Decrease Risk with Higher-Accuracy EPDs

December 10, 2009 06:00 PM

Source: Merial press release

Since the late 1970s, expected progeny differences (EPDs) have changed the way beef producers make selection and mating decisions. Matt Spangler, assistant professor and beef genetics extension specialist, University of Nebraska-Lincoln, says the introduction of EPDs empowered producers to make better decisions, leading to faster genetic progress.

"EPDs allow commercial and seedstock producers to focus on the genetic component of sire selection, which is the most important,” he says. "The use of EPDs has resulted in tremendous genetic change — particularly regarding growth and carcass traits.”

EPDs are a combination of information from various sources such as individual performance, pedigree and progeny data. Each EPD comes with an associated accuracy, which helps measure the reliability of the EPD. Dr. Spangler says though EPDs are an important factor to consider when evaluating young animals, producers should remember that these accuracies are typically very low on young animals.

"The accuracies associated with EPDs increase as more information becomes available,” he says. "The first EPD calculations for a young animal are an estimate based on its parents' pedigree index values and possibly some of its own performance data. For this reason, the accuracies are low until an animal has recorded progeny data, which may never happen in a commercial setting.”

Low-accuracy EPDs present a challenge for producers evaluating young seedstock. Dr. Spangler says, traditionally, there is essentially no difference in the accuracies of young sires, which means two bulls could have different EPDs, but due to the low accuracies, the difference may not be significant.

"For example, if one bull has a weaning weight EPD of 44 and another has a weaning weight EPD of 48, but both have an accuracy of 0.30, we cannot say that one of these bulls is any different than the other,” he says.

In addition to helping assess the true difference between animals, higher-accuracy EPDs mean the window of possible change for the respective traits decrease. The example below outlines this possible change and true EPD range for sires with two different accuracies for the same EPD value. This example uses an Angus breed-average EPD of +0.12 for ribeye area.


Ribeye Area


Possible Change

True EPD Range




+/- 0.26

-0.14 to +0.38




+/- 0.06

+0.06 to +0.18

Dr. Kevin DeHaan, technical services director, IGENITY®, explains that both bulls in this example start with the herd average for this EPD. Bull "A” has an accuracy of 0.20, which translates to a possible change of +/-0.26 inch of ribeye area — and a potential true EPD variation of more than a 0.5 inch of ribeye area from worst case to best case. Bull "B” has the same EPD value but an accuracy of 0.80. This higher accuracy reduces the true EPD range to only 0.12 inch, so the producer is exposed to much less risk with Bull "B”. 

"With a higher-accuracy EPD, producers can have more confidence that the young animal's true EPD is much closer to its current value — meaning less risk and more confidence in the animal's true potential for the given trait,” Dr. DeHaan says.

He adds that the good news is Angus breeders now have the option of gaining and supplying their customers with higher-accuracy EPDs in the form of genomic-enhanced EPDs. Dr. Spangler says adding DNA information to the Angus National Cattle Evaluation (NCE) is a step in the right direction for producers evaluating young cattle.

"DNA technology has the potential to supply us with information early in the animal's life that can help increase the accuracy of its EPDs,” he says. "If the EPD accuracies are increased on a young animal, producers have the ability to make decisions about that animal with more confidence.”

The genomic-enhanced EPDs from Angus Genetics Inc.® (AGI) are powered by the first breed-specific DNA profile that is exclusively available from IGENITY. Dr. DeHaan says these genomic-enhanced EPDs help producers evaluate young cattle in a way that was previously impossible.

"With this information in hand, producers can make more confident herd sire and replacement heifer selection decisions, which is especially important when we consider these animals represent the future genetic direction, and success, of a herd,” Dr. DeHaan says.

Genomic-enhanced, and therefore, higher-accuracy EPDs, can benefit both seedstock and commercial producers, Dr. Spangler says.

"It is very important for all producers to start understanding the potential benefit of the inclusion of DNA information in EPDs,” he says. "It comes down to mitigating risk and picking animals that truly are superior at a younger age.”

For more information about IGENITY, producers should contact their IGENITY sales representative, call (877) 443-6489 or visit For more information about the genomic-enhanced EPDs available from Angus Genetics Inc., producers should contact their Angus regional manager or call (816) 383-5100.

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