173. Feed Smarter: Supplementation of Bacillus and Other Microbial-derived Feed Additives and Their Impact on Finishing Cattle Production.

Abstract Prebiotics are substrates for microorganisms, probiotics are live microorganisms, and postbiotics are inanimate microorganisms. Probiotics have modulatory effects over the microbiome and the host, while prebiotics are only associated with the effects on the microbiome that indirectly benefit health and productivity. We have conducted a series of seven feeding trials to evaluate a variety of microbial-derived products. Feeding 10 g/steer daily during an initial 47 d receiving period, steers fed live-yeast (Levucell SC Advantage Titan, CNCM-1-1077, Lallemand) had greater ADG by 4.3% (P = 0.01). However, no other improvements in growth performance were noted during the 77 d study. Feeding 0.50 g/steer daily of Bacillus subtilis PB6 (Clostat-500, Kemin) to yearling finishing steers, tended to increase ADG by 5.81% (P = 0.10) from d 29 to 56 and on d 112 tended to decrease fecal Salmonella prevalence by 66.7% (P = 0.17). Two supplements were fed in a 2 × 2 factorial arrangement: the probiotic Certillus CP B1801 Dry (28 g/steer daily; Arm and Hammer) and the yeast cell wall Celmanax, (YCW; 18 g/steer daily; Arm and Hammer) to steers from weaning until finish. Feeding YCW tended to increase (P ≤ 0.07) observed dietary NEm and NEg by 1.2 and 1.5%, respectively. In two additional studies, we evaluated growth performance of newly weaned steers during the initial feedlot receiving phase, offered a low-moisture, molasses-based block that contained organic trace minerals (Availa-4, Zinpro) and a saccharomyces cerevisiae fermentation culture product (Original XPC, Diamond V). Daily gain was enhanced from 6 to 22% (P ≤ 0.10); however, it cannot be determined if the growth response was related to the additional organic trace minerals or the yeast fermentation culture. Another study evaluated a drench of Megasphaera elsdenii NCIMB 41125 (Lactipro, Axiota) in steers abruptly transitioned from a receiving to growing diets, with 4 and 38% dietary starch (DM basis), respectively. Supplemental Megasphaera elsdenii NCIMB 41125 had no effects on growth performance (P ≥ 0.20). A further study with growing steers fed a corn silage-based diet, a product containing a blend of Bacillus licheniformis and Bacillus subtilis, plus essential oils (Palisade, Sulutions) was compared with monensin sodium alone, or their combination (monensin + Palisade) After the 83 d growing period, steers fed monensin had greater BW, ADG and efficiency than the other two groups. Overall, there are vast compositional differences among the many feed additives of microbial origin. Their use seems to be most beneficial during the initial feedlot entry period when feed intake is depressed, and cattle are undergoing some degree of stress.