Interpreting the Sire Summary - CCA Breed Improvement

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The heritability estimates and genetic correlations given below are those used in the North American analysis (only growth traits) and in the Total Genetic Evaluation (all traits except Milk). Heritabilities are on the diagonal and genetic correlations on the upper diagonal. TGE parameters were estimated using C to C and CHARM data. Trait CE BWT WWT PWG Milk SC CWT REA Fat PLY Marb Calving Ease 0.11 -0.65 Birth Weight 0.50 0.47 0.22 0.14 0.39 0.21 -0.21 0.21 0.30 Weaning Weight 0.25 0.49 -0.32 0.25 0.79 0.19 0.30 -0.25 0.14 Post Weaning Gain 0.31 0.35 0.49 0.38 0.21 0.06 -0.38 Milk 0.14 0.00 Scrotal Circumference 0.49 Carcass weight 0.33 0.47 0.18 -0.05 0.21 Rib-eye area 0.43 -0.35 0.72 0.10 Fat thickness 0.39 -0.88 -0.19 Lean yield 0.46 0.24 Marbling score 0.34 Expected Progeny Differences (EPDs) 1) EPDs are a very simple to understand and easy to use selection tool for the purebred and the commercial cattlemen. 2) EPDs are the most accurate means to date for estimating the true breeding value of an animal in regard to certain economically important traits. 3) EPDs provide a genetic description for the traits included in the Charolais Sire Summary – calving ease, birth weight, weaning weight, yearling weight, scrotal circumference, milk, total maternal, as well as carcass traits - carcass weight, rib eye area, back fat thickness, lean yield and marbling score. 4) EPDs are expressed in the actual unit of measure for a given trait. As an example, EPDs for traits such as birth weight, weaning weight and yearling weight are expressed in pounds. The tables below shows how the EPDs of two bulls within the North American Cattle Evaluation may be compared to estimate the differences that can be expected in progeny performance. Birth WT EPD (ACC) Wng WT EPD (ACC) Ylg WT EPD (ACC) Milk EPD (ACC) Tot Mat EPD (ACC) Sire A +3.5 (.94) +35.0 (.93) +60.5 (.85) +12.5 (.78) +30.0 (.83) Sire B -1.0 (.92) +20.0 (.90) +40.0 (.83) 0.0 (.81) +10.0 (.84) Difference 4.5 15.0 20.5 12.5 20 Based on the values given, you would expect the average weights of progeny by Sire A to exceed the average weights of progeny by Sire B by 4.5 lbs at birth, 15.0 lbs at 205 days and 20.5 lbs at 365 days, given they were mated to cows with the same genetic merit and the resulting calves were raised in the same environment. Thus, we could expect that if large numbers of daughters from the above matings were put into production, the progeny of Sire A’s daughters would average 20 lbs more than the progeny of B sired daughters at weaning. The maternal influence (milk and mothering ability) supplied by the daughters of Sire A would account for 12.5 pounds of this weight advantage. Another 7.5 pounds could be attributed to growth genetics (1/2 the weaning weight difference) from the daughters of Sire A resulting in a 20 lb overall advantage for sire A for Total Maternal.
Predicted Mating EPDs Rather than using EPDs for individual animal selection or culling decisions it is also possible to predict the outcome of a proposed mating by averaging the EPDs of the sire and dam in question. This allows us to estimate the genetic merit of a proposed breeding without actually investing all the time and effort into breeding the animals unless there is potential to produce an animal of superior genetic merit. The table to follow gives an example of how you can predict the EPDs for the progeny of a proposed mating. Birth WT EPD (ACC) Wng WT EPD (ACC) Ylg WT EPD (ACC) Milk EPD (ACC) Tot Mat EPD (ACC) Sire +4.0 (0.76) +9.2 (0.66) +25.2 (0.59) +4.6 (0.50) +9.2 (0.55) Dam -0.7 (0.42) -0.4(0.57) +4.3 (0.52) -4.1 (0.49) -4.3 (.52) Progeny Est. +1.65lbs +4.4lbs +14.75lbs +0.25lbs +2.45lbs Genetic Trend The average EPD by birth year for animals born in successive years illustrates changes in the breed’s genetic merit for each trait over time. Genetic trends indicate where our breed has been, where it is headed and how fast it is moving. The first graph shows the genetic trend for Calving Ease, Birth Weight, Weaning Weight, Scrotal Circumference, Total Maternal, Milk, and Carcass Weight. The second chart has genetic trends for Ribeye Area, Back Fat, Intramuscular Fat Percentage, and Percent Lean Yield.
Page 2 and 3: Introduction Mark Lowerison, Dr. Bo
Page 4 and 5: same sex, 2) animals of similar age
Page 8 and 9: Base In the North American Charolai
Page 10 and 11: Possible Change Values ACC CE BWT W
Page 12 and 13: Critères de publication Taureaux
Page 14 and 15: Name Of Bull Date of Birth Reg No T
Page 52: Multi-trait analysis - a genetic ev

Interpreting the Sire Summary - CCA Breed Improvement

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