The haybiome: Characterising the viable bacterial community profile of four different hays for horses following different pre-feeding regimens.
Authors: Daniels Simon, Hepworth Jacob, Moore-Colyer Meriel
Journal: PloS one
Summary
# Editorial Summary: The Haybiome Study Understanding the microbial load in hay is crucial for respiratory health management, yet little has been known about how common pre-feeding treatments—soaking and steam heating—alter the viable bacterial communities horses actually ingest. Using molecular profiling of the bacterial 16S rRNA gene from four hay types sourced across two UK locations, Daniels and colleagues characterised how dry hay, water-soaking (12 hours at 16°C) and high-temperature steaming (HTS) affected both total and viable bacterial populations, employing propidium monoazide treatment to distinguish living cells from dead DNA. High-temperature steaming proved most effective, substantially reducing viable bacteria associated with equine respiratory and dental disease whilst maintaining overall bacterial diversity; soaking, whilst reducing certain pathogenic bacteria, paradoxically increased Gram-negative species and reduced microbial diversity compared to untreated hay. The pre-feeding regimen itself had the greatest influence on bacterial community composition overall, with treatment effects varying somewhat between hay types and source locations. For practitioners aiming to minimise disease risk through forage preparation, these findings provide robust evidence that HTS offers superior microbial control without the diversity-reducing drawback of soaking, making it the preferred option for horses prone to respiratory compromise or dental disease.
Read the full abstract on PubMed
Practical Takeaways
- •High temperature steaming is superior to soaking for reducing pathogenic bacteria associated with respiratory and dental disease in hay
- •Soaking, while reducing some pathogens, paradoxically increases Gram-negative bacteria and reduces beneficial diversity — HTS maintains better microbial diversity while eliminating more pathogens
- •For horses prone to respiratory or dental issues, HTS pre-feeding treatment offers the most comprehensive microbial benefit regardless of hay source or location
Key Findings
- •High temperature steaming (HTS) reduced proportions of microbiota compared to wetting and dry hay (P < 0.001)
- •HTS reduced viable bacteria known to cause respiratory and dental disease more effectively than wetting or dry hay
- •Soaking reduced bacterial diversity and increased Gram-negative bacteria proportions
- •Pre-feeding regimen had the greatest effect on bacterial community profile compared to hay type or location