Feeding Distillers' Grains
May Affect Beef Color
Seeking answers to questions regarding potential consequences of including distillers' grains in cattle finishing diets, University of Nebraska meat scientist Chris Calkins says the most significant impact on meat characteristics may be the way distillers' grains influence beef' appearance in the retail meatcase. According to Calkins, feeding wet distillers' grains (WDG) seems to compromise shelf life in terms of color.
Calkins says research findings suggest feeding the byproduct feed ingredient has no negative effect on beef marbling score. In some instances, marbling was enhanced among cattle fed diets containing WDGs. The ability of U.S. Department of Agriculture (USDA) graders to visualize marbling for determining quality grade appears to be unaffected. Neither is tenderness negatively affected.
However, evidence does suggest that meat from animals finished on diets containing distillers' grains may be more susceptible to oxidation. Consequently, the beef may more quickly lose the bright red color that consumers associate with fresh product. While the discoloration or “browning”of beef is not a safety issue, it is a very real marketing issue for meat retailers.
“Color really isn't an indicator of spoilage. That's a misperception among consumers,”says Calkins. “But U.S. consumers expect their beef to be bright red. And many of our export markets are even more likely to object to discoloration. It doesn't take much brown, and the deal is off.”
Calkins says beef color is influenced by the polyunsaturated fatty acid content of the muscle. As the inclusion rate of WDGs increases, so do levels of polyunsaturated fatty acids in the muscle, as well as the rate at which beef will lose its red color due to oxidation.
To suppress oxidation, Calkins says, supplemental vitamin E can be fed during the finishing phase. Feeding at least 300 IU (international units) per head, daily, provides significant benefit. The issue for cattle feeders is the cost, which, though variable, can be $1.50 or more per head. Further studies also will explore the effects different beef packaging methods may have on oxidation. It appears that oxidation rate matters less when beef is vacuum-sealed.
Calkins says discoloration has not yet become a source of major consumer complaint. This may be because many cattle diets contain no more than 30% distillers' grains on a dry-matter (DM) basis. However, as utilization of WDGs increases — perhaps at higher inclusion rates — Calkins says it is important to identify viable, cost-effective solutions.
“We need to do it for the good of the (beef) industry,”Calkins states.