Angus to Limousin=Apples to oranges

They know Angus EPDs (expected progeny differences) like nobody’s business. Er, nobody else’s business. They can recall what were good numbers in say a milk EPD from two decades ago and how that compares to today. I’m not sure how much they could tell you these measures in other breeds, because frankly it doesn’t matter a whole lot to them.

So today’s myth hasn’t come up lately, but we do hear it out in the country so I’m bringing it to light here, too:

Myth: You can compare EPDs from one breed to the next straight up. No conversion needed.

Fact: The Angus.org EPD page describes an EPD 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.” If you’re reading carefully it’s that very last part that carries so much importance.

“Relative to the progeny of other animals listed in the database.”

Each breed compares all its sires to other sires in the same breed registry. As a hypothetical example, if you lined up all the Charolais bulls and found one that would be considered fairly low birthweight compared to that whole population and then you took that same bull and put it in a lineup of all the Angus bulls it probably wouldn’t register as a “low birthweight bull” by Angus standards.  You’re comparing against different measures.

So the U.S. Meat Animal Research Center (MARC) in Clay Center, Neb., has calculated across-breed EPDs for years. They use Angus as the base.

Rather than go through and list all the traits and the adjustments, I’ll point to this article that appeared in BEEF Magazine, written by  MARC scientists: MARC Releases 2012 Across-Breed EPD Table

“Bulls of different breeds can be compared on the same EPD scale by adding the appropriate adjustment factor to the EPDs produced in the most recent genetic evaluations for each of the 18 breeds. The AB-EPDs [across-breed EPDs] are most useful to commercial producers purchasing bulls of more than one breed to use in crossbreeding programs. For example, in terminal crossbreeding systems, AB-EPDs can be used to identify bulls in different breeds with high growth potential or favorable carcass characteristics.

As an example, suppose a Simmental bull has a yearling weight EPD of + 52.1 lbs., and a Gelbvieh bull has a yearling weight EPD of + 84.0 lbs. The AB adjustment factors for yearling weight (Table 1) are 22.4 lbs. for Simmental and -13.5 lb for Gelbvieh. The AB-EPD is 52.1 lbs. + 22.4 lbs. = 74.5 lbs. for the Simmmental bull, and 84.0 – 13.5 = 70.5 lbs. for the Gelbvieh bull. The expected yearling weight difference when both are mated to cows of another breed (e.g., Angus) would be 74.5 lbs. – 70.5 lbs. = 4.0 lbs.”

Of course if you want to avoid all that math, you could just go with straightbred Angus.

Only kidding.

Well, kind of.

May your bottom line be filled with black ink,

Miranda

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