In horses with severe equine asthma (RAO/heaves), airway obstruction increases the effort needed to breathe, particularly during expiration. The classic 'heave line' along the abdomen reflects increased abdominal (expiratory) effort, with hypertrophy of the external abdominal oblique muscles.
Increased abdominal effort during expiration (double lift); heave line visible along the costal arch; exercise intolerance; chronic cough; nasal discharge; worse in dusty environments.
In horses with severe equine asthma (RAO/heaves), airway obstruction increases the effort needed to breathe, particularly during expiration. The classic 'heave line' along the abdomen reflects increased abdominal (expiratory) effort, with hypertrophy of the external abdominal oblique muscles.
Increased abdominal effort during expiration (double lift); heave line visible along the costal arch; exercise intolerance; chronic cough; nasal discharge; worse in dusty environments.