The Equine Faecal Microbiota of Healthy Horses and Ponies in The Netherlands: Impact of Host and Environmental Factors.
Authors: Theelen Mathijs J P, Luiken Roosmarijn E C, Wagenaar Jaap A, Sloet van Oldruitenborgh-Oosterbaan Marianne M, Rossen John W A, Zomer Aldert L
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Dutch researchers characterised the faecal microbiota of 79 healthy horses and ponies under typical commercial management to establish baseline variation and identify which host and environmental factors influence microbial composition. Using 16S rRNA sequencing on spontaneously-collected faecal samples (validated against rectal sampling), they found Bacteroidetes dominated the microbiota at 50.1%, with Firmicutes comprising 28.4%, and demonstrated that microbial diversity and richness declined significantly with age, whilst location, season, horse type and pasture access all significantly altered community structure. These findings have important implications for clinical and research practice: when interpreting microbiota results or using faecal analysis as a diagnostic tool, practitioners should account for the horse's age, management system (particularly pasture access) and sampling season, as these variables substantially influence what constitutes a "normal" microbiota profile for any given individual. Establishing these standardised baseline data strengthens our ability to identify genuinely pathological shifts in the microbiota and avoid misinterpreting natural variation as disease-associated dysbiosis.
Read the full abstract on PubMed
Practical Takeaways
- •When comparing microbiota between horses or interpreting microbiota-related health issues, account for age, season, housing location, breed/type, and pasture access as these factors significantly influence microbial composition in healthy animals
- •Non-invasive faecal collection from stall floors is a valid alternative to rectal sampling, making large-scale microbiota studies more practical on farm
- •Use this Dutch baseline data as a reference for what constitutes normal microbiota composition in healthy horses and ponies under standard management conditions
Key Findings
- •Bacteroidetes was the dominant phylum (50.1%) followed by Firmicutes (28.4%) in healthy equine faecal microbiota
- •Alpha-diversity and richness decreased significantly with increasing age
- •Location, age, season, horse type, and pasture access all significantly affected beta-diversity of the microbiota
- •Faecal samples collected up to 6 hours after spontaneous defaecation showed similar microbiota composition to rectal samples, validating non-invasive collection methods