Coughing in Horses

Key Takeaways

Coughing, the act of suddenly expelling air from the lungs, is a common symptom in horses.

• Can be caused by an array of underlying conditions, such as equine asthma and bacterial or viral infections

• The severity of the underlying cause of coughing can range from mild to life-threatening

• Coughing horses that have a fever, nasal discharge, reduced appetite, swollen lymph nodes, or a recent history of long-distance travel require immediate veterinary attention

• Diagnosis involves physical examination, blood work, diagnostic imaging, and nasal swabs

• Treatment and prognosis vary greatly depending on the underlying condition causing the cough

• Horses with a noteworthy cough should be isolated from other animals to limit the spread of any viral or bacterial infections

A Closer Look: What is Coughing in Horses?

Coughing is common in horses. It can be caused by an array of factors, from a mild respiratory irritation to severe underlying conditions that require prompt medical attention.    A cough can arise in several different situations: 

Coughing only during exercise: Consistent coughing during exercise but not at rest may be a sign of a respiratory infection, abnormalities in the airway such as displacement of the soft palate, or inflammatory airway disease. 

Coughing at rest: Coughing while at rest in a non-dusty environment can indicate:

• Tumors pressing against the animal's airways • Infectious conditions • Traumatic injury to the ribs

• Pneumonia

Prompt veterinary attention and isolation from other animals are warranted in these cases.

Coughing that produces mucus: If the cough produces mucus, it generally indicates that the trachea or lungs are inflamed. Inflammation can be caused by a number of different underlying conditions such as equine heaves, bacterial infections, and viral infections.  

Note that mucus can range in color, with allergies and viruses typically causing a clear or light colored mucus, and bacterial infections producing a thick yellow or white mucus.  

Coughing horses that produce nasal discharge should be isolated from others to limit the spread of any viral or bacterial infections. If the animal presents swollen lymph nodes or a fever, immediate veterinary attention is warranted. 

Coughing after transport: Horses presenting with a cough immediately after transport could have contracted a potentially life-threatening viral (e.g. equine influenza) or bacterial (e.g. shipping fever) respiratory disease. 

A coughing horse with a recent history of long-distance transportation requires immediate veterinary attention and should be isolated from others.

Coughing in young horses: Two unique causes of cough in young horses (under 2 years of age) are:

• Ascarid infections • Rhodococcus equi pneumonia

These conditions are rarely seen in older horses. 

Coughing while eating: Most cases of coughing while eating resolve on their own, nonetheless veterinary attention is recommended, as the cough be caused by a number of factors, including:  

• Dental issues • Abscess or throat infection  • Abnormal swallowing leading to feed in the trachea

• Entrapment of the epiglottis

Horses that are coughing and have feed material coming out of their nose are choking, and require immediate veterinary care.

Possible Causes

Coughing is associated with an array of different conditions, including:

• Aspiration pneumonia • Inflammatory airway disease (IAD) • Equine Influenza • Rhinopneumonitis • Strangles

• Pleuropneumonia (shipping fever) or other bacterial pneumonias • Recurrent airway obstruction (heaves)

• Exercise-induced pulmonary hemorrhage (EIPH) • Guttural pouch infections • Heart failure

• Laryngeal hemiplegia (“roaring”) • Parasitic infections such as equine roundworm in young horses

Risk Factors

Occasional coughing (no more than a few coughs) is not necessarily alarming in and of itself. If accompanied by the following symptoms, immediate veterinary attention should be sought:

• Fever • Nasal discharge • Lack of appetite  • Swollen lymph nodes • History of recent long-distance travel 

Even if other symptoms are  not present, medical attention is warranted, as coughing can be a symptom of serious underlying conditions and requires prompt veterinary attention.  If a horse has a cough, keeping the animal separate from healthy horses is recommended to decrease the probability of any possible infection spreading.

Testing and Diagnosis

A horse presenting with a cough requires the following diagnostics to determine the underlying cause and subsequent course of treatment: 

• Physical examination • Specialized examination of the respiratory tract • Blood work • Ultrasound 

• Endoscopy, including endoscopy during exercise • Skull x-rays  • Bacterial swabs • Electrocardiograms

Treatment options vary greatly in accordance with the underlying cause of coughing. 

• Antibiotics: antibiotics can be administered in the case of a bacterial infection 

• Environmental changes: reducing exposure to dust and cold air can improve the animal’s condition

• Exercise restriction • Anti-inflammatory medications • Bronchodilators that open the airways to improve airflow

Many causes of coughing are highly contagious. Isolating the affected animal decreases the probability of the disease spreading through the herd.

Similar symptoms

Coughing once or twice when beginning to exercise is considered normal. This kind of cough is probably caused by small amounts of debris in the animal’s sinuses and does not require any medical attention. 

Coughing that persists throughout the ride may be a sign of a respiratory infection. If the coughing persists and the horse seems less energetic than usual, activity should be halted, and veterinarian attention is warranted.

Associated Symptoms

A horse presenting with a cough can show other symptoms: 

• Fever • Yellow nasal discharge • Swollen lymph nodes • Lack of appetite • Swelling of the limbs

• Abortion (in pregnant females) • Rapid breathing • Lethargy