179 Effect of feeding alternative coproducts in finishing calves

Recent expansion of oilseed crushing facilities and multiple designations of renewable diesel fuel have created competitive markets in protein supplements for beef cattle. More research on the direct comparison to identify differences in finishing of beef cattle fed alternative coproducts produced across the northern US is needed for these expanding opportunities. The objective of this study was to determine the effects of alternative coproducts on dry matter intake (DMI), growth performance, and carcass characteristics of calf-fed finishing steers. Two hundred fifty-one crossbred steer calves (n=251, initial shrunk body weight [BW], 344 ± 9 kg) were stratified by source, and assigned to one of twenty-four pens (n=10-11 steers/pen) and one of three dietary treatments. Diets were formulated to provide similar amounts of crude protein and NEg with dried distillers grains plus solubles (DDGS), canola meal (CM), or soybean meal (SBM). Steers were fed for a total of 155 and 170 days with individual weights taken on d -1, 0, 23, 50, 78, 110, 154, and 155 and d -1, 0, 31, 56, 85, 112, 169, and 170 for block 1-3 and block 4, respectively. A 4% pencil shrink was applied to the initial and final BW. Growth and carcass data were analyzed in a generalized randomized block design using the GLIMMIX procedure of SAS 9.4 with dietary treatment and block (source) as fixed effects and pen serving as experimental unit. Dietary treatment differences in growth performance were detected with final BW (P = 0.04), BW gain (P = 0.02), and average daily gain (ADG, P = 0.02). Steers fed CM had greater final BW (P = 0.03), BW gain (P = 0.01), and ADG (P = 0.01) by 2.3%, 5.8%, and 5.8% to steers fed SBM, respectively. No differences were detected in DMI and gain:feed (P > 0.1). Dietary treatment differences in carcass characteristics were detected with hot carcass weight (HCW, P = 0.02), 12th rib fat thickness (RF, P = 0.03), and dressing percentage (DP, P = 0.01). Additionally, dietary treatment tended to influence USDA yield grade (YG, P = 0.06). Steers assigned to CM had 3.6% greater HCW (P = 0.01) and tended to have 2.5% heavier HCW (P = 0.09) compared to steers receiving SBM and DDGS, respectively. The USDA YG tended to be greater for CM than SBM (3.87 and 3.66, respectively) which corresponds to 0.16 cm greater RF for the CM fed steers (P = 0.02). No differences were detected in ribeye area or marbling score (P ≥ 0.16). No performance adjusted net energy differences were detected between the coproducts (P ≥ 0.71).