Silver Dapple is an uncommon horse color, mostly appearing in the Shetland Pony, Rocky Mountain Horse, Mustang, Miniature Horse breeds, and a few others, having likely originated in the Shetland pony.
Silver dapple is a confusing term because the color itself is not actually silver (this would be a gray horse or blue roan), and not all horses actually have dapples. As foals they may look "silver". In the Rocky Mountain horse breed the color is often called “Chocolate”.
A horse cannot be solid black with a white mane and tail but the color silver dapple often comes close to this. The horse often looks a little like a liver chestnut with a flaxen mane and tail, but with some subtle differences.
Silver Dapple is a dominant gene symbolized as Z which acts on a black. The gene specifically dilutes black. A horse with the genetics for black, when carrying the silver dapple gene, will have a flaxen mane and tail and a deep colored body.
In a horse with genetics for bay, the silver dapple gene will cause the mane and tail to look flaxen, and the legs to look a silvery color, not quite like a proper chestnut, these horses are sometimes mistaken for palominos.
Part of the reason why there is so much confusion around this color is that the gene acts on other genes and does not create one uniform color, such as “Black” or “Bay”.
How to Determine if a Horse is Silver Dapple or Liver Chestnut with Flaxen Mane and Tail
A liver chestnut horse with flaxen mane and tail will have a the flaxen color fairly even throughout its mane, but the silver dapple will have a darker, almost dirty, colored roots. The liver chestnut will not have the dappling effect that occurs on the legs of a silver dapple. The liver chestnut will tend to have reddish tones throughout its body where as the silver dapple tends to look more muddy-brown.
Because chestnut is a homozygous color, two chestnuts bred together cannot produce anything other than a chestnut, as such if two horses that were thought to be chestnuts produce a black, or bay horse, then clearly one of them must be a silver dapple with the gene masking the color black, making the horse appear chestnut.
Photos by Author, both are copyright owned, not for reproduction.
The horse in the two above pictures has genetics for black, but the silver dapple gene is masking her black gene, making her look almost like a liver chestnut with flaxen mane and tail. This is the same horse in both photos (and in the thumbnail above), she is a miniature horse.
Note that chestnut horses, and palominos (horses that normally have no black) are not affected by the silver dapple gene, but may be carriers of it.