I am hoping someone here might have an idea about this. My 4 yr old Morgan gelding is very green and we just started lessons with a dressage trainer. Last Sunday was our third lesson. I had lunged and long-lined him on Saturday, and then warmed him up for about a half hour before the lesson. He seemed pefectly fine. But as soon as I mounted him and started to ride he seemed "off". At first I thought he was just not into it, as it was a fairly hot day, but then every time we picked up a trot he stumbled and once almost fell down. He IS due for a trim, and my farrier is coming this week, but his feet don't look terrible. There is no sign of any injury, no swelling or heat anywhere and he appears sound at a walk, and even running around in the field, etc. Yesterday I took him out and lunged him again, and he seemed fine. I did not ride as I decided to wait until the farrier has been out. My trainer suggested it might be a stone bruise, but I actually think he was just being lazy. I am hesitant to call the vet right away as we already have a lame older mare and a sick dog, both of which I am still paying for. But it almost seemed like his foot had gone to sleep when he stumbled- is there a condition like that? I am at a loss.