Study links faecal microbiota to inflammatory responses in dairy cows

Researchers analysed blood and faecal samples from 411 dairy cows kept on 25 dairy farms, collecting material before and after parturition. The work focused on the transition period around calving, when cattle undergo hormonal, metabolic and immune changes and may develop disease or metabolic disorders.

To assess immune responsiveness, the team stimulated whole-blood samples outside the animal with lipopolysaccharide. Cytokine and chemokine secretion was then measured using a 15-plex assay. Faecal microbial communities were characterised through 16S ribosomal RNA metabarcoding.

The analysis grouped the animals into four profiles based on cytokine production around calving. These clusters were not clearly separated by their faecal microbiota composition, according to the study. The researchers nevertheless found associations between microbiota variation and the expression of individual cytokines.

Microbial differences accounted for as much as 9.4% of the variation in a single cytokine, CCL3. Several other inflammatory mediators, including interleukin-17A, interleukin-1α and interleukin-1β, were associated with different bacterial taxa.

Higher levels of Clostridium sensu stricto 1 were associated with higher concentrations of interleukin-17A. Lower levels of Monoglobus were associated with higher concentrations of interleukin-1α. The study described these relationships as associations rather than evidence that the bacteria directly caused the changes in cytokine levels.

The authors said the findings support the hypothesis that the microbiota present before calving may contribute to post-calving inflammatory responses. They also identified the gut microbiota as a possible source of early microbial indicators of immune challenge during the transition period. The paper was published in Scientific Reports on 21 August 2026 after being accepted on 28 July; the project was funded by APIS-GENE.