I agree, it's hard on them, but it has to be done. The calves can't keep suckling after they reach a certain age/ weight, they take too much from the mothers. If you leave them together the calves will continue to suckle even as adults! The ranchers need the calves to wean so the cows can go back into estrus and be bred back to bear more calves. Simple economics. They recover in a few days.I agree. It's painful listening to those cows call for their calves and the calves crying for their mammas. Sometimes you can hear them all night.