A cow typically remains in the dairy herd until about 5 years of age, although many cows are capable of remaining productive in the herd for 12 to 15 years. Following birth, the calf is usually removed from her mother after only a few hours. The newborn calf is fed milk or milk replacer until weaning at 6 to 8 weeks of age. The calf will then be raised until it reaches appropriate breeding weight at about 15 months of age.........Read More

Source: epa.gov