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Heaves in Horses – What to do?


I have a 10 year old 1/2 Percheron 1/2 Quarter Horse mare, and we live in the Midwest outside of Chicago. My mare suffers from severe seasonal allergies – she is the worst in spring/fall. She will cough, have a runny nose & eyes, sometimes has hives, and becomes a little lethargic. I keep her on Cough Free year round. I’ve tried Tri-Hist to no avail (she will not eat it, and I board, so force-feeding it 2x days is not feasible). Dex works great, but is not show legal – any suggestions on other supplements/medications I can try that are show legal? She does get all day turnout in grass pasture, is inside at night on shavings. She eats alfalfa mix hay and Safe-Choice pellets, along with her SmartPak which includes MVP 4-in-1, Cough Free, and Stress-Dex.

Shame on me for jumping to conclusions, but I’m going to assume from your description that your mare has been diagnosed with “heaves,” or, as it’s being called now, Recurrent Airway Obstruction (RAO). For years the scientific name of heaves was Chronic Obstructive Pulmonary Disease or, COPD, but the name was changed recently because COPD in humans is nonreversible and associated with smoking. RAO, on the other hand, IS reversible, and not generally caused by horses using cigarettes (horses have their vices, but smoking usually isn’t one of them!)

You’ve already mentioned some of the signs of RAO and I’d like to add to your list:

  • Coughing (can be dry or productive)
  • Labored breathing (can make a horse anxious and sweaty)
  • Flared nostrils at rest
  • Nasal discharge
  • Depression and/or inappetance
  • Elevated respiratory rate at rest
  • Exercise intolerance or poor performance
  • Increased movement of abdomen during breathing (causing the “heave line”)

Veterinarians are able to diagnose heaves without too much trouble using just the history owners give them, a physical examination and bloodwork. However, it’s important to rule out other diseases with similar signs, so specific tests may need to be performed, such as blood gas measurements, endoscopy, chest X-rays, bronchoalveolar lavage (BAL), lung biopsy and lung function testing. And having a baseline or beginning value can help determine if the horse is responding to treatment.

Unfortunately, there is no cure for RAO, but it can be successfully managed. Have you tried taking your mare off hay completely? Dust and mold in hay are the main triggers for an episode of “heaves.” If this is not practical—or you can’t find a suitable alternative like hay cubes to replace the fiber in her diet—try wetting the hay before feeding it. Better yet, see if your barn is willing to try a HAYGAIN Steamer, which kills mold and significantly reduces dust in hay.

I’m glad to see that your mare spends at least some time outside on pasture. Is there any way she could be kept outside 24/7? The dust in barns from bedding, traffic in the aisles and even hay that other horses are eating nearby can also trigger episodes. If she must be stalled, avoid straw bedding.

You mention that you have not had any success using antihistamines to treat your mare. This is fairly common. The two categories of medication that DO work are corticosteroids (for example the dexamethasone that you mention) and bronchodilators (for example clenbuterol). These two drug classes work well together as corticosteroids relieve airway inflammation and bronchodilators relieve airway obstruction. However, they are to be used to treat acute episodes of RAO, tapering off as improvement is noticed and dietary and environmental management changes are instituted. They are not to be used year-round or in place of removing hay or keeping the horse outside. Ask your veterinarian if the temporary combination of corticosteroids and bronchodilators might be right for your horse, and if giving them through a special equine inhaler would be helpful.

From speaking to other horse owners struggling with RAO, it seems as if the over-the-counter supplements intended to help horses with heaves work in some but not in others. If Cough-Free works for your mare, that’s great! Other choices are plant adaptogens, which restore the body’s natural equilibrium; botanical preparations combining the extracts of several medicinal herbs; and antioxidants, like Vitamin C especially, which may neutralize the oxidative stress associated with RAO.

Lydia F. Gray, DVM, MA SmartPak Staff Veterinarian and Medical Director Dr. Lydia Gray has earned a Bachelor of Science in agriculture, a Doctor of Veterinary Medicine (DVM), and a Master of Arts focusing on interpersonal and organizational communication. After “retiring” from private practice, she put her experience and education to work as the American Association of Equine Practitioner’s first-ever Director of Owner Education. Dr. Gray continues to provide health and nutrition information to horse owners through her position at SmartPak, through publication in more than a dozen general and trade publications, and through presentations around the country. She is the very proud owner of a Trakehner named Newman that she actively competes with in dressage and combined driving. In addition to memberships in the USDF and USEF, Dr. Gray is also a member of the Illinois Dressage and Combined Training Association (IDCTA). She is a USDF “L” Program Graduate and is currently working on her Bronze Medal. Find Dr. Gray on Google+

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9 comments on “Heaves in Horses – What to do?
  1. Bernie Hill says:

    BAD BARN VENTILATION is the primary issue. Why put the horses on medication, including steroids, so they can breathe when fresh air is free and readily available. Turn them out, they won’t break or melt. Open the barn doors, they won’t freeze, especially with the blankets put on them. Sweep the barn when NO horses are in it. NEVER use a leaf blower in the barn.
    Don’tforget, BAD BARN VENTILATION also affects humans.

  2. Sydney says:

    I have an appy with heaves. My barn is super well ventilated with big windows on three sides and doors. He’s the bottom of the totem pole, so I can’t leave him out 24/7 because the other two will bully him out of his hay (and he’s a hard keeper to begin with!). So I use pelleted bedding for him. It seems to really help, and there’s been a big improvement in his cough since switching. Plus it’s way easier to clean. More expensive in the long run than truckloads of shavings, but no cough. Just a thought!

  3. Karen Morris says:

    As an owner with two horses with RAO and an an asthma sufferer myself, I have concerns about the continued use of a “rescue” inhaler such as Clenbuterol. I use inhalers and an equine spacer for my mares. I’ve discussed the issues with both my veterinarian and my allergist. Any rescue inhaler loses its effectiveness after 10-14 days and as such is of little to no use on a continuing basis. My mares are out 24/7 but our Texas Gulf Coast heat and humidity are the culprits for these “girls”. I’ve had good results maintaining them on a combination inhaled steroid and long term bronchodilator.

    • Dana Carte says:

      Karen I am so on the gulf coast. My mare only suffers during the hot months of the summer. But she gets really bad- nostrils flaired, labored breathing and weight loss. She’s on clenbuterol. Do you think an inhaled steroid would help?

  4. Amber says:

    My new guy was just diagnosed with heaves. This will be my first experience with a horse with heaves (or RAO if you prefer!). One thing I wanted to mention is that my vet said that alfalfa is ESPECIALLY bad for setting off heaves. He instructed me to keep my gelding on, quote, “the most boring hay you can find”.

  5. Ryan W says:

    My appy mare was diagnosed with heaves…soaking her hay has worked…but i wanted more relieve…Smart Breathe is awesome!!! within 2 days being on it she was breathing alot better…my mare is pastured 24/7 with access to run and developed heaves…she has never been locked up and feed good quality hay 🙁 I highly recommend trying the smart breathe!!!

  6. terry says:

    outside board is the best

  7. Kevin McDowell says:

    My 5 year old mare gave birth 4 months ago.
    She is in an 8 acre pasture 24/7. This week the vet
    said that she has the heaves. Coughing, wheezing, labored breathing.
    She cannot be ridden. Is this a forever problem?
    I have had since she was a yearling. I am at a loss for the right questions to ask. Does this mean that I cannot ride her anymore?
    We are treating with steroids and inhalers. HELP?

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