Association of residual feed intake with peripartal ruminal microbiome and milk fatty acid composition during early lactation in Holstein dairy cows
Feed efficiency in peripartal Holstein cows is associated with differences in ruminal bacterial profiles and milk FA composition during the transition period. Compared with L-EFF, M-EFF cows had greater relative abundance of carbohydrate-fermenting and acetate-producing bacteria during early lactation, suggesting a better capacity for utilizing complex carbohydrates in the rumen. In contrast, L-EFF cows had greater DMI and lactate-producing bacteria, indicating they were more susceptible to developing acidosis. The concentrations of LCFA and MUFA in the milk of M-EFF cows were greater than L-EFF cows, whereas MCFA and SFA were lower. Acetate-producing bacteria and Prevotellaceae had opposite correlations with 16:1 cis-9 and 17:1 cis-10 concentrations in milk. Concentration of 15:0 in milk might reflect the population of bacteria related to butyrate metabolism in the rumen during the transition period. Overall, the data provide support for additional studies during the transition period to expand our understanding of the consequences of selective breeding based on RFI.