The influence of hay steaming on clinical signs and airway immune response in severe asthmatic horses.
Authors: Orard Marie, Hue Erika, Couroucé Anne, Bizon-Mercier Céline, Toquet Marie-Pierre, Moore-Colyer Meriel, Couëtil Laurent, Pronost Stéphane, Paillot Romain, Demoor Magali, Richard Eric A
Journal: BMC veterinary research
Summary
# Editorial Summary: Hay Steaming and Severe Equine Asthma Reducing antigenic exposure is well-established in managing equine asthma, yet the specific impact of hay steaming on clinical and immunological outcomes remained unexamined until this 2018 investigation. Researchers compared severely affected asthmatic horses with healthy controls using a crossover design, monitoring clinical signs, bronchoalveolar lavage cytology, and airway cytokine profiles when fed either steamed or dry hay over consecutive periods. Steamed hay significantly reduced clinical respiratory signs and neutrophilic inflammation in the lower airways of asthmatic horses, alongside measurable improvements in cytokine expression patterns associated with airway remodelling and eosinophilic response. These findings provide objective evidence supporting hay steaming as an effective environmental modification strategy in severe asthma cases, offering farriers, nutritionists and veterinarians a practical, evidence-based intervention that complements conventional therapeutic approaches and may reduce reliance on repeated medication cycles in chronically affected animals.
Read the full abstract on PubMed
Practical Takeaways
- •Steaming hay is an evidence-based management strategy for horses with severe asthma and should be considered a primary intervention alongside other dust-avoidance measures
- •The clinical improvement in asthmatic horses suggests steaming is worth the practical effort, particularly for horses that cannot be managed on complete pasture
- •Non-asthmatic horses tolerate both hay types well, so steaming decisions should be tailored to individual respiratory disease status rather than applied universally
Key Findings
- •Steaming hay significantly reduced clinical signs of airway obstruction in horses with severe equine asthma compared to dry hay exposure
- •Steamed hay resulted in improved airway immune response with reduced inflammatory markers in lower airway cytology
- •Control horses showed minimal airway response to both steamed and dry hay, indicating asthma-specific sensitivity
- •Hay steaming effectively reduces antigenic dust load, mitigating respiratory inflammatory responses in susceptible horses