Separating calf from its mother is called

Separating calf from its mother is called Weaning.
Weaning is the process of gradually introducing an infant human or another mammal to what will be its adult diet while withdrawing the supply of its mother's milk.
Two-step weaning is used to wean off beef calves from their dams over the space of a couple of weeks. With this method the calf is fitted with a nose flap that prevents suckling for some time, after which the calf is separated from the dam preventing contact.