I am the outcast here because we feed retained heifers feed from weaning time until they are turned out with the bulls.
With our adult cows the plan is on a good year to feed stockpiled fescue until Christmas and then go to rye grass in March. So between Dec and Mar we feed our cows. It works better for us to sell our best hay and lately our good hay to the horse people and then take that money and buy gin trash, cotton seed, sometimes soy bean hulls and only this year corn. Believe it or not it is cheaper to feed our cows the quote bad hay aka (johnson grass, rained on hay and crab grass) and sell the fertilized bermuda and fescue to the horse people. I can't fertlize hay and then use diesel to cut rake and bale and then store the hay just to give it to my cows and make any money. The only way I can see any money from all that is to sell to the horse guys.
Jan and Feb are our worst winter months so feeding helps bring the fall calvers back in heat to get bred and keeps the spring calvers going until Rye grass and then fescue. We take the Fall cows off the rye and leave their calves on it and wean them and sell them in April. And then sell the spring calves in August.