Equine asthma is one of the most common respiratory conditions affecting horses and ponies. From an occasional cough or slight dip in performance to more obvious breathing difficulties, equine asthma can present very differently from one horse to another.
While there is no cure for the condition, there is plenty that can be done to manage it. Reducing exposure to environmental triggers, recognising changes early and working with your vet to develop an appropriate treatment plan can all help horses with asthma breathe more comfortably.
So, what causes horse asthma, what should you look out for and what are the options when it comes to treatment?
What is equine asthma?
Equine asthma is a chronic inflammatory disease affecting the lower airways. You may previously have heard terms such as recurrent airway obstruction (RAO), heaves or inflammatory airway disease (IAD), but these conditions are now generally considered under the umbrella term of equine asthma.
The condition develops when a horse’s airways react to inhaled particles and allergens in their environment. This triggers inflammation, increased mucus production and narrowing of the airways, making it more difficult for air to move freely in and out of the lungs.
The severity can vary considerably. Horses with mild to moderate equine asthma may show few obvious signs at rest, while horses with severe disease can experience significant breathing difficulties. Persistent inflammation can also lead to long-term changes within the airways, making early recognition and management important.
What causes equine asthma?
There isn’t usually one single cause of equine asthma. Instead, susceptible horses can react to a range of microscopic particles found in their everyday environment.
Common triggers include:
- Dust from forage and bedding
- Mould and fungal spores
- Pollen
- Poor stable ventilation
- Ammonia and other airborne irritants
For some horses, problems are more apparent when they spend longer periods stabled and are exposed to dust from hay and bedding. Others may struggle during spring and summer when pollen levels rise.
Understanding when symptoms occur and what has changed in your horse’s environment can help you and your vet identify potential triggers.
What are the symptoms of equine asthma?
When you think of horse breathing problems, coughing or laboured breathing may immediately come to mind. However, equine asthma isn’t always that obvious.
Signs can include:
- Coughing, particularly during or after exercise
- Nasal discharge
- Increased respiratory rate
- Increased breathing effort
- Reduced stamina or willingness to work
- Taking longer to recover after exercise
- Reduced performance
- Abnormal respiratory noises
In horses with mild disease, a change in performance can sometimes be one of the first signs. Your horse may feel less enthusiastic, tire more quickly or struggle with work they previously found easy.
Horses already place significant demands on their respiratory system during exercise. As obligate nasal breathers, they cannot breathe through their mouths to increase airflow. Even relatively small changes in airway function can therefore affect performance and recovery.
Of course, coughing and poor performance can have many different causes. If you notice changes in your horse’s breathing, stamina or recovery, speak to your vet.
How is equine asthma diagnosed?
Your vet will usually begin by taking a detailed history and examining your horse, including listening to their lungs and airways and assessing their breathing.
Depending on the individual case, further investigations may include endoscopy, which allows the vet to look directly inside the respiratory tract for changes such as excess mucus or inflammation.
A bronchoalveolar lavage (BAL), sometimes referred to as a lung wash, may also be recommended. A small amount of sterile fluid is introduced into the lower airways and then collected so that the cells present can be examined. This can help identify airway inflammation and inform the most appropriate management plan.
How is equine asthma treated?
Managing equine asthma usually requires a combination of environmental changes and, where necessary, veterinary-prescribed medication.
Creating a respiratory-friendly environment
Environmental management forms the foundation of equine asthma care because medication alone cannot remove the triggers responsible for irritating the airways.
Practical changes can include:
- Maximising turnout where appropriate
- Keeping stables clean and well ventilated
- Using low-dust bedding
- Keeping horses away from the stable while mucking out
- Steaming or soaking hay to reduce exposure to airborne particles
- Feeding forage from floor level to encourage natural airway drainage
- Adjusting turnout for horses affected by seasonal pollen
The right approach will depend on your horse and their individual triggers.
Medication for equine asthma
Many horses will also require prescribed medication to control inflammation and improve airflow.
Corticosteroids help reduce the underlying inflammation within the airways. Depending on the severity of disease, they may be administered systemically or delivered directly to the respiratory tract through inhaled therapy.
Bronchodilators relax the muscles surrounding the airways, helping to open them and improve airflow. As they don’t address the underlying inflammation, they should not be used in isolation. They are commonly used alongside corticosteroids rather than as a replacement for them. Bronchodilators should also only be used in the short term as horses can become refractory to them with longer term use – recommended use is for no more than 21 days.
Your vet will determine which medication and route of administration is most appropriate for your horse.
What role does inhaled therapy play?
Inhaled therapy allows prescribed medication to be delivered directly to the lungs and lower airways, targeting the area where it is needed while reducing systemic exposure.
Depending on the medication, this may involve a nebuliser or a metered dose inhaler used with an equine-specific spacer.
A spacer holds medication released from an inhaler until the horse breathes it in. Horses have very different tidal volumes and inspiratory flow rates to people and small animals, so using a device designed specifically for equine breathing can help optimise medication delivery.
Nebulisers work differently, converting a liquid into a fine mist that can be inhaled into the respiratory tract. Alongside prescribed medication, nebulisers can also be used with non-drug options such as saline as part of a wider respiratory management routine.
Can horses with asthma still be ridden?
An equine asthma diagnosis doesn’t automatically mean the end of a horse’s ridden career.
With appropriate veterinary treatment and careful management of environmental triggers, many horses can continue to exercise and compete. The appropriate level of work will depend on the severity of disease, how well controlled it is and the individual horse.
Exercise shouldn’t, however, be used to push through breathing difficulties. If your horse is coughing, struggling to recover, showing increased breathing effort or experiencing an unexplained decline in performance, speak to your vet.
Supporting a horse with asthma long term
Managing horse asthma is often about making small, consistent changes.
Keeping an eye on forage quality, stable ventilation, bedding, pollen levels and subtle changes in performance can help you identify when your horse’s airways may be coming under increased pressure.
Most importantly, don’t wait for severe horse breathing problems before asking for advice. Mild coughing, slower recovery or subtle changes in performance can all be early indications that something isn’t quite right.
By combining veterinary care with a respiratory-friendly environment and an appropriate long-term management plan, you can help keep airway inflammation under control and support your horse’s breathing, wellbeing and performance.
Speak to your vet to learn more about the benefits of nebulisation and whether it can make a difference to your horse. Or, shop our range of equine nebulisers here: