Understanding Your Horse's Microbiome: A Complex Ecosystem

I realise most of us are not big on the ‘Sciency stuff’ but bear with me because these studies are good!  Besides, we really need to see more science-based backing on the incredible value and importance of a healthy gut and our precious microbes, so here goes!

Recent scientific research has shown how important the microbiome is in the health of our horses. In 2018 a groundbreaking study by Costa and Weese (2018) in Veterinary Clinics: Equine Practice demonstrated that horses host one of the most complex microbiomes in mammals.  Their guts harbour hundreds of bacterial species that play essential roles in digestion, immunity, and overall health!  What’s important is to understand the difference between probiotic options in the marketplace today.

MicroMed’s Commensal Microbes

What’s SO special about MicroMed’s product is that it is a live COMMENSAL formulation of over 80 different strains of microbes that change slightly with every batch, as it is batch brewed.  Many of these microbes should be naturally occurring in the microbiome of our horses but due to environmental toxins and drugs administered, are actually not!   A commensal probiotic means they are a complete eco-system in and of themselves, also known as a meta-organism.  Think of them as a team working together in a workplace.  Each one has its own unique skills and abilities but they all work together as a team to make the magic happen.  Our microbes work together in and on the host in a symbiotic relationship, as opposed to ‘single’ or even multi-strain probiotics that are available in the marketplace. Most marketplace probiotics are not ‘native microbes’, they are transient.  Commensal microbes are NATIVE!  Most transient microbes, while travelling through the body doing good, are out within 24hrs!  Not commensals!  So, let’s carry on….

The Scientific Evidence Behind Commensal Microbes

Core Microbiome Composition

Metcalf et al. (2017) in FEMS Microbiology Ecology mapped the core bacterial communities in healthy horses, identifying key commensal species including:

• Firmicutes (particularly Clostridiales)
• Bacteroidetes
• Proteobacteria
• Verrucomicrobia

Costa and Weese’s (2018) comprehensive review highlighted several key areas where microbiome health directly impacts equine well-being:

Digestive Health

·       Proper fibre fermentation

·       Maintenance of gut barrier function

·       Protection against pathogenic bacteria

·       Production of beneficial metabolites

Disease Prevention

·       Colitis

·       Diarrhoea

·       Certain forms of colic

·       Gastrointestinal inflammation

Costa and Weese (2018) demonstrated that their ‘native commensal’ bacteria perform crucial functions that commercial probiotics ie. single or multi-strain probiotics often cannot replicate, including:

• Nutrient processing and absorption
• Immune system function
• Protection against pathogens
• Overall gastrointestinal health

These researchers found that disruptions to these natural populations could significantly impact horse health and well-being.

Early Life Development

Schoster et al. (2017) demonstrated the importance of early microbiome development in foals:

·       Distinct bacterial communities establish within the first weeks of life

·       Early disruptions may increase disease susceptibility

·       Health microbiome development correlates with reduced diarrhoea risk

Impact on Digestive Health

Research by Schoster et al. (2020) in the Journal of Veterinary Internal Medicine demonstrated clear links between microbiome disruption and various equine health issues:

• Changes in commensal bacterial populations preceded the development of colitis
• Horses with disturbed microbiomes showed increased susceptibility to pathogens
• Recovery from digestive issues correlated with restoration of normal commensal populations

Diet and Microbiome Interaction

Kim et al. (2021) in Animal Bioscience revealed how diet directly influences the equine microbiome:

• Sudden feed changes disrupted beneficial bacterial populations
• Fibre-rich diets promoted healthier microbial diversity
• Specific feed components supported different beneficial bacterial groups

Clinical Applications Supported by Research

Colic Prevention

Studies have shown that maintaining healthy commensal populations may help prevent colic through:

• Enhanced fibre digestion (Costa & Weese, 2018)
• Improved gut motility (the ability of an organism to move independently, using metabolic energy)
• Better regulation of inflammatory responses

