how do you know its about time for a cow to calve
Calving takes place in three stages. The initial stage of calving, when many of these signs first appear, can last between two and six hours. Once the water bag breaks, the second stage -- the actual delivery -- begins. For a heifer, or first-time mother, normal delivery lasts about an hour. Experienced cows might deliver in as little as a half-hour. If a heifer is still in labor after two hours, or a cow after an hour, call the vet. The third stage, expelling the placenta, should occur within 12 hours postpartum.