## Overview Horses with severe equine asthma (heaves/RAO) have an increased work of breathing. Increased abdominal effort can cause hypertrophy of the external abdominal oblique muscles, producing the heave line. Horses show labored breathing at rest, prolonged recovery after exercise, nostril flaring, and a double expiratory effort. ## Causes Chronic airway obstruction from allergic inflammation. ## Diagnosis Clinical signs of heaves and confirmation of lower-airway inflammation. ## Treatment Environmental control plus medications to reduce airway resistance, thereby decreasing the work of breathing. ## Recovery and Prognosis Fatigue improves when airway obstruction is controlled. ## Prevention Strict dust management in susceptible horses.
heave line; labored breathing at rest; prolonged recovery after exercise; nostril flaring; double expiratory effort
## Overview Horses with severe equine asthma (heaves/RAO) have an increased work of breathing. Increased abdominal effort can cause hypertrophy of the external abdominal oblique muscles, producing the heave line. Horses show labored breathing at rest, prolonged recovery after exercise, nostril flaring, and a double expiratory effort. ## Causes Chronic airway obstruction from allergic inflammation. ## Diagnosis Clinical signs of heaves and confirmation of lower-airway inflammation. ## Treatment Environmental control plus medications to reduce airway resistance, thereby decreasing the work of breathing. ## Recovery and Prognosis Fatigue improves when airway obstruction is controlled. ## Prevention Strict dust management in susceptible horses.
heave line; labored breathing at rest; prolonged recovery after exercise; nostril flaring; double expiratory effort