Horse Coughing: Causes, When to Worry & What to Do

Coughing in horses is a sign, not a diagnosis. One of the most common causes is equine asthma, a broad term that includes mild to moderate airway inflammation in athletic horses and more severe dust-related airway disease in older horses. Dusty hay, mold, poor barn ventilation, and bedding particles are common triggers. Horses with asthma may cough during warm-up, after eating hay, or when stalled for long periods.

Infectious respiratory disease is another major cause. Viral infections such as equine influenza and equine herpesvirus can cause cough, fever, nasal discharge, dullness, and swollen lymph nodes. Bacterial infections may follow viral disease and can progress to pneumonia, especially if a horse is stressed, traveling, very young, older, or already ill. Strangles can also cause cough along with fever, nasal discharge, and enlarged lymph nodes.

Some coughing starts higher in the airway. Laryngeal or throat irritation, inflammatory conditions, and structural upper-airway problems can trigger coughing, especially during exercise. Horses may also cough with choke, where feed gets stuck in the esophagus. In that situation, you may see drooling, repeated swallowing, anxiety, and feed material or saliva coming from the nostrils.

Less common causes include aspiration pneumonia after choke or improper tubing, fungal disease, parasites in young horses, and exercise-related airway bleeding or inflammation. Because the list is broad, a cough that keeps happening should be evaluated by your vet rather than treated as a minor nuisance.

A single brief cough in an otherwise bright horse may be reasonable to monitor for 24 hours, especially if there was obvious dust exposure and no other signs. During that time, stop riding, improve ventilation, offer low-dust forage if available, and check your horse's rectal temperature. If the cough does not quickly fade, or if it returns with exercise or feeding, schedule a veterinary exam.

See your vet the same day if your horse has repeated coughing, nasal discharge, reduced appetite, lethargy, poor performance, or a fever. These signs raise concern for infectious disease, lower-airway inflammation, or pneumonia. If one horse in a barn is coughing and febrile, it is smart to limit horse-to-horse contact until your vet advises next steps because contagious respiratory disease is possible.

See your vet immediately if your horse has labored breathing at rest, flared nostrils, a heaving abdomen, blue or gray gums, marked distress, or cannot settle. Emergency care is also needed if you suspect choke because saliva, water, or feed is coming from the nose, or if coughing started suddenly after tubing or oral medication. Those situations can lead to aspiration pneumonia and can worsen quickly.

When in doubt, use the whole picture. Cough plus fever, breathing effort, exercise intolerance, or feed from the nose is much more concerning than an isolated cough after a dusty hay net.

Your vet will start with a history and physical exam. Expect questions about when the cough happens, whether it is linked to exercise or feeding, recent travel or new horses, vaccination status, barn ventilation, hay type, bedding, and whether any horses nearby are sick. They will listen to the lungs and upper airway, check temperature, heart rate, breathing rate, and may perform a rebreathing exam to better hear abnormal lung sounds.

From there, testing depends on how sick your horse is and what your vet suspects. A basic workup may include a farm exam and temperature monitoring plan. If infection is possible, your vet may recommend nasal or nasopharyngeal testing, bloodwork, or both. If lower-airway disease is suspected, they may suggest endoscopy to look at the upper airway and trachea, plus airway sampling such as a tracheal wash or bronchoalveolar lavage to identify inflammation, mucus, bacteria, or other changes.

If pneumonia, pleuropneumonia, or aspiration is a concern, your vet may add thoracic ultrasound and sometimes radiographs if available. Horses with suspected choke may need sedation and passage of a tube to relieve the obstruction. Horses with severe breathing effort may need urgent stabilization before a full workup.

Treatment is based on the cause. That may include environmental changes for equine asthma, rest and isolation for viral disease, targeted antimicrobials when bacterial infection is confirmed or strongly suspected, anti-inflammatory medication, or emergency care for choke and aspiration pneumonia. Your vet will help match the plan to your horse's needs, use, and your goals.

Home care should support your vet's plan, not replace it. Start by reducing airway irritation. Move your horse to the best-ventilated area available, avoid dusty indoor arenas, and keep them away from sweeping, leaf blowing, or shaking out hay nearby. If your vet agrees, switching to lower-dust forage or soaking or steaming hay may help some horses with dust-triggered coughing.

Rest matters. A coughing horse should usually be taken out of work until your vet says exercise is safe. Riding through a cough can worsen airway inflammation and may stress a horse with infection or lower-airway disease. Monitor rectal temperature once or twice daily, note appetite and water intake, and watch for nasal discharge, breathing effort, or coughing during meals.

If contagious disease is possible, use practical biosecurity. Separate the horse from shared water sources, avoid nose-to-nose contact, use dedicated buckets and tools, and wash hands between horses. This is especially important if there is fever, nasal discharge, or more than one horse on the property is coughing.

Do not give leftover antibiotics, human cough medicine, or sedatives unless your vet specifically directs you to. If feed or saliva is coming from the nostrils, if breathing becomes hard work, or if your horse seems distressed, stop home care and seek veterinary help immediately.