I'd like to see a better picture to see how close to the floor your fetlocks are. Judging on this one though you look quite stiff in the hock and tense in the back too so I would suggest that you tell the horse to simply stop eating and run around the field 5 times a day until he's a size 0 because it's very cruel and totally unnecessary for him to be riding you, he should just get a motorbike.