March/early april calving is the worse time for us.  I am in the process of swithcing the herd to late october/november calving.  I feed a little more hay but the quality that we can make in my area will support the cows.  I also put up balage in the early part of hay season and the late part due to hard time drying it down to make dry hay.  I also have an extremely good market for heavy weight feeders.