CONFORMATION AND ROARING RISK

Horsemen and veterinarians have long suspected that tall horses with long necks are more at risk for recurrent laryngeal neuropathy (RLN), a noisy upper respiratory tract condition commonly called roaring. Now researchers at the University College Dublin have confirmed the connection.

RLN occurs when the nerves that control the muscles surrounding a horse’s larynx weaken. As the condition progresses, the muscles are unable to fully open the larynx, often leading to a whistling or roaring noise as air is pulled through a smaller opening with each breath.

To examine the relationship between conformation and risk of developing RLN, the Irish researchers examined 188 flatracing Thoroughbreds from the same training yard, comparing several conformation traits between horses with and without RLN. They found that height at the withers was the physical trait most strongly associated with RLN—taller horses were more likely to have the condition. The second most common trait among horses with RLN was a long neck, measured along the underside.

Reference: “Exploratory factor analysis of signalment and conformational measurements in Thoroughbred horses with and without recurrent laryngeal neuropathy,” Equine Veterinary Journal, June 2018