When I first moved to Louisiana I lived in a development that was generally surrounded by pasture. I would take my German Shepherd, Timber, on walks around the network of quiet country roads. On one stretch there was a pasture occupied by a small herd of cows, accompanied by one of the biggest, bluest Brahmas I've ever seen. We were about 150 yards away from the gaggle of beef when we first approached, and as we strolled down the road, the Brahma left his harem and jogged over to check us out. My shepherd saw him coming and got into defensive posture and the bull stopped about 20 yards away, with he and my shepherd locking stares with two very, very thin strands of barbed wire between us. Of the three creatures there (Timber, me and the bull) it quickly became obvious that I was the only one that had any notion of the concept of, "fear," and while I'm confident Timber would have given his life (in a futile effort) to protect me, we made a quick exit from the area with the bull carefully watching each and every step until we were out of sight.
Had the bull felt threatened enough to come through the wire, I doubt I'd have survived the experience.