Understanding EPD s Expected Progeny Differences (EPDs) are the most effective tool available for comparing the genetic potential of bulls. EPDs predict how a bull’s calves are expected to perform compared to the calves of another bull. The difference between two bulls’ EPD values represents the expected difference in performance of their calves. EPDs help producers select bulls that match the goals of their operation such as calving ease, growth, maternal strength, or carcass value. Key EPD Traits • CE (Calving Ease) Percent of unassisted births when used on heifers. Higher numbers indicate easier calving. • BW (Birth Weight) Predicts calf birth weight in pounds. Lower numbers typically indicate lighter birth weights. • WW (Weaning Weight) Predicts calf weight at weaning. Higher values indicate greater growth to weaning. • YW (Yearling Weight) Predicts growth from birth to one year of age. • MLK (Milk) Predicts the pounds of weaning weight from a calf due to the milk production of a bull’s daughters. • MWW (Maternal Weaning Weight) Predicts the combined influence of milk and growth on a calf’s weaning weight. • MCE (Maternal Calving Ease) Predicts the ease with which a bull’s daughters will calve as first calf heifers. • STAY (Stayability) Predicts the percentage of daughters that remain productive in the herd to six years of age. • CW (Carcass Weight) Predicts carcass weight in pounds. • MRB (Marbling) Predicts marbling score and potential for higher quality grades. • REA (Ribeye Area) Predicts ribeye muscle size in square inches. $ Indexes combine several traits with economic values to estimate profitability. API (All Purpose Index) Evaluates sires used across the whole herd where daughters are kept as replacements and remaining calves are fed and sold. TI (Terminal Index) Evaluates sires used on mature cows when all offspring are sold on a carcass basis and no replacements are kept.
Indexes are expressed in dollars per cow exposed. The difference between two bulls indicates the expected profit difference.
If you keep replacement females, focus on API. If you sell all calves and retain no replacements, focus on TI.
These indexes allow buyers to quickly compare bulls and estimate long term value to their operation.
Rancher’s choice Bull Sale, March 28 I Philip, SD
Made with FlippingBook - Share PDF online