Effects of soaked hay on lung function and airway inflammation in horses with severe asthma.
Authors: Westerfeld Roxane, Payette Flavie, Dubuc Valérie, Manguin Estelle, Picotte Khristine, Beauchamp Guy, Bédard Christian, Leclere Mathilde
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Soaked Hay and Severe Equine Asthma Inhaled dust is a well-established trigger of severe asthma in horses, yet evidence supporting common management strategies remains limited. Researchers compared soaked hay against alfalfa pellets in ten clinically affected horses, measuring lung resistance via pulmonary function testing and airway inflammation through tracheal mucus scoring and bronchoalveolar lavage at baseline, 2, 4, and 6 weeks. Both interventions reduced lung resistance substantially over the trial period; the soaked hay group achieved a median decrease of 1.31 cmH₂O/L/s (statistically significant), whilst the pellets group decreased by 1.06 cmH₂O/L/s, with soaked hay demonstrating a numerically greater benefit despite overlapping confidence intervals. These findings provide the first documented evidence that soaking hay effectively mitigates airway obstruction in horses with severe asthma, likely through mechanical dust reduction, though the practical demand of soaking for 45 minutes and discarding wetted hay between feeds may limit owner compliance and real-world adoption. Farriers and veterinary teams should discuss these results when counselling owners on dust-control strategies, acknowledging both the clinical efficacy and the labour-intensive nature of the protocol relative to pelleted alternatives.
Read the full abstract on PubMed
Practical Takeaways
- •Soaked hay effectively controls airway obstruction in horses with severe asthma, with benefits evident within 2-6 weeks
- •Alfalfa pellets provide a simpler feeding alternative but with less dramatic improvement in lung function
- •The practical inconvenience of the soaking protocol (45-minute immersion, waste disposal) may limit client compliance despite proven efficacy
Key Findings
- •Soaked hay reduced lung resistance by 1.31 cmH₂O/L/s over 6 weeks (P<0.001) in horses with severe asthma
- •Alfalfa pellets reduced lung resistance by 1.06 cmH₂O/L/s over 6 weeks (P=0.03, not significant after correction)
- •Soaked hay showed greater improvement in airway obstruction compared to alfalfa pellets
- •Protocol required hay to be soaked for 45 minutes and dried-out hay discarded between meals