In order to lactate, cows must calve on nearly a yearly routine. A cow has her first calf at about 2 years of age. She then needs to calve again in twelve to fourteen months and again after that as long as she will breed back.
The resulting heifer calves are raised as replacements for cows that cease to be in the herd for one reason or another.
Baby calves are started in individual hutches and are kept in them for two to three months. They then graduate to group pens which they progress with their herd mates until they have their first calf at the age of two.