RAO - Summer
Kate Hore RNutr(Animal). Snr Nutritionist at NAF
RAO, or recurrent airway obstruction, is commonly a likened to asthma in humans and can be a difficult problem to manage. It is a chronic disorder which usually shows its self as a consistent cough with nasal discharge, and frequently limits the horses performance.
If the horse is only mildly affected then symptoms may only occur during or just after exercise, however those with more serious cases may wheeze almost constantly, with crackling being heard upon use of a stethoscope. These more severe cases may also be accompanied by heave lines, muscular lines around the area of the ribcage, caused by muscles having to work harder in order to breathe. Normally affected horses won’t demonstrate a high temperature, though if opportunistic bacterial infections take hold, then antibiotics may be needed. For those cases where impact on performance is mild brochoalveolar lavage may be used to assess neutrophil levels, which indicate lower respiratory tract inflammation.
A number of allergens contribute to RAO, and in summer these can drastically increase. High levels of pollen and dust exist during the warmer months, a time when many horse owners like to turn out their horses. Pollen is a common trigger in respiratory disorders, along with mould spores, and their ubiquitous nature can make it very difficult, if not impossible, to avoid them. These allergens cause irritation and inflammation of the delicate lining of the lungs as well as bronchoconstriction; this inflammation leads to fluid production and hence the mucus discharge and crackling chest noises.