What is the young one of a cow called?

The answer is Calf.

A calf is a young cow. The term is used from birth to weaning, when the animal is referred to as a weaner or calf, though in some areas the term "calf" may be used until the animal is a yearling. The birth of a calf is known as calving. A calf that has lost its mother is an orphan calf, also known as a poddy or poddy-calf in British English.

The other options are not correct.

• Cattle is a term for a group of cows.
• Shed is a structure that provides shelter for animals.
• Moo moo is the sound that a cow makes.