Equine Contribution in Methane Emission and Its Mitigation Strategies.
Authors: Elghandour Mona M M Y, Adegbeye Moyosore Joseph, Barbabosa-Pilego Alberto, Perez Nallely Rivero, Hernández Saúl Rojas, Zaragoza-Bastida Adrian, Salem Abdelfattah Z M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Equine Methane Emissions and Mitigation Approaches Whilst horses produce considerably less methane than ruminants due to their hindgut fermentation physiology, the growing equine population could amplify their contribution to the estimated 1.2–1.7 Tg of annual equine methane emissions. This 2019 review synthesised current evidence on the microbial and dietary drivers of methane production in horses, identifying key methanogenic archaeal clades (Methanomicrobiales, Methanosarcinales, Methanobacteriales, and Methanoplasmatales) and explaining how diet composition, feeding frequency, seasonal variation, genetics, and protozoal populations influence gas output. The authors propose several practical mitigation strategies—including biochar supplementation, targeted fibre enzyme inclusion, plant-derived extracts, and facilitation of acetogenic pathways—which could reduce methane production whilst simultaneously improving feed energy utilisation. For practitioners, these findings suggest that dietary manipulation and carefully selected feed additives may offer cost-effective means of reducing environmental impact without compromising equine nutrition or performance, though further field validation of these interventions is needed before widespread adoption.
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Practical Takeaways
- •Dietary management including feed frequency optimization and supplementation with fiber enzymes and plant extracts can reduce methane losses and improve feed efficiency in working horses
- •Biochar and other additives targeting hindgut microbiota may provide practical on-farm solutions to decrease environmental impact while maintaining or improving horse performance
- •Consider seasonal variations in methane production when planning nutrition programs and environmental sustainability initiatives for equine operations
Key Findings
- •Horses produce 1.2-1.7 Tg of methane annually through hindgut fermentation, less than ruminants but with increasing equine populations potentially raising contribution
- •Four methanogenic clades identified in equine hindgut: Methanomicrobiales, Methanosarcinales, Methanobacteriales, and Methanoplasmatales, with Methanocorpusculum labreanum being common
- •Diet, feeding frequency, season, genome, and protozoa population significantly influence methane production in horses
- •Biochar, increased acetogens, fiber enzymes, plant extracts, and fecal energy recycling through anaerobic fermentation are proposed strategies to reduce equine methane emissions