Equine asthma, formerly called heaves or recurrent airway obstruction, is a chronic inflammatory lung disease in horses that causes persistent breathing difficulty and significantly reduces quality of life.
Equine asthma causes chronic respiratory discomfort that horses cannot report verbally — meaning many cases go unrecognized until severe. A horse coughing repeatedly during exercise or showing double-barreled breathing at rest is experiencing significant distress. The welfare impact is compounded when affected horses are still ridden or worked through respiratory compromise. The cornerstone of equine asthma management is environmental modification: maximizing turnout, using rubber mats instead of dusty bedding, feeding haylage or steamed hay, and ensuring excellent stable ventilation. These changes alone can return mild-to-moderate cases to comfort without medication. Owners and trainers must recognize that working a horse with uncontrolled asthma causes harm and should seek veterinary management before resuming exercise.