Horses come in a fantastic array of colors from black to gray, from bays to chestnuts, and with or without varying amounts of white. The glorious spotted coats of Appaloosas are a common sight for western Canadians, as are golden palominos.

On the other hand, silver dapple is a color that’s still on the unusual side. The color occurs in several breeds–including the gaited Rocky Mountain Horse, in which the typical, smoky chocolate coat with flaxen mane and tail is often seen and highly admired.

Veterinarians aren’t usually concerned with the coat color of their equine patients, but when a particular color or pattern is associated with disease conditions or abnormalities that can affect horse health, it becomes an issue.

Such is the case with congenital stationary night blindness (CSNB) in Appaloosas. A few years ago, a research team led by veterinary ophthalmologists at the Western College of Veterinary Medicine (WCVM) confirmed that CSNB is linked with horses that are homozygous for the leopard spotting gene