Heaves in Horses
Heaves is a respiratory condition in horses that creates difficulty breathing. This chronic condition of respiratory difficulty can be mild, moderate, or severe and most definitely interferes with a horse’s quality of life in severe cases.
Recurrent Airway Obstruction (RAO) is known as heaves in horses. It’s similar to asthma in humans. In a nutshell, heaves make it hard for your horse to breathe. It’s a chronic disease that often worsens over time. Early intervention is key, and there are lots of management changes and meds that are a great treatment for heaves.
Table of contents
What’s the difference between heaves, RAO, equine asthma, and COPD in horses?
- The umbrella term of equine asthma has largely replaced the term heaves when describing respiratory disease. You may have heard the terms chronic obstructive pulmonary disease (COPD), inflammatory airway disease (IAD), recurrent airway obstruction (RAO), and summer pasture recurrent airway obstruction (SPRAO), which all fall under this umbrella. RAO is the one most closely linked to the previous term of heaves.
- Here are the specifics of each:
COPD – chronic obstructive pulmonary disease.
This term, now outdated, describes a general lung condition that causes exercise intolerance, lung function decline, and coughing. The term is now just called equine asthma.
IAD – inflammatory airway disease.
This is mild or moderate equine asthma that shows up as vaguely poor performance and trouble reaching maximum effort during exercise. You won’t notice any signs of respiratory distress when a horse with IAD rests. You will also not hear any wheezing that accompanies trouble breathing at rest. During lighter work, you usually don’t have any clues about breathing troubles.
ROA – recurrent airway obstruction.
This more specific label is closest to the “severe heaves” label. This is severe asthma in the horse’s lungs, as demonstrated by dyspnea – the feeling of being out of air and unable to breathe quickly or deeply. You will see this at rest in horses with ROA, usually in fits or episodes. Horses with ROA also can’t exercise easily, and nasal discharge is usually present. These signs of heaves may appear and disappear as if to have resolved, but then they appear again.
ROA also makes a horse wheeze when exhaling, and the lungs have crackles when listened to with a stethoscope. Perhaps there is a chronic cough, too.
SPRAO – summer pasture recurrent airway obstruction.
This condition is part of ROA – that is, severe heaves. In mature horses living in hot and humid areas, this asthma pops up in summer (usually) as a presumed response to allergens like pollens and spores from grass and fungus.
Dust is a major contributor to heaves.
Causes of heaves
- The cause of heaves is more of a mystery for less severe cases. In advanced cases, it’s more clear. Horses can be hypersensitive to things in the air, creating an allergic reaction in the lungs.
- Organic dust from molds, endotoxins, microbes, pollen, ammonia in stalls, or poor air quality can trigger this. This usually happens when a horse is 10-ish, although heaves can affect younger and older horses alike.
- Signs of heaves usually appear in stabled horses that eat hay. Their noses are next to the dusty action – bedding, dusty hay, and ammonia smells.
A more detailed and science-based article can be found here.
What’s happening in the horse’s airway
- The allergic reaction begins when a horse inhales the allergen – like dusty spores and pollen.
- The horse’s lungs will swell and secrete mucus, helping the immune system clear the allergens.
- With this extra mucus and inflammation, air pockets become stuck, and exhalation is difficult. This is why a wheezing noise can be heard during exhalation.
- Over time, the airways will thicken. This creates difficulty breathing and can increase the chance of infections as the lungs can’t clear bacteria and microbes. Hence, case a of secondary pneumonia occurs.
- Pay attention to your horse’s respiratory system; there’s a lot their nose and breathing can tell you.
Coughing and other signs of heaves
- There are some big signs that a horse is suffering from equine asthma.
- The cough – A cough, especially during exercise and when there’s dust around, is a giant hint.
- Track your horse’s respiratory rates and look for trends over time. Respiratory problems create an increased respiratory rate. It’s essential to track all of your horse’s vital signs at rest and after exercise. Note – measure your breathing rate and notice how much their nostrils flare.
- Your horse is a hard keeper. Weight is hard to keep on, and you need thicker blankets in the winter to keep your horse warm. You may even see weight loss.
- You may notice your horse has difficulty exercising. Fair warning: This is also a sign of dozens of other horse ailments. Hence, the importance of looping in your vet for diagnosis and treatment.
