Strange symptom - poop & bolt

Hi all,

I need help identifying if anyone has had this symptom with their horse before. I’ve spoken to my vet but she’s just as puzzled as I am and between her, my trainer, and me we are all not sure what this is.
Sometimes when my mare poops she flips and bolts like she’s been stabbed in the rear by satans pitchfork. Almost like her brain is on autopilot. Today she did it, pooped, then bolted and ran into the rail and nearly went down. I somehow stayed on and got her calm, and once it was over she was relaxed as could be. In the past when she’s done this we’ve worked her for another 30 minutes to make sure she doesn’t develop a habit, but my trainer thinks there’s something wrong internally. Anyone seen this before?

My vet is gonna come out for a rectal this week, but I wanted to see if anyone had this experience before. My mare has been a superstar all summer, I was at the point where we were bareback riding and I trusted her completely but this new thing is definitely strange and not like her and my trainer agrees.

Does she only do this when you’re riding her when she poops? Have you seen her do it when she’s not being ridden? In the field or stall or tied? Does she seem startled when she poops during those times? If not, it could be she’s feeling constricted by her girth or something when she poops, and that makes her bolt forward?

It’s only when she’s saddled so far that I’ve seen. She’s done it once while I was walking her on the ground (saddled), pooped and then immediately flipped out and almost yanked my arm off. Once it’s over and she’s had a minute she’s relaxed again. But it definitely seems to startle her, there’s no warning to it at all, and she clamps her tail down and tucks her butt when she explodes. It genuinely seems like a shock to her. It only seems to happen when she’s working/moving at least at a brisk walk. She’s been fine on trail, pooped last time and seemed fine but she stopped to poop then. I’ve seen her poop in turnout, standing still, and be fine.

I’ve wondered about the girth because in the last 2-3 weeks she’s become cinchy out of nowhere. Never had an issue with it before. I started her on a probiotic that seemed to help that, but I’m wondering possibly ulcers? But I’m not sure if even treating her for that will fix the poop issue. It seems to be like something triggered right when she does it or maybe right before like she’s uncomfortable and it hurts. No blood in poop, tho.

I’d put saddle fit or kissing spines on the list of suspects. The saddle may suddenly pinch (and/or put direct pressure on the areas affected by KS) when she lifts her back and tightens her abdominal muscles to defecate.


I’ve only seen this once - and it was a horse with bad hind gut ulcers. Kissing spines would also be on my list.


The saddle fits well from when I’ve checked and had others check, but I didn’t realize kissing spine could be a problem. I’ll ask my vet about it!

I’m glad to hear this has been seen before, I was suspecting hindgut ulcers but there’s no blood or other signs that I can tell. I was gonna treat with ulcerguard but I’ve heard they don’t really help hindgut ulcers, I’m hoping possibly the rectal might show something and if that doesn’t show anything ill for sure ask about kissing spine. Hope it’s not that.

Does she have diarrhea?

Have not seen this in a horse, but I have seen it in a cat with spine cancer. Pooping became painful so he would bolt from the pain. It was a shock to see because his meds had seemed to be doing a good job of keeping him comfortable and happy.

So, I vote, check spine and then check guts. My fingers are definitely I’d you find a treatable problem!


The horse I knew that did this had other signs that pointed to gas/poop as being painful. He’d refuse to keep trotting if he had to fart. He’d also “gear up” to poop, gradually getting crankier and more difficult as he trotted around, occasionally throwing a big buck or temper tantrum. Sometimes, as he was pooping he’d shoot forward as if it hurt. Then when he was truly done, he’d look relieved and relax over his back and go to work.

Ulcerguard would not help if it is hind gut. Current thinking is that it may make things worse. You’re unlikely to see any blood with the naked eye. The best diagnostics we have to gain information on the hind gut are a fecal occult blood test and an ultrasound of the colon. Some vets also do ph tests. The rectal may feel a tumor or blockage, or maybe some really bloated intestines, but my vets don’t routinely do rectals as part of a diagnostic exam for hind gut ulcers.

If evidence points that direction, they overhaul the diet (removing long stem forage for 90 days in bad cases), and start the horse on misoprostol and sucralfate.

That said, I do think kissing spines should be high on the list as well. These are odd cases, so there is no telling that your horse will end up in the same place as the one I knew.


and with mares, always rule out growing ovarian cysts / tumors which can be quite painful. I am sure that will be checked during vet exam.

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Not for nothing, I would also investigate this from a training standpoint. Like the horse that spooks at its own farts (I’ve known two who would be seriously startled by their own loud fart), she might be reacting to the movement of the pile hitting the earth behind her hind feet, especially as this seems to be most prevalent when she’s walking. She may just not be making the association of her passing manure and the movement behind her.

It’s not completely unheard of for horses to be well broke and accepting of environmental motion and movement everywhere except directly behind them.

