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EPD TERMINOLOGY
Expected Progeny Difference (EPD) - The expected difference in performance of a sire’s progeny compared to the performance of another sire’s progeny. Accuracy (Acc.) - a measure of reliability of an
EPD expressed between 0 and 1.0. Accuracies closer to 1.0 means the EPD is a more reliable estimate of a sire’s true genetic value for the trait. % Rank - Based on percentages, this indicates where a sire’s EPD ranks him in the entire population of his respective breed. Stayability (STAY - Red Angus & Simmental) -
The stayability EPD predicts the probability of a sire’s daughters staying in production to at least six years of age compared to daughters of another sire. Reported as a percentage, a higher value is desirable. ANGUS: Claw Set EPD (Claw) - is expressed in units of claw-set score, with a lower EPD being more favorable indicating a sire will produce progeny with more ideal claw set. The ideal claw set is toes that are symmetrical, even and appropriately spaced. Foot Angle EPD (Angle) - is expressed in units of foot-angle score, with a lower EPD being more favorable indicating a sire will produce progeny with more ideal foot angle. The ideal is a 45-degree angle at the pastern joint with appropriate toe length and heel depth. 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 altitude 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. Hair Shed EPD (HS) - is expressed in units of hair shed score, with a lower EPD being more favorable indicating a sire should produce progeny who shed their winter coat earlier in the spring. Selection for this trait should improve the genetic potential for a sire’s progeny to shed off earlier increasing the environmental adaptability of cattle living in heat stressed areas and producers grazing endophyte-infected (hot) fescue. Heifer Pregnancy EPD (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. Cow Energy Value ($EN) - expressed in dollars saved per cow per year, the EPD assesses differences in cow energy requirements for daughters of sires. A larger value is more favorable when comparing two animals (more dollars saved on feed energy expenses). $EN savings differences account for lactation energy requirements and mature size of cows. Maternal Weaned Calf Value ($M) - an index, expressed in dollars per head, predicts profitability differences from conception to weaning. The model assumes commercial producers will replace 25 percent of their breeding females in the first generation and 20 percent 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, Mature Cow Weight, Claw
Set and Foot Angle. 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 performance 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 value expressed in dollars per head, that blends both maternal and terminal indexes using information and relationships from 14 different traits. SIMMENTAL: All-Purpose Index (API) - expressed in net dollars returned per cow exposed, evaluates Simmental sires being used on the entire cowherd (bred to both Angus first-calf heifers and mature cows) with a portion of the daughters retained for breeding and the steers and remaining heifers fed and sold on a carcass grade and yield basis.
With the exception of shear force (tenderness), all EPDs are considered in this index. Terminal Index (TI) - expressed in net dollars returned per cow exposed, evaluates the merit of sires when bred to mature Angus cows and all progeny are fed and sold on a carcass grade and yield basis. Consequently, maternal traits such as milk, stayability and MCE are not considered in this index. SimAngus - SimAngusTM is a trademark of the
American Simmental Association. RED ANGUS: Profitability and Sustainability Index (ProS) - is an all-purpose index that covers economically relevant traits across all aspects of the beef supply chain from conception to carcass. This updated index will work as a combination of the already-existing HerdBuilder and GridMaster indexes, which include traits from conception to weaning, and postweaning through harvest, respectively. The ProS index is expressed in
dollars per head born. HerdBuilder Index (HB) - As the name indicates, implementation of the HerdBuilder index will assist producers in building profitable herds. The
Angus, ¼ Simmental), replacement heifers retained from within the herd, and all remaining progeny sold on a quality based carcass grid. GridMaster Index (GM) - While Red Angus has traditionally been known as a superior maternal breed, those who have retained ownership in
Red Angus calves know of their potential to excel in the feedyard and ultimately hang a premium carcass. The GridMaster index is built using the following production scenario: Red Angus sires mated to cows (resulting progeny ¾ Red Angus, ¼ Simmental) and all progeny sold on a qualitybased carcass grid. HEREFORD: Baldy Maternal Index (BMI$) - This is an index to maximize profit for commercial cow-calf producers who use Hereford sires in rotational crossbreeding programs on Angus-based cows.
Retained ownership of calves through the feedlot phase of production is maintained and the cattle are to be marketed on a Certified Hereford Beef pricing grid. Brahman Influence Index (BII$) - The Brahman
Influence Index is a maternally focused index that is based on a production system that uses
Brahman x Hereford cross cows. Progeny of these cows are directed towards a commodity beef market since Certified Hereford Beef does not accept Brahman influenced cattle. This index has significant weight on Sustained Cow
Fertility, which predicts fertility and longevity of females. There is a slightly positive weight on
Weaning Weight, Mature Cow Weight and Milk which accounts for enough growth but ensures females do not increase inputs. There is some negative emphasis on Dry Matter Intake, but a positive weighting on Carcass Weight which is anticipated to provide profitability in finishing non-replacement females and castrated males.
Marbling and Rib-eye Area are also positively weighted to keep harvested progeny successful for a variety of commodity based programs. This index targets producers that use Hereford bulls on Brahman influenced cows. Certified Hereford Beef Index (CHB$) - This is a terminal sire index, where Hereford sires are used on British-cross cows and all offspring are sold as fed cattle on a CHB pricing grid. There is no emphasis on milk or fertility since all cattle will be terminal. This index promotes growth and carcass. CHAROLAIS: Terminal Sire Index (TSI) - The AICA Terminal
Sire Index (TSI) is a formal method of combing
Expected Progeny Differences (EPD) – BW, WW,
YW, REA, CW, MARB and FAT – into one single value on which to base selection decisions. The
TSI uses estimates of the genetic relationships between traits with an economic default value based on three year rolling USDA data.
