Source: Rita Jane Gabbett, MEATINGPLACE, 7/27/15


New research from Mississippi State University showed grazing cattle on certain grasses, even when those cattle are finished with grain, increased the percentage of fat in the beef they produce.

For grass-fed cattle not finished with grain, scientists found that fat percentage was greater in steaks from cattle fed on Indiangrass, compared with steaks from cattle fed the mixed native, warm-season grass. Moisture percentage was greater in steaks from cattle fed on bermudagrass than the Indiangrass treatment. There were no other differences in composition among the treatments.

In a similar study that evaluated grain-finished cattle, there was a large difference in fat percentage and only a slight difference in moisture percentage, according to Byron Williams, an associate research and Extension professor in the Department of Food Science, Nutrition and Health Promotion.

Also in the grain-finished beef study, steaks from the bermudagrass treatment had greater fat content and lower protein and moisture percentages, compared with steaks from cattle fed the Indiangrass and mixed native, warm-season grasses.

Overall, the steaks from all the treatments did not differ in color, pH and tenderness. Consumers gave favorable ratings to beef steaks from all the treatments in both experiments.

“In both studies, we found that native, warm-season grasses are acceptable forage for beef cattle during the stocker phase, producing a lean, high-protein product with positive consumer acceptability,” said Wes Schilling, a professor in the MSU Department of Food Science, Nutrition and Health Promotion and food scientist with the Experiment Station.

The studies sought to determine the quality of beef from cattle that foraged on native grasses and bermudagrass.

Bermudagrass is one of the most common warm-season grasses used to graze cattle in the South because of its large biomass production and forage quality. However, this introduced grass provides few benefits to wildlife compared with native, warm-season grasses, such as Indiangrass and bluestem. These grasses provide superior wildlife habitat, but little is known about the quality of beef from cattle that graze on native forages.

In one study, researchers randomly assigned 72 steers to nine pasture plots with three different forage treatments, including bermudagrass, Indiangrass and a mix of native, warm-season grasses (Indiangrass, big bluestem, and little bluestem). Cattle were then forage-finished on tall fescue until marketed.

“Cattle about 6 to 7 months old grazed on these forages until winter and then were fed sudangrass hay/roughage and supplement during the winter,” Schilling said. “Cattle grazed on tall fescue the following spring and summer until they reached the target harvest weight.”

At the MSU Meat Science Laboratory, scientists graded the harvested meat following U.S. Department of Agriculture guidelines and prepared cuts of beef for research objectives.

Scientists simulated retail display conditions by placing cut steaks in Styrofoam trays, overwrapping them with clear film and storing them under lights in refrigerated conditions for nine days. They tested the meat every three days during the storage time. Forage-finished beef had an acceptable storage period of six days under simulated retail display conditions.

The researchers tested numerous variables in the steaks, including percentage of moisture, fat, protein, collagen, color, pH, cooking loss, tenderness and consumer acceptability.

The researchers trained eight panelists to evaluate steaks based on aroma, flavor intensity and various other factors according to standards established by the American Meat Science Association.

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