BREEDIMPROVEMENT
that this bull would exceed that.As additional information is gained on an animal the accuracy values of their EPD increases, which results in a decrease in potential change. Assume that a second bull with a calving ease EPD of 5.8 had an accuracy value of 0.70; the two-thirds probability of potential change is Âą0.5 percent for a range of 5.3 to 6.3 for the true calving ease genetic merit (EPD). Even though the two bulls had the same EPD of 5.8, the second bull could be used with greater confidence of not having a true genetic merit below the 2.0 calving ease EPD minimum for this scenario. Table 1: Example of potential change in EPD associated with different accuracy values. For most commercial producers, the purchase of young, unproven, sires is reality and low accuracy values should not be a discouragement from using EPDs in selection decisions. Low-accuracy EPDs are still the best source of information available for making selection decisions on that trait. However, they can be used to help manage risk on traits that are of extreme importance to the beef cattle operation. In cases where there is little room for error, it is sometimes necessary to go to greater extremes on the EPD, for certain traits, when using low-accuracy bulls.
TABLE 1: POTENTIAL CHANGE Accuracy
0.1 0.3 0.5 0.7
CE
5.2 3.4 1.9 0.5
WW
14.7 11.4 08.2 04.9
YW
23.1 18.0 12.9 07.7
photo Š La ura Bode ll
Expected progeny differences provide beef producers with a reliable tool to make selection decisions. They are not perfect and there is error associated with all EPDs; however, every EPD has an accuracy value associated with it to help producers manage the level of risk they are willing to take for each trait they are selecting. The methodology for computing EPDs will likely continue to change over time and incorporating genomic information in many evaluations is a reality. With all of the successes associated with genetic evaluations it is likely that they will become even better and more accurate in the future. SPJ
contemporary grouping criteria for various traits ADAPTED FROM GUIDELINES FOR UNIFORM BEEF IMPROVEMENT PROGRAMS, 9TH EDITION
calving ease (direct), calving ease (maternal), and birth weight
1. Breeder-Herd Code 2. Year 3. Season (January-June, July-December) 4. Sex (bull, heifer) 5. Breed Composition 6. Birth Management Code 7. Service Type (embryo transfer calves)
1. Birth Weight Contemporary Group Criteria 2. Management/Pasture Code 3. Date Weighed 4. Weaning Sex (bull, heifer, steer) 5. Breed Composition 6. Service Type (embryo transfer calves)
1. Weaning Weight Contemporary Group Criteria 2. Management/Feeding Unit Code 3. Date Weighed 4. Yearling Sex (bull, heifer, steer)
1. Weaning or Yearling Weight Contemporary Group Criteria 2. Management/Pen/Feeding Unit 3. Days on Feed 4. Harvest Date 5. Grading Date 6. Carcass Sex (bull, heifer, steer) 7. Date on Feed 8. Breed of Dam
1. Weaning or Yearling Weight Contemporary Group Criteria 2. Management/Feeding Unit Code 3. Date Scanned 4. Sex (bull, heifer, steer)
1. Yearling Weight Contemporary Group Criteria 2. Heifer Pregnancy Management Code 3. Breeding Season Start and End Dates 4. Exposure 5. Breeding Pasture and/or Sire Effect
1. Breeder-Herd Code 2. Year 3. Date Measured 4. Age at Measurement (years) 5. Breed Composition 6. Birth Management Code
1. Breeder-Herd Code 2. Birth Year 3. Code of the Breeder Herd in which the Cow Produced a Calf 4. Breed Composition
1. Weaning or Yearling Weight Contemporary Group Criteria 2. Feed Efficiency Management/Feeding Unit Code 3. Days on Feed (or date on feed) 4. Date Scanned or Harvested 5. Sex (bull, heifer, steer) 6. Breed Composition
weaning weight
yearling weight and frame score
carcass traits
ultrasound body composition traits
heifer pregnancy
mature cow weight, height, and body condition score
stayability
feed efficiency
T H E S P E C K L E PA R K J O U R N A L
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