Interpreting the Sire Summary - CCA Breed Improvement

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.