- You notice your horse is spending extra energy and using their abdominal muscles more to breathe.
- You may also notice that these signs improve when your horse is turned out, away from barn dust, and does not stick its nose in a pile of dusty hay or round bales.
For more on taking your horse’s vitals, read this.
Learn how to estimate your horse’s weight and look for trends by reading this.
The heave line
- In some horses, the extra effort to breathe forces abdominal muscles to overwork, creating a heave line. This horizontal line under a horse’s ribs delineates those muscles. This usually happens when the heaves have progressed into a ROA situation. It’s most likely you already know about your horse’s respiratory health before you see this line, but it’s an obvious sign.
What about pneumonia?
- Pneumonia, a lung infection, is typically not part of heaves but can become a secondary infection. You will find that your horse has a fever, and blood work, such as a complete blood count (CBC), can confirm an infection, as indicated by a higher count of white blood cells.
The diagnosis of heaves
- Your vet is the best source of information, diagnosis, and treatments. To get to that diagnosis, your vet will usually do the following:
- Physical exam – A head-to-hoof exam of your horse’s overall health.
- Thoracic auscultation – These fancy words mean listening to your horse’s body with a stethoscope. The heart, trachea, and lungs will all be auscultated. Your vet may use a rebreathing bag to boost inhales for a more thorough listen. This is when your horse breaths into and out of a bag. The big problem with thoracic auscultation is that many horses with asthma sound peachy keen.
- Tracheal endoscopy – Your vet will use an endoscope from the nostrils to the trachea to see how much mucus is there. Samples of this mucus can reveal how many immune cells are floating around, indicating how much inflammation there is.
- Bronchoalveolar lavage (BAL) – This is a lung wash. An endoscope travels through the nostrils into the lowest portions of the airway. Saline is then introduced to the area, hence the washing, and removed. The sample is analyzed for inflammatory cells, indicating the severity level.
Treatment for heaves
Horses with heaves can be helped in two big ways – medications from your vet and your management changes.
How your veterinarian can help – corticosteroids and a bronchodilator
- Steroids for the win! Corticosteroids like dexamethasone and prednisolone help with airway inflammation.
- Nebulizer treatments are an option too, where your horse wears a mask, and aerosolized corticosteroids are breathed in. These could be fluticasone, beclomethasone, or ciclesonide.
- There are other immune-supportive drugs, too, and NSAIDS and anti-histamines don’t seem to help.
For more about NSAIDS, read this.
Feeding to support heaves
- As a surprise to almost nobody, Omega-3 fatty acids and MSM supplementation have anti-inflammatory properties and help horses with heaves. Using these two affordable products helps reduce coughing and respiratory efforts. Treatment for heaves can be as easy as adding some delicious fats to your horse’s diet. Bam. Easy. And, it’s been studied. By science!
Zeolites also help your horse’s stall stay dry when they are eating ammonia odors.
How to help your horse in the stall and outside
- The best thing you can do for your horse is remove them from their triggers – and the two big ones are barns and dusty hay. More ideas:
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- Soak or steam hay. Moisture removes the dust!
- Switch to hay cubes, pellets, or chopped forage. Pound for pound, these are identical to long-stem forage. And yes, you can find slow feeders for pellets and cubes.
- Avoid round bales; they tend to be more dusty, and horses will stick their noses right into those bales.
- Don’t sweep or use blowers around your horse.
- If your horse must be in a stall, give them the area with the most ventilation – at the end of the barn aisle, with the biggest windows, away from hay storage, and generally in the breeziest location to keep good air flowing.
- Use cardboard as bedding instead of shaved, flaky, or pelleted bedding. This also applies to outside shelters and sheds.
- Pick bedding and paddocks well and often.
- Use zeolites to soak up ammonia smells anywhere your horse pees.
- Pick manure from riding arenas. Dust in riding rings is from the decomposition of manure. If the footing is generally dusty, see if you can ride after a watering.
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It’s so easy to add Omega into your horse’s diet.
Read more about soaking and steaming hay here.
Science about horses and heaves
Here’s one more interesting tidbit about equine asthma: It seems that equine asthma and human asthma have similar features, and advances in understanding heaves are helping human asthma research.
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