The photo at the left shows two calves. The bull calf at the left is a classic red (with a white face). The bull calf on the right is a classic black Angus calf.

Red and black are probably the two most common coat colors in cattle. They occur as an either/or in breeds such as Angus and Holstein. In other breeds, modifier genes change the shades of these colors to a much wider range of possibilities. Red is more popular in some countries and black in others, but both are common throughout the world.

The gene causing red/black is the the Melanocortin 1 Receptor gene (MC1R), formerly called the Melanocyte Stimulating Hormone Receptor Gene (MSHr). This gene has two common alleles E^D and e. In addition, a less common allele, E⁺, also called "wild type" occurs. When E^D is present in an animal, it is typically black. This is the dominant allele in the series. Cattle that are e/e are red. This is the recessive genotype.

However E⁺ appears to act as a "neutral" allele in most breeds and we think E^D /E⁺ cattle are typically black and E⁺/e cattle are typically red. E^+/E⁺ cattle can be almost any color since other genes, such as the Agouti gene, take over in dictating what pigments are produced. Although such Agouti alleles have not yet been documented in cattle, we have proven this in recent studies in dogs. Oulmouden's group has found a mutation causing brindle in the Agouti gene of cattle. All brindle cattle have at least one E^+/ allele and none have an E^D allele. (See the Patterns Page for more information on brindle).

Note that the E^D allele has been reported to be nonresponsive to agouti and constituitively expressed in cattle by Klungland. It is therefore probably a preferrable allele in cattle which are meant to be solid black in coat color. The E⁺ allele is responsive to agouti and is the allele in cattle with shaded body color such as Brown Swiss or Braunvieh, Jersey and several other rarer European breeds.