10 ways to help horses with heaves

Last Updated on February 23, 2022 by Allison Price

These simple management changes can help protect your horse’s health.

While “wait and watch” may work for some conditions, it is not appropriate for horses with heaves. A horse suffering from a flare-up should be treated immediately. However, horses with heaves under control need to be watched.It has been a proven method to reduce the amount of dust and molds horses inhale while eating.

Technically, heaves can be described as recurrent lung obstruction (RAO). It is caused by inhaling the pollens, molds, and dusts that are often found around farms and barns. RAO can cause chronic inflammation of the lungs, which is caused by hypersensitivity to organic dust particles.

Virginia Buechner Maxwell, DVM MS, DACVIM of the Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, Virginia, states that horses with heaves suffer from bronchoconstriction and airway inflammation due to an allergy-like reaction. Heaves can be described as human asthma. This is caused by allergies to certain antigens and irritants. Heaves, like asthma can have very different effects. Heaves can cause a mild cough or expulsion of mucus. Horses with severe heaves must work hard to breathe even when they are standing still.

Horses can begin to show signs of respiratory distress. The ongoing inflammation and immune reactivity is quite severe. However, this does not necessarily mean that the disease cannot be reversed. This is a sign that the horse needs to make changes to his environment. It’s also a signal to start treatment to get the horse back to normal breathing. He will feel uncomfortable and need to exert extra effort just to breathe. The horse’s difficulty breathing is caused by three main factors:

10 Ways To Help Horses With Heaves

Bronchoconstriction This is when the smooth muscle surrounding the airways of your lungs tightens and narrows the passageways. When the muscle is kept tight for too long, it can “remodel”, causing it to become enlarged or hypertrophic. This causes the muscles to expand, which makes it more difficult for the airways constrict. It is very difficult to stop this cycle without treatment. * Inflammation A buildup of neutrophils0 or other pro-inflammatory substances may cause prolonged tissue swelling and fluid accumulation, which can impair the functioning of small airways. * Mucus accumulation: This type of inflammation is caused by neutrophils and stimulates the production of thicker, more stickier mucus.

A horse with RAO will be more likely to experience flare-ups if he is exposed to small amounts of any substances that can affect him. Laurent L. Couetil of Purdue University, DVM, PhD and DACVIM says, “I explain this to horse owners by comparing it to human allergies.” A few cat hairs can cause severe allergic reactions if you have severe allergies to cats. You can tell if there is a cat in a room because you react to it. Horses are sensitive to mold dusts. Cat allergens can trigger allergic reactions in some people as well.

Amy Johnson, DVM and DACVIM of the University of Pennsylvania says that although we do not yet understand why RAO occurs, management protocols and treatment are well-established. We know what works. It is not controversial.

Your efforts can make a big difference. Your veterinarian may prescribe anti-inflammatories or bronchodilators in order to combat the physiological effects of heaves. However, management is more important than medication when helping horses recover. Couetil knows this firsthand. “I’ve had 100 horses given to me over the years because they couldn’t be managed properly to prevent heaves. But I have only had two horses that required medication because their respiratory problems would flare up. All the rest have been fine with our management and no medication. They are free to roam the pastures and are able to stay outdoors 24 hours a day, even if they’re not in a study. When there isn’t enough grass, they are fed a pelleted diet.

Your veterinarian is your best resource for helping your horse. You may have to do some detective work to find the elements that are most likely to cause RAO in horses. We have compiled a list with the most common measures to reduce stress in horses with heaves.


Dry hay is one source of mold spores and dust that causes RAO. The problem is not limited to “moldy” hay.

Couetil states, “The difficult thing for people to grasp is that high quality hay can cause problems.” They know that moldy hay can be dangerous, but think their hay’s good. Good quality hay still contains some mold spores and dust. It is usually a matter of how much. Even high quality hay can cause a horse to have a problem breathing if they are sensitive to molds. This is supported by studies currently underway. Good hay can contain the same molds, but not as many.

It has been proven that hay can be soaked in water prior to being fed to horses. This will reduce the amount of dust and molds they inhale while they eat. The horse’s level and tolerance will determine the amount of water required. Johnson says that there is a range of horses affected by dry hay. Some horses are able to tolerate dry hay as long as it is fed outside. For others, a simple wetting with a hose may suffice. To soak sensitive horses, you may need to submerge the Hay in a bucket or trough.


