I don't disagree with what's already been said, but my personal experiences with deer left overnight have been positive except those that foxes found before me. My strangest experience of that type involved me shooting a nice buck still in full velvet on Sept 21st some years ago. For a number of reasons - including recovering a friend's deer that was shot 1 minute before mine, I wasn't able to get out until the next afternoon - had to work and couldn't get off. I found the deer at 4pm the next day, gutted it and took it to a butcher who originally figured that it wouldn't be any good (overnight temps were about 55 and it was about 75 at recovery). After thoroughly checking the deer out, she said the meat seemed perfectly fine. I immediately butchered it and it remains possibly the best we've ever eaten and we suffered no ill effects whatsoever.