Quick Reference to ASA EPD and $ Indexes Expected Progeny Differences (EPD): EPD are the most accurate and effective tool available for comparing genetic levels. In using EPD, the difference between two sires’ EPD represents the unit difference expected in the performance of their progeny. For example, if sires A and B have EPD of +10 and –5, a 15-unit difference would be expected in their progeny (moving from -5 to +10 yields 15 units). Key to using EPD is knowing what units they are expressed in. For example, if the above case re - ferred to weaning weight EPD, A would be expected to sire 15-pounds more weaning weight than B. If calving ease were the trait, A would be expected to sire 15-percent more unassisted births in first-calf heifers; in other words, if B sired 30 assists in a group of 100 heifers, we’d expect A to require 15 assists. A percentile-ranking chart is required to determine where a bull’s EPD rank him relative to other bulls in the breed. For percentile rankings or more detailed information about EPD and $ indexes visit www.simmental.org. Listed below are the units ASA EPD are expressed in: All-Purpose Index (API): Dollars per cow exposed under an all-purpose-sire scenario. (See below for more details.) Back Fat (BF): Inches of backfat. Birth Weight (BW) : Pounds of birth weight. Calving Ease (CE): Percent of unassisted births when used on heifers. Calving Ease (CE): Percent of unassisted births when used on heifers. Carcass Weight (CW): Pounds of carcass weight. Maternal Calving Ease (MCE): Percent of unassisted births in first-calving daughters. Milk (MLK): Pounds of weaning weight due to milk. Marbling (MRB): Marbling score. Maternal Weaning Weight (MWW): Pounds of weaning weight due to milk and growth. Ribeye Area (REA): Square inches of ribeye. Warner-Bratzler Shear Force (WBSF): Pounds of force required to shear a steak. Stayability (STAY): Percent of daughters remaining in the cowherd at 6 years of age. Terminal Index (TI): Dollars per cow exposed under a terminal-sire scenario. (See below for more details.) Stayability (STAY): Percent of daughters remaining in the cowherd at 6 years of age. Though EPD allow for the comparison of genetic levels for many economically import - ant traits, they only provide a piece of the economic puzzle. That’s where $ indexes come in. Through well- conceived, rigorous mathematical computation, $ indexes blend EPD and economics to estimate an animal’s overall impact on your bottom line. The same technology that led to the dramatic progress in swine, poultry and dairy genetics over the last several decades was used to develop the following $ indexes: All-Purpose Index (API): Evaluates sires for use on the entire cow herd (bred to both Angus first-calf heifers and mature cows) with the portion of their daughters required to maintain herd size retained and the remaining heifers and steers put on feed and sold grade and yield. Terminal Index (TI): Evaluates sire for use on mature Angus cows with all offspring put on feed and sold grade and yield. Weaning Weight (WW): Pounds of weaning weight. Yearling Weight (YW): Pounds of yearling weight. Yield Grade (YG): Yield grade score. $ Indexes
Using API and TI: First, determine which index to use; if you’re keeping replacements use API, if not, TI. Then, just as with EPD, zero in on the unit difference between bulls. (As described above, index units are in dollars per cow exposed.) The difference can be used to determine how much a bull is worth compared to another. Or, put another way, how much you can pay for one bull compared to another. For example, when buying an all-purpose-type sire, you can quickly figure a bull scoring +100 for API is worth an extra $6,000 over a +50 bull if both are exposed to 30 cows over 4 years ($50 diff. x 30 hd. x 4 yr. = $6,000). A percentile-ranking chart is required to determine where a bull’s index value ranks him relative to other bulls in the breed. For percentile rankings or more detailed information about EPD and $ indexes visit www.simmental.org. Genomically Enhanced EPD Genomically Enhanced Expected Progeny Differences (GE-EPD) are a game-changer for commercial, seedstock, and all beef producers in between. ASA currently offers two different genomic panels to match your goals: the GGPuLD or the GGP100K. In the case of the GGP100k, the panel evaluates the molecular makeup of approximately 100,000 specific locations on the animal’s genome, some of which have influence on various traits we predict (growth, carcass, stay, etc). The difference between GE-EPD and standard EPD is mostly seen in the form of increased prediction accuracy. Animals that have GE-EPD have significantly improved accuracy for all EPD as young animals. The way this improvement in prediction accuracy can be measured is by reflecting any improvement in a progeny equiva - lent. A progeny equivalent is the amount of progeny an animal would have to have born, measured for a trait, and reported to the ASA to receive the same increase in accuracy from a genomic panel. In the case of most of the growth traits, it would take ~25 progeny before a non-genotyped animal would receive the same prediction accuracy as a genotyped animal. Important GE-EPD distinctions A genomic panel is not guaranteed to move EPD in a favorable direction. In fact, all animals have equal opportunity to have EPD move in a favorable or unfavorable direction after a test. The real value in performing a genomic panel on groups of young animals is by increasing accuracy of the prediction. This allows potential purchasers to have more confidence in the predictions, as well as increasing the rate of genetic progress in their herds. You must allow at least one and up to two weeks from the date a genomic sample finishes at the lab for those results to be incorporated into the genetic evaluation. Phenotypes are still needed to continue to predict traits with accuracy. A genomic test will improve the accuracy of low- to medium-accuracy animals, but genomics alone can never replace the need for phenotypic measurements. An important fact: While genomic tests add accuracy to low-accuracy animals, they can never replace reporting phenotypic data. For genomics to continue to have value, it is vital that breeders continue to submit quality phenotypic data.
CE BW WW YW ADG MCE MILK MWW STAY DOC CW YG MARB BF REA API TI 11.40 0.00 78.00 121.30 0.27 7.00 23.90 63.20 15.10 12.70 38.40 -0.18 0.39 -0.03 0.69 135.20 82.80 2026 Average Hybrid Simmental EPDs CE BW WW YW ADG MCE MILK MWW STAY DOC CW YG MARB BF REA API TI 9.80 1.30 79.50 118.50 0.25 5.70 23.20 63.30 15.50 11.80 33.40 -0.35 0.17 -0.07 0.88 132.50 81.60 2026 Average Purebred Simmental EPDs
19 Saturday, March 7, 2026 :: 1 PM CST :: at the Farm 39088 224th St. Alpena, SD
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