I think it was Buck Branaman who coined the phrase “changing eyes” for the evaluation and training of sensitivity to motion in a horse’s rear blind spot. Certainly, he’s not the only one, just who comes to mind as I type this.

Might be something to consider, and hopefully it’s a resolvable training issue for you all and not a medical one. Wishing you lots of luck!

Have you fried a forage elimination trial? Could be a hindgut/displaced colon/gassy condition that is causing pain. Take away long stem forage for a couple weeks and see if you have any incidents during that time. Replace the hay she would get with soaked pellets instead to get her by. If you are incident free for two weeks, I’d suggest 3-5 months like this, gradually adding in chopped hay, and working way back up to alfalfa at the end of the time period. Gives the GI time to heal from whatever could be going on in there.

Spent thousands in diagnostics for a horse with GI issues, delayed manure, etc. and it ended up being that he couldn’t digest coastal hay (all we have locally). After the elimination diet and switch to alfalfa, horse has ZERO issues whatsoever.

Is it only when you keep her moving while pooping under saddle?

Seems so. She has only done it while gaiting, or briskly walking saddled. Once while I wasn’t on her, though every other time when I was on her. She used to just stop and poop, though my trainer made her keep going. I preferred her to stop and go myself. The bursting panic is totally new and seems exclusive to going while in motion.

This seems in line with my girl. She’s been progressively more angrier during lessons. The thing is, I assumed she was growing confidence and going through a naughty phase since she never kicked/bucked, just stomped extra hard and would put up an argument but always did what I asked. She used to be more timid and since having her join with a herd and working her more she’s been really coming into her own. But I’m wondering now that maybe her attitude might be due to pain and she’d be more pleasant otherwise. My judgement with her is limited since I’ve only had her nearly 2 years, and only 1 of those years she’s been medically sound (colic surgery due to stones) so it’s hard to tell what’s really her and what’s her in pain.

I’ll mention hind gut ulcers and ask for a blood test. It’s more my theory than my vets based on stories I’ve heard from other people and the fact her only symptoms seem to be these outbursts and recent girthyness. I have been noticing her not want to groom as much with her herd, which is highly not like her as she’s very bonded with them. I wonder if that’s possibly a side effect of feeling sick?

Also, just to ask, is Timothy hay trouble for ulcers?She’s on a pure Timothy hay diet and one very small bucket for supplements for the past year. I was always under the impression it was good forage for horses with gut issues.

I haven’t ruled out kissing spine either, I really hope it’s not that, but we will start looking for that if nothing comes up with her gut. Hopefully I can pin it down quickly.

I wondered if this may be the case too when I was reading your original post. Did this behavior begin after you followed your trainer’s advice and begin forcing your mare to keep moving while pooping? I can see how that could make her anxious about the act itself, especially if you’re urging her forward, forward, forward while she’s trying to poop, and then she gives that burst of “Okay! I’m moving!” afterward. Maybe she’s trying to be obedient, but it’s just not comfortable.

I’d let her stop and poop while riding and see if the behavior diminishes. I’ve never been big on keeping my horses going while pooping. Most of the time they don’t poop when I’m working them seriously, it’s only afterward when I’m walking them to cool out that they’ll go, and if they want to stop then, that’s fine. I’d hate to have to walk while pooping.


The crazy thing is, I’ve seen my trainer have her poop and walk, and she’s done it with me as well no issue totally relaxed. I prefer to let her stop and do it personally, as it must be the most comfortable thing for them. I do wonder if the motion is uncomfortable now for her in some way. The way she shoots off after is almost like she’s running from her own behind, she clamps her tail down and tucks her butt and scoots forward like she’s been shocked.

:frowning: That is a very good description of what my cat did due to spine pain.

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I would say definitely have a vet check her out, and consider back xrays if you can swing it. It could be so many things. I’ll share my late gelding’s story, and I wish I had gotten the xrays sooner. He was having trouble passing manure under saddle, and was a little balky until he pooped, and then clicked on and was ok - this went on for awhile, checking and treating for ulcers, trying to increase motility, but nothing really helped. In July he deteriorated quite suddenly. There was a bit more going on for him in lower limbs and his SI that we were addressing with IRAP after other therapies had been tried. This led us to take back xrays and found a lot of issues with his thoracic spine - he had spondylosis on the ventral side of every vertebrae we could see on the xrays. From that point he was deteriorating at an even faster clip even after he was retired from riding, having issues laying down, getting up - like he’d be shocked/zapped upon getting up after a roll outside (but stopped laying down in his stall altogether). He also started tripping pretty often and was having problems standing for the farrier. Given the deterioration even in his non ridden life and the extensive list of other issues he had, I ended up euthanising him in October as we were struggling to effectively control his pain levels.