Angus cattlemen have worked to include both the cow and the carcass in herd goals, and researchers at Iowa State University have the data to prove that’s a valid path.
“There's a perception out in the industry that there may be some negative relationships there. They found very few relationships between marbling and reproduction. The one thing they did find was a positive relationship between milk production and marbling, but the other reproductive traits, very, very little relationship. You can select for high quality, for marbling, and the traits that consumers want currently and still have a functional, effective cow herd,” says Dan Loy, director of the Iowa Beef Center.
After Iowa State researchers spent two decades on single-trait selection for marbling, they found all other traits maintaining at the Angus breed average. A key interest led to finding a positive link between fertility traits and marbling or intramuscular fat.
“We're mostly interested in heifer pregnancy and then calving interval, and then also the stayability, or the longevity, of a cow in the herd. And we did find a small correlation, about 0.2, which means that it explains about 4% of the variation in the trait between marbling and heifer pregnancy,” Loy says.
Seedstock breeders raising these kind of sires can ease concerns, too.
“We looked at the analysis of two calf crops on bulls that we had retained, and it was about 60 bulls a year, and they were on as part of research projects where we're doing BSE exams as well harvested the bulls and collected complete carcass data on those bulls. And so we were interested in, you know, is there relationships between semen quality and marbling and scrotal circumference. And there was some positive relationships between scrotal circumference and marbling, but really no effect on semen quality,” Loy says.
With maternal and carcass traits as a unified goal, producers can achieve more consistent improvement in both.