Chronic obstructive pulmonary disease (COPD), also known as “heaves” is a chronic lung condition in which connective tissue forms in the lungs and the elasticity of the alveoli decreases. A wheezy horse can be recognised by poor stamina due to reduced lung function, violent pumping respiratory movements and frequent coughing due to irritated throat and airways. At times COPD can cause nasal discharge, as the excess mucus from the lungs is discharged through the nose. In general, COPD or heaves in horses worsens slowly as the alveoli lose their elasticity. The coughing causes more and more alveoli to collapse, making recovery increasingly difficult.
Vapour is caused by narrowed airways. This can be caused by: allergies, neglecting a viral infection or a cold that has not been properly treated but also by a poor living environment for the horse (mouldy hay, ammonia vapour, continually inhaling dust.