Effects of wet corn gluten feed and yellow grease on digestive function of cattle fed steam-flaked corn-based finishing diets

Twelve ruminally cannulated, English-crossbred steers (436±16kg) were used in a completely random experiment to evaluate the influence of dietary wet corn gluten feed (WCGF) and yellow grease (fat) in steam-flaked corn-based finishing diets on diet intake, digestibility, and rumen fermentation characteristics. Treatments consisted of steam-flaked corn-based diets containing the following WCGF/fat combinations: (1) 0g/kg WCGF/30g/kg added fat (STD3), (2) 250g/kg WCGF/0g/kg added fat (WCGF0), and (3) 250g/kg WCGF/30g/kg added fat (WCGF3). Steers fed WCGF3 consumed more (P=0.01) dry matter (DM) than did those fed STD3 or WCGF0 (23.5>18.4=18.8±0.9g/kg of body weight (BW) daily, respectively). Organic matter intake was also greater (P≤0.02) for WCGF3-fed steers than steers fed STD3 and WCGF0 (22.1>17.7=17.8±0.8g/kg BW, respectively). Total tract digestibilities of DM, organic matter (OM), neutral detergent fiber (aNDF), acid detergent fiber (ADF), and crude protein (CP) were not different (P≥0.15) in the 3 groups. Digestion of aNDF was greater in cattle fed WCGF3 and WCGF0 than in those fed STD3 (1.6=1.3>0.8±0.1g/kg BW, respectively). Ruminal fluid dilution rate (0.075>0.057=0.052±0.4/h for WCGF3, WCGF0, and STD3, respectively) and particulate passage rate (0.059>0.042=0.036±0.4/h, for WCGF3, WCGF0, and STD3, respectively) increased (P<0.03) in steers fed WCGF3 compared with those fed WCGF0 and STD3. Ruminal pH was greater (P<0.05) in steers fed WCGF0 than in those fed WCGF3 and STD3 (5.9>5.4=5.3±0.1, respectively). Total ruminal volatile fatty acids (VFA) in WCGF0-fed steers tended to be less (P<0.09) than in steers fed WCGF3 or STD3 (97.8<119.4=122.6±6.8mM, respectively). Ruminal propionate concentration (mol/100mol) tended to be greater (P≤0.06) in steers fed WCGF3 (43.4±2.1) than in those consuming WCGF0 (35.0±2.1) or STD3 (34.0±2.1). The acetate:propionate ration tended to be greater (P<0.09) in steers fed STD3 and WCGF0 than in those fed WCGF3 (1.3=1.3>0.9±0.1, respectively). Supplementing 30g/kg fat to a finishing diet containing 250g/kg WCGF increased DM intake due to faster liquid and particle passage rates, and to increased total tract nutrient digested.