Understanding Heaves (Recurrent Airway Obstruction) in Horses

Heaves, also known as recurrent airway obstruction (RAO), is a chronic respiratory disease that affects horses. It is similar to asthma in humans and causes inflammation, mucus production, and bronchospasm in a horse's airways. Heaves is a common condition, especially in older horses, and can negatively impact a horse's performance and quality of life if left untreated. In this blog post, we will discuss the causes, symptoms, diagnosis, and treatment options for heaves in horses.

Causes of Heaves in Horses

Heaves is caused by an allergic or hypersensitivity reaction to inhaled particles such as mold, dust, and pollen in a horse's environment. It is not caused by infection. Horses with heaves develop chronic inflammation in their airways when exposed to these allergens over time. Some factors that can increase a horse's risk of developing heaves include:

• Age - Older horses are more likely to have heaves

• Genetics - Inheritable factors may play a role

• Stabling - Horses kept predominantly in barns are at higher risk

• Climate - Hot, humid environments promote mold and dust

• Hay - Dusty, poor quality hay may trigger reactions

Symptoms of Heaves

The most common symptoms of heaves in horses include:

• Coughing, especially at night or during exercise

• Increased breathing effort and flared nostrils

• Breathing sounds like wheezing or whistling

• Nasal discharge

• Lethargy, exercise intolerance

Horses may show worse signs when stabled and improve when turned out. Mild cases may only exhibit poor performance. Severe cases involve labored breathing even at rest.

Diagnosing Heaves

Veterinarians use a combination of a physical exam, medical history, and specialized tests to diagnose heaves. They will likely use a stethoscope to listen for wheezing or whistling lung sounds. Other diagnostic tools include:

• Endoscopy - Allows visual examination of airway inflammation

• Bronchoalveolar lavage - Fluid sampling to check for inflammatory cells

• Lung function testing

• Allergy testing - Identifies specific allergies

Treatment for Heaves

While there is no cure for heaves, treatment can help control symptoms and allow horses to lead relatively normal lives. Keys to managing heaves include:

• Avoiding dust and allergens in the horse's environment through pasture turnout, wetting hay, low dust bedding, well-ventilated barns, etc.

• Medications - Bronchodilators open airways while corticosteroids reduce inflammation

• Nebulization - Delivers medications via mist inhaled into the lungs

• Supplements - Some supplements may reduce airway inflammation

With proper management and treatment, most horses with heaves can be successfully controlled and ridden and worked lightly. However, acute flareups are possible. Veterinary guidance is important for developing an effective treatment plan for any horse diagnosed with heaves.

In summary, heaves is a chronic respiratory disease triggered by inhaled allergens and leading to significant airway inflammation and obstruction in horses. While incurable, heaves can often be well-controlled with environmental management, medications, and veterinary oversight. Horse owners should be alert for signs of the condition, especially in older horses, and work with their vet to protect their horse's respiratory health.