What is the term for the forced expiratory effort in horses due to the narrowing of the airways in the lungs?

The term for the forced expiratory effort in horses due to the narrowing of the airways in the lungs is "heaves." Heaves is a chronic respiratory condition often caused by an allergic reaction to inhaled allergens, such as dust or mold. When the airways become narrowed or obstructed, horses experience difficulty in exhaling, leading to a distinct heaving motion of the abdomen as they try to force air out of their lungs. This condition can result in coughing, nasal discharge, and abnormal lung sounds, and is characterized by a "heave line," which is a muscular ridge that may develop along the horse's abdomen due to the chronic effort of trying to breathe.

Understanding heaves is crucial because it highlights the importance of maintaining good air quality and managing environmental stressors for equine respiratory health. While asthma, bronchitis, and pneumonia may also affect horse respiratory systems, they present with different signs and underlying causes, differentiating them from heaves.