Here's a time-honored observation worth pondering ahead of bull shopping season: The only thing more futile than doing the same thing and expecting different results is doing something exceedingly well that doesn't need doing in the first place.

For instance, next spring there will be plenty of folks utilizing expected progeny differences (EPDs) as a selection tool and paying for genetic potential they don't need or that their environment can't support. In addition, some producers will sacrifice incremental gains in one area of production for exponential losses in another.

As to the former, Matt Perrier, director of commercial programs for the American Angus Association, says he's still surprised by the number of buyers who ignore bulls with a hole in their EPD profile.

For example, a producer shopping for a terminal sire may find just what he needs in color, structural correctness, breed complementarity and a strong weaning and yearling weight performance, but who is sub-par for milking ability and maybe a touch heavy on birth weight.

Depending on the breeds and the cows involved, if the producer is only going to use the bull on mature cows, the birth weight EPD may not be an issue. And, since no heifers will be retained as replacements, milking ability certainly loses its value. Plus, the same EPD holes that dissuade that bull buyer from making the purchase will likely limit the market on that bull. That means our buyer could end up with exactly what he needs but for a bargain price.

Perrier also points out there is still a fair number of buyers who try to compare EPDs directly between breeds, even though that can't be done. While some estimating is possible using a conversion table like that developed by the Meat Animal Research Center, there's no way to look at a Limousin birth weight EPD, for instance, and compare it directly to one for Angus.

As an example, since the breed averages are different, a bull that is 0.0 in one breed may actually carry more potential for increased birth weight than a bull in another breed that is +4.0.

Never mind the fact that EPDs don't equate to actual performance. No matter how much producers might wish it so, a particular EPD for yearling weight, for example, isn't equivalent to any number of pounds of actual yearling weight.

Perhaps it's just human nature to want EPDs by themselves to mean something, but they don't. The only meaning an EPD has comes in its comparison to another one.

EPDs Are No Guarantee

For instance, if you know a bull of a particular breed is +20.0 for weaning weight and that the breed's average is 0.0, you do know that the bull in question is better than breed average for weaning performance. But its real value comes in comparing this bull to another in the same breed that is +12.0. That tells you that, on average, you can expect the progeny of the first bull to sire calves that would weigh 8 lbs. more at weaning than the other bull, plus or minus the expected change associated with a given accuracy level.

When it comes to the virgin, non-parent bulls most folks are trading for, that means accuracy will be relatively low. Consequently, once bulls have actually sired calves, and performance data is reported on those calves, their EPD for any trait can change dramatically. So, paying extra for minimal gain in a trait that happens to be the current fad may not represent much value.

However, a young bull's EPD based on his pedigree, contemporary group information and his own performance still offers a more precise snapshot of his genetic potential than his actual and adjusted performance.

Still, the flux inherent in EPDs may be one reason some folks have never fully embraced them as a selection tool. Although their very definition means EPDs will change over time and are expected to, some folks want to buy a guarantee of expected actual performance and none exists.

Though imperfect, what does exist is a time-proven tool to help choose bulls for future genetic performance far more accurately than any eye ever could. That doesn't mean very many producers should be content to buy bulls based solely on the numbers. It does mean, however, that a powerful tool is available that can save and make producers money on genetics if they take the time to understand what EPDs are and, even more important, what they aren't.

“It goes back to the analogy of using a map to get to where you want to go,” Perrier says. “EPDs can help chart the course, but you have to know where you want to go and where you're starting from before you can figure out how to get there.”