New horse owner here, first time with horse worm problems...Bought my mare in July from the barn where she is currently boarded. They owned her the previous two years. Throughout that time, she was always on a regular, rotational dewormer schedule. Per my boarding contract, BM is responsible for deworming of all horses owned by the barn, as well as boarders' horses to keep everyone on the same schedule.
The first week of August, I'm going through my normal grooming routine and see what I'm sure is a worm poking out of my mare's rectum. It is pale white/translucent, the best I can describe they way it looks is like a bean sprout. I removed the worm, saw no others, and no evidence of tail scratching. I did inform BM; all horses were due for dewormer anyway, so everyone got their Ivermectin. No one else showed signs of worms.
A couple of weeks later, same thing- grooming, see worm poking out, and also notice lots of crusty yellow/white discharge around the area. Unfortunately no one else was there to help me assess, and everyone at the barn sort of shrugged it off when I brought it up, told me she was probably passing dead worms, etc. Still, I was sure I had seen the same bean sprout thing, did a lot of research and suspected pinworms because of the discharge and tail rubbing that I was now seeing, so insisted on doing something. Called the vet, who said the only worm likely to be seen this time of year was tapeworm (?) so recommended deworming again with something praziquantel-based. He said a fecal egg count wouldn't be useful for tapeworms or pinworms, so not to bother, just go ahead and deworm again, so I did.
Now it's another two weeks on, and there has been a LOT of tail rubbing- 3 distinct sores under the dock of her tail. She's also been in heat, so I thought maybe she was rubbing because of that, but today I saw two more bean sprout-like worms emerging from her rectum. I'm embarrassed to post the picture below because it's pretty gross, but if you can make it out on the right, it's a clear worm essentially disgorging a slew of yellowy sticky liquid, which again makes me think pinworms laying eggs? When we attempted to pull it off, it retracted back into her body. Can anyone help me with what this might be based on your own experience?
Tomorrow morning I'm heading to the vet's office with a manure sample and this picture, as this just doesn't seem right to me. I have no idea what the next step would be- yet another dewormer??- but I'm getting really nervous about that because deworming too frequently just builds resistance, right?
One other piece to this- over the spring, my mare really seemed to have a bad hay belly, but most of the other mares at the barn did too. Around July, the barn switched to a far higher quality hay, and slowly all the other horses started to look better. My mare never lost that hay belly look, although admittedly she's only being ridden ~3x/week right now, so that may just be lack of fitness. As I looked at her today though, I wondered if her hay belly was really a wormy belly? The 2nd picture is her from last week, shows her belly.
I'm really at a loss here, so while I'll be consulting with the vet tomorrow, I'm also interested in other opinions.