Selecting the best crossbreeding system
Crossbred calves often outperform their purebred counterparts through what is known as hybrid vigor, or heterosis.
“Hybrid vigor is the improved performance of specific traits from the crossing of two genetically different animals,” said Brittni Littlejohn, an assistant professor of animal science at the University of Arkansas. “More specifically, offspring exceed the average performance of either parent for specific traits.”
Fertility and growth are among the traits that can be amplified via heterosis. Farmers raising replacement heifers can utilize heterosis to breed for the most prolific female. Similarly, farmers who market their calves solely on weaning weight may select a crossbreeding program that results in the fastest-growing offspring.
Cattle can be divided into two basic classifications. Bos Taurus cattle are non-humped cattle like Charolais, Hereford and Angus. Bos indicus breeds, on the other hand, are humped cattle like American Brahman or Indian Zebu.
Littlejohn said crossing two different breeds within the same classification can result in offspring that exhibit some heterosis, but perhaps not as much as offspring with more genetically diverse parents.
“Where we typically get the most benefit is by crossing a Bos indicus breed with a Bos taurus breed because they have such different genetic backgrounds,” Littlejohn said.
Some of Littlejohn’s graduate research used purebred Angus, purebred Brahman and crosses between the two. Calves from this mating exhibit high heterosis, often showing improved growth rates compared to their purebred counterparts.
“In the crosses of the Brahman and Angus cattle, the average weaning weights far surpassed those of either purebred Angus or Brahman raised in the herd at the exact same time under the same conditions,” Littlejohn said.
Whether the genetic differences are as minor as mating a Hereford to an Angus or as significant as mating a Brahman to a Shorthorn, commercial producers can maximize their operation’s productivity by increasing heterosis. For more information on selecting the best crossbreeding system, consult this fact sheet from Oklahoma State University Extension: https://extension.okstate.edu/fact-sheets/crossbreeding-beef-cattle-i.html
