A Steak in Genomics™

In the last blog post, I defined Expected Progeny Differences (EPDs), the accuracy of said EPD, and the percentile rank. An EPD is an estimate of the genetic merit an animal will pass on to its progeny, on average. They can be used to sort animals according to their potential to make genetic change within a herd, or when making bull buying decisions. A percentile rank simply reports where the specific EPD for that animal ranks across the entire breed from 1 (top) to 100 (bottom). While I touched on the value of genomics and how it increases accuracy, to do that justice really takes a separate post – so here goes. Remember, EPD stands for ‘Expected’ Progeny Difference. In other words, it is the evaluation’s best assortation of an animal’s genetic merit based on the information available at the time. Traditionally, that would be the animal’s (assumed) pedigree, phenotype data, and progeny information. In the case of young sires, sometimes that can be limited simply due to their age.

As a dry 2023 ends, with hopefully a little more moisture, and we enter spring bull buying season, it is imperative that producers arm themselves with information to make educated purchasing decisions. As you continue to flip through various catalogs, selecting bulls as you have so many times before, I would like to take this opportunity to provide what I believe are fundamental pieces of information to better assist a producer in their bull buying decisions.  In addition to overall soundness and conformation of a bull, it is always important to select a sire who is ‘backed by data’. You wouldn’t necessarily go out and buy a new pickup truck without researching its horsepower, torque, and overall tow-rating. Instead, you would ensure that the overall mechanics of the engine matched your daily needs. The same should be true about purchasing a new herd bull or AI sire. Instead of an owner’s manual you now have EPDs. Figure 1. Sources of information used to calculate an Expected Progeny