Abstract: Under the dual background of the implementation of industrial policies on antibiotic reduction, restriction, and replacement, as well as the advancement of the global "dual carbon" strategy, rumen phages, as important regulatory factors of the rumen microbial ecosystem of ruminants, has become a research hotspot in ruminant microbiomics. Existing studies have shown that rumen phages have typical characteristics such as large population size, high community abundance, strong host specificity and unique genomic genetic diversity. They can regulate rumen fermentation metabolic efficiency, livestock and poultry production performance and rumen methane production, and demonstrate dual values of disease prevention and control and ecological emission reduction. At present, the research technologies of rumen phages has been upgraded from traditional pulsed-field gel electrophoresis and laser densitometry-based qualitative and quantitative detection to new technologies such as high-throughput metagenomic sequencing and single-cell sequencing, which have overcome the bottleneck of traditional technologies that cannot distinguish species. However, the existing technologies show a high dependence on the databases, and technical limitations such as difficulties in annotating novel viruses have not been completely resolved. This paper comprehensively reviews the latest research results in the field of rumen phage in ruminants from the four dimensions of rumen phage community structural characteristics, detection and analysis technologies, microbial regulatory mechanisms and community dynamic succession patterns. Diet composition and host physiological status are the core regulatory factors that determine the abundance and community composition of rumen phages. External dynamic conditions such as feeding cycles, seasonal changes, host growth stage and farming environment continuously drive the phage community to undergo phased replacement and succession. Prospects for subsequent key research directions of rumen phages are provided, aiming to offer theoretical support for the development of antibiotic-free and green farming technologies for ruminants and promote the low-carbon sustainable transformation of animal husbandry industry.

Key words: rumen phages, ruminants, methane emission reduction, community succession, antibiotic reduction and replacement, green livestock farming