In Practice 22: 370-381 (2000)
© 2000 British Veterinary Association

Diffrential diagnosis of abnormal respiratory noises in the exercising horse

¹ Gloucestershire

UPPER respiratory tract airflow in horses can increase from 240 litres/minute at rest to 4500 litres/minute during maximal exercise. At the same time, the respiratory rate may increase to 148 breaths/minute. In normal horses, the nostrils, pharynx and larynx dilate during exercise to accommodate this increased airflow and relatively little respiratory noise is produced. Abnormalities of the upper respiratory tract that restrict airflow during fast exercise cause turbulence and often result in poor exercise tolerance and the production of abnormal respiratory sounds. It is important that clinicians are able to identify abnormal exercise-related respiratory noises, differentiate them from the normal sounds produced by exercising horses and assess their significance with regard to the exercise capacity and use of the horse.

Note:

The author would like to acknowledge the helpful comments of Kirstie Pickles, Tim Brazil, Dr Paddy Dixon and Dr Bruce McGorum during the preparation of this article, and the assistance of Bob Munroe in the preparation of the photographs and slides.