Excessive Pooping / Anxiety about Pooping
My horse is an 8 year old warmblood gelding. He poops 5+ times per lesson. I know horses poop excessively when they are anxious, but he does not exhibit this behavior when anxious and not being ridden. Additionally, he poops at the same frequency when being lunged or worked in a way which does not appear to cause him any anxiety.
If it was just the frequency of his pooping, I wouldn't be concerned. However, his need to go seems to be a cause of very real anxiety for him. This issue has been going since we started him under saddle. When he was younger he'd feel the urge to go (I could feel he had to go because he'd lift his back and move funny) and try to bolt a bit. Then he'd come to a dead halt, try to poop and fail, then try to run off.
Through a lot of very compassionate training my trainer and I have taught him not to run off (both when he needs to poop and generally). He no longer bolts, but he really struggles to poop and move. He is capable of it (a clinician was riding him and forced him to keep going once with serious some leg and spurs), but I can't / haven't been willing to force him. The urge to poop makes him so anxious that i'm quite concerned its pain related. I understand this type of issue is typically a training problem, but that just doesn't feel right to me.
Sometimes he poops so much that I literally can't make it once around the arena at the trot without him slamming on the breaks and trying to poop. Half the time nothing actually comes out. This is starting to become a real issue, as its very disruptive to any kind of effective training. He is not colicky, as he has many normal piles of poop in his stall each day.
I've treated him for ulcers twice. He had ulcers both times he was scoped, even though we have him on a pretty serious ulcer prevention regime. Ulcer treatment seems to help the problem to a limited degree in that he's less anxious / explosive when he needs to poop. The frequency and the struggle to move remains the same, and it obviously is still a source of anxiety for him. My trainer is similarly concerned. She said she wouldn't feel right dropping the hammer, so to speak, to make him keep moving while pooping. This is way beyond just encouraging him to keep moving, turning him, or catching him before he stops all the way. We've tried all of that.
Has anyone ever dealt with a similar issue? Has it always turned out to be training related? I'm wondering if doing an x-ray of his back or ultrasound of his intestine (i'm not sure if that's possible) is warranted. I've spoken with my vet, and she has said that its a tricky problem and the medical testing is going to be expensive if I decide to pursue it. I would rather not spend thousands of dollars to confirm its just behavioral, but I also don't want to work a young horse who is in pain.
Thanks for your feedback, it's really appreciated.