I did a little poking around... this may shed (oooh a pun) some light on it. I'll see if I can find anything else...

http://www.qdma.com/articles/details.asp?id=21
"the specific date when a buck will shed his antlers may be determined more by his individual antler cycle than any other factor. This cycle is independent of other bucks and is believed to be centered on each animal's birth date.
Penned deer studies have allowed scientists to measure the exact dates of antler shedding for individual deer year after year. One study in Mississippi found that individual bucks usually shed their antlers at the same time each year and almost always during the same week. "