We used to calve in February and March. Had to keep a close eye on them.
Now we calve in May - June. Check them once every couple of days - out on green grass.
Loose a few now and then but nothing like we lost in Feb-March.
You do loose some pounds if you wean November - but sounds like you can change your
program to keep the weaned calves a little longer and hit the spring market.
Best of Luck