Back to my comment about bailing out of jumpers:

Any horse (I don't care how small or old) should be able to clear 3'6" so long as it is sound.

HOWEVER weak loins and a smaller butt makes it harder for a horse to make a hairpin turn, to one stride to a 4 foot fence. Just ain't happening without significant conditioning. Sorry I didn't make clear what I meant ...

Much different than hunters where the turns are very wide and the horse can be more on the forehand.

Hey, you give equitation a thought yet??? I think your boy could do it.

Speaking of cows ... I don't think I've seen one jump ... what do they look like? Do they crow hop? Hmmmm ...