Optimizing use of distillers grains in finishing diets containing steam-flaked corn

Two hundred ninety-nine crossbred yearling steers (363 +/- 15 kg initial BW) were fed for an average of 114 d in a finishing study comparing 7 diets in which steam-flaked corn was used as the principal energy source. Forty-nine pens were used in this study with 7 BW blocks, 7 pens per treatment, and 5 to 7 steers per pen. A control diet with no distillers grains with solubles (DGS) was compared with 6 diets containing 15% DGS (DM basis). The diets contained wet sorghum DGS with 0 or 6% alfalfa hay, dried sorghum DGS with 0 or 6% alfalfa hay, wet corn DGS with 6% alfalfa hay, or dried corn DGS with 6% alfalfa hay. Apparent total tract digestibilities were calculated by total collection of fecal material from the concrete-surfaced pens over a 72-h period. Dry matter intake, ADG, G: F, and carcass characteristics were similar (P >= 0.18) for steers fed finishing diets with or without 15% DGS. However, apparent total tract digestibilities of DM and OM were 2.8% less (P <= 0.03) for finishing diets containing 15% DGS (DM basis). Dry matter intake, ADG, G: F, apparent total tract digestibility, and carcass characteristics were not different (P >= 0.09) for steers fed finishing diets containing sorghum or corn DGS. Dry matter intake, ADG, G: F, apparent total tract digestibility, and carcass characteristics also were not different (P >= 0.10) for steers fed finishing diets containing wet or dried DGS. Steers fed sorghum DGS with 6% hay consumed more DM (P < 0.01) and gained more BW (P < 0.01) than steers fed diets without hay, but G: F were not different (P > 0.78). Sorghum DGS diets containing alfalfa hay were 4% less (P = 0.01) digestible than sorghum DGS diets containing no hay. Carcasses of steers fed sorghum DGS diets without hay were lighter, leaner, and had decreased USDA yield grades (P = 0.01) compared with steers fed sorghum DGS diets containing hay. Feeding moderate levels (i.e., 15%, DM basis) of DGS resulted in growth performance and carcass characteristics similar to those of cattle fed no DGS. In addition, sorghum- and corn-based DGS had similar feeding values, and wet (approximate to 31% DM) and dried (approximate to 91% DM) DGS also had similar feeding values. Complete removal of alfalfa hay in diets containing DGS improved diet digestibility but reduced growth performance and carcass finish.