By: Dr. Lydia Gray

What is it?

The technical name for "Roaring" is left recurrent laryngeal hemiplegia. Basically this means that the nerve controlling cartilage on the left side of the throat is damaged allowing the cartilage to hang or droop into the airway. This results in poor athletic performance, a characteristic whistling or roaring sound during exercise and even an unusual whinny. While Roaring can be caused by direct trauma, a misplaced injection or toxic substance, it is generally considered an inherited disorder. Three to five percent of thoroughbreds have laryngeal hemiplegia, which is also seen in standardbreds and larger (greater than 17 hands) horses of any breed.

What can be done about it?

A diagnosis of "Roaring" is confirmed through endoscopy, but since the condition doesn't always show up at rest, this may require "scoping" while exercising on a treadmill or the use of a portable endoscope. Surgery is currently the only method of treatment, and while several alternatives exist, the laryngoplasty or "tieback" is considered the Gold Standard.

What else do I need to know?

The prognosis for a full return to the previous level of athletic performance is good, although there can be complications from the surgery such as a chronic cough, chronic aspiration of feed, and infection or failure of the sutures used to permanently tie back the cartilage. Researchers are exploring the use of electroacupuncture as a non-surgical treatment for "Roaring" while antioxidants that specifically target respiratory tissue such as Vitamin C and N-Acetyl Cysteine may be of benefit.


SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.