To find a progressive cattleman who does not use Expected Progeny Differences (EPDs) would be as hard to find as one that does not want a good rain. The old saying, “you can’t measure what you can’t see,” does not hold true here. In fact, EPDs allow us to look beyond the hide by predicting the genetic potential of the individual. The American Angus Association currently has EPDs for 20 different performance traits. While EPDs have been utilized since 1980, there still seems to be some unanswered questions as to their meaning and calculation.

While the purpose of this article is not to explain the complex calculation of Expected Progeny Differences, EPDs are calculated based on individual, ancestral, and progeny performance information. EPDs are developed for both males and females in a breed and are calculated from performance data that producers submit on their cattle. The American Angus Association uses the National Cattle Evaluation (NCE) at Iowa State University to calculate their EPDs. However, the NCE for Angus is performed only twice a year, once in December and again in June.

Those animals that are registered and have weights recorded between semi-annual National Cattle Evaluations are provided American Angus Association “Interim EPDs,” which are figured in-house. This EPD value is preceded by an “I” and appears on Angus Herd Improvement Record forms, Performance Registration Certificates, and Angus Performance Pedigrees.

For example, a bull might have EPDs printed in a sale book as:

An animal with interim EPDs will no longer be interim after the semiannual National Cattle Evaluation if one of these happens:

1. Individual performance weights and measures have been turned in to the American Angus Association within a proper contemporary group. For example, if a bull’s weaning weight has been taken and reported, then a NCE Weaning Weight EPD can be calculated.

2. Progeny performance weights and measures have been turned in to the American Angus Association within a proper contemporary group. For example, if a bull’s offspring has a weaning weight taken and reported, then this information can be related back to the sire and a NCE Weaning Weight EPD can be calculated.

Therefore, there should not be any concern when a young animal has an interim EPD. As stated above, this simply means that they have not had the opportunity to be processed through the NCE since they have been registered, or there is not quite enough performance information available. Interim EPDs predict the same genetic information as a NCE EPD.

Note from the author: Keep in mind that given the data available for analysis, an EPD is always the best estimate of an animal’s genetic worth. However, it is extremely important for the seedstock producer to provide additional comprehensive performance data to their customer (i.e. carcass ultrasound measurements, actual and adjusted weights, average daily gains, etc.). Donnell Cattle Company recognizes the importance of measuring animal performance and strives to provide all available information to their customers.