Genomic DNA was extracted from sheep rumen fluid samples using a DNA extraction kit. The qualified DNA was randomly fragmented by ultrasonication to a size of approximately 350 bp. The fragmented DNA was then end-repaired, A-tailed, and ligated with sequencing adapters. PCR amplification was performed to enrich the adapter-ligated fragments. The resulting libraries were sequenced on an Illumina NovaSeq 6000 platform using the paired-end 150 bp (PE150) strategy.