It was deleted, I just found out this. The explanation It is in the book "the way I am" :
There was some weird shit in 8 Mile too. I fought tooth and nail (and won) to get this scene with the horse out of the fucking movie because it made no sense whatsoever. Jimmy gets in a fight with his mother and takes his little sister next door to the babysitter and then he sits down and starts crying, just thinking about his life and how fucked up everything is. But then he turns around and—get this— he sees a horse. As in one of those horses the cops ride through the city and shit. He sees this horse in a junkyard and he doesn’t know why it’s there. He walks up and starts petting it. Now, there’s something about horses and the way they throw their heads up-they jerk their heads around out of fucking nowhere. Curtis kept telling me to grab the reins and pet it. But the horse was doing this crazy head-jerking movement, and I thought, Any minute this motherfucker’s going to lift his head up and bust my fucking jaw and knock me the fuck out. Horses and me, we don’t get on too well. I wouldn’t fuck with a horse. If a horse dissed me, I wouldn’t say anything back. -Eminem/The Way I Am.
