What Is Heaves In Horses?

Last Updated on January 12, 2022

Many horses suffer from breathing problems, and one of the most common of these is one called heaves. But what is heaves and why do horses get this condition?

Heave is a name given to respiratory disease of horses, which is also known by many other names. Heaves can be difficult to treat and often recur time and time again. Let’s find out all about heaves and how to manage a horse with this condition!

What Is Heaves In Horses?

horse heaves

The condition heaves is more correctly known as recurrent airway obstruction (RAO). You may also hear it referred to as equine asthma, inflammatory airway disease (IAD), broken wind, or chronic airway obstruction.

The name heaves come from the effect this condition has on the horse’s breathing. The horse will struggle to inhale enough air and will need to put much more effort into breathing. This creates a line along the horse’s abdomen, known as the ‘heave line’.

RAO occurs when the narrow airways within the lungs become narrowed and constricted. They may go into spasm, meaning they cannot relax, and sometimes fill with mucus. The result of this is that the horse cannot breathe in enough air through normal respiration.

What Is Heaves In Horses Caused By?

RAO is normally caused by a hypersensitive response within the lungs to an allergen. There are two types of RAO, one of which is associated with horses living in barn conditions, and the other with horses that live out at pasture. If your horse has RAO, it will be easy to identify which type he has by when and where the symptoms occur.

Horses with barn-associated RAO normally react to dust, molds, and endotoxins. These are commonly found in hay, straw, and bedding. This type of RAO is more common in winter and spring.

Pasture-associated RAO is more likely to be triggered by pollens. Horses with this condition will suffer more when pollen counts are high, particularly in summer and early fall.

What Are Symptoms Of Heaves In Horses?

The most common symptom of RAO is difficulty breathing. This may be characterized by the horse taking deeper breaths, or breathing faster than normal. You may notice that the horse’s nostrils are flared and that a heave line appears on the side of the flank.

A horse with RAO may also have a recurrent cough, and if there is secondary bacterial infection then you might see mucus at the nostrils. Your horse might be lethargic, and any movement or exercise will cause him to be short of breath.

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How Are Horse Heaves Treated?

There are two main aspects to managing RAO – medical management, and reducing exposure to allergens:

  • Medical management of RAO

Although some mild cases of RAO may resolve without treatment, most horses will need medical management at some point. This is because the narrow airways in the lungs can go into spasm, and need medication to help them relax. To alleviate this, your veterinarian may prescribe a drug called a bronchodilator.

Horses with RAO also often have persistent swelling of the airways, that can take a long time to ease. A course of corticosteroids may help to reduce this inflammation.

Both of these medications can be given systemically, but are more effective if inhaled. This means that your horse may need to be trained to accept an equine inhaler. This is not as daunting as it sounds and is often the best method of keeping RAO under control.

If your horse has a secondary bacterial infection, then a course of antibiotics may also be required.

  • Environmental management of RAO

If your horse has RAO, one of the most useful things you can do is reduce his exposure to allergen-triggering pathogens! However, this is not always as easy as it might sound.

Barn-associated RAO is normally caused by dust, mold, and endotoxins in hay, straw, and bedding. The aim is to make the environment as dust-free as possible.

To do this, firstly look at where the dust is coming from in the first place. Swap your bedding for a dust-free option, such as rubber matting or chopped paper. Hay and straw should be stored away from the barn, and soaked before feeding.

The second thing you can do is ventilate the airspace as much as possible. Ensure that there is good airflow through the barn, and keep windows and doors open whenever possible. It makes common sense that a horse with barn-associated RAO should spend as much time outside as possible!

If your horse has pasture-associated RAO, then you need to aim to reduce his exposure to pollen. This means he should be kept stable when pollen counts are high, particularly during the summer. Nose nets can also help to reduce the amount of pollen your horse is breathing in.

Can You Ride A Horse With Heaves?

If you have a horse that suffers from RAO, you might be wondering if you can ride it? If a horse is displaying any symptoms of heaves it should not be ridden, as any exertion will make the problem worse. It may take several days or every week for a horse’s lungs to return to normal following an episode of RAO.

Lung tissue takes a long time to repair, and repeated episodes of RAO means that it loses elasticity over time. If a horse with RAO is ridden, the lungs will be put under increased pressure and it will take longer for them to return to normal.

Read more about Can Pregnant Women Ride Horses – Safe Or Not?


So, as we have learned, heaves is more correctly known as recurrent airway obstruction and is very similar to asthma in humans. Horses with this condition need careful management to reduce their exposure to factors that might trigger heaves. You should not ride a horse with heaves unless it is completely free from symptoms and can breathe easily.

We’d love to hear your thoughts! Have you ever cared for a horse with heaves? Perhaps you have some good tricks for keeping the symptoms of heaves at bay? Leave a comment below and we’ll get back to you!