Fecal Microbiota, Forage Nutrients, and Metabolic Responses of Horses Grazing Warm- and Cool-Season Grass Pastures.
Authors: Weinert-Nelson Jennifer R, Biddle Amy S, Sampath Harini, Williams Carey A
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Warm-season grasses offer a practical solution for extending summer grazing availability in temperate climates, yet their effects on equine digestive function remain poorly characterised. Weinert-Nelson and colleagues tracked eight mares across seasonal pasture transitions (cool-season spring, warm-season summer, cool-season fall), collecting faecal samples to profile microbial communities and correlate them with forage nutrient composition and glucose metabolism. The researchers found that microbial composition shifted markedly between pasture types with 90% accuracy, and—remarkably—could predict forage crude protein and non-structural carbohydrate content directly from microbiota profiles. Two taxa emerged as particularly responsive: *Akkermansia* and *Clostridium butyricum* were enriched on warm-season pasture, positively associated with crude protein and inversely associated with non-structural carbohydrates, with the latter genus negatively correlating with peak plasma glucose during oral sugar challenges. For practitioners, these findings suggest that the hindgut microbiota may serve as a biological indicator of pasture quality and metabolic stability, and that certain bacterial populations warrant investigation as potential markers or modulators of glycaemic control—particularly relevant for managing insulin dysregulation in grazing horses.
Read the full abstract on PubMed
Practical Takeaways
- •Integrating warm-season grasses into grazing systems shifts the fecal microbiota in ways that may improve metabolic stability; monitoring these shifts could help optimize pasture management strategies
- •Specific bacterial taxa (Akkermansia and Clostridium butyricum) enriched on warm-season pastures are associated with better glucose regulation, suggesting forage selection impacts hindgut fermentation and metabolic health
- •Fecal microbiota composition may serve as a practical biomarker to assess forage quality and predict metabolic responses without requiring direct forage analysis
Key Findings
- •Random forest classification predicted forage type from microbial composition with 90% accuracy
- •Akkermansia and Clostridium butyricum were enriched in horses grazing warm-season pasture and positively correlated with crude protein
- •Clostridium butyricum was negatively correlated with peak plasma glucose concentrations following oral sugar tests (p ≤ 0.05)
- •Microbial regression models successfully predicted forage crude protein and non-structural carbohydrate concentrations (p < 0.0001)