The Cobalt mutation produces a higher concentration of melanin offering an effect, pigmenting the chest, flanks and mainly the abdomen, up to the area of the sewer, a gray color, more or less dark or brown. The background lipochrome will be shown less luminous and pure. The corneas parts are not affected. Its form of transmission to the offspring is recessive and free. It is recognized by OMJ/COM in black, BRUNO and AGATA types.