167. Feed Smarter: Probiotics in Beef and Dairy Cattle: Where Are We Really?.

Abstract The cattle industry is under increasing pressure to produce more beef and dairy products using fewer resources while leaving a smaller environmental footprint. For many years, antimicrobials were used to improve the efficiency and precision of cattle feeding and production, but following the implementation of regulations limiting the use of antibiotics, probiotics (often called eubiotics) have become an increasingly important alternatives to antibiotics to improve food animal production efficiency. Direct Fed Microbials (DFM) or eubiotics (including probiotics, postbiotics, and prebiotics) approaches are widely used today within the beef and dairy industry to improve production, quality, health, and food safety metrics. However, despite the positive results reported with many eubiotic products, the impacts on beef and dairy production remain variable because much remains unknown about how eubiotic approaches interact with the resident microbial population of the gut, and with the host animal as part of a “black box system”. Adding eubiotics to cattle diets can interact with both the native microbial ecosystem and host animal physiology in the gut, and these interactions are crucial to understanding the variability in eubiotic impacts. The benefits of eubiotic approaches depend on production demands, diet composition, the specific microbial products used, as well as specific microbial ecological factors within the host gut microbiome. Recent years have seen an increased interest in the use of Bacillus products because the spores can survive feed processing and then vegetate (grow) in the gut. Traditionally, the effects of DFM were thought to be directly mediated through changes in the gut microbial ecosystem and resultant changes in fermentation endproducts. The advances and widespread implementation of Next Generation Sequencing has provided new insights into how eubiotic approaches can alter beef and dairy cattle production efficiency (including methane production), milk and carcass quality, animal performance, food safety, and animal health. Increasingly, data demonstrates that DFM feeding to beef and dairy cattle can directly impact cattle gene expression including: growth hormone production, inflammatory responses (and associated non-growth energy expenditure), pathogen recognition receptors, and immune function. Overall, this presentation will present the state of the art analysis as to where our current understanding of the inclusion of Pro-, Pre- and Post-biotic approaches. This presentation will highlight that impacts are not the relatively simple traditionally hypothesized mechanisms; but are instead part of a complex cascade of microbial ecological and host animal physiological effects that ultimately impact beef and dairy production and profitability.