The steaming method is a more modern way to treat hay. There are many manufacturers that make hay steamers. They can be used to steam whole bales or half-bales, as well as individual portions. When choosing a steamer, make sure it gets the core temperature of the Hay up to 212 degrees Fahrenheit. This will eliminate or reduce microbes. Buechner Maxwell recently completed a study on the benefits of steaming hay. RAO horses that were given steam hay showed a lower respiratory rate than those who were fed untreated hay.

Steamers require care and preparation. The steamer produces small amounts of water which can be directed through a hose to a drain. Buechner-Maxwell says that steamers should be stored in warm areas to prevent freezing. Steaming is a bit more work, but owners have reported that steaming hay helps reduce or eliminate the need for long-term medication like corticosteroids.


Round bales can be a problem for horses with asthma who are kept in pasture. Johnson explains that round bales contain more endotoxins, dusts, and molds than other forage sources. People think that the horse will be fine because it is outside on pasture. Then they wonder why the horse isn’t improving. It’s because the horse is breathing in the dust from a round bale.


Johnson says that sometimes even soaking the hay is not enough. “Some horses still inhale enough particles/allergens of wet hay, and must be removed from hay completely.” These horses should be fed cubed hay, or pelleted rations with no loose forage.


Horses with RAO prefer to be out on grassy pasture 24-7. Johnson says Johnson that if that is not possible, the horse should be kept in a stall with the lowest exposure to the particles in the horse’s air. For horses suffering from summer-pasture-associated RAO (which is caused by allergens made by pasture plants), it may be best to keep them in the barn during summer. The dust levels in the indoor environment should be kept as low as possible.


When placing a horse in a barn, the first thing to do is choose a stall. You want the best ventilation possible, away from dust sources like an indoor arena or hay storage. Johnson says, “Ensure that the barn has maximum airflow away from storage stalls or areas where straw or hay may be stored.” Johnson says that barns with an overhead hayloft are most dangerous, as particles can fall from the ceiling. It is a good idea to have a corner stall near an exterior door that can remain open all year.


It is important to consider stall bedding. Johnson says straw is one of the worst options because it molds easily and retains dust. Johnson recommends that you look for low-dust bedding. Our hospital uses cardboard or chopped paper bedding for these horses. Also, sawdust is better than straw. Also, stall mats can be covered with pellets.

If horses are still stirring their straw in adjacent stalls, changing the bedding in one stall will not solve the problem. Buechner Maxwell says that dust must be controlled throughout the barn. It is worth changing the stall of a horse that is prone to flare-ups if you board him.


Before you sweep the aisles or do other chores that generate dirt, remove your horse. Couetil says that cleaning out barn stalls can generate a lot dust. Even in winter, it is possible to take your horse out of the barn and clean the stalls while you do this. Our lab has shown that dust settles in the barn after cleaning it. You should wait at least an hour before you bring the horses in. You can also sweep the aisle with a leaf blower or use a leaf blower, but you should remove horses first.

Don’t forget to do your cleaning chores. Buechner-Maxwell says that in some cases, there may be additional irritating factors. This can also be problematic if you find ammonia under the stall bedding. Clients are advised to sit down on their knees and place their heads where the horse is.


You may need to improve ventilation in your barn if you notice persistent problems like ammonia smells or dusty air. It may be as easy as opening doors and windows in winter to let air flow through each stall. An experienced contractor may be able recommend affordable fixes such as installing ridge vents or cupolas to increase airflow. Cleaner air will be a benefit to all your horses.

1O. 1O.

Omega-3 fatty acids can be used in human medicine to manage inflammation conditions. Couetil recently published a study that suggested that horses suffering from heaves might also benefit. His double-blind study showed that horses with heaves experienced significant improvements in their clinical signs compared to horses who didn’t receive the supplement. Couetil says that people started using them for heart disease and arthritis, as well as asthma. This is the first study with an algal source of omega-3 fat acid in horses and the first to show an effect. This is why I now recommend it to my clients as a non-drug supplement.

Allison Price
Allison Price

I’m Allison, born and raised in San Diego California, the earliest memory I have with horses was at my grandfather’s farm. I used to sit at the stable as a kid and hang out with my Papa while he was training the horses. When I was invited to watch a horse riding competition, I got so fascinated with riding!