Fall calving. Do both, but I love the fall herd. If you have the facilities, I say go spring and go early. But calving the fall herd is barely a blip on my radar, whereas the spring herd, even calving in April, can really stir me up. Something about getting up in the middle of the night with below freezing temps.
The talk about extravagantly higher feeds costs and the winter being hard on calves is a lot of BS. One of the rules to making it work is that all the calves have to be born at least a month before snow flies. 2 months is better.
And on average by my numbers, the wet fall cows eat 8 lbs more a day over the dry spring cows. So about 1/4 more feed in my terms.