Equine asthma is a condition that causes some horses to be hypersensitive to molecules in the air (known as allergens). This results in symptoms that range from mild to severe. This hypersensitivity (allergy) causes lower airway inflammation and results in increased mucus production and constriction of the airways in the lungs. A particular type of equine asthma involves horses that suffer during summer while spending most of their time outside. The condition is better known as summer pasture associated obstructive pulmonary disease (SPAOPD). It’s thought that SPAOPD is associated with an increase in airborne particles and environmental allergens such as pollen, mould spores and mycotoxins. Some horses can be affected throughout the year and also suffer with the more classical form of equine asthma called RAO (also known as ‘heaves’) when stabled and on dry roughage during the winter. SPAOPD is most commonly seen in horses that are aged seven and over.
SPAOPD has been linked to an increase in pollen in summer