Common causes of coughing in the horse

February 8, 2022

Spring is in sight, and after a damp and dark winter we look forward to the end of our horses’ ‘coughing season’. Horses can however pick up coughs all year round, which are generally caused by either allergies or infectious disease. It is important to understand and be able to determine the cause in order to know how to manage and treat your horse’s cough appropriately.

Allergic Airway Disease

Equine Asthma, previously called Respiratory Airway Obstruction (RAO) or Inflammatory Airway Disease (IAD) is a common cause of coughing and breathing difficulties in horses. It is non-infectious, cannot be spread to other horses and can affect individuals seasonally or all year round. Equine Asthma is generally caused by an allergy to environmental factors, such as dust or mould spores and grass or crop pollens during the summer months. Management changes are the best way to reduce exposure to allergens. For example;

  1. Changing bedding from straw to shavings a low dust alternative
  2. Changing dry hay to soaked/steamed hay or haylage
  3. Increase stable ventilation and turnout
  4. Reduce pollen exposure during the summer months

If management changes alone are not enough or your horse’s symptoms are severe, please contact our equine vets as further diagnostics and treatment may be required.

Infectious Respiratory Disease

Infectious coughs can be caused by viruses including Equine Influenza and Equine Herpes Virus. They can also be caused by bacteria such as Strangles and other secondary bacterial infections. In rare cases they can be caused by parasites such as Lungworm.

With an infectious respiratory disease you may see other clinical signs as well as a cough, such as a high temperature and or nasal discharge.  You should also be mindful of in-contact horses which may also show similar signs. In these situations, it is important to speak to your vet and put biosecurity measures in place immediately to stop the disease from spreading to other horses and or yards. Some infectious respiratory diseases are self-limiting with supportive therapy, but some may cause severe illness. Diagnostic tests such as nasal swabs, endoscopy and blood tests are often required to determine the precise cause and to allow our equine vets to make the most appropriate treatment plan for your horse.

Given that the differences between allergic and infectious causes of dry horse coughs can be subtle… The most important thing to understand is that if you are concerned about your horse’s cough, you should contact our equine vets without delay.

Gwen Davies BVMedSci BVM BVS MRCVS

Towcester Equine Veterinary Surgeon

University of Nottingham

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