Changes in the faecal microbiota of mares precede the development of post partum colic.
Authors: Weese J S, Holcombe S J, Embertson R M, Kurtz K A, Roessner H A, Jalali M, Wismer S E
Journal: Equine veterinary journal
Summary
# Editorial Summary Postpartum colic remains a significant clinical concern in mares, yet its aetiology is incompletely understood. Weese and colleagues hypothesised that disruption of the gastrointestinal microbiota during the periparturient period might predispose mares to colic, and investigated this by collecting faecal samples from pregnant and postpartum mares across three Kentucky farms, with 13 mares subsequently developing colic and 13 remaining unaffected; next-generation sequencing of bacterial 16S rRNA genes characterised the microbial communities across 85 samples. The most striking finding was a marked elevation in Proteobacteria abundance in samples collected before colic episodes (8.2% versus 3.7% in non-colic mares, P = 0.0006), whilst all samples with Firmicutes representing ≤50% of the microbiota preceded colic development, and 86% of those with >4% Proteobacteria were colic-positive; protective bacterial families including Lachnospiraceae and Ruminococcaceae were significantly depleted in mares that subsequently developed large colon volvulus. Surprisingly, the faecal microbiota changed little following foaling itself, suggesting that the critical microbiotic shifts occur during late pregnancy rather than in response to parturition. These findings suggest that microbiotal profiling—particularly monitoring the Firmicutes:Proteobacteria ratio—could enable practitioners to identify high-risk mares and potentially implement targeted dietary or probiotic interventions to prevent or mitigate postpartum colic.
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Practical Takeaways
- •Faecal microbiota composition—particularly elevated Proteobacteria and reduced Firmicutes—may provide predictive markers for postpartum colic risk; monitoring these changes could identify high-risk mares for preventive intervention.
- •Foaling itself causes minimal microbiota disruption, suggesting postpartum colic risk is linked to pre-existing microbial dysbiosis rather than the birth event, allowing for pre-emptive management strategies.
- •Specific bacterial families (Lachnospiraceae and Ruminococcaceae) are protective against large colon volvulus; future probiotics or dietary interventions targeting these taxa may help prevent this life-threatening condition.
Key Findings
- •Faecal microbiota of late-term pregnant mares differed from nonpregnant controls in community membership and structure, but foaling had minimal impact on the microbiome.
- •Samples preceding colic episodes had significantly higher relative abundance of Proteobacteria (8.2% vs 3.7%, P=0.0006) compared to non-colic mares.
- •All samples with Firmicutes ≤50% preceded colic development, and 86% of samples with >4% Proteobacteria preceded colic.
- •Sixty-one indicator operational taxon units distinguished control mares from those developing large colon volvulus, predominantly from families Lachnospiraceae and Ruminococcaceae.