Making Genetic Selections
Selecting for any one trait while ignoring others does not lead to a commercially successful livestock production. The key is balance in selecting for all traits that affect profit, both short- and long-term.
However, balance need not mean “equal.” Strong selection pressure can be put on a few traits that greatly improve Certified Angus Beef ® acceptance rates without compromising other areas.
- EPD recommendations
- Understanding EPDs
- DNA Selection
Below are general recommendations for selecting a herd bull or AI sire to target a quality endpoint of the Certified Angus Beef ® brand. When choosing sires that are right for your herd, it is important to consider marketing goals in addition to economically relevant traits. Using EPDs, you can select sires to compliment your maternal goals without sacrificing the ability to improve carcass merit of calves not retained on the ranch. Targeting the Brand recommendations are 50th percentile or better for marbling EPD and $ Grid of non-parent Angus sires. Actual EPD minimums are below, and are based on percentiles from the Spring 2017 Angus Sire Summary.
A note on the accuracy (ACC) of EPDs or the reliability that can be placed on the EPD: When this number is close to 1.0, you can be more confident of the results in the next generation. The number of progeny and ancestral records in the database, along with genomic testing results, largely determine accuracy. When selecting an AI sire, consider utilizing bulls with high-accuracy carcass EPDs. When purchasing a herd sire, consider those that have been DNA tested and have genomic enhanced EPDs–as they will have greater accuracies.
Expected Progeny Differences (EPDs) aren’t just for seedstock cattle producers. They comprise a useful tool that you should use every time you buy breeding stock for your commercial cow herd, and maybe even when you buy steers to feed.
In concept, EPDs are the expected differences in performance and carcass quality of an animal’s sons or daughters, compared to a “zero base” that relates to foundation stock or a standard data year.
records tell you is
needed to complement
the maternal base.
Commercial cows generally do not have known EPDs, but that shouldn’t prevent producers from using EPDs effectively. After all, sire selection affects half the genetics of your calves, and you can shop for bred replacement females based partly on their sire EPDs. Evaluate what your records tell you is needed to complement the maternal base.
Here are a couple examples to help illustrate how reading EPDs can impact your herd:
- Consider Bull A with a +40 EPD for weaning weight and Bull B at +20. On average, you can expect calves from Bull A to wean 20 lb. heavier than those from Bull B.
- Consider Bull C with a marbling EPD of –0.20 units, and Bull D at +0.20 units. On the average, calves would differ by a marbling score of 0.40. Is that important? Yes, because many of your calves can end up near the Choice-Select line of 5.0, or the premium Choice line of 6.0.
EPD traits are correlated to high, medium or low degrees, positively or negatively, and with accuracy from a high of .99 (time proven) to less than .40 (best guess). When one trait is negatively correlated to another it means that, on the average, the value of that second trait will decrease as the value of the first increases. This is often called antagonism, and has been used as a reason to ignore or choose between certain traits in selection, but that can be a mistake.
Today, EPDs are backed by more data than ever before. Many registered Angus breeders are using DNA to produce genomically-enhanced EPDs, which are especially helpful in cultivating more information on younger animals. The American Angus Association is leading the industry, showing how DNA can be incorporated into a whole suite of selection information.
Always remember the EPD toolbox is all about averages: There are often individual sires that defy antagonisms and allow selection for several traits simultaneously. That allows for real progress and greater consistency in the beef supply.
Additional Resources: Genomic-Enhanced EPDs
First there was eye appeal, then breeding values and sire summaries. Now expected progeny differences (EPDs) are the basis of many genetic decisions, but DNA technology is opening a whole new horizon of opportunities.
The use of genomics testing for DNA markers can make EPDs more reliable and maximize the value of an animal’s genetic profile. “Integrity of pedigree is everything,” says Kevin Millner of Zoetis. “Genomics testing does not replace EPDs; it enhances them.”
Purebred breeders aren’t the only ones who can benefit from the technology. Tests, made up of many of the “snips” (from SNPs, single-nucleotide polymorphisms), are being developed for everything from feed efficiency to carcass quality.
Today, DNA technology is available to commercial Angus cattlemen with GeneMax™, a DNA tool to measure gain and grade in high-percentage Angus cattle. It’s designed to help identify females with the genetic potential to pass on the most profitable traits and select feeder cattle with the most potential to perform on the grid.
Genomic-enhanced EPDs: http://www.angus.org/AGI/GenomicEnhancedEPDs.pdf