Grey

Almost all grey horses are born black and have very little or no white at all. When the baby hair begins to shed from areas around the heads, feet and legs, the very first scattering of white hairs appears around ears and eyes. Later a few white hairs appear in the coat, these scattered along the horse's back and rump. As a two-year-old, there is a lot more white in the horse's coat when it sheds. At this time, the head will begin to have a dark grey appearance. Each year the coat will become lighter, the white hairs gradually replacing black hairs. the horse's color is created by white and black hairs on a black hide, and there are no individual "grey" hairs.

Referred to as steel grey, two- and three-year olds have a much lesser quantity of white hairs than black. A dappling grey pattern appears on four- to seven-year-olds, and is often called dapple blue or blue-grey. the white to black hair ratio is nearly even, creating a blue-grey appearance. By the time the horse is eight to nine years old, it is actually a dappled grey. Now the white hair makes up a greater percentage of the overall coat. Over the next several years, the color continues to lighten until it appears white. Though the horse may now be improperly referred to as "white," he still has a black hide. There are slight grey markings around the leg joints ad feet, and the horse is never a true white, but really a grey-white.

Though greys have been referred through the ages as having "diseased" hide, this misconception has been repeatedly accepted without investigation. A disease is caused by one of many forms of infection and it is not hereditary. Body conditions are hereditary, and a body condition could cause the animal to be susceptible to disease. The body condition that causes the hide of a grey horse to become deficient in pigment production is hereditary.

In an unborn foal, there is an abundance of pigment in all pigment layers of its tender hide. While not all hair is rooted at the same depth, even the most shallowly rooted hairs will have an abundance of pigment. This explains why the grey foal is actually born black. These shallowly rooted hairs are located in the first pigment layers, which produce a lesser amount prior to the age of one year. Most of these are found around the eyes and ears, accounting for the first signs of greying. While the first three layers of the dermis (skin or hide) contain the skin pigment, it is the next four layers which determine the hair pigment. It is the fourth of these layers which has the first pigment available, thus it is the layer that continues to produce pigment throughout the horse's life.

In the aging process, the outer pigment layers begin producing less pigment, causing the pigment to recede. This process affects the layers of pigment, but the fourth pigment layer is the least affected as it is the deepest layer. The pigment glands in the other three layers cease to function by the time the horse is ten or twelve years old. And as the fluid content of these pigment layers recede, a grey horse will develop the toughest hide of any horse, regardless of color.

Look for an update on this article with genetic information soon.

Source:

• Green, Dr. Ben. The Color of Horses, The Scientific and Authoritative Identification of the Color of the Horse. Northland Publishing. 1974.

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