Horse coughing can be harmless but sometimes it may be the first sign of serious trouble. All horses cough occasionally, for example, if they get a bit of debris in their airways, whilst eating or drinking or at start of exercise “to clear the throat”. In these situations, coughing is just a normal sign of a healthy airway keeping itself clean. However, beyond this, why do horses cough? And when is it an indication of something more sinister?

Signs of Respiratory Problems in Horses
A cough indicates that there is irritation in the horse’s respiratory system. There are many different types of coughs and their differences can help to determine the cause.

  • How long and how often is the horse coughing?
    • An occasional cough is usually nothing to worry about, but if the coughing persists or is accompanied by other signs this can be indicative of a more serious respiratory problem.
  • Is the cough dry or accompanied by nasal discharge?
    • A dry cough means there is no phlegm. Whereas discharge from the nose indicates excess mucus or phlegm is being produced as part of the respiratory condition.
  • Are a number of horses on the same premises coughing?
    • A whole yard or barn of horses coughing is most likely due to an infectious agent which is being transferred from horse to horse, such as a respiratory virus. One horse coughing on its own, in the company of others, suggests the problem is not infectious.
  • Has the horse just eaten?
    • Sudden onset coughing can be a sign of choke. This is when food gets stuck in the horse’s oesophagus. Whilst not a respiratory condition it can be a very scary experience. If you suspect your horse is suffering from choke remove all food and allow your horse to fully relax their neck, then call your veterinarian.
  • Has the horse recently travelled?
    • A cough that starts to occur after the horse has travelled should be investigated promptly. It may be that the horse has picked up a viral infection from another horse at an event or during transport, another possibility is Shipping Fever, which affects horses that have travelled long-distances.
  • Has the horse any other clinical signs?
    • If the cough is occurring along with other symptoms such as the horse being off its feed, an elevated temperature or reduced performance these are further signs that the horse is sick due to a respiratory infection.

Veterinary Investigation
Coughing accompanied by nasal discharge, high temperature, reduced performance, or that has affected several horses on the same premises should always be investigated by a veterinarian. A full veterinary investigation may include; listening to the horse’s chest, blood work, nasal swabs, endoscopic examination, tracheal or lung wash. These tests are used to get a clearer picture of what is affecting the animal and try to reach a conclusive diagnosis and an effective treatment plan.

What Causes a Horse to Cough?

  • Influenza:
    • Despite vaccination, influenza (Flu) infection is still a common cause of respiratory infection and coughing in horses. Influenza is caused by a virus and spreads rapidly through a yard to all horses stabled together. Influenza is usually accompanied by an elevated temperature along with reduced appetite. For unvaccinated horses, influenza infection can be prolonged and even life-threatening.
  • Equine Herpes Virus (EHV):
    • A common cause of coughing and clear nasal discharge in young horses. This virus can spread quickly to all previously uninfected horses in the yard. It is usually a mild infection, although it can cause elevated temperatures and reduced feed intake. Vaccination can reduce the incidence of the EHV in a yard.
  • Strangles:
    • This is one of the most common causes of respiratory infection in horses and is caused by the highly infectious bacteria Streptococcus equi. Strangles transfers rapidly through contaminated exudates such as, nasal discharge to all horses in a yard. The typical signs are increased temperature, reduced appetite, nasal discharge, coughing and swollen lymph nodes (glands). Often the swollen glands will burst and release pus onto the skin.
  • Equine Asthma:
    • Also known as inflammatory airway disease (IAD), recurrent airway obstruction (ROA), chronic obstructive pulmonary disease (COPD) or heaves is a common cause of coughing in older horses. It is caused by allergic reaction in the horse’s lung to dust, fungi, mould spores, bacterial products and other irritant particles found in forage, bedding, and the environment.This allergic response results in increased mucus production and a reduction in the diameter of the airways, thus predisposing the horse to coughing. Equine asthma is not transmitted between horses.
  • Lungworm:
    • An infection of the lower respiratory tract, usually resulting in bronchitis or pneumonia, caused by the parasitic roundworm Dictyocaulus arnfieldi. Horses are not a primary host for lungworms, so it is usually only seen in horses pastured with donkeys.
      Exercise Induced Pulmonary Haemorrhage (EIPH): Most commonly seen in racehorses. The majority of EIPH affected horses do not have a bloody nasal discharge but coughing is common as the horse attempts to clear the blood from its airways.
  • Shipping Fever:
    • Shipping fever is a bacterial pneumonia which can occur when the horse is unable to drop its head for lengthy periods of time and therefore cannot clear mucus, dirt and debris from their airways (e.g. if tied-up during long-distance transport). Shipping fever, if left untreated, can lead to severe pleuropneumonia, which can be life-threatening.
  • Ascarids:
    • Usually only a problem in horses less than three years old, equine roundworm (Parascaris equorum), emerge in the gut before migrating to the lungs where they cause considerable inflammation. Older horses develop resistance to roundworms so even if they consume the eggs, the roundworms are usually not a cause of coughing in mature horses.
  • Rhodococcus Equi Pneumonia:
    • Rhodococcus equi is a bacterium that inhabits the soil and can cause pneumonia in foals aged 1 to 6 months. Foals acquire the disease by inhaling pathogen-laden dust particles. Once Rhodococcus equi is established in the soil it is almost impossible to eradicate it and it will remain a threat to future generations of foals.

