| Abstrakt: |
Cross-bred steers (n = 397; initial BW = 247 ± 21 kg) from a single ranch were used to determine the effects of supplementing a Bacillus subtilus direct-fed microbial (DFM; CLOSTAT, Kemin Animal Health, Des Moines, IA) at a rate of 13 g ∙ steer−1 ∙ d−1 on feedlot performance, carcass characteristics, and clinical health during receiving and finishing. Steers were randomly assigned to pens by BW and pens were pairwise assigned 1 of 2 experimental treatments, control (CON) or DFM. Steers were housed in 12.2 x 30.5 m soil surfaced pens, and pen served as the experimental unit. There were no differences during the receiving period for overall BW (P = 0.97), ADG (P = 0.91), DMI (P = 0.77), or G: F (P = 0.79). There was a tendency (P = 0.09) for the DFM fed steers to be 14% more efficient from d 0 to 14 of the receiving period. There were also no differences in final BW (P = 0.40) or overall DMI (P = 0.46) during finishing, but there was a difference in ADG (P = 0.03) from d 29 to 56 of the finishing period where steers supplemented with DFM had greater ADG. The DFM supplemented steers also tended to be more efficient overall during finishing and for the entirety of the experiment (P = 0.07 and P = 0.08, respectively). There were no differences in carcass characteristics (P ≥ 0.31) between the experimental treatments. While limited research has been conducted examining the effects of Bacillus subtilis on feedlot performance, carcass characteristics, and the clinical health of growing and finishing steers, the results of this experiment suggest that the supplementation of a strain Bacillus subtilis at a rate of 13 g ∙ steer−1 ∙ d−1 may improve feed efficiency [ABSTRACT FROM AUTHOR] |
