A deer? Never met a moose on the highway, have you? To avoid deer-auto collisions don’t drive. 
Sorry, now for a serious answer. I don’t see how you can avoid the risk of animal collision. All I can say is avoid panicking if it happens to you. You see a dear, slow down, don’t break, you might get rear-ended by another car, which could be worse. Your better off hitting a deer than plunging into a ditch, so don’t do extreme maneuvers either. Save yourself first, the car, second.
Deer aren’t that big. On the other hand, a moose will decapitate you if you hit it with a car…
Only humans commit inhuman acts.