The 1st solution would be to keep and expose cows to rebreeding for spring/tumble calving. The 2nd alternative will be to put weight on and sell as cull cows afterwards. Bob Birdell, who farms and has a cow-calf herd near Stanberry, Missouri, explained he tries to take into account age, https://lostcalfhat24579.tkzblog.com/26040456/facts-about-lost-calf-hats-revealed