All calves born at Johnson Dairy in Eaton, Colo., receive vaccinations — even bulls. With several calves born each day at the 7,000-cow dairy, green chalk is used to mark the backs of heifers. This way, when employees vaccinate calves, they automatically know which vaccination protocol to follow on which calf without having to stop and check each calf to verify sex. This allows employees to work more efficiently, and ensures that each calf gets the right vaccines.