Equine asthma is a common disease that can significantly affect your horse’s ability to breathe. Our Leatherstocking Veterinary Services team knows how hard it is to watch your horse struggle to breathe. We provide information about equine asthma and management techniques to reduce triggering factors.
Equine asthma terminology
Numerous terms have been used to describe equine airway problems, and current guidelines use the term equine asthma syndrome to characterize the following conditions:
- Inflammatory airway disease (IAD) — IAD is a respiratory disease that typically affects young horses, causing coughing, poor performance, and excess mucus in the airways. Affected horses usually don’t exhibit increased respiratory effort at rest.
- Hay-associated recurrent airway obstruction (RAO) — RAO typically affects older horses, appearing after exposure to indoor environments that contain excessive dust particles from moldy hay and dusty bedding. Certain mold spores, including Aspergillus fumigatus, Micropolyspora faeni, and Thermoactinomyces vulgaris, that are commonly found in moldy hay are important triggering factors for hay-associated RAO. Affected horses usually exhibit increased respiratory effort at rest.
- Summer pasture-associated obstructive pulmonary disease (SPAOPD) — SPAOPD is a form of RAO that appears after exposure to pasture during late spring to mid-fall. This disease is most commonly reported in the Southeast, especially Florida, Georgia, Louisiana, and Mississippi. Affected horses are typically older than 6 years of age and often kept at pasture more than 12 hours a day throughout the year. Signs range from exercise intolerance and coughing to increased respiratory effort and labored breathing.
Equine asthma causes
Equine asthma is a complex disease that involves numerous factors, such as genetics, ineffective lung clearance, and exposure to certain environmental allergens that cause a hypersensitivity reaction. The most common allergic triggers for equine asthma are mold, organic dust, and endotoxins present in hay and straw.
Equine asthma signs
Signs observed in horses affected by equine asthma vary in severity and include:
- Poor or decreased performance
- Persistent cough
- Longer recovery period post work
- Exercise intolerance
- Increased respiratory rate
- Flared nostrils
- Increased respiratory effort
- Clear or white nasal discharge
- Absence of fever
- Weight loss
- Heave line along the bottom edge of the ribs
Equine asthma diagnosis
Diagnosing equine asthma involves the following:
- History — Our team takes a thorough history to determine what signs your horse exhibits and when they appear.
- Physical examination — We thoroughly examine your horse, including auscultating their lungs. Equine asthma causes inflamed, narrowed bronchial tubes, which usually cause wheezing.
- Blood work — We may recommend blood work to assess your horse’s overall health and rule out infection.
- Endoscopy — In some cases, we use an endoscope to assess your horse’s airways.
- Bronchoalveolar lavage (BAL) — Another helpful test is a BAL, which involves performing a lung wash to obtain cells lining the airways deep in the lungs. Evaluating these cells helps distinguish among possible causes of respiratory problems.
- Ultrasound — In cases that fail to respond to therapy, we may recommend an ultrasound to evaluate the lungs.
Equine asthma medications
Medications most commonly used to manage equine asthma are corticosteroids and bronchodilators. These medications can be administered via two routes:
- Systemically — Corticosteroids can be administered orally or by injection and are commonly used to control acute episodes. These medications can cause serious side effects, including laminitis, and should be used at the lowest effective dose. Bronchodilators can be administered orally, but they may lose their effectiveness if given for long periods.
- Aerosolized — Aerosolized medications deliver a specific medication dose in liquid form directly to the airways for rapid effect. This allows a lower dose to be used, lowering the risk of potential side effects. Several inhaler devices designed specifically for horses are on the market. Inhalation therapy is the preferred method to manage equine asthma, but it requires a financial investment to purchase the inhaler device and medications.
In many cases, a combination of systemic and aerosolized medications are used to manage equine asthma, and our team will devise an appropriate treatment plan that works for you and your horse.
Equine asthma management
Medical management for equine asthma is ineffective unless good environmental management occurs as well. Recommendations include:
- For hay-associated ROA, maintain horses on pasture full time, and for SPAOPD, avoid access to pasture except for winter months.
- Avoid feeding round bales, which are high in endotoxin and organic dust.
- Ensure housing has good ventilation.
- Avoid storing hay above the stalls.
- Use low dust bedding such as chopped paper, peat moss, or cardboard.
- Soak hay and feed in water to lower dust content.
- In severe cases, removing hay from the diet and feeding only a pelleted diet may help.
- Take horses outside when grooming, cleaning stalls, and sweeping barn aisles.
Horses affected by equine asthma require lifelong management, but in many cases, they can be managed effectively to allow them to be excellent pleasure, trail, or potentially even competition horses. If your horse is exhibiting signs that may indicate equine asthma, contact our Leatherstocking Veterinary Services team so we can evaluate their condition and devise a treatment strategy to help them breathe easier.
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