Evaluation of wheat or corn dried distillers' grains with solubles on performance and carcass characteristics of feedlot steers

A study was conducted on crossbred steers (n = 275; 376 ± 24 kg) to evaluate performance and carcass quality of cattle fed wheat or corn dried distillers' grains with solubles (DDGS). The control ration contained 86.6% rolled barley grain, 5.7% supplement and 7.7% barley silage (DM basis). The four treatments included replacement of barley grain at 20 or 40% of the diet (DM basis) with wheat or corn DDGS. Steers were slaughtered at a common end weight of 645 kg with 100 steers randomly (n = 20 per treatment) selected for determination of the retail yield of sub-primal boneless boxed beef (SPBBB). Data were analyzed as a completely randomized design using pen as the experimental unit. Feeding increasing levels of wheat DDGS led to a quadratic increase in dry matter intake (DMI) (P < 0.01), whereas increasing levels of corn DDGS led to a quadratic decrease in DMI (P = 0.01). Average daily gain was not influenced (P = 0.13) by feeding wheat or corn DDGS, but cattle fed corn DDGS exhibited a quadratic increase (P = 0.01) in gain:feed. As a result, a quadratic increase (P < 0.01) in calculated NEg of the diet was observed as corn DDGS levels increased. A linear decrease (P = 0.04) in days on feed (169, 166 and 154 d) was noted when increasing levels of wheat DDGS (0, 20 and 40%) were fed. Dressing percentage increased in a linear fashion with wheat DDGS (P < 0.01) inclusion level and in a quadratic fashion (P = 0.01) as corn DDGS inclusion level increased although other carcass traits were not affected (P > 0.10) by treatment. The results indicate that replacement of barley grain with corn or wheat DDGS up to 40% of the diet (DM) can lead to superior performance (improved gain:feed or reduced days on feed, respectively) with no detrimental effect on quality grade or carcass SPBBB yield.