Bay Horse

A bay horse is a horse color characterized by a brown or reddish-brown coat with a black mane, tail, ear edges, and lower legs. These black markings are referred to as "black points" and are a defining feature of the bay color. The shade of the brown body coat can range from a light tan to a dark, almost mahogany color.

The genetic basis for the bay color is complex and involves the Agouti gene (ASIP) acting upon a black base coat. The Agouti gene restricts the expression of black pigment to the points, resulting in the characteristic bay pattern. The E allele at the Extension locus must be present for a horse to be bay; without E, the horse will be chestnut (red).

Bay is one of the most common horse colors, found in numerous breeds worldwide. There are several variations within the bay color spectrum, including:

• Blood Bay: A bright, deep red-brown bay.
• Standard Bay: A medium brown body color.
• Dark Bay: A very dark brown, almost black, body color but still distinguishable from black due to reddish undertones.
• Mahogany Bay: A deep, rich reddish-brown body color.
• Wild Bay: A bay with restricted black points; the black markings do not extend as high up the legs as is typical for bay horses.

White markings, such as blazes, socks, or stockings, can occur on a bay horse, but these are separate from the underlying bay color. These white markings are caused by different genes and are overlaid on the base coat color.

The bay color is frequently described in horse breed standards and used in equine identification. It is an easily recognizable and historically significant color in the equine world.