‘Expected Progeny Differences’ in beef cattle

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By David Harrison

Expected Progeny Differences, or EPD, may actually be the best tool beef producers have to use in the genetics of their herds.

The breed average EPD provides a benchmark to compare beef cattle’s genetics. They are averages for the animals included in that run of genetic evaluation.

Many associations split the breed averages into those for proven sires, young sires, dams and non-parents. Some breeds traditionally had a base year where the EPD were set to zero, so any difference from zero represents a difference from the base year. However, some breeds may vary from the base-year idea.

EPD values are divided into several types. Growth traits EPD are the standards for all breeds including birth weight, weaning weight, milk, yearling weight and height, total maternal and mature weight and height.

Reproductive trait EPD includes scrotal circumference, gestation length, calving ease direct, calving ease maternal and heifer pregnancy. Carcass trait EPD includes carcass weight, ribeye area, fat thickness, marbling, retail product, yield grade, tenderness, ultrasound and percent intramuscular fat.

Some other EPD trait inclusions are stayability, as an indicator of bulls’ daughters longevity in the cow herd; maintenance energy, which refers to the energy a cow needs to maintain herself; docility, a measure of the behavior of bulls’ calves as they leave the chute; and pulmonary arterial pressure, which provides an indicator of longevity in the cowherd.

Each breeder must ultimately set their own selection criteria. One might think the simplest thing would be to just pick the highest EPD and believe they are the best. But it’s not that simple. Some traits have higher heritability than others, and a producer has to decide what’s most important.

An EPD can’t be used to compare bulls and cows of different breeds. Check out the different breed associations websites for their EPD information.