I'm trying to switch Luke from a kimberwicke to a snaffle. Luke is a 5 year old ex-race Thoroughbred gelding.
So, today I decided to quick hop on Luke bareback and plop around on him. We warmed up, did nice sloooww jog/trots, etc. etc. I asked him to canter, and I couldn't get him to stop! Well, after awhile I could, but I was doing so many half halts, and he still ignored them. I tried to circle him to get him to slow but he kept tripping and I didn't want us to fall down. Finally I just yanked (I know, really bad of me) back on his bit sharply and he stopped cantering. I got quite nervous and decided to just walk/trot the rest of the time. But the thing that confused me was that on our lesson on tues. He always slowed when I told him to, I even practiced some really basic lateral things. It was a little bit cooler today, but not much difference than on tues. He had his snaffle on tues. And today. Why did he act this way? I'm positive it's the bit change but why was he so bad today and not on tues.? He was almost uncontrollable. How can I correct this from happening again? I try circles but he gets unbalanced and sloppy. I'm just lucky I didn't land in the dirt today, after all, it was bareback! I know he's not trying to be bad, he's still a baby, but i'm scared he won't stop in the snaffle! He always stopped in the kimberwicke. I just want him to go back to a mild bit and start re-training him to give to the bit.
Suggestions so I don't die would be helpful (haha). This is my first horse.