Dietary energy requirements of a mature beef cow, in total megacalories (Mcal) of net energy for maintenance (NE_m) per day. Values are expressed as the average daily amount required during each month after calving and were calculated for a 1,400-pound (635-kg) cow that has a gestation length of 283 days, gives birth to a live 85-pound (39-kg) calf once per calendar year, has a peak milk production of 18 pounds (8.2 kg) of milk per day, raises the calf through weaning at ~7 months old, and is managed under a plane of nutrition such that dietary protein does not limit the animal’s use of energy provided by the diet.