Equine Asthma: Respiratory Welfare in Horses and Ponies

Equine asthma (formerly known as heaves or recurrent airway obstruction) is a common chronic respiratory condition in horses and ponies caused by hypersensitivity to airborne dust and mould spores.

Key Facts

Equine asthma affects an estimated 10-15% of horses in temperate climates and is most common in stabled adult horses
The condition is classified as mild-moderate or severe based on respiratory effort at rest and exercise tolerance
Severe equine asthma causes visible abdominal effort in breathing, exercise intolerance, coughing, and nasal discharge
The primary trigger is inhaled organic dust from hay, bedding, and stable environments containing mould spores and endotoxins
Turning affected horses out to pasture dramatically reduces exposure and typically produces rapid clinical improvement
Soaked or steamed hay, dust-free bedding, and stable ventilation are the core management strategies
Bronchodilators (clenbuterol) and corticosteroids (dexamethasone, fluticasone) provide symptomatic relief during acute episodes

Welfare Considerations

Equine asthma causes respiratory distress that varies from subclinical exercise intolerance to severe breathing difficulty at rest. Horses with severe equine asthma use their abdominal muscles visibly to force air through constricted airways — a state of chronic respiratory effort analogous to severe asthma in humans. The welfare impact extends beyond the physical: horses in respiratory distress are reluctant to move, may be unable to exercise at previous levels, and experience the anxiety associated with breathing difficulty. The strong link between stable environment and disease severity means that management changes — increasing turnout, improving bedding and hay management — are the most effective welfare interventions, often producing improvement within days. Owner understanding of environmental triggers is crucial; many horses are exposed repeatedly to triggering environments during winter housing, extending their welfare compromise unnecessarily.

What You Can Do

If your horse coughs regularly or shows laboured breathing, seek veterinary assessment for equine asthma
Maximise turnout time for affected horses — fresh air management is the single most effective intervention
Switch to soaked or steamed hay and dust-free bedding (paper, cardboard, or rubber matting)
Ensure stabling has adequate ventilation — poor air exchange concentrates airborne triggers
Work with your veterinarian to establish a management and medication plan for acute episodes