This appears to be a 4-5yr old bull searching for something. This is not a herd bull, so cow numbers will be small if at all. Watch your wind, it is a big deal here! Do you have a lane for him to get to you? If yes, put your head down and quietly cow call to left or right to get him to turn his head in that direction and watch his reaction. If he stretches his neck out and makes any vocalization other than a bark, he will probably come to you. Might not be fast, but he will come to you, but don't call again. If you don't have a lane, you better find one quick, because he will be moving on. If he is talking, answer him by all means, but make it sound like you are a ways away so he will want to move. DON"T pour it on be subtle, cause you could blow this deal easy. This is a bull looking to steal some cows, I would work him.
Gselkhunter