One of the most common pitfalls of using EPDs is an often misplaced assumption that EPDs are a prediction of some general phenotype. Yes, there are some EPDs that are useful in predicting a few specific phenotypical traits like mature height, claw, angle, hair shed and soon to be teet and udder. These are all useful and should be leveraged accordingly paired with some good ol cowboy sense.
With that said, what EPDs don’t tell us is arguably just as important because it is here where the rubber meets the road and seedstock producers must do their job and incorporate art/science/and common sense into animal evaluation.
EPDs tell us very little, if anything, about structure or soundness, such as hock angle, breaking behind a shoulder, or flexible/free movement. They also don’t shed much light on fleshing ability, tail head set, length of spine, heart girth, depth of body, clean frontedness, wedge shaped females, muscle expression, bone thickness, crest size, “hair curl in the neck/crest”, feminine look in cows, rat tails, head shape, red tinted hair color, length of coat, fly resistance, hip length, hook to pin angle, foot size, etc, etc, etc. The list is endless.
I’d suggest all of us, to varying degrees, DO think that much or all of those traits are at least relevant in breeding decisions if not very important.
Moreover, EPDs also don’t tell a comprehensive story. They can’t talk about the beautiful power cows in the pedigree, or have a sense of the scrappy mothering ability multiple generations deep, or describe the aggressive breeding propensity of the sires in the pedigree, and have very little sense of survivability/adaptability of animals multiple generations deep.
No my friends, EPDs don’t do that, only we can, and thats what makes breeding an exciting challenge where we incorporate science, art, common sense, and sometimes even poorly supported “gut feels” that somehow actually turn out to be right on the money!
But what are EPDs (expected progeny difference)? Simply put, they are practical statistical tools that incorporate millions of data points from measured phenotypical/performance traits to help us predict a handful of traits that the industry has deemed as useful. They combine both the data from pedigree (ancestors), the animal itself, and its progeny. Moreover, EPDs are further supported by genomic information where real life performance traits have been correlated to various SNPs (think little codes/pieces within a DNA molecule) to further improve the accuracy of EPDs. In other words, they are an incredibly helpful tool to help us predict and assess risk for future progeny and sire/dam mating selections.
Animals of vastly varying phenotypes can retain a set similar EPDs. We observe this all the time. For example, YW is any easy one to pick on. We could raise an 1400 lb yearling stud teaming with masculinity, performance, and soundness. Simultaneously, we could also raise a 1400 lb alien that’s as unattractive and unsound as they come. Both may have a YW EPD of +140. The EPD tells us nothing of the phenotypical package these animals come in. They only tell us what the YW EPD is intended for, which is a predictor of a sire's ability to transmit yearling growth to his progeny compared to that of other sires. That’s it. Marbling is another great example. There are high marbling sires that look more like high flanked wagyu, but there are also high marbling sires that are the pasture kind.
Use the tools available, but never forget to use your eyes. Good luck and have fun!
To end, here is a picture of an absolute meat wagon and resident VICCI herd sire, Sterling Hitman (20681138) as an 18 month old. He is an outstanding phenotypical example of what physical traits we believe an angus bull should possess. Uniquely though, he is a prospect that also retains a rare combination of balanced EPD traits that won't cheat you in any area that makes or saves you money - growth, efficiency, & carcass wrapped in a functionally sound and masculine package.
Happy breeding
Josh Bedell,
President & Owner
VICCI Cattle Co.
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