Apparatus respiratorius
The equine respiratory system delivers oxygen to the blood and removes carbon dioxide. It consists of the upper respiratory tract (nostrils, nasal passages, pharynx, larynx, guttural pouches) and the lower respiratory tract (trachea, bronchi, lungs). Horses are obligate nasal breathers; the soft palate normally seals the oral cavity from the airway, so they cannot breathe effectively through the mouth. The guttural pouches are unique air-filled extensions of the Eustachian tubes. The larynx contains the arytenoid cartilages; left-sided recurrent laryngeal neuropathy (“roaring”) is common in performance horses and causes partial airway obstruction. At full gallop the lungs process large volumes of air (on the order of 1,800 liters per minute). Gas exchange occurs in the alveoli. Locomotor-respiratory coupling (usually one breath per stride at the canter and gallop) links breathing rate to stride rate, and respiratory limitations can reduce athletic capacity.
Common conditions include strangles, equine influenza, equine herpesvirus, inflammatory airway disease, recurrent airway obstruction (“heaves”), exercise-induced pulmonary hemorrhage (EIPH), and guttural-pouch mycosis. Diagnosis often involves endoscopy, auscultation (with rebreathing), and tracheal or bronchoalveolar lavage.
Normal resting respiratory rate is 8–16 breaths per minute. Nasal discharge, coughing, labored breathing, or exercise intolerance warrant veterinary attention. Good barn ventilation and dust control are essential. Any abnormal respiratory noise at exercise should be investigated.
Common conditions include strangles, equine influenza, equine herpesvirus, inflammatory airway disease, recurrent airway obstruction (“heaves”), exercise-induced pulmonary hemorrhage (EIPH), and guttural-pouch mycosis. Diagnosis often involves endoscopy, auscultation (with rebreathing), and tracheal or bronchoalveolar lavage.
Normal resting respiratory rate is 8–16 breaths per minute. Nasal discharge, coughing, labored breathing, or exercise intolerance warrant veterinary attention. Good barn ventilation and dust control are essential. Any abnormal respiratory noise at exercise should be investigated.
See the Equine Respiratory System on our interactive 3D horse model. Open 3D Model