Depends not only on the area, but other factors such as how hard the rut was on a buck and diet can play a role too. Here in MI, a cousin was dragging his buck out in the middle of December when the antler he was hanging onto came off. Another guy on the same property had the same experience. Last year, I watched deer with antlers in the middle of April. That's probably ususual though, not sure why - it was three different bucks too.