I have all Black Cows and Bred to a Black Bull, How did I end up With Some red Calves?

Megan Rolf (Kansas State University): For black and red coat color inheritance, black is dominant to red. So, in this situation, the bull is heterozygous black. We know because he has produced red calves. So, he has one black allele and one red allele. A certain proportion of those cows are also heterozygous black in this scenario because we know they have produced red calves. When we mate the heterozygous black bull with the heterozygous black cows, we get, on average, about 25% frequency of red calves. Some of those cows may also be homozygous black, in which case we won’t get any red calves out of that particular mating.