Abstract

Three herds of dairy cattle, each consisting of 24 cows, were rotationally grazed under three treatments: standard pastures (perennial ryegrass–white clover) under contemporary management (Std-Con), diverse pastures (multi-species sward) under regenerative management (Div-Reg), and diverse pastures under contemporary management (Div-Con). To investigate the impact of diet on the diversity of the gut microbiome, faecal samples were collected from 10 cows per treatment during spring (October and November) 2022. Genomic DNA was extracted, and 16S rRNA amplicon sequencing was performed to characterise the gut microbiome using the Greengenes 16S database. Faecalibacterium prausnitzii dominated across all treatments, showing significantly (p < 0.05) higher relative abundance in Div-Con (41.6%) compared to Div-Reg (28.6%) and Std-Con (27.2%) in October. By November, the relative abundance was increased in Div-Reg to 42.9%, which was significantly greater (p < 0.05) than Div-Con (32.5%) and Std-Con (28.9%). Notably, Ruminococcus bromii was only detected in Div-Reg (October) and Div-Con (November). Bacteroides uniformis (24.2%) and Ruminococcus flavefaciens (19.8%) were also prominent across treatments over time. These findings indicate that, during spring 2022, diverse pastures supported a greater abundance of specific and potentially beneficial gut bacteria. Further research will investigate temporal dynamics of the cattle gut microbiome under these pasture management systems.

Jayaneththi, U., Sneddon N.W., Jeyakumar P., Burkitt L., Gedye K., Anderson C.W.N., Fermin L.M., and Donaghy D.J.

Hamilton, Volume 85, Hamilton, 1-4, 2025