What cattle eat affects everything from their health to rate of gain. It’s one of the most significant economic inputs into the animals, and can produce some of the greatest variability in quality.

That’s why Certified Angus Beef (CAB) LLC examined the effects of some popular feeding trends on carcass quality. CAB vice president Larry Corah and supply development director Mark McCully compiled university research and discovered that some popular combinations of cattle feed and processing are no friends of beef quality. Steam flaked grain and ethanol co-products are two examples they found that could detract from the ability to reach higher beef quality grades.

Cattle feeders recognize the benefits of feeding ethanol co-products. Dried distillers grains (DDGs), corn gluten meal and wet distillers grains usually are cheap substitutes for grains in traditional grain-based rations. They may not negatively affect average daily gain or feed efficiency, but they may have negative effects on quality grades.

Research by Chris Reinhardt at Kansas State University showed a 20-point drop in marbling, on a 1,000-point scale, when cattle were fed a diet of 30 percent or more distillers grain, rather than none.

“That may not sound like much of a drop, but it is significant, especially when grid premiums are on the line. For producers trying to hit a high-quality target, like the Certified Angus Beef brand, this is one of dozens of little things that can add up,” says Corah.

DDGs have a lower starch content, which may cause a metabolism switch that makes fewer cells into taste fat—marbling—and more into external waste fat, he adds. Today, distillers grains are commonly fed at 10 percent to 40 percent of feedlot diets, on a dry-matter basis.

As the supply grows, Reinhardt predicts more producers will use more ethanol co-products and include them as a greater percent of the diet. Already the majority of Nebraska feedlots feeding more than 2,000 head include ethanol co-products in their rations, typically at rates exceeding 20 percent of the diet.

“In the long run, the supply of these products will likely exceed demand,” Reinhardt says.

Last year, nearly 15 percent of the corn crop was used in ethanol production, according to the National Corn Growers Association. With more ethanol plants being built in the Midwest, Reinhardt says the price of DDGs may drop dramatically in certain areas. Driven by cheaper cost of gain, some producers may include distillers grains as 60 percent to 70 percent of the dry ration.

“Understanding all the interactions and effects of such a high feeding level is critical as the feeding industry moves forward,” says McCully.

Corah adds, “This research does not amount to a warning that says, ‘Stop all use of distillers grains.’ But it is important to find the threshold of feeding them that won’t cause an excessive decrease in quality grade.”

The more you dilute DDGs with processed grain, the lower its negative effect on marbling.

In an Oklahoma State University review presented at the 1999 American Society of Animal Science meetings, Fred Owens and Brett Gardner pointed out that flaked corn resulted in a lower marbling score than whole grain or dry rolled corn. The average marbling score was ‘Small’ (USDA Choice > 500) at 512 with whole corn and 524 with dry rolled, but fell to ‘Slight’ (USDA Select) at 482 for steam flaked corn.

Most large feedlots steam-flake grains to improve feed efficiency and increase average daily gain. That means fewer days on feed, which could partially explain the lower quality grades, Owens says. Moreover, an increased rib eye area could also “dilute” marbling scores, he adds.

“More and more cattle are being fed at large feedlots where they’re fed steam flaked grain,” says McCully. “As this trend continues, it will have a negative impact on marbling and ultimately Certified Angus Beef acceptance rates.”

The type of grain helps determine marbling, too, says Owens. Milo and wheat may shift the site of digestion, and reduce quality grades by 13 and 14 points, respectively.

“If you lose a dozen points here and a dozen points there, the next dozen points begin to affect your bottom line,” says McCully. “When there is a difference of $200 or more between CAB and Select, it pays to take the little things into account.”

Corah and McCully’s summary, “Declining Quality Grades: A Review of Factors Reducing Marbling Deposition in Beef Cattle,” is available through the authors at 785-539-0123, or 330-345-2333, or on the Web at http://www.cabpartners.com/news/research/declining_quality_grades.pdf.