The effect of supplementing CLOSTAT® 500 (Bacillus subtilis PB6) to yearling steers in a commercial feedyard on health, Salmonella spp. prevalence, feedlot growth performance and carcass characteristics

Authors: WORD, ALYSSA - Cactus Feeders, Inc; Broadway, Paul; Sanchez, Nicole; Carroll, Jeffery - Jeff Carroll; HALES, KRISTIN - Texas Tech University; KARR, KENDALL - Cactus Feeders, Inc; HOLLAND, BEN - Cactus Feeders, Inc; ELLIS, GUY - Cactus Feeders, Inc; MAXWELL, CASEY - Cactus Feeders, Inc; CANTERBURY, L - Kemin Industries, Inc; LEONHARD, J - Kemin Industries, Inc; LAFLEUR, D - Kemin Industries, Inc; HERGENREDER, J - Kemin Industries, Inc; TROJAN, SARA - Peak Beef Nutrition And Management Consulting, Llc

Submitted to: Translational Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2022
Publication Date: 9/18/2022
Citation: Word, A.B., Broadway, P.R., Sanchez, N.C., Carroll, J.A., Hales, K.E., Karr, K.C., Holland, B.P., Ellis, G., Maxwell, C., Canterbury, L.G., Leonhard, J.T., Lafleur, D., Hergenreder, J.E., Trojan, S.J. 2022. The effect of supplementing CLOSTAT® 500 (Bacillus subtilis PB6) to yearling steers in a commercial feedyard on health, Salmonella spp. prevalence, feedlot growth performance and carcass characteristics. Translational Animal Science. https://doi.org/10.1093/tas/txac131.
DOI: https://doi.org/10.1093/tas/txac131

Interpretive Summary: The beef industry has dedicated decades of research to addressing the economic burden of the bovine respiratory disease (BRD). However, beef cattle feedyard mortality rates continue to rise, and BRD remains the most economically detrimental disease to the industry. The recent estimated direct cost of BRD mortality to the beef industry is $907.8 million, annually, and the average cost for BRD treatment for feedlots is $75 million. Further, public concerns with antibiotic use in food animal production has led livestock industries to evaluate alternative approaches to disease management. As a result, nutraceutical compounds have come to the forefront of new product development and application in livestock production with implications for health. Yet, given the nature of neutraceutical compounds, modes of action are diverse, and health and performance responses to are highly variable by compound type and application. The active microbial supplement, Bacillus subtilis PB6 contains a unique, patented strain of B. subtilis. Previous research with B. subtilis PB6 in beef cattle has demonstrated a reduction in BRD treatment rate and reduced overall treatment cost. Additionally, B. subtilis PB6 has been reported to improve immune response to a Salmonella challenge and reduced Salmonella colonization in small intestinal tissues. Therefore, scientists from industry and academia teamed up with scientists from ARS’ Livestock Issues Research Unit to evaluate the effect of B. subtilis PB6 supplementation to steers in a commercial feedyard on health, Salmonella prevalence, performance, and carcass outcomes. Results from this study demonstrated that supplementing B. subtilis PB6 to feedlot steers resulted in less morbidity, a lower prevalence of Salmonella, and fewer steer removals. Thus, these results demonstrate that B. subtilis PB6 is an effective supplement for improving the overall health of feedlot cattle. These results will be of interest to commercial feedlot producers, feedlot veterinarians, feedlot nutritionists, and scientists working in the fields of beef cattle nutrition, health, and immunity.

Technical Abstract: British and British × Continental crossbred beef steers, n = 2,100; 313 ± 38 kg of initial body weight (BW) were used to evaluate the effects of the Bacillius subtilis PB6 supplementation to yearling steers in a commercial feedyard on health, prevalence of Salmonella spp., growth performance, and carcass characteristics. Cattle were blocked by arrival date and assigned randomly to pen within block; pens were randomly assigned to 1 of 2 dietary treatments within block. Treatments, replicated in 15 pens/treatment with 70 steers per pen, included: 1) control (CON), diets containing no supplemental direct fed microbials; 2) CLOSTAT (CLO), diets supplemented with 0.5 g/hd/d Bacillus subtilis PB6 (CLOSTAT® 500, Kemin Industries, Des Moines, IA) to provide 6.6 × 109 CFU/g of active ingredient. Supplementing CLO reduced the overall incidence of morbidity (P = 0.03), 10.38% (CLO) vs. 13.43% (CON), decreased the percentage of cattle treated once for bovine respiratory disease (BRD; P < 0.01), 9.14% (CLO) vs. 12.76% (CON), and decreased the incidence of BRD retreatment (P = 0.03) compared with CON. Mortality did not differ among treatments (P = 0.23); however, mortality combined with the number of removals tended to be less for CLO than CON (53 head vs. 73 head respectively, P = 0.06). Prevalence of fecal Salmonella did not differ among treatments, (P = 0.35); the overall fecal Salmonella counts tended to be less for CLO (1.59 log CFU/g) than CON (2.04 log CFU/g; P = 0.07). The concentration of Salmonella in subiliac lymph nodes was not different (P = 0.62) between CON (0.22 log CFU/g) or CLO (0.19 log CFU/g); however, there was a 46% reduction in the overall mean prevalence of lymph node Salmonella (15.48% vs. 28.66%) for CLO and CON, respectively). With deads and removals included, final BW was heavier for CLO supplemented steers than CON, (654 kg vs. 641 kg, respectively, P = 0.05), and average daily gain (ADG; P = 0.08), and gain efficiency (G:F; P = 0.06) tended to be greater for CLO than CON. With deads and removals excluded, final BW, ADG, and G:F did not differ among treatments (P = 0.30). Carcass traits were not different between treatments (P = 0.15). Supplementing CLO throughout the feeding period in a commercial feedyard improved the health outcomes of yearling steers by decreasing overall and BRD treatment rates, lowering the overall abundance of Salmonella, and resulted in fewer cattle removed from the experiment.