EPDs: sorting beef from bull

Tom Hook | May 01, 2000

Technology has made genetic predictions (EPDs) possible on traits that animal breeders and scientists could only once dream about. But, a beef producer can never focus on the “EPD of the year,” jumping from fad to fad.

Likewise, producers should never lose sight of basic breeding principles that include a primary focus on the entire genetic puzzle, not just a piece of it. This holistic approach means genetic progress for individual traits will be slower than selecting for single traits. But, multi-trait selection allows producers to avoid the extremes and negative financial consequences that often accompany a walk on the edge of naturally occurring biologic limits.

The Blue Collar Approach Once breeding goals are established and breeds selected, evaluate the potential seedstock suppliers. As an example, assign each one a score for integrity and another for their commitment to keeping accurate records. After all, accurately reporting birth weight, calving ease and growth performance in unbiased contemporary groups is essential to genetic evaluation.

Think of the contemporary groups and resulting performance ratios as the cornerstone and bricks to building accurate genetic parameters (EPDs). Honest reporting is the mortar that holds it all together. Bottom line, EPDs for the various traits can be only as accurate as the data that has been recorded.

So, get to know seedstock suppliers and their management practices. Ask to see their ratios, the size of their contemporary groups (the effective progeny number, or how much competition an individual beat to earn his superior numbers).

Also, ask to see the lifetime dam production records for the bulls you’re interested in. Be sure the seedstock producers you’re dealing with are as interested in your bottom line as their own.

Once you start sorting individual bulls, comparing a bull’s percentile ranking within a breed for a given trait can be more useful than comparing the actual numeric EPDs. The numeric EPD of an individual changes as more performance data on his progeny are reported, reflecting “real-time” genetic evaluation. But, that number doesn’t tell the prospective buyer anything about how the bull ranks genetically within the respective breed compared to other bulls.

With that in mind, rather than selecting bulls based on their specific numeric EPD – for instance, a +65-lb. yearling growth – switch the focus to bulls that are in the upper 25% of the breed for yearling growth, and let the numeric EPDs fall where they may. Common sense suggests using breeds or composites known to excel in the traits you’re seeking to improve, and to select bulls that are in the top quartile (upper 25% or higher) of that respective gene pool.

In fact, when you start thinking in terms of percentile rankings rather than the numeric EPDs, you can easily construct a useful multiple-trait selection index, a power index of sorts. Just take the sum total of the percentile ranks for each trait on a given bull and divide by the number of traits.

For easy illustration, a bull in the top quartile of his breed for birth, weaning, yearling and milking ability would have a combined power index of 25 [(25+25+25+25)#4]. A bull that only ranked in the top half of the breed in each trait would have a power index of 50. A bull with a power index of 25 or less is genetically excellent in multiple traits.

Across-Breed EPDs Across-breed EPDs are helpful in assessing the comparative strengths and weaknesses of different breeds. But, caution must be used in comparing the numeric EPDs of different breeds unless proper conversion tables are used, or the EPDs are generated by a multi-breed statistical model like that used by the American Simmental Association.

Next, keep your environmental resources and marketing options in mind. For instance, if you’re raising and selling bred replacement females, your selection criteria will be far different than your neighbor who is using the same breed ingredients, but is involved in a terminal breeding program. Select genetics that meet your production goals relative to your available labor, management and feed resources.

Finally, keep the destination in mind. Today, marketing grids and alliances are as plentiful as EPDs. These information and marketing systems offer producers an opportunity to exploit the value of their genetics. But to do so, you have to know what you have to start with, what you’re selecting for, and how valuable that is compared to the available opportunity.

Tom Hook and his family operate Hook Farms, a Simmental seedstock operation in Tracy, MN. For more information about Hook Farms, call 507/629-4946.

Published by