American Angus Association® Selection Tools
Calving Ease Direct (CED) , is expressed as a difference in percentage of unassisted births, with a higher value indicating greater calving ease in firstcalf 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 EPD (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 EPD (WW) , expressed in pounds, is a predic- tor of a sire’s ability to transmit weaning growth to his progeny compared to that of other sires. Yearling Weight EPD (YW) , expressed in pounds, is a predic- tor of a sire’s ability to transmit yearling growth to his progeny compared to that of other sires. Scrotal Circumference EPD (SC) , expressed in centimeters, is a predictor of the difference in transmitting ability for scrotal size compared to that of other sires. Docility (DOC) , is expressed as a difference in yearling cattle temperament, with a higher value indicating more favorable docility. It predicts the averagedifference of progeny from a sire in comparison with another sire’s calves. Calving Ease Maternal (CEM), is expressed as a difference in percentage of unassisted births with a higher value indicat- ing greater calving ease in first-calf daughters. It predicts the average ease with which a sire’s daughters will calve as first-calf heifers when compared to daughters of other sires. Maternal Milk EPD (Milk) , is a predictor of a sire’s genetic merit for milk and mothering ability as expressed in his daugh- ters compared to daughters of other sires. In other words, it is that part of a calf’s weaning weight attributed to milk and mothering ability. Mature Weight EPD (MW) , expressed in pounds, is a predictor of the difference in mature weight of daughters of a sire com- pared to the daughters of other sires. Mature Height EPD (MH) , expressed in inches, is a predictor of the difference in mature height of a sire’s daughters compared to daughters of other sires. Pulmonary Arterial Pressure EPD (PAP) , is expressed in millimeters of Mercury (mmHg), with a lower EPD being more favorable indicating a sire should produce progeny with a lower PAP score. PAP score is an indicator of susceptibility to high al- titude disease commonly experienced at elevations greater than 5,500 feet. Selection for this trait aims to improve the genetic potential for a sire’s progeny to have lower PAP scores thus a lower chance of contracting high altitude disease increasing the environmental adaptability of cattle living in mountain areas Maternal Weaned Calf Value ($M) , an index, expressed in dollars per head, predicts profitability differences from concep- tion to weaning with the underlying breeding objective assuming that individuals retain their own replacement females within herd and sell the rest of the cull female and all male progeny as feeder calves. The model assumes commercial producers will replace 25% of their breeding females in the first generation and 20% of their breeding females in each subsequent generation.
Traits included are as follows: calving ease direct, calving ease maternal, weaning weight, milk, heifer pregnancy, docility, ma- ture cow weight, claw set and foot angle. Carcass Weight EPD (CW) , expressed in pounds is a predictor of the differences in hot carcass weight of a sire’s progeny com- pared to progeny of other sires. Marbling EPD (Marb) , expressed as a fraction of the difference in USDA marbling score of a sire’s progeny compared to progeny of other sires. Ribeye Area EPD (RE) , expressed in square inches, is a predic- tor of the difference in ribeye area of a sire’s progeny compared to progeny of other sires. Fat Thickness EPD (Fat) , expressed in inches, is a predictor of the differences in external fat thickness at the 12th rib (as measured between the 12th and 13th ribs) of a sire’s progeny compared to progeny of other sires. Weaned Calf Value ($W) , an index value expressed in dollars per head, is the expected average difference in future progeny performance for preweaning merit. $W includes both revenue and cost adjustments associated with differences in birth weight, weaning direct growth, maternal milk, and mature cow size. Feedlot Value ($F) , an index value expressed in dollars per head, is the expected average difference in future progeny per- formance for postweaning merit compared to progeny of other sires. Grid Value ($G) , an index value expressed in dollars per head, is the expected average difference in future progeny performance for carcass grid merit compared to progeny of other sires. Beef Value ($B) , an index value expressed in dollars per head, is the expected average difference in future progeny performance for postweaning and carcass value compared to progeny of other sires. Combined Value ($C) , an index, expressed in dollars per head, which includes all traits that make up both Maternal Weaned Calf Value ($M) and Beef Value ($B) with the objective that com- mercial 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. Expected progeny differences (EPDs) directly influenc- ing a combined index: calving ease direct (CED) and maternal (CEM), weaning weight (WW), yearling weight (YW), maternal milk (Milk), heifer pregnancy (HP), docility (DOC), mature cow weight (MW), foot angle (Angle), claw set (Claw), dry matter intake (DMI), marbling (Marb), carcass weight (CW), ribeye area (RE) and fat thickness (Fat) Genomically Enhanced EPD Percentile Ranks, While per- cent ranks (1-100) are also provided to producers for each trait, GE-EPDs remain the selection tool of choice since they account for all sources of information including vital phenotypic mea- sures. All elements together provide the best possible resource for a producer making important genetic decisions.
SV Cattle Company
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