Large strongyles or roundworms- dewormer resistance?

[CHT]

I have a horse in my barn that seems to have de-wormer resistance - she came last winter and has been on outside board. Back in November she had to be on stall rest and day two, I noticed her poop full of large strongyles or round worms. We dewormed her right away, and for the next 5 days it was disgusting how many worms came out. Her pasture mates were dewormed at the same time.

Fast forward to two weeks ago and one of her pasture mates pooped out what looked like to be poop covered in eggs. Yesterday, mare’s owner noticed similar eggs in her horse’s poop.

When mare came she was thin, and had watery poop, but she has put on weight, and a feed change fixed her watery poop. Her owner had previously tried to resolve the worm issue with the power pack dewormer among other things.

Looking for advice on what I can try, including timing of when we should do it. (We are currently in mid winter/below freezing -the last dewormer was equimax and was done once we had a good hard frost).

[Scribbler]

Horses transmit worms to each other and reinfect themselves through grazing in temperate seasons. It takes a few days for worms to become larvae and crawl up the grass, so if you pick poop in a stall or dry lot that should break the cycle.

I’d suggest talking to your vet or local agriculture authority about conditions in your area and identying worms. Could they be tapeworms?

[Texarkana]

You can’t see large strongyle eggs with the naked eye.

Worms in manure = dead worms.

I’d start with a fecal egg count and go from there.

[CHT]

So what would they be? They looked like little sesame seeds covering the poop balls. It is winter, so no grazing - they don’t get fed anything that would be that many seeds.

[CHT]

Not tapeworms. Large strongyles or maybe round worms?

[Texarkana]

My first guess would be something in the hay. There are often seedheads that might not be readily apparent.

They could be bot larvae, but they are MUCH larger than a sesame seed. More like peanut or cashew sized.

It could be some kind of mold or fungus growing on the manure; it can even happen in the winter, but cold temps will keep it from becoming totally fuzzy like it sometimes does in warmer seasons.

[CHT]

It was in fresh poop, so not mold. Hopefully seeds? That would be better and make sense. Phew. Makes me feel better about my horse. Still need to help the other mare with her worm load. For a horse that is dewormed regularly (more than our other horses) the quantity of worms was astonishing.

[FjordBCRF]

Did you take photos by chance? If you get the opportunity to, that might help. I’m guilty of texting people weird horse poop

[Scribbler]

My understanding is that you need a microscope to do a fecal egg count, so I figure the eggs are pretty small.

[RedHorses]

Fecal counts are necessary. First to find out what her current load is, then again 10-14 days after deworming (ask your vet about timing) to find out what kind of resistance the worms have to the drug used. If she has resistant worms, you would stop using that drug to deworm her in the future, and immediately deworm with an alternative drug, then follow up with another fecal.

Once you have a year or so of fecal checks, you’ll have a good idea of how often she’ll need deworming, and which drugs to use, and won’t need to fecal check every time. My herd health through the vet includes two dewormers (late fall, late spring/early summer) and two fecals (early spring and late summer). Any dewormer required after a fecal is extra $.

Even a power pack isn’t a guarantee. My senior horse (with a history of high natural resistance to worms) colicked in December due to a high worm load. He got a five day Panacur Power Pac deworming at that time. I had a fecal done three weeks after the final dose and his count was just barely over the “needs deworming” number, so I gave him Quest Plus at that time.

I will be doing quarterly fecal counts this year to find out if this was a one off, or if his age/health conditions/medications have affected his natural resistance. That colic cost me more than the annual herd health package, so I’m going to do the extra $38 fecal checks.

[Simkie]

The AAEP has a really good deworming guideline paper that may be useful:

https://aaep.org/guidelines/internal-parasite-control-guidelines

I agree that you’re not seeing strongyle eggs, but also curious about what it is! Post pics!

[HiJumpGrrl]

the resistance to febendazole (the wormer in panacur) is extremely high in most places–so high as to make a “power pac” useless. It is not a recommended agent unless you have done testing to assure that there is not resistance in your area. The link posted from the AAEP is very useful in terms of how to do a “re-emergence time” and estimate resistance. The only remaining agents without widespread resistance seem to be moxidectin and ivermectin.

[PaddockWood]

I’d be doing a FEC and so curious. And also a FECRT after deworming - what 10 or 14 days out? Something like that. AND, keep that horse separate from others and pick the poo out of there every day and compost or get it out of there.

My new horse tested a 2100 FEC shortly after arriving and for 6 mos I kept him separate from the others and picked his manure daily and got it out of my field.

[PaddockWood]

And yes, I learned from this board to do Quest Plus which causes less problems than_______? With Quest the worms are paralyzed and die off slowly and let go of the intestinal wall versus the other drug and they die attached and cause sores.

[JB]

@CHT

poop covered in eggs.

As said, you need a microscope to see large/small strongyle and ascarid eggs

Since it’s been long enough since you used Equimax, just get a FEC done and see what’s what

@CHT

They looked like little sesame seeds covering the poop balls.

what’s the hay? What you describe definitely sounds like seeds from something. Bot larva aren’t even that small, and don’t look like seeds even if they were

@RedHorses

ecal counts are necessary. First to find out what her current load is, then again 2-4 weeks after deworming

It’s 10-14 days post-deworming to do a reduction test

@HiJumpGrrl

The only remaining agents without widespread resistance seem to be moxidectin and ivermectin.

sadly, that’s a real growing problem too

This is a VERY good video everyone should watch, done by Dr Martin Nielsen (parasite guru), showing current resistance issues even with moxi and ivermectin https://www.facebook.com/GluckEquineResearchCenter/videos/1621929098332868

@PaddockWood

And also a FECRT after deworming - what 10 or 14 days out?

Yep!

[Simkie]

@CHT

They looked like little sesame seeds covering the poop balls

Are you sure they’re not tape segments?

That would be one hell of a load, but they’re often described as looking like sesame seeds.

[JB]

Info I find says tapeworm eggs are around 60-80 micrometers, which is .06-.08mm, where sesame seeds are in the 3-4mm range, as well as:

“The eggs of redworm, roundworm and tapeworm, the ‘usual suspects’ of horse parasites, are microscopic and not visible to the naked eye. Any eggs you see in horse poo will not be from intestinal worms.”

Eew what’s that in my horse’s poo?!

[Simkie]

And yet they’re still compared to sesame seeds as the screenshot from the vet I posted above so aptly demonstrates…

[JB]

“animal hospital” makes it seem like a small animal hospital. Horse tapeworms, Anoplocephala perfoliata, aren’t cat or dog tapeworms, Dipylidium, and I have no idea how big those piece-parts are.

Science direct says 60-80 microns for A. perfoliata. An actual fecal testing lab says you need a microscope.

[JB]

The CDC says

" D. caninum eggs are round to oval (average size 35 to 40 µm; range 31 to 50 µm by 27 to 48 µm)"

So even SMALLER than equine tapeworms (which makes sense).
https://www.cdc.gov/dpdx/dipylidium/index.html