What causes melanosis in cattle?

Melanocytic hyperplasia, sometimes referred to as black hair coat of cattle, is caused by a genetic mechanism with a simple recessive mode of inheritance, or as a lethal homozygous recessive trait.

* The coat color of affected animals is generally dark brown to black.

* The animals are commonly horned and in some may be polled.

* The melanocyte (melanin-producing cells) population in the skin, dermis, and epidermis of the affected cattle markedly increase in number.

* Melanocytic hyperplasia is caused by a mutation in the KITLG gene which codes for stem cell factor.