Summer pasture-associated recurrent airway obstruction (SP-RAO) represents a distinct form of equine asthma triggered by outdoor allergens requiring different management from stable-based disease.
SP-RAO presents a welfare paradox for horses: the outdoor access that is generally welfare-positive becomes the source of respiratory distress for affected individuals during summer months. A horse who breathes easily all winter but develops labored breathing with audible wheeze when turned out in May is experiencing significant respiratory discomfort each time it encounters its allergen triggers. Management requires accepting that the standard welfare approach of maximizing turnout is wrong for this specific condition — stabling during peak allergen periods is the welfare-protective intervention for these horses.