Rumen microbes of early and late lactating dairy cows differing in methane yield

This study aimed to assess relationships of enteric methane yield (g of CH4 per kg of DMI) with immunocompetence, rumen microbiome, and feed efficiency in early- and end-lactating dairy cows. For microbiome analysis, the DNA was extracted from rumen content samples (esophageal tubing), and the gene amplicon of the V4 region of 16S rRNA was subjected to Illumina sequencing for microbial population identification and relative abundance analysis. The grouping of cows were divided retrospectively into an equal number of cows with low (LMY) and high (HMY) CH4 yield within each lactation group (early and late lactation) according to the observed methane yield. The results showed that at the genus level, the rumen fluid of LMY animals in early lactation was enriched for Methanospaera and Marvinbryantia while the genus Butyrivibrio was more abundant in HMY animals. In late lactation, several genera including Prevotella 7, Ruminococcus gauvreauii group, Shuttleworthia were enriched in LMY cows. In late-lactating HMY cow, an elevated abundance of several genera including Methanobrevibacter, Veillonellaceae UCG-001, Succinivibrionaceae UCG-002, Rikenellaceae RC9, and CAG-352 were observed.