Heat stress, colic, PSSM or something else??

I immediately called my vet, but first I couldn’t get signal, then i finally had signal but no one answered. Called a 3rd time and was told they were in the middle of surgery.

I went riding this morning with some friends. My horse wasn’t quite herself when I mounted up. She was walking very slowly. I assumed maybe her feet were a little tender from the farrier. We had a very nice 2 hour walking ride. On the way back she started with a urinary stance, i kicked her forward by accident. Then she repeated the behavior 5-6 times where she would stretch out without going. Then she started looking at the ground. I dismounted and she laid down. Got her back up and walking, and she went down again. Her veins were all popped out and she looked hot. Pulse was 55, capillary refill normal. She repeatedly went down on the way back. I dumped all my ice water on her and she started to look a bit better. Got back to the barn, immediately cold hosed for about 20-30 minutes , and by then she was completely back to normal, looking for grass or treats. In the middle of this she never did lose her appetite. I offered her cookies and she ate them.

My friend who was riding with me works at the vet school and she thought it might be colic, but wasn’t entirely sure either. My mare had been nibbling grass all along the ride. Ate the cookies even though she didn’t feel good.

Once back, we waited around for a good long while, as i didn’t want to load her in the trailer and have her go down. She was fine by that point. Took her home and she is completely normal again. I was prepared to trailer straight to the vet if needed. They said they could squeeze us in but were in the middle of a really complicated surgery, so i decided to wait. By that point, she seemed fully recovered.

She did this once before about 2 years ago. That was an extremely hot day and we had a more strenuous ride then today. I was near a creek, so i got her in and dumped water on her until she was fully cool and then she was fine. We walked all the way back that day, got home and she was normal. All her symptoms were the same- urinary stance, followed by laying down. Then a quick recovery once i got her cooled off. It never happened again until now.

Now that I think about it, she had something similar many years ago- stopped on the way back, with urinary stance but no laying down. That was a cool day, and afterwards she seemed fine. I didn’t put it together until now. At the time, i had assumed she didn’t want to pee with a rider on.

This mare has some undiagnosed lameness issues in the hind end. I’ve had several vets look at her, x rays taken. No one could locate the problem. We tried injections but they did nothing. She looks fine at the trot, but cow hops and cross canters in the hind. As a walk trot trail horse in light work, she seems happy. The lameness issues were noticeable as a 2 yr old, which was strange. They never got worse or better. I even had her ovaries checked, thinking maybe it was reproductive. She’s 15 years old now. Daily exercise seems to help improve her lameness issues. Time off seems to make it worse. Today was her first ride in 2 weeks.

I sort of wonder about Pssm? Something that is exasperated in hot weather? Or perhaps I’m trying to link two unrelated issues?

I had another horse temporarily who had pssm or hypp. That mare tied up badly. Not even being worked. Different presentation. She had a normal canter, but never felt energetic. Always seemed sort of depressed. Couldn’t put my finger on it, until she got sick. Her abdomen tucked up and she had muscle spasms, fever, looked like going down but didn’t. Her owner didn’t want the vet out and came to pick her up. So no diagnosis but it was definitely tying up.

It’s hard to diagnose something that occurs so randomly. I could go to the vet this afternoon just for them to tell me she’s normal again. I did think about having her tubed for colic. But she’s out on pasture grazing right now, happy as can be. The only two similarities between incidents are hot weather and exercise.

She has passed manure and urinated. I did wonder about urinary issues?

I plan to set another appointment with the vet and take her in. See if they can run bloodwork and give her a physical. Might have to wait til Mon though.

How hot was it when you were riding? If she hasn’t been ridden in 2 weeks and is normally ridden infrequently , she is unfit to begin with. Then you add hot temperatures, 2 hours of walking ( carry a rider and tack) and her being " off" to start and it could be colic and heat stress combined.

Was she breathing hard or blowing? Sweating a lot or not at all?

I am glad she is feeling better and I would have a vet out or take her in myself.

If you don’t find anything listening for hoofbeats and are starting to think zebras, here is one rare possibility:

https://ker.com/equinews/malignant-hyperthermia-horses/

If you are going to run a DNA test for other metabolic disorders, ask your vet if they should add that one to the list.

I was riding a colt that did something like that, once.
By the time we were back he seemed fine.
The vet came anyway, could not find anything wrong and told me to carry bute and give him some if that happens again.
I did for a while, but he never had another episode, so I quit carrying it.

That was decades ago, not many tests to find out if it was a metabolic disorder or colic or what at that time.

You can have a blood test done to see if she tied up, but you should do it within 24 hours. Usually costs about $50 in this neck of the woods.

Was the urine normal color? A bad tie-up will often cause urine to turn a reddish brown due to myoglobin.

Sounds like she tied up. As ecileh said do a blood test and see. If she did tie up have her checked for PSSM1 and PSSM2.

What is her breeding?