rankings help pare the list of bulls in which you are interested.

    • 4

      Compare the bulls on your remaining list for EPD accuracy. Accuracy is the relationship between estimated EPDs and true EPDs for an animal. This relationship, as explained by Greiner, is expressed as a number between zero and one. As the accuracy value approaches 1.0, the reported EPD is more likely to represent the true genetic merit of the animal. EPD accuracies are an important genetic measure and should be used to further pare the selected bull list.

    • 5

      Contact owners listed in the sire summary to obtain bull prices once your selected list is completed by using EPDs, percentile rankings and accuracies.