Figuring out how much emphasis to place on carcass traits in commercial bull selection, relative to their value in the real world, just got easier.
The American Gelbvieh Association (AGA) is the first breed organization to unveil an expected progeny difference (EPD) for grid merit.
“We believe seedstock producers in general and commercial producers in particular have a hard time understanding what carcass traits mean to the bottom line,” says Nick Hammett, AGA director of seedstock marketing. “So we wanted to design a system that makes it easier for them to use.”
In a nutshell, the grid merit EPD embraces basic animal index selection theory and hopefully ushers in a new age of genetic evaluation tools for economically relative traits, rather than just predictor traits. In this case, the grid merit EPD simply predicts the value difference, in dollars, between sire progeny marketed across what most folks would consider a mainstream pricing grid.
“According to our best ability, we looked at where we thought the industry would be five years from now and made some assumptions,” says Don Schiefelbein, AGA executive director. “All things being equal, on average, in the future we believe cattle with more marbling will be more valuable than cattle with less marbling. And, we believe cattle with more muscle and leanness will be more valuable than cattle with less muscle and leanness.”
In addition, the grid utilized in calculating the new EPD narrows the carcass weight window to 600-850 lbs. It also places more premiums on Prime and the upper two-thirds of Choice than most grids today.
With that in mind, look at the bulls in the latest AGA Sire Summary (see Table 1 example). These bulls are described for carcass weight, ribeye area, marbling, fat thickness and the new grid merit EPD that accounts for the economic value of the other carcass EPDs.
So, using the bulls in this example, Twinkle Toes is expected to sire calves that, on average, should bring $9.55 more grid premium than those sired by Guts ‘N Butts.
Folks familiar with the joys of cattle feeding won't be surprised to find that the sires ranking highest for grid merit tend to be fairly balanced and positive but non-extreme in the specific carcass traits.
However, Schiefelbein says, what will surprise some is how much this indexing approach confounds traditional eye-logic when it comes to ranking bulls.
For instance, he and his family have fed cattle for years. Yet, he says, “When you use an index like this, it's amazing to see how inept you've been at ranking animals based on their overall carcass merit, relative to a grid.”
He adds that AGA could create the EPD much of it through the efforts of Patrick Doyle, AGA director of research and education because of the database AGA has created through the Gelbvieh Alliance. This feeding and carcass data, tied to specific sires and pricing grids, gives them the population distributions necessary to calculate such an index.
Perhaps even more powerful than the tools itself, though, are the application spin-offs that such dollar-based selection technology makes possible. As an example, with AGA's Value-Bull software, producers can plug in specific carcass EPDs for bulls they're considering, along with a specific pricing grid they're interested in. Then, with a keystroke calculate the predicted grid merit of the progeny.
Schiefelbein does caution, however, “There is a lot of sexiness in making an index like this specific to a value-added program. But, because cattle breeding is such a long-term proposition, I think producers should be careful and compare bulls based upon mainstream grids rather than those that represent a niche.”
Doyle also calls for keeping the new tool in perspective. “As with other EPDs, the grid merit EPD may be used to estimate how the future progeny of one animal will compare to the future progeny of another animal within the same breed.
“However, carcass traits are just one component of a balanced selection program. It's never a smart management strategy to select sires based on a single trait,” he adds.
Indeed. But hopefully this is the type of real-world, consolidated, selection information producers can hope to access more in the future.
“As we move in the direction of genetic evaluation tools that allow producers to see the economic impact associated with a combination of traits, we're confident that they'll be more comfortable in taking advantage of them,” says Hammett.
Table 1: Example of Gelbvieh Grid Merit EPD
|Bull||Carcass Weight |
|Ribeye Area |
|Fat Thickness |
|Grid Merit |
|Twinkle Toes||+10 |
|Guts 'N Butts||+23 |
|(Source: American Gelbvieh Association)|