Very nice composition, nice pose and sharp head. Image got enough sense of motion for me and I like it. Orange part in ULC is kind of making my eye go there once in a while and grabbing attention. I would try to tone down the yellows a little bit.
You panning was just perfect to get a sharp view of the animal. Since the shutter was released just after he/she passed your position you got them going away. Did you get any more of deer running towards you?