Heaves in Horses & Respiratory Health

By: Dr. Lydia Gray

SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.

Brief Description

Recurrent Airway Obstruction (RAO) is the preferred term by veterinarians for what is commonly referred to as “heaves.” In the past, it has also been referred to as COPD or Chronic Obstructive Pulmonary Disease but experts now recognize that this respiratory condition in humans is not the same as the one in horses.
RAO is defined as episodes of obstructive lower airway disease in horses triggered by exposure to hay and bedding and characterized by: difficulty breathing, severe airway inflammation, a large number of neutrophils (white blood cells), airway hyper-reactivity, and reversibility with bronchodilator treatment.  Signs include:

  • Coughing
  • Labored breathing
  • Flared nostrils at rest
  • Nasal discharge
  • Depression
  • Elevated respiratory rate at rest
  • Exercise intolerance or poor performance
  • “Heave line” (abnormal abdominal muscle development caused by coughing and labored breathing)

Possible Diagnostic Tests

“Heaves” can usually be diagnosed based on the horse’s medical history and a physical examination.  However, additional tests to rule out other conditions or monitor the horse’s response to treatment may be needed.  These include:

  • Bloodwork
  • Endoscopy
  • Bronchoalveolar lavage (BAL)
  • Blood gas measurement
  • Chest x-rays
  • Lung biopsy
  • Lung function tests
While there is no cure for RAO, it is possible to successfully manage it using a four-pronged approach:
1) prescription medications
2) supplements
3) diet
4) environment

Prescription Medications Available

Corticosteroids—which reduce airway inflammation—include dexamethasone and prednisolone or the newer beclomethasone and fluticasone. The most common bronchodilators—which relieve airway obstruction--are in the beta-adrenergic agonist family and include clenbuterol and albuterol. 

Supplements that May Lend Support

There is good evidence that some herbal supplements may be beneficial to horses with “heaves.” Because the condition may place them under additional oxidative stress, antioxidants are recommended. Vitamin C in particular is being investigated for its role in neutralizing the free radicals associated with “heaves.”

Other Management Suggestions

Dust and mold in hay seem to the best worst offenders to a horse with “heaves,” so steaming or soaking hay—or feeding hay cubes—is often recommended. Completely replacing hay with another fiber source such as a complete feed is an additional alternative.

For horses with “heaves” that live inside, good ventilation is vital, especially in the winter when most barns are closed up.  If they must be stalled, dust-free bedding should be used such as specially treated wood shavings, shredded paper or cardboard, peat moss, or other materials. Straw is a particularly poor type of bedding for these horses.  Ideally, horses with “heaves” should be turned out as much as possible.


Questions to Ask Your Veterinarian

  • Can I continue to ride and show my horse if he has “heaves”?
  • How long will my horse have to be on steroids and bronchodilators?
  • Will this condition continue to worsen?


About Dr. Lydia Gray

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Mollie and Eden
I started riding when I was 9 years old and quickly got swept up into the competitive hunter/jumper world. I showed my first pony, Chloe, in the Small Pony Hunter divisions were we competed at shows like Fairfield Hunt Club, Old Salem, HITS, and West...

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