I'm wondering why there would be an advantage to 2-step weaning over straight fenceline weaning? From what  I've seen, as long as the calves can see mama on the other side of a good fence there is no big deal. Same for mama seeing junior on the other side of the fence. Maybe its related to the age of the calf?

I have seen cows bawling longer than calves which seems to be because their udders are full and they are calling the calf for dinner. This lasts a few days until they start to dry off.