1. “Heaves” is the common term for equine asthma, a respiratory disease characterized by a narrowing of the small airways of the lungs, which makes exhaling difficult.
2. Tiny dust particles pulled deep into the airway trigger inflammation in the lungs. Research suggests that some horses inherit an increased sensitivity to dust, which makes them more susceptible to RAO.
3. fast, deep breathing along with coughing and mucus discharge from the nose. In advanced cases, a horse’s nostrils flare and an audible “wheeze” may be heard with each breath. Horses with chronic RAO can develop a distinct “heaves line” along the abdomen as the muscles that help them exhale get overused.
4. Steroids and bronchodilators given orally or inhaled can be used in “rescue” situations, but long-term treatment of a horse with heaves requires eliminating as much dust as possible from his environment. This often requires that the horse be kept outdoors on grass pasture and fed hay that has been thoroughly watered down to reduce dust. Horses with heaves may also benefit from a dust-free pelleted ration.