So I need some clear thoughts. I have a 12yr old pinto/arab that I just ADORE! Have had her for about 18 months. When I bought her she would walk and BARELY jog. She had horrific awful scar on left rear leg down to the bone. took me about 2 moths to get her to the point of letting me pick her back feet. Also had to find a blacksmith with a gentle touch that she likes. We trail ride a lot in rocky hilly terrain. We show in some local shows (4 a year) and do a parade and a games show.This is my second year going thru this cycle with her. Mare is awesome. NO spook, well behaved, not hot, and a joy to ride. She is AWESOME in obstacle classes and will let me do ANYTHING on her, ring spearing, potato race, costume class with really crazy costumes, she is a gem!! So first year out I worked on the basics, walk/halt a half halt, trotting, upward trasitions, downward trasitions. When doing ring worl LOTS of figure 8's and serpentines as she gets bored. With all the hill work on trail and circles etc, I got her to the point of walking, jogging or trotting, lenghtening these gaits, half halts and backing up. Now last Oct I had had her about 6 months and had set a goal for us to be able to do canter classes by NEXT october which would be now. SO over the summer I did work on it. She wouldn't even canter before now, i ask and she bucks and then its a 50/50 shot of me being able to smooth out the cmater OR she just bucks, canters a few strides, bucks again. So I did my tried and true trick I tried UPHILL in 2point. SHE STILL bucked!! So I take her to daughters trainer this week and ask her to ride and see if she has better luck or can give me some direction.So games show was saturday so we truck up on thur to take advantage of trainers nice ring. I ride thur and mare is wonderful, bendy, soft, fluid.Trainer says wow she is really working thru her topline. She felt fabulous, so I close my outside leg, cluck and say canter and mare pinns her ears,bucks and canters about 5 strides, bucks again and then quits. Then she of course is no longer feeling fabulous and it takes me about 10 minutes to get it back and mare is really anticipating me askeing her to canter again which I never did. SO friday trainer asks and mare drops her head and gives the BIGGEST buck I have ever seen other than bucking broncs. Never could get mare to canter more than about 5 strides. THEN she is clearly lame on what I thought was left front but dd's trainer thought was right rear. SO yesterday is the games show and I give her 2 grams of bute as I am sure she hurts. Wonder of wonders she is sound, AND we show and she will canter for me in both directions with NO BUCK!! SO WHERE or where do I go from here?? Obviously something hurts when she canters. She is so much better at everything else, I am thinking I am going to keep working on strenghtening her with the hills etc and if no better in 6 months THEN I am thinking a vet work up at state I guess. Just not sure what this means. no but buck at canter, bute all is well. UGH any advice, and don't say dump the mare cuz that ain't happening.