The coughing horse

COUGHING is the most common sign of equine respiratory disease and is a familiar clinical problem. There are no definite figures available as to the current incidence of respiratory disease in horses in the UK, but in a survey carried out by the British Equine Veterinary Association in 1963, 10.3 per cent of the horses attended by veterinarians suffered from a respiratory complaint. Establishing a definite diagnosis is very complex and in a sizeable number of cases, especially in viral respiratory infections, no aetiology will be defined. An accurate history will allow a subdivision into acute and chronic cases (more than three months duration). Coughing is a highly co-ordinated reflex action designed to remove irritants from the tracheobronchial tree. The receptor organs are situated beneath the epithelium of the larynx and the airways down to the level of the respiratory bronchioles. Stimulation by mechanical or chemical agents initiates the cough reflex. The common causes of coughing in the horse will be discussed under the headings of acute and chronic disease. ACUTE COUGHING