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Heaves and Scratches: Two Issues Impacting Senior Horses Part 1: Heaves

Part 1: Heaves


Gail M. Staines, Ph.D.

Founder, The Senior Horse

July 22, 2021

This past weekend I volunteered as a scribe and ring steward at the National Dressage Pony and Small Horse Cup in Lake St. Louis, Missouri. Of all the shows I have been to over the years, this was by far the best! Professional and friendly management, horses of all ages and all breeds, rides from introductory level through FEI, and riders from children through people in their 70’s.

I had the opportunity to talk to many horse owners, riders, and officials. Almost every person said that they had a horse over the age of 18 at home! Some horses were still competing, though not as often; some are schoolmasters, teaching riders the art of dressage; and some are happily retired.

Two medical issues that were commonly mentioned by these owners of older equines were heaves and scratches.

Below is what I have learned about heaves. In my next blog post I will address scratches.

(NOTE: I am not a veterinarian. For information regarding your specific horse, please consult with your veterinarian.)

Heaves in Horses

Heaves is known as recurrent airway obstruction (RAO). It is uncommon to see heaves in horses under 5 years of age. There is no ‘cure’ for this condition. Once a horse is diagnosed with heaves it has it forever.

How does a horse get heaves?

Dust, mold, and other airborne particulates enter the horse’s system when they breathe. Going deep into their lungs, the horse’s system reacts by creating mucous which, in turn, narrows their airways making it difficult to breath, especially when trying to exhale. According to Frederik Derksen, DVM, the horse is experiencing an allergic inflammatory reaction to what they are breathing in. (Barakat, 2021). Horses with a more severe case of heaves may develop a ‘heave line’ on their sides from overuse of their muscles trying to breathe.

Typically, horses who are stalled most of the time and eat hay in their stall are more likely to contract heaves, as opposed to horses that live outside. However, some horses experience difficulty breathing only during the summer months. This is known as summer- or pasture-associated heaves. Instead of heaves, this is referred to as equine asthma. (House, 2016)

Is heaves genetic?

This is a very interesting question and may answer why some horses get heaves and others do not, even though they both live in similar environments. Veterinarians, researchers, and other equine practitioners gathered at The Havemeyer Workshop in 2019 to share research and discuss future directions in equine asthma and related diseases. This group of experts shared information on current causes of RAO as well as other areas that require more research, such as bacterial and viral infections as well as possible genetic predispositions. (Couetil, et al., 2019) Although there is some research that indicates genetics may play a role in the development of heaves in offspring, there is no definitive causation to date. (Ramseyer, et al., 2007)

Keeping Your Horse Breathing Healthily

According to Crabbe (2020), you can do the following to help your horse that has heaves and even ones that do not:

  • Turn your horse outside to get fresh air.

  • Make sure your barn and other structures where your horse goes is very well ventilated.

  • Instead of placing feed and hay on the ground, put it in a container that is chest-high to your horse.

  • Wet your horses hay in clean water for 20 minutes prior to feeding. This reduces the amount of dust and other particles while keeping most of the nutrients intact.

  • Keep your horse’s stall as dust free as possible (e.g., sprinkle water on shavings once a day after cleaning or use dust-free bedding).

  • Your horse should be out of its’ stall when you clean it, otherwise they can inhale airborne particulates.

  • Ride in dust-free areas, both indoors and outside.

Consult with your veterinarian to determine if medication is needed to reduce the symptoms of heaves.


Barakat, C. (2021). Protecting Your Aging Horse’s Respiratory Health, Equus.

Couetil, L. et. al (2020). Equine Asthma : Current Understanding and Future Directions. Frontiers in Veterinary Science.

Crabbe, B. (2020). Horse Heaves: Symptoms and Treatment, Horse & Rider.

House, A. (2016). Recurrent Airway Obstruction (RAO), American Association of Equine Practitioners.

Ramseyer A, Gaillard C, Burger D, Straub R, Jost U, Boog C, et al. (2007). Effects of genetic and environmental factors on chronic lower airway disease in horses, Journal of Internal Veterinary Medicine, 21:149–56.


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