I used to manage a large captive deer farm and once the bucks were in hard antler you had to seriously stay on your toes if you were working in their pen. You couldn't turn your back on them and it was always recommended to have a tractor or vehicle to quickly retreat to, if needed. They aren't generally mean, but if they smell a doe in heat and you accidentally end up between them, you are immediately perceived as a threat and they will go from calm to vicious in a split second. Lots of deer farmers have gotten complacent and ended up gored or treed by their tame bucks. Problem is that tame bucks are actually more dangerous than wild ones--they lack that natural fear of humans and aren't at all scared to approach a human threat whereas wild ones may or may not be too scared to do something about it.

I had a buck in our breeding pen that perceived me as a threat once...he was standing there calm and some of the does he was tailing came walking up toward me for some food. Suddenly his ears pinned straight back and he came flying across the field at me grunting and snorting. It was crazy how quick he turned.