EPD’s: What They Are and How to Use Them

Introduction EPDs = Expected Progeny Differences Progeny = Offspring, usually the offspring of the sire Differences = how the progeny of that sire differed from the progeny of other sires Expected = reflects the estimate is for a group of animals

EPD’s Today Information Overload Calving ease Pre-weaning growth Post-weaning growth Expectations of progeny of daughters Carcass traits Efficiency traits Value Genomic enhanced

Where to Begin BEGIN with the END in mind How and When do you market calves? Salebarn at weaning vs at slaughter with grid pricing Do you retain heifers or purchase replacement females Maternal traits vs terminal traits

Go Find Information Internet makes EPDs easily accessible Search features available for registration numbers Find the Percentile Ranking Chart for the Breed 50 th percentile is the median which will be very close to breed average Provides an idea of how the sire ranks compared to all other sires in the registry

Example 1. Scenario Herd consists of mature cows weighing 1175 lb Plan to use a Hereford bull on Angus cows Avoid calving problems Retain ownership Keep heifers

Example EPD’s BULLCEDBWWWYWMILKCEMCOW MW A EPDs B EPDs BREED AVG EPDs BULLCEDBWWWYW A RANK7%27%65%73% B RANK57%60%17%13%

Example EPD’s BULLCEDBWWWYWMILKCEMCOW MW B-A

Consider Trade-off’s Correlation Correlation is a measure of association between traits. Correlation may be positive or negative Heritability Variation in the expressed trait (such as weaning weight) due to genetics vs all genetic and environmental factors affecting the variation in the expressed trait.

Across Breed EPDs These are tables to adjust within breed EPDs for across breed comparison Useful when changing breed types to examine the EPD’s of current sire being used of one breed to potential sires of another breed

Example Across Breed EPD WW EPDEPD-AdjAdjusted WW Hereford Red Angus Diff ~0

Heterosis (aka Hybrid Vigor) When the offspring of a breed cross performance better than the average of either breed, this is called hybrid vigor. The further the two breeds are in type, the greater the hybrid vigor. Angus, Charolais, Angus x Charolais Desirable and undesirable traits of breeds and breed combinations should be considered when switching to a different sire breed.