Coughing is a common clinical sign in horses that can be entirely benign or the first clue of a medical condition.

Your horse’s cough is a normal reflex that keeps his airway healthy and clean. But some conditions associated with coughing require immediate veterinary care.

Horse owners should learn to identify different types of coughs to determine when to call the vet. While certain diseases only respond to medical treatments, feeding and environmental changes can also help manage coughing in horses.

This article will review the causes, symptoms and diagnosis of coughing in horses. We will also discuss treatment options for breathing conditions and how horse owners can address respiratory health with management changes and nutritional support.

Types of Coughing in Horses

Frequent coughing is a reliable indicator of an underlying medical problem. But many different factors and conditions can contribute to coughing.

Additional symptoms and circumstances associated with your horse’s cough can help you identify the cause.

Early diagnosis of health conditions reduces the risk of complications. Always consult your veterinarian if you have any concerns about your horse’s cough.

Coughing During Exercise

A single cough or two at the beginning of a ride is not unusual. Horses cough when exercising to clear a small amount of mucus or debris in the upper airway as they begin breathing harder. [1]

However, persistent coughing throughout a ride is a cause for concern. Horses may struggle to breathe due to a respiratory infection, or they could have a physical abnormality.

A displaced palate can cause horses to cough during work as the soft palate obstructs the opening to the trachea and interferes with breathing. The coughing caused by this abnormality is more of a dry cough. [2]

Coughing during exercise is also a symptom of exercise-induced pulmonary hemorrhage (EIPH). Horses with this condition cough to clear blood from their lungs.

Coughing That Produces Mucus

Unlike dry coughs, wet or productive coughs expel mucus. These coughs generally indicate inflammation in the horse’s airways. Airway inflammation is associated with several conditions in horses. [3]

Examination of the mucus offers additional insight into the cause of the cough. Allergies are associated with light or clear-colored mucus, while bacterial infection produces thicker, white/yellow mucus. [3]

Coughing After Transportation

Even a cough or two after transportation in a trailer calls for prompt investigation. This may indicate shipping fever, a life-threatening form of bacterial pneumonia.

Horses tied in trailers for hours can’t drop their heads to clear their airways. Inhaled foreign bodies, such as hay and bedding particles, carry pathogens that enter the lungs and cause infection. [4]

The stress of trailering also compromises the horse’s immune response to the infection, so immediate treatment is necessary to improve outcomes. [4]

Coughing While Eating

Violent coughing after eating is a sign of choke, which occurs when food gets stuck in the horse’s esophagus. Most cases resolve spontaneously, but horses can accidentally inhale food during the choke episode. [5]

A veterinary examination will determine if the horse needs medical intervention to reduce the risk of aspiration-induced pneumonia. Sporadic coughing while eating also warrants a closer inspection.

Dental issues prevent the horse from adequately chewing his food. But other physical problems with the mouth can cause food to go down the throat before it’s ready. These include entrapment of the epiglottis and neurological issues. [6]

Coughing in Young Horses

Some parasitic and bacterial infections primarily affect young horses. Coughing in horses under two years of age is often associated with Ascarid infection. Unlike older horses, foals don’t have resistance to this parasite. [7]

Young foals under four months old can develop a severe lung infection from Rhodococcus equi. This bacteria lives in the soil and enters the foal’s airways through inhaled dust particles. [8]

Coughing Without Obvious Cause

Some coughs have obvious causes that horse owners can address right away. Coughs caused by excessive dust from the footing, bedding, or feed are typical examples. [9]

Other coughs don’t have an obvious culprit. You should consult your veterinarian if your horse suddenly coughs without an apparent instigating factor.

Unusual issues that can cause coughing in horses include tumors, injuries, or problems with other organs. [10]

When to worry about your horse’s cough

An occasional cough is not cause for alarm. But any coughing that becomes frequent or severe warrants investigation. While the horse may not have an infection, frequent coughing indicates that your horse has compromised breathing ability.

Any coughing onset accompanying changes in attitude or performance also needs immediate attention. Other symptoms associated with respiratory infections include fever, nasal discharge, and lethargy. [11]

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Causes of Coughing in Horses

Coughing in horses can arise from infectious and non-infectious causes. No matter what type of cough your horse has, identifying the underlying cause is the first step in any effective treatment plan.

Here are some of the most common causes of coughingin horses.


Equine influenza is a highly contagious viral infection of the respiratory tract. This airborne disease spreads primarily through coughing. Other symptoms include fever, inappetence, and nasal discharge. [12]

The airway inflammation caused by the virus leads to the destruction of cells in the respiratory tract. These cells take weeks to regenerate, leaving horses with influenza at risk of secondary bacterial infections. [12]


Pneumonia is inflammation of the lungs due to bacterial infections, viral infections, or aspiration.

Aspiration pneumonia occurs when foreign material gets stuck in the lungs. Shipping fever pneumonia is a type of aspiration pneumonia. [13]

Signs of pneumonia include coughing, depression, nasal discharge, and fever. This respiratory tract infection isn’t typically contagious to other horses. Foals have a higher risk of the disease, but adult horses frequently develop pneumonia as a secondary infection. [13]


Also known as recurrent airway obstruction or COPD, heaves is a chronic allergic respiratory condition in horses. This disease is similar to asthma in humans and induced by environmental exposure to allergens. [14]

Heaves is the most common respiratory condition in mature horses. Symptoms include chronic coughing, nasal discharge, and performance-limiting respiratory difficulty.

Although it is incurable, medication can help reduce lung inflammation in horses with heaves. [14]

Inflammatory Airway Disease

Inflammatory airway disease is a little-understood condition that affects young racehorses and performance horses. This condition causes periodic poor performance and can progress to heaves in later years if left untreated. [15]

Endoscopic examinations of horses with IAD typically find excess mucus and inflammatory cells in the airways. Possible etiologies of this disease include recurrent pulmonary stress, persistent infections, and inhalation of allergens. [15]


Rhinopneumonitis is another highly contagious viral disease characterized by fever and coughing. Herpesviruses EHV-1 and EHV-4 cause this disease in unvaccinated horses. [16]

This virus most commonly results in respiratory issues, but it may also cause other issues. Pregnant mares with rhinopneumonitis may abort their fetuses. In rare cases, some strains can cause fatal neurological complications. [16]


Strangles is a contagious upper respiratory tract bacterial infection caused by Streptococcus equi bacteria. This infection causes abscesses and swollen submandibular lymph nodes that obstruct the airway. [17]

Horses with strangles frequently develop a cough and have thick, yellow nasal discharge. Most horses recover from strangles with supportive care, but others need antibiotics to treat the infection. [17]


Ascarid infections can cause coughing in foals. Ascarids are equine roundworms that migrate to the lungs of horses after ingestion.