The effect of five different wetting treatments on the nutrient content and microbial concentration in hay for horses.
Authors: Moore-Colyer Meriel Jean Scott, Lumbis Kimberly, Longland Annette, Harris Patricia
Journal: PloS one
Summary
# Editorial Summary: Optimising hay treatment for horses Researchers compared five different hay treatments—dry control, steaming alone, soaking alone, steaming then soaking, and soaking then steaming—to establish their effects on water-soluble carbohydrate (WSC) levels and microbial loads in UK hay samples. All three wet treatments (soaking, steam-then-soak, and soak-then-steam) significantly reduced WSC content to 79–83 g/kg dry matter, compared with 122–126 g/kg DM in untreated hay, yet the hygiene implications differed markedly between methods. Soaking alone proved counterproductive for microbial control, increasing bacterial counts from 6.0×10⁴ CFU/g DM in dry hay to 3.5×10⁵ CFU/g DM, whilst soaking followed by 50-minute steam treatment achieved the most substantial reductions in both WSC and mould spores. For practitioners managing horses with insulin dysregulation or respiratory disease, the soak-then-steam sequence offers an optimal balance—substantially lowering metabolically problematic carbohydrates whilst simultaneously improving hay hygiene—though practitioners should note that soaking alone, despite reducing NSC levels, actually elevates bacterial contamination and may compromise immune-compromised animals.
Read the full abstract on PubMed
Practical Takeaways
- •If treating hay for high sugar content (e.g., laminitis-prone horses), always soak THEN steam—soaking alone creates dangerous mould and bacterial loads that could harm sensitive horses
- •Steaming alone is ineffective for reducing sugar but works well for mould control; choose your treatment based on your primary concern
- •The 9-hour soak + 50-minute steam protocol offers the best all-around result, though equipment cost and time commitment must be considered against your caseload
Key Findings
- •Soaking for 9 hours followed by steaming for 50 minutes most effectively reduced water soluble carbohydrates (79-83 g/kg DM vs 126 g/kg DM in dry hay)
- •Soaking alone significantly increased bacterial contamination from 6.0×10⁴ to 3.5×10⁵ CFU/g DM, making it unsuitable for immunocompromised horses
- •Steaming alone reduced mould content to 2 CFU/g DM but failed to reduce water soluble carbohydrates, requiring combination treatments for optimal results
- •Protein and ash content remained unchanged across all treatments, preserving nutritional value