Feeding condensed distillers solubles to feedlot finishing steers and the effects of feed additives in adaptation diets

Performance and carcass characteristics were evaluated using five concentrations of condensed corn distillers solubles (CCDS) replacing steam-flaked corn (SFC) and urea in finishing diets of crossbred steers (initial BW = 399 ± 27 kg). Concentrations of CCDS were: 0, 9, 18, 27, or 36% CCDS on a DM basis. Urea and soybean meal were included in all diets to meet or exceed NRC requirements for metabolizable protein. Steers were utilized in a randomized block design, blocked by BW, stratified by BW within block, and assigned randomly to pens. Pens were assigned randomly to treatment within BW block, with 8 pens/treatment and 11 steers/pen. Steers were fed for an average of 97 d. Dry matter intake decreased quadratically (P < 0.01) as the concentration of CCDS increased in the diet. Average daily gain increased quadratically (P < 0.01) with greatest gains observed at 27%. Similar to ADG, G:F increased quadratically (P < 0.01), with greatest G:F observed at 27% before decreasing at 36% CCDS. Hot carcass weight increased quadratically (P < 0.01), also maximized at 27% CCDS. Calculated YG and marbling score increased quadratically (P = 0.06 and 0.08, respectively). Fat thickness and LM area also tended (P = 0.13 and 0.07, respectively) to increase quadratically as CCDS concentration increased in the diet. Additionally, as CCDS increased in the diet, dressing percentage increased linearly (P = 0.01). Based on the first derivative of the quadratic response, the concentration of CCDS was calculated to be 18.2% and 24.5% for maximizing ADG and G:F, respectively. Feeding condensed distillers solubles can effectively be used to replace SFC in feedlot finishing diets while improving ADG and G:F.