Harnessing the early-life gut microbiome for sustainable ruminant production

The gut microbiome is a dynamic and complex ecosystem that plays an important role in determining ruminant health, productivity, and environmental footprint. Its plasticity during early life presents a critical window for potential programming of long-term physiological and functional capacities, with early interventions demonstrating greater effectiveness compared to those applied in the stable adult microbiome. This review synthesizes current evidence on the assembly of the early-life gut microbiome, elucidates the mechanisms and effectiveness of various interventions (including nutritional, microbial, and genetic approaches), and evaluates their impacts on feed efficiency, animal health, and methane emissions. While various intervention strategies offer promise for advancing ruminant production, challenges remain due to the inconsistency and variability in the persistence and long-term efficacy of these protocols. We highlight the urgent need for integrated and standardized intervention strategies, alongside longitudinal, multi-omics research, and the application of artificial intelligence, to fully unlock the transformative potential of early-life microbiome modulation. Such efforts are essential to aligning ruminant production systems with global food security and climate sustainability goals.