Chuck Grove

Association Perspective

Put birth weight EPDs in perspective.

by Chuck Grove, regional manager, American Angus Association

As I attended bull sales this spring, one very obvious trend was the added value cattlemen place on low-birth, high-CED (calving ease direct) genetics. Consistently, "heifer bulls" are sale toppers and the high-averaging group.

Obviously, a live calf is the most important trait to any producer. After all, a large dead calf has a distressingly low growth rate! Just as obvious, no one enjoys pulling calves in the middle of the night — or at any other time, for that matter.

All of this is plain old common sense, right? Maybe, but have you ever compared Angus expected progeny differences (EPDs) with those of other breeds using the U.S. Meat Animal Research Center (MARC) adjustment factors to estimate across-breed EPDs (see Table 1)?

As you study the data, it appears Angus bull buyers are being overly cautious when Angus bulls are compared with other breeds. You wouldn't buy an Angus bull with a birth weight (BW) EPD of +4.8 to use on your heifers, but that's the additive BW EPD factor that comes with a Simmental bull. In other words, a bull with a Simmental BW EPD of 0 would equate to an Angus EPD of 4.8. For a Charolais BW EPD, the additive factor would be +8.5.

New AB-EPDs released this month

At the Beef Improvement Federation (BIF) Annual Meeting in Bozeman, Mont., USMARC released the 2011 AB-EPD adjustment factors in Table 1. Whereas EPDs from different breed associations are not on the same base and are therefore not comparable, these adjustment factors allow breeders to estimate across-breed expected progeny differences (AB-EPDs) for 18 breeds, adjusting them to an Angus base.

Most breed associations publish EPDs once or twice annually. These EPDs predict differences expected in performance of future progeny of two or more bulls within the same breed for traits including birth weight, weaning weight, yearling weight and maternal milking ability (as reflected in progeny weaning weights). Normally, the EPDs of bulls from different breeds cannot be compared because most breed associations compute their EPDs in separate analyses, and each breed has a different base point. The across-breed adjustment factors allow producers to compare the EPDs for animals from different breeds for these traits; these factors reflect both the current breed difference (for animals born in 2009) and differences in the breed base point. They should only be used with EPDs current as of June 2011 because of potential changes in EPD calculations from year to year.

As an example, suppose a Charolais bull has a BW EPD of +1.8 and an Angus bull has a BW EPD of +4.2. The across-breed adjustment factors for birth weight (see Table 1) are +8.5 for Charolais and 0.0 for Angus. The AB-EPD is 1.8 + 8.5 = +10.3 for the Charolais bull and 4.2 + 0.0 = 4.2 for the Angus bull. The expected birth weight difference when both are mated to cows of another breed (e.g., Hereford) would be 10.3 – 4.2 = 6.1 lb.

Another example:

In the example above, the Hereford bull would be expected to sire calves averaging 1.8 lb. heavier at birth than the Angus bull when mated to cows of a third, unrelated breed.

Summary

My intent is not to be critical of other breeds. The facts are what they are. Angus bulls are consistently lower in birth weight than other breeds. So if you are breeding cows, why would you discriminate against a +3 BW EPD or higher Angus bull? The reality is that higher-BW-EPD Angus bulls are probably one of the great values at any sale. They sell for significantly less money and have lower AB-EPDs for BW than bulls of other breeds. If you need a "heifer bull," buy him, but don't overreact when selecting herd sires for your cow herd.

Editor's Note: Regional Manager Chuck Grove covers Region 5, including the states of Kentucky, Ohio and Tennessee. Click here to find the regional manager for your state.

[Click here to go to the top of the page.]