The rumen microbiome represents a cornerstone of ruminant digestive physiology, orchestrating the anaerobic fermentation of plant biomass into short-chain fatty acids (SCFAs)-critical metabolites underpinning host energy metabolism, immune function, and environmental sustainability. This comprehensive review evaluates the transformative role of pan-genomics in deciphering the genetic and metabolic networks governing SCFA production in the rumen ecosystem. By integrating multi-omics datasets, pan-genomic approaches unveil unprecedented layers of microbial diversity, enabling precise identification of core functional genes and their dynamic contributions to carbohydrate degradation and SCFA biosynthesis. Notable advancements include the following: mechanistic insights into microbial community assembly and metabolic pathway regulation, highlighting strain-specific adaptations to dietary shifts; precision interventions for optimizing feed efficiency, such as rationally designing microbial consortia and screening novel feed additives through pan-genome association studies; and sustainability breakthroughs, demonstrating how targeted modulation of rumen fermentation can simultaneously enhance production efficiency and mitigate methane emissions. This synthesis underscores the potential of pan-genomics to revolutionize ruminant nutrition, offering a blueprint for developing next-generation strategies that reconcile agricultural productivity with environmental stewardship. The translational applications discussed herein position pan-genomics as a critical tool for advancing animal science and fostering a resilient livestock industry.