Laryngeal Dysfunction

This ailment affects the larynx and can cause whistling and roaring when the horse exerts itself. The damaged nerves cannot control the muscles that open the larynx and so during exercise it causes the muscles to partially block the flow of air as it travels towards the trachea.

Surgery either removes the part which is causing the noise. This is called the Hobday procedure. Or the Tie back procedure is used, which involves the damaged part of the larynx to be held back to open the airway.