CARRIER–Developmental Duplication (DD)
Developmental Duplication (DD) is an abnormality that has been long-observed in Angus cattle, but was previously thought to be caused by conjoined twins or other anomalies during fetal development. This abnormality was recently found to be a simply inherited recessive genetic condition passed through certain lines of Angus cattle. Animals affected with this condition can sometimes be born with an extra limb or part of an extra limb (a condition referred to as polymelia).