Inflammatory Airway Disease in Horses: Managing Chronic Respiratory Conditions

Inflammatory airway disease and equine asthma cause chronic respiratory discomfort in horses. Environmental management and appropriate treatment significantly improve quality of life.

Key Facts

Inflammatory airway disease (IAD) and severe equine asthma (formerly RAO/heaves) represent a spectrum of chronic respiratory conditions
Equine asthma affects approximately 14% of adult horses in temperate climates
Exposure to dust, mould spores, and ammonia in hay and bedding are primary environmental triggers
Clinical signs range from reduced performance and mild cough (IAD) to severe laboured breathing at rest (severe asthma)
Horses with severe asthma develop a characteristic heave line from chronic abdominal muscle hypertrophy
Environmental management — soaked or haylage forage, low-dust bedding, and good ventilation — is more effective than medication alone
Corticosteroids administered by inhalation or systemically are the mainstay of pharmaceutical management
Summer pasture-associated asthma triggered by pollen occurs in warm climates and requires different management

Welfare Considerations

Equine asthma causes significant chronic respiratory discomfort ranging from reduced exercise capacity in mild cases to laboured breathing at rest in severe forms. Horses with severe asthma experience the distress of chronic dyspnoea — an inability to breathe comfortably that fundamentally affects wellbeing. The condition is driven primarily by inappropriate stable environments, meaning that management changes are both welfare-positive and highly effective. Horses kept in poorly ventilated stables fed dusty hay have their condition perpetuated by their environment despite medication. The welfare-first approach to equine asthma prioritises environmental optimisation: outdoor living, low-dust forage, and appropriate bedding deliver better outcomes than medication without environmental change.

What You Can Do

Soak hay or switch to haylage/hay replacer to dramatically reduce dust and mould exposure
Maximise turnout time for horses with respiratory conditions to reduce stable dust exposure
Choose low-dust bedding materials such as paper, cardboard, or rubber matting over straw or shavings
Ensure stable ventilation is maximised through open windows, doors, and ridge ventilation
Work with your equine vet to establish appropriate pharmaceutical management alongside environmental changes
Monitor exercise tolerance and respiratory rate at rest as indicators of treatment response