Serum and milk metabolites of Holstein dairy cattle for the establishment of objective indicators in a subacute ruminal acidosis-induced.

Our results show that different concentrate and forage feed ratios impact the metabolite levels in the serum and milk of lactating Holstein cows. A higher number of metabolites in milk, including those associated with milk fat synthesis and the presence of Escherichia coli in the rumen, differed between the two groups compared to that in the serum. The results of this study provide a useful insight into the metabolites associated with different concentrate and forge feed ratios in cows and may aid in the search for potential biomarkers for subacute ruminal acidosis.