My husband and I recently purchased a farm and home in NW Oklahoma. We also purchased a herd of bred Hereford heifers, which will start calving this month. Can someone tell me some of the sure-fire signs that will indicated that the heifer is within a short time of giving birth. How soon after they start making bag can we expect the calf and when they start (springing or is it stringing) can we expect the birth to take place? Any and all help greatly appreciated.