As cattle producers continually strive to do more with less, industry experts from coast to coast and border to border have been offering similar advice lately.
“It’s time to rediscover crossbreeding,” says Roy Burris, University of Kentucky Extension beef specialist. Many of his colleagues agree. Scott Greiner, Virginia Tech Extension animal scientist, says it’s one of the oldest and most fundamental principles to reducing costs and enhancing productivity.
“Crossbreeding beef cattle offers two primary advantages relative to the use of only one breed,” he explains. “Crossbred animals combine the strengths of the various breeds used to form the cross, and crossbred animals exhibit heterosis.”
Commercial cattle producers must realize that no single breed excels in all areas that affect profitability, says Matt Spangler, University of Nebraska-Lincoln beef geneticist. “Breed combinations can be engineered to accommodate environmental constraints and meet marketing objectives,” he says.
The amount of heterosis expressed for a given trait relates inversely to its heritability, which is the proportion of the measurable difference observed between animals that is due to additive genetic differences and passes from one generation to the next.
Because reproductive and maternal traits have low heritabilities, their responses to selection will be slower; however, producers can make significant improvement in those traits through crossbreeding programs that maximize heterosis. With growth traits, which are moderate for heritability and heterosis, progress is possible through both selection and crossbreeding.
David Daley is associate dean in the California State University-Chico College of Agriculture, where he directs the school’s beef program. He also manages his own herd of several hundred commercial cows.
“Recently, I am hearing concern from some very large, progressive producers as their cows become more straightbred in a tough environment. Longevity, rebreeding and calf survivability all become important issues,” Daley says. “I don’t think it’s because they have bought the wrong bulls or managed their ranches incorrectly. It’s because they have forgotten or ignored heterosis.”
The subtle, cumulative improvement that heterosis provides doesn’t lend itself to maximums, he notes, adding, “Because heterosis is expressed as a small net positive in many traits, we do not know it when we see it.” Although the individual change in one trait is small, he says lifetime production can increase by more than 20% in programs designed to capture both direct or individual heterosis in crossbred calves and maternal heterosis in crossbred cows.
“I am confident that we can no longer forget how to reduce input costs, and heterosis has to be part of that equation,” Daley says.
-- North American Limousin Foundation release