Companion Animals

Heaves (RAO) in Horses: Long-Term Welfare Management

Welfare guide for horse owners on recurrent airway obstruction (RAO) — a chronic respiratory disease causing significant distress.

Key Facts

RAO (formerly called heaves or COPD) is one of the most common chronic diseases in horses
It is caused by hypersensitivity to airborne allergens — primarily dust and mould spores in hay and bedding
Affected horses show chronic cough, nasal discharge, exercise intolerance, and laboured breathing
In severe cases, horses use significant abdominal effort to breathe — causing the characteristic heave line (hypertrophy of external abdominal muscles)
Environmental management is the single most important treatment — reducing dust exposure dramatically reduces signs
Turning affected horses out full-time is among the most effective interventions
Soaking or steaming hay reduces dust by over 90% and significantly reduces airway challenge
Bronchodilators and corticosteroids provide symptom relief but do not address the underlying cause

Welfare Significance

RAO causes chronic respiratory distress that significantly impairs quality of life. The anxiety of struggling to breathe affects every aspect of a horses welfare. Environmental management — maximising turnout, using dust-free bedding, soaking or steaming hay — is far more effective than medication alone and should be the first-line approach.

What You Can Do

Maximise turnout time — even a few extra hours per day significantly reduces airway challenge
Use dust-free bedding such as paper, cardboard or rubber matting
Soak or steam hay before feeding — this reduces dust by over 90%
Ensure stabling has adequate ventilation — avoid closing up stables