Horse Recurrent Airway Obstruction Welfare

Recurrent airway obstruction (RAO, also known as heaves or equine asthma) is a common inflammatory airway disease in horses, causing breathing difficulty and reduced welfare if poorly managed.

Key Facts

RAO is triggered by inhaled dust, mold spores, and endotoxins, primarily from hay and stable bedding
Affected horses show flared nostrils, prolonged exhalation, exercise intolerance, and abdominal muscle hypertrophy from respiratory effort
Summer Pasture-Associated RAO (SPARAO) is triggered by outdoor allergens and affects horses in different seasons
Environmental management - reducing dust exposure - is the single most effective intervention
Bronchodilators and corticosteroids provide medical relief but do not address underlying allergen exposure

Welfare Considerations

Horses with poorly controlled RAO experience what amounts to chronic breathlessness - a distressing sensation. The heave line (hypertrophied abdominal muscle from chronic expiratory effort) is visible evidence of prolonged respiratory strain. Affected horses often show reluctance to work, weight loss, and behavioral changes indicating chronic discomfort. Management is highly effective when owners commit to environmental changes: soaked or haylage forage, rubber or paper bedding, and outdoor living. The welfare cost of inadequate management is significant and continuous.

What You Can Do

Switch to soaked hay or haylage to reduce spore levels for RAO-affected horses
Consider outdoor or barn-free living for horses with severe RAO - fresh air dramatically reduces symptoms
Ask your vet about inhaled corticosteroids delivered via equine aerosol mask for effective airway treatment
Avoid dusty arenas and round bales for horses with respiratory sensitivity