A GUIDE TO EPDS
EXPECTED PROGENY DIFFERENCE (EPD) is the prediction of how future progeny of each animal are expected to perform relative to the progeny of other animals listed in the database. EPDs are expressed in units of measure for the trait, plus or minus.
Calving Ease Direct (CED) , expressed as a difference in percentage of unassisted births, with a higher value indicating greater calving ease in first-calf heifers. It predicts the average difference in ease with which a sire’s calves will be born when he is bred to first-calf heifers. Birth Weight (BW), expressed in pounds, is a predictor of a sire’s ability to transmit birth weight to his progeny compared to that of other sires. Weaning Weight (WW), expressed in pounds, is a predictor of a sire’s ability to transmit weaning growth to his progeny compared to that of other sires. Yearling Weight (YW), expressed in pounds, is a predictor of a sire’s ability to transmit yearling growth to his progeny compared to that of other sires Scrotal Circumference (SC), expressed in centimeters, is a predictor of the difference in transmitting scrotal size compared to that of other sires. Docility (DOC), expressed as a difference in yearling cattle temperament, with a higher value indicating more favorable docility in a sire’s offspring compared to another sire Maternal Milk (Milk), expressed in pounds of calf weaned, is a predictor of a sire’s genetic merit for milk and mothering ability in his daughters. In other words, it is the part of the calf’s weaning weight attributes to milk and mothering ability. Heifer Pregnancy (HP), is a selection tool to increase the probability or chance of a sire’s daughters becoming pregnant as first–calf heifers during a normal breeding season. A higher EPD is the more favorable direction, and the EPD is reported in percentage units. Marbling (Marb), expressed as a fraction of the difference in USDA marbling score of a sire’s progeny compared to progeny of other sires. Ribeye Area (RE), expressed in square inches, is a predictor of the difference in ribeye area of a sire’s progeny compared to progeny of other sires. Maternal Weaned Calf Value ($M), expressed in dollars per head, predicts profitability differences in progeny due to genetics from conception to weaning by decreasing mature cow size and improving docility, foot structure and fertility while maintaining weaning weights consistent with today’s production. Beef Value ($B) , expressed in dollars per carcass, represents the expected average differences in the progeny post-weaning performance and carcass value compared to progeny of other sires. This index assumes commercial producers wean all male and female progeny, retain ownership of these animals through the feedlot and sell on a carcass merit grid. Combined Value ($C) , expressed in dollars per head, which includes all traits that make up both Maternal Weaned Calf Value ($M) and Beef Value ($B) with the objective that commercial producers will replace 20% of their breeding females per year with replacement heifers retained within their own herd. The remaining cull heifer and steer progeny are then assumed to be sent to the feedlot where the producers retain ownership of those cattle and sell them on a quality-based carcass merit grid.
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