EPD’s are Expected Progeny Differences. They are defined by the American Angus Association as, “the prediction of how future progeny of each animal are expected to perform relative to the progeny of other animals listed in the database. EPDs are expressed in units of measure for the trait, plus or minus. Interim EPDs may appear on young animals when their performance has yet to be incorporated…” They can be great tools if you have a breeding program, but you want to focus on specific traits and how heritable they are, in order to use them effectively.
South Shadow Angus has a great explanation of how to read EPD’s- with a chart that shows heritability:
According to this EPD Basics article,“Studies have shown that using EPDs are seven to nine times more effective than selecting based on actual phenotypes. While most producers think of increasing the economic efficiency of their operation by changing management systems (i.e., grazing schemes, calving dates, etc.) or utilizing different nutritional programs, the importance of correct genetic selection is all too often overlooked. If selection is based on nongenetic factors, as is the case when selecting on actual or adjusted measurements instead of EPDs or economic indexes, then an inefficiency is automatically built into the cow/calf enterprise. It is critical to understand how to interpret EPDs and to know breed averages, and be able to use percentile ranks in order to identify potential sires that fit the desired breeding objective.”
To fully understand EPD’s, it might take hands- on experience and time buying and selecting cattle. One way to get some practical knowledge is to go to local stockyards and look at the sales books. EPD’s for each animal are listed in a chart-like fashion, typically.
There are various kinds of EPD’s- such as Production, Maternal, Carcass and Foot score. The specific EPD has an accuracy level of that EPD to show its reliability. This shows up as an ACC following the specific EPD code( see above chart). Angus.org states, “An accuracy of close to 1.0 indicates higher reliability. Accuracy is impacted by the number of progeny and ancestral records included in the analysis.”
There are also Value Indexes and PAP EPD’s, and the ability to compare data across breeds (see chart below), to name a few other aspects of this highly technical part of cattle production. As an introductory, this piece is highly simplified in order to provide you basic knowledge of what these numbers mean and where to find or apply them. Check out all the links above and do some research to further your understanding of this great breeding tool!
