The Dairy Ruminant Gut Microbiome: Profile, Responsiveness to Seasonality and Impact on Milk Quality

The gut microbiome (GM) and particularly the rumen microbiome (RM) affect the ruminant health and they are associated with milk quality and safety. The bovine RM has been extensively studied due to the importance of cattle in Agriculture. Studies of the gastrointestinal microbiome (GITM) of other livestock ruminants like goats, lag behind, comparatively. Sheep and goat rearing sustains livelihoods in unprivileged areas, globally. Dominant ruminant GM shaping factors are host and diet. Exposure to seasonal stimuli (e.g., diet) is associated with livestock GITM shifts. These seasonal microbial changes correlate with milk production and milk microbiota (MM) variation, with mechanistic links to remain unclear. The seasonality impact could be intensified during extensive rearing. Goats are frequently described as resilient livestock due to behavioural and dietary adaptability. If the goat GM responsiveness to seasonal stimuli plays a functional role in the livestock resilience and milk quality remains unresolved. Goats are discussed here as a comparatively underexplored system for investigating microbiome-mediated adaptation to variable environments. Here, we overviewed the current knowledge on the ruminant GM with emphasis to goats, and how seasonality may affect its configuration, and explored evidence linking seasonal GM variation to MM, milk quality and safety.