Effect of Including Optaflexx® 45 in the Diet of Cull Beef Cows on Feedlot Performance and Carcass Value

Two experiments were conducted over two years to evaluate the effect of including Optaflexx® 45 in cull cow finishing diets on performance, carcass characteristics, and carcass value. Experiment 1 evaluated the inclusion of Optaflexx® 45 in the diet, whereas Experiment 2 evaluated different inclusion concentrations in the finishing ration. In each experiment crossbred cows (Experiment 1, n=93; Experiment 2, n=95) from the same location were utilized. The cows began the feeding phase in Experiment 1 and 2 in low body condition score (4.2 and 3.5, respectively). High energy diets were offered to the cows for 90 d and Optaflexx® 45 was included for the last 35 or 28 d (Experiment 1 and 2, respectively) of the finishing period. The inclusion of Optaflexx® 45 did not improve cow finishing performance compared to the control treatment in either experiment. Carcass characteristics were not affected by the inclusion of Optaflexx® 45. Carcass value of cull cows fed for 90 d was improved by feeding high energy diets compared to the carcass value of nonfed cows.