Focus on carcass traits
The trait most related to hitting the CAB target is marbling, but ribeye area and fat thickness also have some effect. Done correctly, improvement can be made for these carcass traits with no negative impact on reproductive, maternal or growth traits. In fact, improvement can be made in all of these areas at the same time with the proper use of expected progeny differences (EPDs).
- Ribeye Area
Research at the Meat Animal Research Center (MARC) has proven over the years that the Angus breed is superior in marbling to all other mainstream beef breeds.
The CAB brand requires Modest or higher degrees of marbling (“Upper 2/3 of Choice” or “Premium Choice”). In more than 90% of the Angus influenced (black-hided) cattle that fail to meet CAB specifications, inadequate marbling is to blame. Keep in mind that the percentage of Angus genetics varies greatly in black-hided cattle.
- The EPD for Angus cattle that predicts marbling is MARB.
- The amount of marbling needed in a herd sire depends on the cowherd he will service and your goals. If the cowherd is of Continental or highly crossbred genetics, selection for higher marbling is recommended. If the cowherd is Angus or English-based and known to produce calves that can marble, moderate to high levels may suffice.
Read more about why marbling is important to beef demand here.
CAB specifications call for a ribeye area from 10 to 16 square inches (in2). A ribeye smaller than 10 in2 results in a poor-yielding carcass while greater than 16 in2 presents challenges in portion size. Ribeye area is dependent on carcass weight and increases as weight increases.
Typically, a 10 in2 ribeye area comes from a finished animal that is lightly muscled, and a 16 in2 REA comes from a fairly thick and heavily muscled animal. An ideal target on finished cattle is 12 to 14 in2.
The EPD that predicts ribeye area in Angus cattle is REA.
The CAB brand allows a maximum fat thickness of 0.99 inch, but an ideal target is 0.5 to 0.6 inch on finished cattle. While extremes can be minimized with genetic selection, fat thickness is often a function of sorting and marketing in the feedlot.
- Selection for extremely low backfat can have a negative impact on fleshing ability of daughters retained in the herd. However, it is a viable strategy when many progeny from a herd finish with more than 0.80 in.
- The EPD to predict backfat in Angus cattle is FAT. If you’re having trouble with excessive backfat in your calves, refer to our genetic recommendations as outlined in our Best Practices Manual.