Feed intake, digestibility, and live weight gain by cattle consuming forage supplemented with rice bran and(or) corn

Effects of supplementing cattle consuming forage with rice bran and(or) corn on feed intake, digestibility, and live weight gain were determined. Holstein steer calves (176 +/- 4.3 kg average trial BW), in two simultaneous 4 x 4 Latin squares, had ad libitum access to bermudagrass or ryegrass-wheat hay without supplementation (Control) or with (DM basis) .5% of BW of ground corn (C), .64% of BW of rice bran (R), or .25% of BW of corn plus .32% of BW of rice bran (CR). Total OM intake with bermudagrass diets was less for R than for C, but values for R and C were not different with ryegrass-wheat (forage source x supplement type interaction; P < .05). An interaction (P < .06) between supplement type and forage source also occurred in digestible OM intake (3.33, 3.66, 2.93, 3.37, 3.77, 4.04, 3.73, and 3.94 kg/d for Control, C, R, and CR with bermudagrass and ryegrass-wheat, respectively). Mature beef cows (504 +/- 25.5 kg BW), in a 6 x 6 Latin square, were limit-fed ryegrass-wheat and alfalfa hay (3:1; air-dry basis) without supplementation (Control) or with (DM basis) .2 or .4% of BW of ground corn (L-C and H-C), .26 or .52% of BW of rice bran (L-R and H-R), or .2% of BW of corn plus .26% of BW of rice bran (H-CR). Duodenal flows of total (125, 122, 123, 137, 136, and 129 g/d) and microbial N (63.3, 64.7, 64.8, 70.3, 73.1, and 65.1 g/d for Control, L-C, H-C, H-R, and H-CR, respectively) were greater (P < .05 and .06, respectively) for rice bran than for corn supplements. Crossbred beef steers (96; 235 +/- 3.2 kg initial BW) of two frame sizes, with half treated with an estrogenic growth promotant, grazed fescue-clover and received Control, L-C, H-C, L-R, H-R, and H-CR supplements for 84 d. Supplement amounts were 50% greater relative to BW than in the preceding experiment. Overall ADG was increased (P < .05) by supplementation and was affected (P < .05) by a supplement type x level interaction (.71, .76, .97, .85, .76, and .94 kg/d for Control, L-C, H-C, L-R, H-R, and H-CR, respectively). Neither frame size nor growth implant modified effects of supplement treatments on ADG.