Use of a novel direct-fed microbial as an alternative for tylosin phosphate to control liver abscesses and decrease antimicrobial use in finishing beef steers

Our goal was to evaluate the use of a novel direct-fed microbial as an alternative to antimicrobials to decrease liver abscesses in finishing beef cattle. Beef steers (n = 240; initial BW = 263 ± 18.0 kg) were used in a randomized complete block design comprising 3 BW blocks and 3 pen replications per treatment during the receiving period and 3 BW blocks and 14 to 15 pen replications per treatment during the finishing phase. Experimental treatments were assigned randomly to pen within BW block and consisted of (1) negative control, dietary supplement with no tylosin phosphate; (2) positive control, dietary supplement formulated to supply 90 mg of tylosin phosphate daily (Tylan-100; Elanco Animal Health); (3) positive control with tylosin phosphate removed the last 65 d of the feeding period; and (4) novel direct-fed microbial Bacillus licheniformis fed daily at 1 × 1011 cfu/steer. From d 0 to 59, ADG, DMI, DMI as a percentage of BW, and G:F did not differ. During the finishing period, live- and carcass-adjusted final BW did not differ among treatments. Likewise, in the finishing period, there were no differences in ADG, DMI, DMI as a percentage of BW, or G:F. No differences in hot carcass weight, DP, marbling score, longissimus dorsi area, 12th-rib fat thickness, or calculated yield grade were detected among dietary treatments. Liver abscess incidence and severity were not affected by dietary treatments. The use of a novel direct-fed microbial, B. licheniformis, in beef cattle fed in small research pens did not affect growth performance, carcass characteristics, or liver abscess prevalence or severity. Bacillus licheniformis is not a viable strategy to decrease liver abscesses in growing and finishing beef cattle.