Abstract
This research letter discusses a heritable defect of the penis in cattle, known as persistent frenulum. The condition results in a skew penis, that prevent bulls from mating naturally with cows. Although veterinarians in South Africa are familiar with this condition, it seems that animal scientists are not. The condition is briefly described, and it is indicated that it is caused by a single recessive allele. The condition can be corrected surgically, but this is not recommended, since it is a heritable defect. Animal scientists should take note of this condition and advice farmers accordingly.