Optimizing the Length of Feeding an Elevated Level of Dried Distillers Grains plus Solubles-Soybean Hull Diet to Feedlot Cattle

The rapid expansion of ethanol production has resulted in an abundance of co-products available to cattle feeders. Two hundred forty steers were used to determine the optimum length of time for feeding a diet containing 40% dried distillers grains with solubles (DDGS) and 35% soybean hull (SH, DM basis) to feedlot cattle. Treatments consisted of feeding the DDGS-SH diet for 56, 84, 112, 140, and 196 d before switching to a corn-based finishing diet. All cattle were harvested after 196 d and serial ultrasound measurements were taken every 28 d. Data were analyzed for linear and quadratic effects, and orthogonal polynomial contrasts of 56 vs. 196 and 84 vs. 112 to 140 d were analyzed. Adjusted final BW and ADG increased linearly (P < 0.01) and G:F decreased linearly as length of time on the DDGS-SH diet increased. Dry matter intake increased linearly as days on the DDGS-SH diet increased. Adjusted final BW tended (P = 0.09) to be greater and ADG was greater (P = 0.01) for 196-d steers than 56-d steers. However, G:F was reduced (P < 0.01) for 196-d steers compared with 56-d steers. Dry matter intakes were greater (P < 0.01) for 196-d steers than 56-d steers. Liver scores and hot carcass weights increased linearly (P = 0.04) as days on the DDGS-SH diet increased. Cost of gain was not significantly different. These data indicate that the use of a DDGS-SH diet can achieve comparable performance and carcass characteristics to cattle fed a typical corn finishing diet.