Get near him, back up when he attacks. Hit him twice or somthing right after. If you can bait his vertical swings, you don't have to wait for the combo to end, just keep moving to the side. He won't turn well while swinging. He will often counter with a spinning combo if you are flanking him, so backing up is good. After his counter, you can rush in and chip at him again, then back off. You need some timing to dodge his throw move. Dodge too early and you are hit. There is merit to aiming for his head, maybe throw something or hit him when he slams. You can stun him for a while if you damage his horns enough.