What is black or brown pigment found in horses called?

The black or brown pigment found in horses is called melanin. Melanin is a pigment that is responsible for the coloration of skin, hair, and eyes. In horses, melanin is produced by cells called melanocytes. Melanocytes are found in the skin, hair follicles, and eye tissue. The amount of melanin produced by melanocytes determines the color of a horse's coat. Horses with a lot of melanin will have a black or brown coat, while horses with less melanin will have a light-colored coat.