A calf is by definition immature. If it was mature, it'd be an adult, not a calf.
The tail from a calf (young immature bovine).
A baby buffalo is called a calf.
A calf is a general term for an immature bovine that relies on its mother or the bottle for milk for several months of its life until weaned.
A young camel is called a calf or a git which is the child of a camelA young camel is called a calf
A lost calf is called a loose calf.
Such a calf is called a stillborn calf.
A baby dolphin is called a calf.
Female whales are called cows. The calf is a calf.
An immature butterfly is called a caterpillar.
An immature or baby eagle is called an eaglet.
A female walrus is called a cow.
A baby ox is called a calf.