Quick Reference to ASA EPDs and $ 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. Using API and TI: First, determine which index to use; if you’re keeping replacements use API, if not, TI. Then, just as with EPDs, 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 EPDs and $ indexes visit www.simmental.org.
Expected Progeny Differences (EPDs): EPDs are the most accurate and effective tool available for comparing genetic levels. In using EPDs, the difference between two sires’ EPDs represents the unit difference expected in the performance of their progeny. For example, if sires A and B have EPDs 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 EPDs is knowing what units they are expressed in. For example, if the above case referred to weaning weight EPDs, 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 EPDs rank him relative to other bulls in the breed. Calving Ease (CE): Percent of unassisted births when used on 1st calf heifers Birth Weight (BW) : Expressed in pounds and predicts the average difference that can be expected in an animal’s offspring compared to the average.
Weaning Weight (WW): Pounds of Weaning Weight Yearling Weight (YW): Pounds of Yearling Weight Milk (Milk): Pounds of Weaning Weight due to milk Stayability (STAY): Percent of daughters remaining in the cowherd at 6 years of age. Marbling (Marb.): Predicts the average difference Marbling score Rib-Eye Area (REA) Predicts the average difference in square inches of Ribeye $ Indexes: Though EPDs allow for the comparison of genetic levels for many economically important traits, they only provide a piece of the economic puzzle. That’s where $ indexes come in. Through well- conceived, rigorous mathematical computation, $ indexes blend EPDs and economics to estimate an animal’s overall impact on your bottom line.
ASA HYBRID BREED AVERAGES
% CE BW WW YW MLK STY MRB BF REA API TI Avg 12.50 0.20 75.50 116.90 23.80 14.60 0.36 -0.04 0.67 133.49 80.95
We were enrolled in the Calf Crop Genomics program, meaning all bulls sell with Genomically Enhanced EPD’s and Parental Verification. Genomic testing is a cost-effective and quick way to add information to what is known about an animal’s genetic potential. One way to think of the information gained is by asking how many progeny would this animal need to see a similar increase in the accuracy of the EPD for that trait? These are referred to as progeny equivalents. Typically, EPD’s on yearling bulls are of very low accuracy and are essentially pedigree estimates. Below are the progeny equivalents as of spring 2020. The way to interpret progeny equivalents is like adding over 25 calving ease records, 22 birth weights on progeny, etc. In other words, while a bull calf is still nursing, breeders can know an equivalent of 15 stayability records
on his daughters - something that would take years to generate through progeny testing. ADDING A GENOMIC TEST IS LIKE ADDING • 25+ Calving Ease Scores • 22 Birth Weights
• 25+ Weaning Weights • 25+ Yearling Weights • 8 Marbling Scores • 6 Ribeye Measurements • 15 Stayability Records
Bottom line is that the EPD’s provided on our bulls are more valuable than in years past because they come with greater accuracy to allow you to make more informed decisions!
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