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Feeding a Horse With Heaves, All You Need to Know.

Last updated: July 3, 2022

By: Miles HenryFact Checked

One of our older mares has heaves, and it seems her breathing is getting worse as she ages. We want to ensure the food she’s eating isn’t contributing to her condition, so I did some research on feeding horses with heaves.

Heaves are a chronic respiratory condition caused by an allergic reaction to inhaled particles. Proper feeding of horses with respiratory diseases is critical because most hay contains mold and dust, to reduce these particles, the hay should be steamed, soaked, or fed as pellets or cubes.

Respiratory diseases in a horse can be costly for the owner. Horses that suffer from heaves, often have underlying conditions such as allergies, infections, or parasites.

What are Heaves?

Heaves is a common horse disease similar to asthma in humans, which is caused due to an allergic response to airborne irritants like dust and molds. Therefore, when feeding horses suffering from heaves, you must considerably reduce their exposure to air irritants.

picture of a mare with signs of heaves and her foal,

The best way to take care of horses with heaves is to keep them outside as much as possible. Fewer irritants outside will lead to fewer problems for the respiratory system. Moreover, there are high chances that the dust from hay will blow into the horse’s respiratory system.

This is why what you feed, particularly the selection of hay is essential. Round bales, while staying outside, can be counterproductive to heaves, as a horse often sticks its entire head inside the round bale when eating.

Also, round bales are often comprised of inferior grass, which contains more dust. Smaller square bales are preferable.

Heaves are also called RAO (recurrent airway obstruction) and were initially known as COPD (chronic obstructive pulmonary disease). It is a result of an allergic reaction to inhaled particles.

Allergens such as molds, found in hay and straw, are one of the primary causes of heaves. Once such allergens are inhaled, the resulting allergic reaction obstructs the small airways in lung tissue.

Three factors that cause difficulty in breathing –

  • The smooth muscle around the lung airways tightens and narrows the passageways. It is called Bronchoconstriction.
  • Inflammation is the accumulation of neutrophils and other pro-inflammatory substances. Inflammation can result in prolonged tissue swelling that obstructs the functioning of the small airways.
  • Neutrophil inflammation creates thicker, stickier mucus in the airways.

With obstructed airways, a horse with heaves has to work harder than a healthy horse to inhale and exhale air from the lungs. Thus, the horse will resort to using its abdominal muscles for exhalation.

picture of a horse with his head in hay,

Horses that consistently use their abdominal muscles to exhale often result in the expansion of abdominal muscles and the formation of a heaving line. As the disease progresses, the horse faces difficulty exhaling, causing over-inflation of the lungs, which is called emphysema.

If the horse with heaves is left untreated, the lung tissue will undergo non-reversible damage, resulting in the permanent loss of lung function.

However, heaves are relatively easy to deal with and are not fatal diseases. Following simple feeding and management protocols with proper treatment from your veterinarian can help a horse with heaves recover.

Feeding Tips for horses with heaves.

As any horse owner knows, feeding time can be a bit of a challenge. Not only do you have to make sure that your horse is getting enough food, but you also have to be careful about what you’re feeding them.

For example, horses with heaves often have trouble digesting hay, so it’s important to give them a diet that is low in dust and easy to digest. Here are a few different ways to do this:

Wet Hay

Dry hay is the primary source of dust and mold. Owners feel that there are no mold spores or dust in good-quality hay. However, that is not true. Both poor and high-quality hay, have some amount of dust and mold spores.

The question is how much. Once your horse gets allergic to molds, even good-quality hay can trigger breathing problems. High-quality hay can have the same irritants, just not as many.

Feeding wet hay to horses with heaves is a proven way to reduce dust and mold in the hay a horse inhales while eating. How much you should moisten the hay depends on the horse’s allergy level. Dry grass can still work for some horses.

picture of horses eating hay,

For horses with extreme heaves, it is important to submerge the hay in a bucket and thoroughly soak it.

Steamed Hay

Steaming can also help reduce dust and molds in the hay. Specially designed, commercial hay steamers in various sizes can effectively eliminate airborne irritants from hay. However, you can also opt for homemade steamers as they work well too.

When you steam the hay, you’re adding moisture as well as reducing fungi and molds that are the main causative agents of heaves. According to a study, horses, when fed with steamed hay, experienced reduced respiratory problems.

Though steamers require some extra effort, the process eliminates the need for heavy medications like corticosteroids.

