Many horses will have an episode of coughing at some point in their life. In most cases this will resolve without any treatment. The most common respiratory problem in horses and ponies is recurrent airway obstruction (RAO), this is caused by exposure to allergens, such as moulds and dust which causes coughing and breathing difficulties. Another common condition is summer pasture associated recurrent airway obstruction (SPARAO), where the allergens that cause lung damage are pollens. It is not uncommon for horses to suffer from both RAO and SPARAO which can be very difficult to manage.
Other serious respiratory diseases are bacterial and viral infections, such as equine influenza and Strangles. These diseases are highly contagious and can spread very quickly between horses, therefore it is essential that they are recognised and treated early. Other infections include bacterial pneumonia, herpes virus, adenovirus and rhinovirus among others.
If your horse has been coughing for more than a couple of days or is unwell in any other way with a cough, runny nose or respiratory difficulties, you should contact your vet for advice.