Angus VNR: Follow the Marbling

Selecting for just one trait can be ruinous in the cow-calf business—but it depends on how that one trait is related to others, and how well you keep the others balanced. An Iowa State University research herd show it can work out well.

“We decided to single trait select because the industry doesn't do that and someone needs to learn, to find out what happens when you do that? We wanted to see what the progress would be for selecting for marbling over that time period. And then also what some of the negative implications might be. And so, this is kind of the retrospect in that regard,” says Dan Loy, Director, Iowa Beef Center, Iowa State University.

At Iowa State’s McNay research farm near Chariton, Iowa, in 1996, foundation Angus heifers were selected for marbling, or intramuscular fat. Ultrasound at the start gave way to expected progeny differences, or EPDs, from the American Angus Association.

“Then, over a period of time it still was a selection for intramuscular fat but using mostly the marbling EPD from the Angus breed to do the selection. So, they've been selected for marbling for 20 years,” Loy says.

Loy recently led an analysis of the genetic and phenotypic results of that selection program and co-authored a research paper for the Certified Angus Beef brand.

“If you're concerned about selecting for carcass traits or cattle that will do well in the feedlot, because it may have negative effects on the reproduction in your cow herd – or negative effects on your bull buyers that are looking for heifer bulls or bulls that would be more maternal – I think we've eased some of the fears there,” he says. “You can select for high quality, for marbling, and the traits that consumers want currently and still have a functional, effective cow herd.”

How this Iowa herd compares to the rest of the country’s Angus across all other traits is mostly average – except when it comes to marbling.

“This herd, the average carcass data, just to put her in perspective, the quality of this herd is in, in the last couple of years, they've averaged about 57 percent Prime. Between 50 and 60 percent Prime. They run virtually a hundred percent Choice, 97, 98 percent Choice. And I believe there are 90 percent would be Certified Angus Beef, average Choice and higher,” Loy says. “So that's where, you know, if you select for marbling for 20 years, that's where you can be. And with where we're at currently in the ... We were much lower in the Angus breed when we started. So you've got a head start, if you're looking at doing this as a breeder today.”

With the long-term focus on marbling in the herd, carcass quality is well past Choice and on to mostly Prime. That’s a bit of a re-set in the way most research projects have been written.

“I do a lot of work with cattle feeders. We may have evaluated whether a technology was negatively affecting carcass quality by its effect on percent Choice. But in this case, they are a hundred percent Choice. So … Prime is the new Choice.  And I think as we increase quality of cattle and we start looking at demands of consumers and look at where we're at and where we're heading as an industry, you know, I think we've moved the goalposts in the beef industry,” Loy says.

“Basically, if we're shooting for low Choice, we're B students. And so we as a beef industry, I think we want to be the A students,” he continues.

As the market rewards those higher grades, ranchers can rest easy that producing better beef won’t come at the cost of maternal functionality in their herds.

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