I can't and won't feed cows.
Heifers get plenty of grain from weaning to breeding. My heifers are bred two weeks earlier than the cows so that they have a little longer to return to heat. When grass comes (late April or early May) and they are pregnant, they go out on grass with the main herd. In the winter, I keep the coming 2 year olds & 3 year olds seperated from the older cows and they receive our best baleage - try to have them in BCS of 6.5 - 7. After calving, again they are kept seperated from the older cows. Receive baleage & mineral/salt. Yes, they may lose some condition, but are expected to breed with the cow herd - or they don't stay here or go to someone else's breeding herd. They are culled.