A calf is the very youngest kind of cow, much like we would call a very young human a baby.

Calves still depend on their mother's milk. When they stop being calves, female cows become heifers. Male calves become bullocks. When they have had their first calf, they are cows. Heifers only develop udders when they are in calf. This is why dairy cows all have calves regularly.

It takes about nine months for a calf to grow inside its mother (about the same time as a human) but unlike babies, calves are able to stand up just a few moments after birth. They begin to take in milk (to suckle) after about an hour.

Even so, newly-born calves are unsteady on their feet and cannot move about with the herd. As a result, mothers often hide their calves in bushes or long grass for a few days, until they are strong enough to move around easily.

Only female cows are useful for dairy farming, of course, but dairy cows give birth to an equal number of males and females. Male calves are therefore mostly reared for meat.

Most calves are kept out on pastures until they are at least nine months old.


Mother cows will be very protective of their calves, and if you walk across a country field on a footpath that goes through a herd of cows with calves, you should be careful to detour around them.