Digestive Health

Research by Schoster et al. (2020) demonstrated that healthy commensal populations:

• Support proper nutrient absorption
• Help maintain gut pH balance
• Create natural barriers against harmful bacteria

Performance Support

Scientific evidence indicates that a balanced microbiome contributes to:

• More efficient feed utilization (Kim et al., 2021)
• Better nutrient absorption
• Enhanced recovery from exercise

Why Natural Commensals Matter

Recent research highlights why horse-specific commensal microbes are superior to generic probiotics:

1. Evolution and Adaptation

• Horse commensals have co-evolved with equines over millions of years
• They possess specific adaptations to the equine gut environment
• They can establish stable, long-term colonies

2. Specialized Functions Research by Metcalf et al. (2017) showed that native commensals:

• Produce enzymes specifically adapted to equine digestion
• Communicate effectively with the horse's immune system
• Create beneficial metabolites that support horse health

Evidence-Based Implementation

Supported by Clinical Research

Incorporating commensal supplements should follow evidence-based protocols:

• Gradual introduction to minimize disruption
• Consistent administration for optimal colonization
• Regular monitoring of horse health markers

Evidence Based Management Strategies

Salem et al. (2018) identified several factors that influence microbiome health:

Diet Considerations

·       Feed type and quality

·       Feeding schedule consistency

·       Dietary transitions

·       Forage-to-concentrate ratios

Environmental Factors

·       Stress management

·       Housing conditions

·       Exercise routines

·       Overall management practices

Best Practices from Scientific Literature

Studies recommend:

• Maintaining consistent feeding schedules
• Providing adequate fibre intake
• Minimizing stress during supplementation
• Regular veterinary monitoring

Young Horses - Schoster et al. (2017)

·       Early microbiome establishment

·       Support during developmental stages

·       Prevention of digestive disorders

Adult Horses – Costa and Weese (2018)

·       Maintenance of digestive health

·       Support during stressful periods

·       Recovery after anti-biotic treatments

Practical Applications

Based on current research, commensal supplements may be particularly beneficial for:

• Horses recovering from anti-biotic treatment
• Animals with recurring digestive issues
• Performance horses under stress
• Aging horses with declining digestive efficiency

Looking to the Future

Ongoing research continues to reveal new insights:

• Mapping of the complete equine microbiome
• Understanding host-microbe interactions
• Developing more targeted supplementation strategies
• Identifying new beneficial bacterial strains

Promising areas for future investigation:

·       Specific strain identifications and functions

·       Long-term impacts of microbiome management

·       Interactions between diet and microbial populations

·       Prevention strategies for common disorders

Conclusion

The scientific evidence is clear: commensal microbes play a fundamental role in equine health. By supporting these natural populations with research-backed supplements, we can help maintain and restore proper microbial balance in our horses.  While research continues to unveil new insights, current studies provide a strong foundation for understanding how supporting natural microbial populations can benefit horse health and well-being.

References

1. Costa, M. C., & Weese, J. S. (2018). Understanding the intestinal microbiome in health and disease. Veterinary Clinics: Equine Practice, 34(1), 1-12.
2. Kim, H., et al. (2021). The influence of diet on the equine intestinal microbiome. Animal Bioscience, 34(8), 1255-1265.
3. Metcalf, J. L., et al. (2017). Evaluating the gut microbiome of horses: current and future methods. FEMS Microbiology Ecology, 93(12).
4. Schoster, A., et al. (2020). Dysbiosis and restoration of the equine microbiome. Journal of Veterinary Internal Medicine, 34(5), 2156-2166.
5. Salem. S.E., et al. (2018).  A longitudinal study of the faecal microbiome and metabolome of periparturient mares.  PeerJ, 6, e4398.
6. Schoster, A., Staempfli, H.R., Guardabassi, L.G., Jalali, M., & Weese, J.S. (2017).  Comparison of the fecal bacterial microbiota of healthy and diarrheic foals at two and four weeks of life.  BMC veterinary research, 13(1), 1-10.