What you see. The starting point for addressing any equine health related issue is your observation.




A cough is an expulsion of air through the airway caused by a reflex to irritation of the trachea and larynx of the upper airway.

The majority of simple coughs are caused by airborne particles that irritate the airways. Even clean, high quality hay contains an astounding amount of dust that is inspired by the horse eating it.

Other possible causes for cough include upper respiratory tract viral and bacterial infection, and a host of other causes. For this reason, one of the first things to do when a horse begins to cough is to consider that they may be contagious. When in doubt, isolate the horse from others.

Performance horses tend to develop coughs more than others, probably as a result of stress and travel and exposure to infectious respiratory diseases. Air quality in some stables is poor, compared to horses living in more natural environments. Often there are high ammonia levels, and ammonia is highly irritating to the respiratory tract.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the horse seems not quite right, or eating less than normal in addition to this sign.
    • If this problem seems severe and has come on suddenly.
    • If the horse seems to be in distress.
    • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp >101F/38.3C) or heart rate greater than 48 BPM.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the horse's appetite and attitude are normal and you see nothing else wrong.
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.
You also might be observing
Very Common
Less Common
more observations

your role


What To Do

If you notice your horse coughing, first consider the possibility of contagion and when in doubt, isolate the horse and begin quarantine protocol. Also, immediately consider the hay the horse is eating as a potential cause. No matter the cause of the cough, you can immediately begin soaking hay before feeding. This is a step that is usually helpful, regardless of the cause of the cough.

Assess your horse's general health using the Whole Horse Exam (WHE), looking for nasal discharge and paying attention to rectal temperature, pulse and respiratory rate. Cough with fever is respiratory virus unless proven otherwise. Also, feel the area around the horse's throat and under the jaw for lymph node swelling which is very obvious in cases of strangles.

Coughs lasting more than a few days, even if the horse seems otherwise normal, should prompt you to contact your vet. A persistent cough can indicate the development of recurrent airway obstruction (RAO), a kind of allergic airway disease. Once this occurs, more permanent lung changes develop that may be harder to reverse and treat.

Do not force a coughing horse or one with nasal discharge to stand with its head elevated. It may cause inhalation of material into the lungs and predispose to pneumonia.

What Not To Do

Do not force a coughing horse or one with nasal discharge to stand with its head elevated. This may cause inhalation of material into the lungs and predispose to pneumonia.

your vet's role

When faced with the chielf complaint of a cough, your vet considers general health and environmental conditions. By listening carefully to the respiratory tract, your vet may be able to determine whether the problem is upper airway (windpipe, voice box) or lower airway (lungs). To get more information, we use x-ray, endoscopy and sampling of the fluid within the respiratory tract through Trans-tracheal wash or BAL. Blood work and physical exam suggests whether the cause is likely to be infectious.
Questions Your Vet Might Ask:
  • Has the horse been in contact with new horses?
  • What is the horse's age, sex, breed and history?
  • When did you first notice this?
  • How is your horse's attitude and appetite?
  • Are any of the other horses in the group coughing?
  • Is there any nasal discharge and if so, what is it's appearance?
  • What is the horse's travel history?
  • What are the results of the Whole Horse Exam (WHE)?
  • Describe the type and quality of the hay?
  • What is the horse's vaccination status?
  • When is the coughing most obvious (eating, exercising, or other)?
  • Are the horses stabled with donkeys?
  • Describe the type of exercise and riding that you do with your horse.

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

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Author: Doug Thal DVM Dipl. ABVP