Respiratory disease including equine asthma (formerly RAO and IAD) is the second most common reason for veterinary consultation in horses, with welfare implications directly linked to stabling environment and forage dust levels.
Horses with uncontrolled equine asthma experience chronic respiratory distress — laboured breathing at rest in severe cases, with exercise causing disproportionate respiratory effort and distress. Chronic airway inflammation causes irreversible remodelling in some horses. Treatment with bronchodilators and steroids improves welfare but addresses symptoms without removing the environmental cause. Fully soaked hay, haylage, or dust-extracted forage combined with deep clean shavings bedding and maximum ventilation dramatically reduces triggering allergen exposure. Many horses with severe equine asthma improve substantially when managed outdoors.