The best reaction I've ever seen of a deer to rattling came in September in Minnesota. My buddy, Wooly, rattled in a ticked off 6 point. He got the deer too. So now I rattle all year. I've rattled in a couple early bow season bucks too. One time I rattled in a nice buck. He was about 25 yards away and coming right at me when wooly started rattling near by. The buck turned towards wooly and trotted in that general direction. (I shot right over his back)

Anyway, seems to me that rattling works pretty good early season too.