i'm no vet, but if i compare your dog's x-rays to the examples found on the ofa home page ( http://www.offa.org/hd_grades.html ) i would rate those moderate hip dysplasia. maybe even severe on the right side, that socket looks really shallow. regardless what your vet says, I would absolutly send in those x-rays for evaluation. i had an amstaff-female with c/d graded hips (mild/moderate) and i trained very light wp with her to train up her muscles around the hips so that she would become more stable. personaly, i wouldn't train wp with a dog that has moderate or even severe hip dysplasia on both sides. but you should absolutly continue training your dog, but have his hips in mind and do not push him hard. instead for weight pull you could train some very light drag weight instead. take long walks in woods/over fields and let him run lose. that is good for him aswell. let him rest a lot between training sessions. my female got very stiff when she got older (even though i always would massage and stretch her after work out) and one could tell that she was in pain when she woke up. but when off leash she would run like a panther. i think she liked to run because hormones produced during work out work as painkiller. good luck.