250 Effects of Bunk Management and Bulk Density of Steam-flaked Corn on Growth Performance, Carcass Characteristics, and Liver Score of Finishing Beef Cattle Fed Diets Without Tylosin Phosphate

Abstract

Abstract One hundred ninety-two beef steers (BW = 332 ± 8.2 kg) were used in a randomized complete block design to evaluate the effects of differing bunk management and bulk density of steam-flaked corn (SFC) in a randomized complete block design. A factorial arrangement of treatments was used with: 1) slick bunk management (SBM) + 335 g/L SFC; 2) modified ad libitum bunk management (MAL) + 335 g/L SFC; 3) SBM + 425 g/L SFC; 4) MAL+ 425 g/L SFC. Steers were randomly assigned to treatment within BW block, with 12 pen replications per treatment. Data were analyzed using a mixed model with fixed effects of bunk management, SFC bulk density, and their interaction. Block was included as a random effect. Bunk management strategy did not affect growth performance, carcass characteristics, or liver abscess score (P > 0.10). The average daily gain (ADG) of steers fed 425 g/L SFC was greater (P = 0.05) from days 35 to 105 than those fed 335 g/L SFC; however, overall ADG did not differ (P = 0.36). The DMI of steers fed 425 g/L SFC was greater (P ≤ 0.05) than those fed 335 g/L SFC. Gain-to-feed of steers fed 425 g/L SFC tended (P = 0.10) to be lesser from days 0 to 35 but did not differ overall (P ≥ 0.12). Steers fed 425 g/L SFC tended to have greater backfat and calculated empty body fat (P ≤ 0.07) than those fed 335 g/L SFC and had a greater calculated yield grade (P = 0.05). Steers fed 425 g/L SFC had 43.51% fewer (P = 0.04) liver abscesses. Bunk management strategy did not impact growth performance or carcass characteristics; whereas, SFC processed to 425 g/L increased DMI, fat thickness, and yield grade while resulting in a decreased proportion of liver abscesses.