Interpreting the Sire Summary - CCA Breed Improvement

Charolais Association for their cooperation and effort to ensure the success of our North American Charolais Sire
Summary.
The Canadian Charolais Total Genetic Evaluation, Calving Ease, and Scrotal Circumference EPDs are the result of a
joint project between the Canadian Charolais Association and the Lethbridge Research Centre (LRC) of Agriculture
and Agri-Food Canada (AAFC). The co-operative projects with AAFC have been, and continue to be, a great asset
to the Charolais breed in Canada. A very special thank-you is extended to Dr. Denny Crews, Ronda Crews and the
rest of the dedicated staff at AAFC Lethbridge for their tremendous research efforts and contributions.
A special thank you is extended to the Board of Directors, the Breed Improvement Committee, and to all Charolais
breeders enrolled on our CHARM performance program. Without this direction and valuable information we would
be unable to provide the purebred and commercial producers with this tool to assist in the selection of superior,
predictable Charolais seed stock.
North American Charolais Cattle Evaluation
Keith Bertrand, Del Little, Andra Nelson and Brett Middleton - The University of Georgia
Sire genetic values in the form of Expected Progeny Differences (EPDs) in this summary are a result of the analysis
of the combined data from the American International Charolais Association (AICA) and Canadian Charolais
Association (CCA). North American Cattle Evaluation (NACE) represents a joint venture between two Charolais
Associations to provide the breeders of Charolais cattle with EPDs that can be used to evaluate and compare
Charolais cattle for genetic merit across Canada and the United States (U.S.). NACE provides best linear unbiased
predictions (BLUP) of genetic merit (EPDs) on all Charolais cattle in Canada and the U.S. that have legitimate
records or relatives with legitimate records with either of the associations. Thus, NACE is a direct result of the data
collected through the performance and National Cattle Evaluation programs of both associations.
The genetic evaluation procedures use animal model technology to incorporate all available information into the
prediction of an individual’s EPD. The information that may be available for an individual includes: 1) progeny, 2)
relatives in the pedigree, particularly the sire and dam, 3) grand-progeny and 4) the individual’s own record. An
important aspect of the analysis procedure is that the superiority or inferiority of the individual’s mates are
accounted for when progeny are available. This reduces, if not totally eliminates, any potential biases associated
with specific matings of sires and dams. A second important aspect is the incorporation of genetic relationships
among animals in the analysis procedure. Accounting for these relationships incorporates information on all
ancestors and collateral relatives into the prediction of an animal’s EPD and also accounts for genetic trend.
Adjusting for genetic trend allows fair comparisons of young and older animals.
A third aspect of the analysis procedure is the use of a multiple trait model that analyzed birth, 205-day weaning
weight, 160-day post-weaning gain and scrotal circumference simultaneously. The yearling weight EPD that is
reported is the combination of the 205-day weaning weight and the 160-day post-weaning gain. Use of the four-trait
model helps to correct any bias that can be caused by the loss of records between weaning and yearling due to
culling at weaning and helps to correct potential bias in the birth weight EPD due to possible mistakes or
inaccuracies in the reporting of birth weights. Basically, the genetic relationships between the four traits help to
provide information that can be used to adjust the EPDs for those traits that have missing or misreported
information.
All of the sire, dam and non-parent (young animals) EPDs that result from this analysis can be directly compared for
their potential to transmit genes to their progeny. For example, if two Charolais bulls have weaning weight EPDs of
+20 and -10 lbs., respectively, and if they were bred to cows with similar genetic merit and the result calves were
raised in the same environment, then the expected difference between the average weights of the two groups of
calves would be 30 lbs. [20 - (-10)]. The milk EPD is expressed in pounds of weaned calf and provides information
on the resulting weaning weight difference between the grand progeny of two bulls based on the milk provided by
the bulls’ daughters. Therefore, if two bulls differ in their milk EPDs by 40 lbs., the average weaning weights of
their grand progeny would be expected to differ by 40 lbs., provided that the weaning weight EPDs of the bulls
grand progeny were similar and they were raised in similar environments.
The effects of contemporary group environments are adjusted out in the analysis procedure. This results in the
EPDs being computed as though all animals were in one large contemporary group. This is the reason EPDs are
comparable across herds and contemporary groups. The proper identification of the contemporary groups is of
critical importance to the overall accuracy of the analysis. Contemporary groups are defined as 1) animals of the