FAQ – Equine Asthma – COPD – Heaves

Equine asthma has gone through many names over the years. This is because we are continually learning more about the disease. Originally, it was called COPD as it seemed to mimic the human version of the disease. However, more information came to light and it was changed to RAO – recurrent airway obstruction. Now, it’s known as equine asthma. Heaves is the layman’s term for it and this has stayed similar through the years.

Equine asthma is similar to its human counterpart in which there is reversible inflammation and bronchoconstriction (constriction of the lower airways) in the lungs.

Principles of management include:

Environmental management: in general, horses need to be out of the barn completely. One hour of exposure to barn dusts can result in DAYS worth of inflammation in the lungs. If in a barn, it needs to be exceptionally well-ventilated, paper shavings, no hay kept in the barn, and the horse needs to be removed for several hours whenever the barn is cleaned. NO ROUND BALES or hay taken off round bales. Soak or steam the hay or provide hay pellets or cubes. It does not need to be soaked for a long time like for sugar reduction.
Bronchodilators: this opens the lower airways. This can be given via oral medication (oral albuterol or clenbuterol), inhaler (albuterol), or nebulized (albuterol, ipratropium).
Corticosteroids: this provides anti-inflammatory action in the lungs. This can be given via oral medication (prednisolone **not prednisone**, dexamethasone), inhaled (fluticasone, beclomethasone), or nebulized (dexamethasone, budesonide). (medications are examples and there are likely others that can be used)

Inhalers and nebulized medications can be given via a variety of devices. For inhalers, you need a spacer device – not just putting the inhaler up to the nose of the horse. So a baby inhaler device (Baby Haler) or an AeroKat device can be used. Place the mouthpiece over one nostril while covering the other nostril with your hand. Time the spray with an inhale if possible but the spacer device helps mitigate this issue. You can also use a mask such as a Flexineb or a homemade mask as shown using a milk jug. Search web on how to make one.

Nebulizer devices come in all shapes and sizes. Certainly the easiest to use and the most effective is the Flexineb. This is a portable nebulizer so your horse can be walked while receiving the nebulizing treatment. There are other nebulizing devices available at online stores. In a pinch, a human nebulizer can be used with the mask shown above. This is not as effective as the Flexineb or other equine specific nebulizers but can be used until one can be purchased. Ensure there is no air leakage at the top of the milk jug mask by using small towels between the jug and the face. The velcro can be purchased at any place that sells fabric (I got mine at Walmart in the fabric aisle). This helps attach to the halter. The nebulizer cup is held at the top of the jug (circled in red). Your veterinarian can give you information on doses of medications and what meds should be used.

It’s extremely important to have a bronchoalveolar lavage (BAL) done if you suspect equine asthma. This will confirm the diagnosis and also the cell types present – this is especially true if you’ve treated the normal way and are still not seeing improvement – sometimes other unusual cell types are present like eosinophils or mast cells are present and these are treated differently. A BAL involves standing sedation and then either an endoscope or a BAL tube is threaded down into the lungs and saline is instilled and then removed and the removed solution is looked at under a microscope. It is a quick procedure that can be very valuable in the management of the disease.

For more information, this is a great summary of the disease and treatment strategies: https://thehorse.com/features/equine-asthma/