Silver Dapple

In horses, the silver dapple gene, also known as the "Z" gene, dilutes the black base coat color . It will typically dilute a black mane and tail to flaxen, and a black body to a shade of brown or chocolate. Red based horses, such as chestnut, palomino, and cremello, may carry the silver dapple gene, and are capable of passing it on to their offspring, but will not express the gene in their own body color.

The lower legs of a silver dapple horse tend to be incompletely diluted. The black lower leg is usually able to be distinguished when the silver dapple gene is present on a bay base, but the coloring is less-defined. However, one must not confuse the silver dapple gene with the gray or smutty genes, which may produce a similar coloration except the black of the lower leg will continue up past the knee and hock, onto the flanks or shoulders.

Many breeds do not carry the silver dapple gene. Silver dapple is seen in Welsh Mountain Pony, Welsh Pony, Shetlands, Icelandics, Morgans, Missouri Foxtrotters and Tennessee Walking Horses, but the most common breed is probably the Rocky Mountain Horse, in which silver dapple is a very popular and common color.

This gene has been known for 25 years or more, but is only
recently becoming better understood. The name Silver Dapple
was originally applied to Shetland Ponies, in which the color is
fairly common (at one time it was even thought that the gene only
occurred in Shetlands), because it frequently has the extremely
dappled, greyish body color with silver-white mane and tail in
that breed. Now we know that not all (possibly, not even most)
of them are dappled, so the name has been shortened from Silver
Dapple to just Silver. The term "Silver" has been confusing to some,
who expect to see a grey-toned horse perhaps, but it has been in
use too long to change. In Australia the color is called "Taffy",
but the term has never caught on elsewhere. In some of the
breeds in which Silver is common in the USA, such as the Rocky
Mountain Horse, it is simply called "Chocolate".

Some common names for this color are "Classic Silver Dapple",
"Chocolate Silver", or "Black Silver". This is the shade that comes to
mind when hearing the term "Silver Dapple". The body color is diluted
to a chocolate-brown or mocha-brown shade, sometimes light enough
to appear similar to a sooty palomino. The mane and tail are often
near-white, a striking contrast. The lower legs are usually lighter than
the rest, almost flaxen near the hoof, and the lower legs are often dappled
(which is highly unusual in other colors). The mane and tail often have
dark roots. In a horse with the "classic expression" of Silver Dapple,
there will be very distinct and strong dappling present, which, unlike
most colors, does not appear to be related to age or condition, but
rather stays fairly constant throughout the horse's life -- although they
may vary with the seasons, appearing on the summer coat but not the
winter coat, usually. But not all Silvers show the dappling. Some are
a flat chocolate-brown color all year round. Silver on black can be hard
to tell apart from a dark flaxen liver chestnut, and in many breeds they
have indeed been registered as "chestnut" because nobody knew what
they were. Some clues to look for would be the dappling, a drastic change
in color from winter to summer, a bluish cast rather than a reddish tone,
and a silvery mane/tail rather than golden-hued flaxen. Still, it may be
impossible to tell the difference by looking. Luckily, a red-factor test
will distinguish between a silver and a chestnut!
Foal-coats are generally a light greyish-tan color, often described as a
"dead grass" color, or a light pewter-grey shade with light mane and tail,
white eyelashes and vertically striped hooves (on legs with no white markings).