Yep, that's a real longhorn steer. It's impossible to really portray how wide those horns are, but they're massive. I'm not even sure how he got through the gate. The fact that he's pawing the ground while I snap this is probably not a good sign.
You're in his face with the camera, an the sign behind him deals with turning him into leather... Clearly he's not in a good moo-oood... (had to do it...)