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Genetic Testing for Equine Speed GenesBy Kentucky Equine Research Staff · June 5, 2017

Many owners of performance horses embrace genetic testing to help choose optimal race distances or determine whether or not a specific horse will have a successful career. Let’s take a quick look at two of these genes, the speed and gait-keeper genes, and consider other ways these tests, and nutritional supplements, could be helpful.

First, the speed gene refers to the myostatin gene. Myostatin is a protein produced by the myostatin gene that helps control muscling. Years of research revealed that two forms of the myostatin gene exist: one with a “C” form and a second with a “T” form. These letters refer to specific molecules at the DNA level that alter how the myostatin protein affects muscling. In short, Thoroughbred horses with two copies of the C version appear to perform better at shorter distances and make more money as two-year-olds; these horses are often referred to as precociousness. Horses with one C and one T gene classically perform well at mid distances, whereas Thoroughbreds with two T versions reportedly perform better over longer courses (10 or more furlongs).

Second, research suggests that the gait-keeper gene, called DMRT3, helps horses achieve and maintain unusual gaits. Take for example Icelandic horses with five distinct gaits (i.e., walk, trot, pace, canter, and tölt), various harness horse breeds (Nordic trotters, Swedish Standardbreds), as well as Paso Finos.

Similar to the speed gene, there are two forms of the gait-keeper gene: A and C. Some horses, such as Standardbreds and Finnhorses, reportedly have superior performance with two A copies of the DMRT3 gene.

According to a recent study*, two A copies of the gait-keeper gene do not appear to be associated with superior performance, early or late, in the racing career of Coldblood Trotters, a breed derived from breeding light-framed, swifter horses with native North Swedish Draft or Norwegian Dölehest horses.

As with any performance horse, regardless of their official speed or gait-keeper gene status, optimal musculoskeletal health will contribute to success both during their careers and off the track. Recall that joint disease remains a leading cause of retirement and attrition among athletic horses.

Kentucky Equine Research offers several joint supplements to support optimal joint health, many of which can actually help prevent the onset of joint inflammation and joint disease when administered prior to disease onset,” advised Kathleen Crandell, Ph.D., a nutritionist for the company.

Examples of such products include KER•Flex with glucosamine and chondroitin sulfate, Synovate HA containing high molecular weight hyaluronic acid, and EO•3 with marine-derived omega-3s DHA and EPA known for their anti-inflammatory properties. Australian horse owners should also look for Glucos-A-Flex.

*Jäderkvist Fegraeus, K., C. Lawrence, K. Petäjistö, et al. 2017. Lack of significant associations with early career performance suggest no link between the DMRT3 "gait keeper" mutation and precocity in Coldblooded Trotters. PLoS One. 12(5):e0177351.