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

Authors: HOFFMAN, ASHLEY - Texas Tech University; FERNANDO, SAMODHA - University Of Nebraska; Wells, James - Jim; WOERNER, DALE - Texas Tech University; MANAHAN, JEFF - Texas Tech University; LONG, NATHAN - Texas Tech University; MCDANIEL, ZACH - Texas Tech University; SMOCK, TAYLOR - Texas Tech University; LINE, DALTON - Texas Tech University; Broadway, Paul; Carroll, Jeffery - Jeff Carroll; Sanchez, Nicole; HALES, KRISTIN - Texas Tech University

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2023
Publication Date: 6/1/2024
Citation: Hoffman, A.A., Fernando, S.C., Wells, J., Woerner, D.R., Manahan, J.L., Long, N.S., McDaniel, Z.S., Smock, T.M., Line, D.J., Broadway, P.R., Carroll, J.A., Sanchez, N.C., Hales, K.E. 2024. 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. Applied Animal Science. 40(3):307-316. https://doi.org/10.15232/aas.2023-02483.
DOI: https://doi.org/10.15232/aas.2023-02483

Interpretive Summary: Liver abscesses present at harvest continue to increase in the fed beef industry. A recent liver abscess survey indicated that the rate averages 20.3% overall. In feed antimicrobials are used to decrease the frequency of liver abscesses. In feed microbial supplements can change bacteria within the digestive tract. Also, they may be able to replace in feed antimicrobials to control liver abscesses. In collaboration with university partners, scientists at the USDA-ARS assessed the use of a novel supplement to decrease liver abscesses in feedlot cattle. Results from this study found no differences in growth performance or carcass characteristics. Additionally, the supplement had no effect on the development of liver abscesses. Thus, further research is needed to understand whether the supplement influences liver abscesses. These data will be of interest to scientists studying liver abscesses as well as beef producers.

Technical Abstract: Our objective was to evaluate the use of a novel direct-fed microbial as a an alternative to antimicrobials to decrease liver abscesses in feedlot cattle. Angus beef steers (n = 240; initial BW = 263 ± 18.0 kg) were used in a randomized complete block design comprised of 3 BW blocks and 3 pen replications per treatment. Experimental treatments were randomly assigned to pen within BW block and consisted of: 1) negative control, dietary supplement contained no tylosin phosphate (Tylan-100; Elanco Animal Health, Greenfield, IN; NCON); 2) positive control, dietary supplement contained tylosin phosphate (PCON); 3) positive control with tylosin phosphate removed the last 65 d of the feeding period (PCONW); 4) novel direct-fed microbial fed at 1 g mixture/animal with 1 × 1011 CFU/g (DFM). By design, initial BW did not differ (P = 0.79) among treatments, and at the end of the 59-d receiving period, there were no differences in final live BW (P = 0.25). From d 0 to d 30, ADG, DMI, DMI as a percentage of BW, and G:F did not differ (P = 0.21). Likewise, the ADG, DMI, DMI as a percentage of BW, and G:F, from d 31 to d 59, did not differ (P = 0.30). In the overall receiving period from d 0 to d 59, there were no differences in ADG, DMI, DMI as a percentage of BW, or G:F (P = 0.20). During the finishing period, live- and carcass-adjusted final BW did not differ (P = 0.57) among treatments. For the overall finishing period, there were no differences in ADG, DMI, DMI as a percentage of BW, or G:F (P = 0.17). Carcass-adjusted ADG, DMI as a percentage of BW, and G:F also did not differ (P = 0.16). Across treatments, no differences in HCW were noted (P = 0.84). Dressing percentage, marbling score, longissimus dorsi (LM) area, 12th-rib fat thickness, and calculated yield grade (YG) were not different among dietary treatments (P = 0.32). Liver abscess incidence and severity were not affected by dietary treatments (P = 0.13). The inclusion of a novel direct-fed microbial in finishing cattle diets did not affect growth performance, carcass characteristics, or the development of liver abscesses. Given the limited existing literature in beef cattle, further research evaluating the supplementation of B. licheniformis as a direct-fed microbial to decrease liver abscesses is warranted.