The Rumen Microbial Ecosystem in Sheep: The Association of Microbial Populations with Health and Production Efficiency

The rumen microbial population, as a complex and dynamic ecosystem, plays a pivotal role in the health and productive efficiency of sheep. This review aimed to comprehensively evaluate the role of the rumen microbial population in sheep performance, health, and production, identify factors affecting its composition and activity, and examine management strategies for modulating this microbial community. In this study, research conducted over recent decades was reviewed to assess the importance and composition of the rumen microbial population and the factors affecting its dynamics. In addition, strategies for modulating the microbial population, including probiotics, prebiotics, yeasts, plant essential oils, and novel technologies such as microbial population transfer, were considered. The findings indicated that the rumen microbial population plays an important role in nutrient utilization and, consequently, growth, feed conversion ratio, carcass characteristics, and milk production through the fermentation of feed components, fiber digestion, protein metabolism, volatile fatty acid production, and microbial protein supply. Maintaining a balanced microbial population is associated with stable fermentation conditions and animal health and may help reduce the risk of disorders such as acidosis and bloat. However, inter-individual variation, the complexity of microbial interactions, and differences in animals’ responses to nutritional interventions remain important challenges for targeted management of this community. Therefore, understanding the factors affecting the structure and activity of the rumen microbial population and the targeted application of nutritional and management strategies, particularly feed additives and bioactive compounds, may improve nutrient utilization, maintain animal health, and enhance sustainable productivity in sheep, while providing a basis for more precise management of this ecosystem.