Red Holstein

Cattle

The expression of red colour replacing the black in Holsteins is a function of a recessive gene. The genetic combinations possible with simple dominance can be expressed by a diagram called a Punnett square. One parent's alleles are listed across the top and the other parent's alleles are listed down the left side. The interior squares represent possible offspring, in the ratio of their statistical probability. In the case of red colour, R represents the dominant non red (or standard black and white) coloured allele and r the recessive red coloured allele. If both parents are non red coloured, and heterozygous.

http://en.wikipedia.org/wiki/Red_Holstein_(cattle)#Red_and_White_Holsteins