CASE STUDY: Grain adaptation of yearling steers to steam-flaked corn-based diets using a complete starter feed1

ABSTRACT Three hundred six crossbred steers (initial BW = 319 ± 0.5 kg) were used to determine effects of adapting steers to a finishing diet using a complete starter feed (RAMP; Cargill Corn Milling, Blair, NE) for 14 to 30 d on steer performance and carcass characteristics. The RAMP treatments were compared with a traditional step-up procedure (CON). Steers in the CON treatment were adapted from the initial diet containing 45% alfalfa hay (ALF), 32.5% steam-flaked corn (SFC), 20% wet corn gluten feed (Sweet Bran, Cargill Corn Milling), and 2.5% supplement to the final finishing diet containing 65.7% SFC, 20% Sweet Bran, 8% ALF, 3% yellow grease, and 3.3% supplement over a 22-d period. During the step-up period, concentration of ALF was reduced and SFC, yellow grease, and urea were increased. Steers assigned to RAMP treatments were adapted to the same finishing diet using RAMP fed for 14, 18, 22, 26, or 30 d. During adaptation, RAMP decreased and the finishing diet increased. Compared with CON, RAMP increased carcass-adjusted final BW (584 vs. 597 kg; P = 0.05), ADG (1.90 vs. 1.99 kg; P = 0.06), and HCW (372 vs. 380 kg; P = 0.05). As the adaptation period for steers consuming RAMP increased from 14 to 30 d, fat thickness (P = 0.06), and YG (P = 0.01) increased linearly. Adapting steers to a finishing diet using RAMP increases animal BW gain during the finishing phase and reduces the total amount of roughage used by 21 to 28%.