More and more beef producers are switching to “black” cattle since that seems to be what the market wants. Black Angus heifers are sold for a premium and we search for the best black Angus bulls we can find to ensure that the calves will turn out black. However, this mass conversion to “black” may be costing us as much as $100/cow/year in what we give up by not crossbreeding.
Let’s review why crossbreeding is important. Crossbreeding offers two distinct and important advantages over the use of a single breed. First, crossbred animals have heterosis or hybrid vigor. Second, crossbred animals combine the strengths of the parent breeds or what’s known as breed complementarity.
Heterosis refers to the superiority of a crossbred animal relative to the average of its straightbred parents. For example, if bulls from breed A has an average weaning weight of 550 pounds and are mated to cows of breed B which have an average weaning weight of 500 pounds, the average of the two parents would be 525 pounds. However, the F1 (first cross) calves have an average weaning weight of 546 pounds. That means there was a 4 percent heterosis advantage (546-525)/525 = 4% from crossbreeding. The heterosis advantage results from an increase in the heterozygosity of the crossbred animal’s genetic makeup. It is therefore dependent on having two different forms of a gene from different breed parents. In general, animals that are crosses of more unrelated breeds will exhibit higher levels of heterosis. For example, a cross of Angus and Braham will exhibit higher levels of heterosis than a cross of more genetically similar breeds such as a cross of Angus and Hereford.
There are two types of heterosis – individual heterosis and maternal heterosis. Individual heterosis is the advantage of the crossbred calf from parents of two different breeds. Individual heterosis advantages are as shown in Figure 1.
This means that crossbreeding would yield 16.3 lb. of additional weaning weight/calf or 3.9 percent more than the average of the straightbred parent breeds. Survival rate of calves would increase by 2 percent.
The advantages of individual heterosis will have a tremendous impact on a farm’s bottom line. However, the largest economic benefit of crossbreeding to commercial producers comes from having crossbred cows. Maternal heterosis improves both the environment a cow provides for her calf as well as improves the longevity and durability of the cow. She improves the maternal environment for her calf by improvements in calf survivability to weaning and increased weaning weight. But crossbreeding also improves many of the low heritable traits such as reproduction and longevity. Why does that black baldy crossbred cow seem to breed back easier than a straightbred Angus cow? It’s maternal heterosis. Crossbred cows will increase the weaning weight per exposed per cow by between 23 percent and 30 percent. Crossbred cows exhibit improvements in calving rate of nearly 4 percent and will stay in the herd (longevity) more that one additional year due to heterotic effects. Heterosis results in an additional calf and 600 pounds more cumulative weaning weight over a cow’s lifetime. Figure 2 shows the effects of maternal heterosis.
There have been many studies to measure the economic effect of crossbreeding. When individual heterosis is combined with the improvement in reproduction and longevity of maternal heterosis, crossbreeding is valued at approximately $100/cow/year. So when planning your breeding program don’t be too quick to focus in strictly on one breed, trait, or color, because you might be giving up much more in the long run. For more information on crossbreeding you can reference Chapter 5 of the "Sire Selection Manual of the National Beef Cattle Evaluation Consortium" titled “Crossbreeding for Commercial Beef Production” by Dr. Bob Weaber of the University of Missouri. Call your local extension office (listed on page 54 of this issue) for more information.
