I have a Charolais steer that was born around last September. Got him in May of this year and have been training him ever since. He is fine with me off the halter and was decent for a few weeks but now when I begin to walk with him he pulls his head down and tries to knock me over. He sleeps in a pen (on the school barn) and goes into the pasture for about an hour every morning to get some space, I also tie him with his head up every day ranging from half an hour to about two hours while sitting with him. As I said he used to be okay, but within the past month has begun getting frisky when tied up and when practiced with. Any advice on how to get him to listen and mellow out?