Hay versus haylage: Forage type influences the equine urinary metabonome and faecal microbiota.
Authors: Leng Joy, McNally Susan, Walton Gemma, Swann Jonathan, Proudman Chris, Argo Caroline, Emery Sue, La Ragione Roberto, Eustace Robert
Journal: Equine veterinary journal
Summary
# Editorial Summary: Hay versus Haylage: Impact on Equine Metabolism and Gut Health Forage selection is a fundamental management decision for equine practitioners, yet its effects on metabolic health and microbial populations remain poorly characterised. Over a 13-month longitudinal study, researchers monitored 20 Welsh mountain ponies fed either hay or haylage, collecting monthly urine, faecal and blood samples and analysing bacterial composition via 16S rRNA gene sequencing and urinary metabolite profiles using proton magnetic resonance spectroscopy. Significant differences emerged in faecal bacterial communities between groups, with 102 operational taxonomic units showing differential relative abundance according to forage type, whilst urinary metabolic profiles diverged in 12 of 13 months—most notably in hippurate excretion (elevated in hay-fed ponies) and ethyl-glucoside (higher in haylage-fed animals). These findings suggest that forage type exerts measurable effects on both microbial ecology and metabolic pathways, with potential implications for weight management and metabolic disease susceptibility. For practitioners working with metabolically-prone animals, this research underscores the importance of forage selection as a targeted dietary intervention and highlights the need for individualised feeding strategies informed by an animal's metabolic status rather than relying on a one-size-fits-all approach.
Read the full abstract on PubMed
Practical Takeaways
- •Forage choice (hay vs haylage) has measurable effects on gut microbial communities and metabolic profiles in ponies, which may influence health outcomes and weight management
- •For ponies prone to weight gain, understanding these metabolic and microbial differences could inform feed selection decisions to support better metabolic health
- •The distinct urinary biomarkers (hippurate and ethyl-glucoside) associated with each forage type suggest different metabolic pathways are activated, warranting further investigation into long-term health implications
Key Findings
- •Faecal bacterial community profiles differed significantly between hay-fed and haylage-fed ponies, with 102 OTUs showing differential relative abundance by forage type
- •Urinary metabolic profiles were significantly different between groups for 12 of 13 months, with hay-fed ponies showing higher hippurate excretion throughout the study
- •Haylage-fed ponies demonstrated higher ethyl-glucoside urinary excretion compared to hay-fed ponies
- •Long-term forage type influences both the equine faecal microbiota composition and urinary metabolome profiles