Forage Alternatives

Forage alternatives are another way to treat horses with heaves because they are very high in fiber. High fiber will help in maintaining the microbial ecosystem of a horse’s digestive tract.

Byproducts of hay such as haylage, pellets, or hay cubes are a low-dust and excellent alternative to long-stem hay. Make sure to vaccinate your horse against botulism if you’re feeding haylage because it can be contaminated with botulism bacterium.

Picture of a horse eating hay.

Anaerobic conditions, high moisture levels, pH levels, and the raking and baling process create a conducive environment for the growth of botulism. Click here to read my article that compares hay cubes to pellets for horses.

If you are feeding hay cubes, you have to feed in similar weights of long-stem hay. For example, if you feed your horse 20 pounds of hay, you’ll feed them 20 pounds of hay cubes.

Other high-fiber products are rice bran and beet pulp. You can discuss with your veterinarian the amount of rice bran or beet pulp to feed along with other tips to maintain your horse’s diet.

Grains are an essential supplemental feed that increases calories and other nutrients. Again, buy grains that are low on dust and molds. Adding vegetable oil increases the calorie intake of the diet while it decreases airborne particles.

Add Supplements

Adding supplements of Omega-3 fatty acids to the diet helps synthesize hormones, carries oxygen from red blood cells to tissues, prevents inflammation, and improves immune function. Omega-3 fatty acids offset the inflammatory effects caused by Omega-6 fatty acids.

Antioxidants provide nutritional support to minimize symptoms and develop an immune system strong enough to combat an allergic response. Vitamin E, Vitamin C, and folic acid work together to boost immune cell activity and tissue health.

Avoid Round Bales

Horses with heaves kept on pastures should not have access to round bales. Round bales can exacerbate their respiratory condition as they contain higher levels of dust, molds, and endotoxins than other forage supplements.

picture of a round bale of hay,

If your horse is in a pasture and round bales are available, you might wonder why the horse isn’t getting any better even though they are out in the fresh air. It is because the horse is exposed to and inhaling the dust in a round bale.

Bedding Options

Horses living inside can be treated for heaves by following feeding and daily care protocols and limiting their exposure to dust and mold. Your stall bedding plays a crucial role in the health of your horses.

Sawdust and straw are dusty bedding materials, and some shavings as well. However, kiln-dried pine shavings typically have a low amount of dust and mold. This is the bedding material we use, and find it to be acceptable.

Bedding pellets are low-dust alternatives

Bedding pellets are typically made by compressing pine shavings. These are relatively new to the market, and I haven’t tried them for our horses, but they are intriguing.

Manufacturers of bedding pellets claim they absorb moisture faster than traditional shavings and destroy the smell of ammonia in urine. They are also easy to handle and store. Bedding pellets are sold on Amazon; you can click here to check for pricing. You can also find them at Tractor Supply.

Other low-dust bedding options

But, hemp, peat moss, and even shredded newspaper are low-dust products that can be used to line a stall. Look for beddings that reduce ammonia in the environment; these are the least irritating to horses with heaves.

The absorption level of ammonia and liquid in the urine can irritate the respiratory tract. Soft stall mats are very useful as they eliminate the need for deep bedding and hence reduce the dust.

However, to provide the best air for your horse the entire barn’s bedding should be changed, not just the stall you keep the affected horses.

The horses should be stalled in a dust-free, clean, and controlled environment. It is also essential to carefully evaluate a horse’s surroundings, stable design, and ventilation, and follow correct stable management practices.

Although horses with heaves are not sensitive to outdoor dust like road dust, their airways are susceptible to nonspecific stimuli. Hence, horses with airway inflammation should not be stalled near a dry and dusty road or paddock.


Proper nutrition and correct feeding practices play an essential part in taking care of horses with heaves. However, these should be accompanied by appropriate medication to control inflammation and enhance the functioning of the lungs.

Always consult your veterinarian for issues regarding your horse with heaves. Learn specific practices to ensure your horse doesn’t unnecessarily suffer.

Below is a YouTube video that shares tips on how to manage a horse with heaves.

YouTube video


Is there a cure for heaves in horses?

There is no cure for heaves, but the elimination of allergens often reduces the clinical signs in horses. Hay, especially fed in round bales and straw bedding are two primary locations that produce mold spores that lead to heaves.

How do I know if my horse has heaves?

Horses with more serious cases of heaves may struggle to breathe, cough, and wheeze while at rest. They also have a hard time exerting themselves; running is difficult if not impossible.