Display Life and Oxidation of Beef from Cattle Fed Corn Distillers By-Products

This research was conducted to evaluate the effects of feeding different corn by-products on beef discoloration and lipid oxidation. Steers (n=300) were fed for 190 d on either a corn control, 40% high protein dry distillers grains plus solubles (HP-DDGS), 40% dry distillers grains plus solubles (DDGS), 40% wet distillers grains plus solubles (WDGS), or 40% bran plus solubles (Bran) diet. Meat HCW at harvest was 391 kg (SD 31.6 kg). Cattle were grouped 10 per pen. Eighteen Choice carcasses (3 head/pen) were randomly selected within each treatment (n=90). Strip loin samples from the right side were collected and aged for 2, 9, or 23 d. Steaks were fabricated at each aging period and placed under retail display conditions for 0, 4, or 7 d. Discoloration and lipid oxidation were determined for each sample. A split-split-plot design was used with pen being the experimental unit. After 7 d of retail display following 2 and 9 d of aging, steaks from cattle fed HP-DDGS had more discoloration (P < 0.05) than all other treatments (which did not differ from each other). Following 23 d of aging, steaks from cattle fed HP-DDGS had the most discoloration and all treatments except WDGS were higher than corn (P < 0.05) after 6 and 7 d of retail display. Lipid oxidation increased (P < 0.001) during retail display at all aging periods. A retail display-by-treatment effect (P < 0.001) was observed for lipid oxidation. After 7 d of retail display, steaks from cattle fed HP-DDGS had significantly higher TBARS than all other treatments except WDGS. There were no differences in lipid oxidation between steaks from cattle fed WDGS, Bran, and DDGS. The lowest TBARS occurred in steaks from cattle fed corn, which were different (P < 0.05) from all steaks but those from the DDGS treatment. These results suggest that feeding corn distillers by-products to cattle decreases steak color stability and increases lipid oxidation.