That nagging little cough at the beginning of your rides, and that occasional runny nose…could they mean your horse is suffering from recurrent airway obstruction, or RAO?
Possibly. This condition, commonly known as heaves, is the most prevalent lung disease seen in horses. Horse heaves is chronic and can threaten your horse's long-term health and performance. Although your horse's heaves can't be cured, and severe cases are difficult to manage, catching it early will help you manage it as well as possible, and perhaps minimize its damage to your horse's lungs.
Here, I'll give you a checklist of horse heaves symptoms to help you know when to alert your veterinarian, so he or she can begin treatment at the earliest possible point. I'll also help you assess the disease's severity, explain the different stages of treatment, and give you tips on how to prevent heaves in the first place.
Heaves is an allergic-based disease that compromises your horse's ability to breathe, similar to the way asthma affects humans. When your horse is exposed to allergy-producing substances in the air, such as dust and pollens, cells in his lungs react by releasing chemicals that cause air-passage linings to swell, thicken, and produce mucus. When he breathes, air gets trapped within these thickened passages. He then must use extra effort to expel this trapped air. The more your horse is exposed to allergens, the more sensitized his lungs become. The disease is most common among mature and older horses.
As the disease progresses, your horse's airways become ever thicker. More mucus is produced. He begins to cough as he struggles to exhale. Thick mucus appears in his nostrils, and he begins to labor with every breath. Bacteria can become trapped in his airways, leading to a bacterial infection (such as pneumonia), a common complication in advanced cases of heaves.