Horse Cough Treatment
As coughing horses are affected by such a diverse range of causes, there will also be a wide variation of treatments. A good rule of thumb for horse affected by influenza, herpes or strangles is to give the horse two days rest for every day of coughing. So, the recovery takes twice as long as the illness.However, you should discuss this with your veterinarian as riding a horse too soon, when the airways have not fully recovered, may be detrimental. Your veterinarian will also determine if your horse needs any prescription drugs.

Certain management changes will help minimise the risk of respiratory disease; keep your horse up to date with his vaccinations and speak to your veterinary surgeon about the most appropriate deworming measures and treatments. Try to reduce the dust in the horse’s environment as much as possible – ensure ventilation is adequate in the stable or barn, use only dust free bedding and consider soaking or steaming hay.

Daily turn out, or indeed living out 24/7 is indicated for most horses prone to respiratory ailments. However, certain pollens can be a trigger for some horses suffering from equine asthma and may worsen their condition if they are turned out. Consequently, it may be necessary to avoid turning out these individuals during times of high pollen count / poor air quality.

Adding a scientifically formulated supplement to help support and maintain your horse’s respiratory health can also be immensely beneficial and Foran Equine have a number of supplements including:

  • Airvent Syrup & Gel:
    • This vapour releasing syrup or gel contains vitamins C to help maintain immune and respiratory function, honey a natural soothing agent, plus peppermint and eucalyptus to help open the airways for easier breathing.
  • Honey+C:
    • A palatable syrup combining honey, a natural soothing agent, vitamin C to help maintain immune and respiratory function, plus thyme, liquorice, and horehound. Helps to support respiratory health, particularly during times of stress or illness.
  • Zosfor:
    • A powdered supplement designed to support blood vessel health in high performance horses. Zosfor contains the natural super-antioxidant bioflavonoid hesperidin to help prevent cellular damage and protect blood vessels, vitamin C to support healing and vitamin K an essential factor for blood clotting.

If your horse is displaying any signs of a respiratory problems, we recommend that you seek veterinary advice to address any underlying lung conditions before adding any respiratory supplement to you horse’s diet.

If you have any queries on this issue or any other problems you may be having with your horse please contact the Foran Equine team who will be happy to help you.

Related Products



Vapour releasing syrup to open the airways, rich in vitamin C and essential oils for optimal air flow

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Honey C

Honey C

Rich in Vitamin C to support immunity and soothe the airway

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Airvent Gel

Airvent Gel

Vapour releasing gel to open the airways, when optimal air flow is needed most

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Antioxidant rich respiratory support with added vitamin K

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