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Non-hormone-treated beef steers (n = 1625; 371 ± 8.4 kg) were used to determine the impact of a direct-fed microbial (DFM) on growth performance, carcass characteristics, health parameters, and economic outcomes in finishing beef cattle. Steers were blocked based on initial BW, sorted into three optimal marketing groups for each day of enrollment, randomly assigned to one of two treatments (12 replicates per treatment), and fed for an average of 133 days before harvest. Treatments included the following: (1) control (CON) and (2) 50 mg/head per day of a DFM (BDP) containing Lactobacillus animalis 506, Propionibacterium freudenreichii 507, Bacillus licheniformis 809, and Bacillus subtilis 597 (BOVAMINE DEFEND® Plus). Steers were weighed in drafts by pen on a certified scale at closeout, and both pens within a block were harvested on the same day. Carcass characteristics and liver scores were collected upon slaughter. Data were analyzed as part of a completely randomized block design with the pen as the experimental unit. There was no difference in dry matter intake and final body weight between treatments. The BDP steers exhibited a lower number of total outs (deads and removed) throughout the experiment (p < 0.01). Average daily gain (ADG) tended to be greater (p < 0.06), and feed efficiency (p < 0.01) was greater, for steers receiving BDP. Although there were no statistical differences in hot carcass weight and quality grade between treatments, there was a lower incidence of liver abscess scores (p < 0.01) in the BDP steers. These data suggest that BOVAMINE DEFEND® Plus supplementation improves growth performance during the finishing phase, reduces overall mortality, and improves feed to gain efficiency.
Guimaraes et al. (Thu,) studied this question.