Horse colors

Horses have coats in shades of black, red, white, brown and grey, and mane and tail colors that can either match, or contrast, with color of the coat. Those colors lend a distinctive appearance to the individual horse, and sometimes, to entire horse breeds. The genetics behind the inheritance of these colors is a fascinating subject in and of itself, but is also of practical interest to the horse breeder. Not only are particular colors and patterns in more demand by the horse buyer, but sometimes these features are written in to the breed standard. The Paint horse, and the Appaloosa, were originally defined largely for the pattern of their coats. The Lipizzaner horses, famous as the "dancing white stallions" are (like almost all "white" horses) actually grey. Speculation about just how color and pattern is inherited in horses has been around as long as horse breeding has, but it is only in the last decades that an understanding of the genetics has become sophisticated enough to go beyond speculation. Several DNA tests for color genes are now available, and a blood or hair root sample can reveal the genotype of a mare or stallion. Since some of those genes also influence eye and skin color, and the color of hoofs, as well as the patterns of color on the coat and the probability of white markings like socks, snipes, and blazes, the predicted appearance of the foal from parents with known test results can be made with great accuracy. The genetics of color do not simply specify the pigment of horse hair, but also its distribution. In addition to genes that specify a hair pigment, like black, other genes can determine whether that color is limited to the very tip of a hair, or evenly distributed throughout the hair, and these genes are inherited as a separate factor than the color itself.

Solid colors

Chestnut and sorrel

caption: Chestnut police horse with blaze.

This thoroughbred mare is chestnut. The most famous chestnut thoroughbred was probably the racehorse, Secretariat.

Black or bay: the agouti gene

Bay

This quarter horse shows the brown colored body combined with black mane tail and lower legs that is called "bay". Bay is the most common coloration of all horses. The one white hind sock, and white star

Blood bay

When a bay horse has a particularly red coat, the name "blood bay" is often used.

caption: This Arabian is a blood bay.

Black

When a horse with black coat pigment is doubly recessive for the Agouti gene, pigment is spread evenly over each hair and the apearance is black rather than bay. Since a single copy of the dominant allele of an Agouti gene will make that horse bay, and there are two agouti genes in each horse, overall, black horses are unusual. When breeds of horses, like the draft horse XXX are characteristically black, both parents will carry a pair of recessive ag genes, and their foals will share their color. Fresians, a particularly elegant draft breed, are almost always black, for this reason.

caption: A black stallion

Grey horses

This Andalusian is grey.

Most horses called "white" are actually grey. The gene responsible for this color is actually responsible for a process, "greying". Grey foals are born a different color than they will have as young horses, and that color will usually change over time, becoming lighter and lighter.

In youth, many grey horses have lighter coats than manes and tails, and may have a black mane and tail through much of their adult life.

Caption: This Holsteiner is a dappled grey with very light mane and tail.

Dilution genes: The creme gene

Unlike many other mammals, horses are that are albino are not simply unusual, but unhealthy. When a horse has light eyes and pink skin, along with a light coat the gene at work is a dilution gene, rather than some form of lethal white. [1]. The creme gene codes for a modification of color, in its dominant form, CR, there is no modification. A heterozygous recessive, CR/cr, will lighten coat color and a doubly recessive creme gene, cr/cr will doubly lighten it. The resulting color will depend on the base color of the horse and other factors, as outlined below.

Buckskin

Dilution of a bay horse results in buckskin coloration. This horse will have at least one copy of the dominant agouti gene, AG, so that black pigment on the coat is relegated to the mane, tail and points. A well-marked buckskin horse has a tan body, black mane and tail, and black "socks".

There are additional modifications to the body coat color that are known by the colloquial terms "smutty buckskin", "sooty buckskin" and "black buckskin", when a percentage of body hairs are entirely dark.

Smoky black

Dilution of a black horse results in smoky black coloration. Such a horse, like all black horses, will be doubly recessive for the agouti allele (ag, ag) and black pigment will be evenly spread along each hair.

Palomino

A chestnut horse (also caled sorrel) with a single dilute gene yields a palomino horse. Like the buckskin, there can be additional modifications of coat color. A so-called "chocolate palomino" occurs when XXX. The Paso fino Tomaria's Gallardo is an example of a chocolate or smutty palomino.

Cremello

This horse has a cream-colored coat that can range from a rather deep cream to near white. It is a doubly dilute form of a chestnut horse, and will have pink skin and blue eyes.

Perlino

Another double dilute, the perlino XXX

Paint or pinto patterns

Tobiano

Chestnut tobiano with blaze.