The silver gene is a unique little dilution, that tends to confuse the heck out of horse people everywhere, especially in my breed, the Miniature Horse, where it’s very prevalent.
The following information is courtesy of SilverEquine.com
The silver gene is dominant. When present it dilutes the black pigmentation on the body and points of the horse. The dilution can vary greatly within a breed and quite differently from breed to breed. The body color can range from a light silver in color to a dark chocolate brown color. The silver gene also dilutes the points of the horse. These points can also vary greatly from a very light flaxen looking mane and tail to a mane and tail that are the same color as the horse’s body color.
The gene was originally thought to be in just the Rocky Mountain Horses, the American Shetland and the Miniature Horse breeds. However, in 2002 it was discovered in the Morgan and Quarter Horse breed. In 2007, it was discovered and confirmed in the Paint Horse and Welsh Pony. It has also been found to be in Saddlebred and Gypsy horses. In 2008, several more Welsh ponies were tested and confirmed to be silvers.
Since the silver gene dilutes only black pigment, it shows the most dramatic colour changes on a black based horse. Body colour on a silver black can range from a dark charcoal or brown to a pale silvery grey with white dapples. Mane and tail can be steel grey to white. This is my favorite colour – well, not officially, but it’s the one I choose all the time! It can have a huge range of shades, from my “dirt coloured” horse Hawk, with his steel grey in the winter and chocolate brown in the summer coat with a grey mane and tail, to Image (best horse in the whole world, in case you were wondering who held that title) who we always called “taupe”, a pale grey with brown undertones and a snowy white mane and tail.
In a bay horse, the black pigment is confined by the agouti gene to the mane, tail and points (legs, ears, muzzle), so these are the areas most affected by the silver dilution. Just as there is a great range of shades of bay horses, silver bay also shows a wide variety. From a snowy white mane and tail and pale copper body colour that can mimic a palomino, to a rich chocolate with a mane and tail just a shade lighter and every combination in between, silver bays are usually most easily identified by their grey, or sooty colored legs. There are some gorgeous silver bays out there, and even more that are incorrectly advertised as sorrel with a flaxen mane and tail, or palomino, or dun, or inexplicably, buckskin or roan.
Our beautiful broodmare, Robin is a sorrel – or chestnut if you prefer – pinto, and carries the silver gene; she’s the dam of Hawk (silver black) and Max (silver bay) pictured above, among many others. Some people will insist that they can tell by looking if a sorrel horse carries the silver gene, but I sure can’t. A flaxen mane and tail doesn’t necessarily have any bearing on whether or not a sorrel carries silver.