Effects of Graded Levels of Sorghum Wet Distiller’s Grains and Degraded Intake Protein Supply on Performance and Carcass Characteristics of Feedlot Cattle Fed Steam-Flaked Corn-Based Diets

Two experiments evaluated different levels of sorghum wet distiller’s grains plus solubles (SWDG) and effects of increasing the degraded intake protein (DIP) concentration in diets containing SWDG on performance and carcass characteristics of feedlot cattle. In Exp. 1, 200 beef steers (average BW = 404 kg) were fed increasing levels of SWDG (0, 5, 10, and 15% of DM) and one level of corn wet distiller’s grains plus solubles 1This experiment was supported, in part, by a cooperative agreement between the USDA-ARS and Texas Tech University. The mention of trade or manufacturer names is made for information only and does not imply an endorsement, recommendation, or exclusion by USDA-ARS or Texas Tech University. 2Corresponding author: judson. [email protected] (10% of DM), which replaced steamflaked corn in a high-concentrate diet. Final BW (P = 0.04) and overall ADG (P = 0.01) decreased linearly with increasing levels of SWDG. Increasing SWDG decreased overall G:F (P = 0.01), hot carcass weight (P < 0.01), and LM area (P < 0.01). No differences were observed in overall DMI (P = 0.15) or other carcass characteristics (P ≥ 0.09). Neither DMI nor G:F differed between corn wet distiller’s grains plus solubles and SWDG when fed as 10% of the dietary DM. In Exp. 2, 200 steers (average BW = 369 kg) were either fed a control diet without SWDG (8.4% DIP) or three 10% SWDG diets with no urea added or urea added at either 50% or 100% of the difference in the DIP concentration between the diet with no urea added and control diets. Final BW (P = 0.03), overall ADG (P = 0.04), and overall G:F (P = 0.05) were greater for cattle fed the control diet. A linear decrease was observed in overall DMI with increasing DIP (P = 0.02). Likewise, overall ADG decreased with increasing DIP (P = 0.08). Cattle fed the control diet had greater hot carcass weight (P = 0.03), fat thickness (P = 0.02), and yield grade (P = 0.01) than the average of those fed the 3 SWDG diets. Results from both experiments suggest decreased performance and carcass value with increasing levels of SWDG alone or combined with additional DIP. At 10% of the dietary DM, corn and sorghum wet distiller’s grains resulted in similar ADG and G:F.