Two turkey seasons ago I had two cows, a calf, and bull walk within 50 yards of me and my buddy. I was gutting my bird 10 minutes after I had shot it and we heard these heavy foot falls coming towards us...looked out into the woods and all we could see were legs BIG LEGS. First the cow, then the calf followed by another cow. Then we heard what sounded like a freight train mowing down small trees and saw the bull tearing ass away from us (guess he winded us). The first cow turned and faced us while the other and calf slid by her and walked off.
Pretty cool, but I will admit that I was a bit worried when the cow turned to face us as if she was going to charge. I easily agreed to hold my buddies 357 while he grabbed his camera.
At 40 yards they are BIG.