International Symposium on Ruminant Physiology: Stochastic and deterministic factors that shape the rumen microbiome

At the heart of degradation of complex OM within the rumen are its microbes. These microbes can convert unusable OM into usable protein and energy sources and therefore can directly influence an animal's health, performance, and utilization of feed. As such, understanding stochastic and deterministic factors that contribute toward rumen microbial assembly and persistence can provide valuable information for developing methods to improve animal health, performance, and nutrient utilization through microbiome modulation. In this review, we describe how ecological concepts such as colonization history, priority effects, and historical contingency may influence rumen microbial community assembly and in turn affect community composition and function. Additionally, we discuss how such ecological concepts can be used to develop novel microbial community assembly strategies to develop rumen microbiomes with long-term benefits to the host ruminant. Finally, we discuss current knowledge gaps in rumen microbiome research associated with host-microbe interactions and microbial assembly and propose potential opportunities for future microbiome studies to improve understanding of the rumen microbiome to promote animal health and productivity.