Join Date: Feb 2012
Location: Alberta, Canada
To rule out trust/training issues, I would go completely through his ground work again. I would follow Clinton Anderson's book(he's good for building respect and trust) and start at the beginning, perfecting each stage before moving to the next.
If you do that, and he's still inconsistent, he has a screw loose. Any breed that has a big interest in halter competitions(stock breeds and arabs in particular) have lots of crazies. The whole halter industry is focused on looks determined by the current fads, ignoring soundness, usability, and sanity. I worked with a halter bred arab at one point. I was told he was crazy, but I was determined. It took me six months to get him to stand for mounting. It was like the lessons just didn't sink in. Half the time he was good enough for a kid to hop on, neck reining, stopped off your seat, super soft mouth, quiet. The other rides we would be mimicking the "airs above the ground", randomly bucking in mid trot, trying to bolt, bucking me off. I worked on him for over a year before finally selling him to a hard core endurance rider. Had a similar experience with a halter bred aqha gelding. Random temper tantrums with no trigger.