The Anthelmintic Crisis

[leheath]

@Texarkana

Next question: is it still responsible to hit horses 1x or 2x a year with ivermectin or moxidectin to remove bots, regardless of FEC? Or is that practice contributing to resistance as well?

Having just had a very unhappy horse due to a stomach full of bot fly larvae (which don’t show on FEC) and associated ulcers they either caused or exacerbated (plus associated very expensive vet bills), yes you absolutely should if you live in an area where they are a problem. They are not detectable by FEC. I’m now in southern CA, where we don’t have problems with bot flies, so I worry about this less now (horse came from a region where bot flies are common), but I will still treat at least once a year for tapeworms.

With more companies offering mail-in FEC tests for a reasonable price, hopefully more people will start using them, but it all comes down to education and if vets are recommending them, many people aren’t going to get educated. And I’m sure many vets won’t recommend the mail in kits because it doesn’t make them any money…and the vet FECs are a hassle and financially not practical for many people.

[quietann]

Still getting fecals 2x per year and deworming 2x based on that. One is always ivermectin or something similar. The one time the vet said I didn’t need to do a spring deworming, the worms came back with a vengeance and I ended up doing 2 PowerPaks a couple of weeks apart in the fall. It was gross. (The fecal count wasn’t that high, but the worms in the poop after the first PowerPak… ugh.)

Of course that was also the year there was a new pony at the barn, basically a rescue, without much in the way of a history. And my mare was often put in his stall during the day, until the owner did a fecal and it was high. (My mare was living outside, but her paddock was needed for turnout for the stalled horses during the day. Normally I’m not too bothered about horses occasionally using other horses’ stalls, but in this case… ugh.)

[Texarkana]

@leheath

Having just had a very unhappy horse due to a stomach full of bot fly larvae (which don’t show on FEC) and associated ulcers they either caused or exacerbated (plus associated very expensive vet bills), yes you absolutely should if you live in an area where they are a problem. They are not detectable by FEC. I’m now in southern CA, where we don’t have problems with bot flies, so I worry about this less now (horse came from a region where bot flies are common), but I will still treat at least once a year for tapeworms.

Right, but that’s not really my question. I should have been more clear.

Macrocyclic lactones like ivermectin and moxidectin are one of our last classes of dewormer with any effectiveness against cyathostomins, and our only class with effectiveness against bots.

Recent best practices adopted by veterinarians recommend still using a macrocyclic lactone 1x or 2x a year for bots “to be safe.” Yet the British study cites indescriminate use of macrocyclic lactones, especially moxidectin, as a major red flag. So my question are: is using a macrocyclic lactone 1x or 2x a year the most current best practice, or is that 1x or 2x a year contributing to our resistance problems?

I would hope limiting their use to 1x or 2x a year would allow enough refugia to persist to minimize resistance, but I don’t know what the most current data says.

Bots can wreack a lot of havock. I’m glad your horse’s problem wasn’t worse!

[JB]

@Texarkana

So my question are: is using a macrocyclic lactone 1x or 2x a year the most current best practice, or is that 1x or 2x a year contributing to our resistance problems?

I think it just depends on where you are. Some places just don’t have much in the way of bugs - dry desert-like areas. For those, and especially if you have zero grass (tapeworms), then maybe 1x a year with Quest Plus is all you need. Or heck, maybe only every 18 months if bugs really aren’t an issue. Gnats bring neck threadworms, grass brings tapeworms, botflies bring bot larva

@Texarkana

I would hope limiting their use to 1x or 2x a year would allow enough refugia to persist to minimize resistance, but I don’t know what the most current data says.

I would hope as well, and TBH I haven’t seen any newer research suggesting otherwise. Does that mean it’s not starting? No. I hope it’s a long ways away.

[leheath]

Gotcha…thanks for clarifying! I’m glad we caught my horse’s problem when we did - I thought he had pyloric ulcers because he wasn’t responding the way I expected to omeprazole so had him scoped…and found the bot fly larvae.

@JB

I think it just depends on where you are. Some places just don’t have much in the way of bugs - dry desert-like areas. For those, and especially if you have zero grass (tapeworms), then maybe 1x a year with Quest Plus is all you need. Or heck, maybe only every 18 months if bugs really aren’t an issue. Gnats bring neck threadworms, grass brings tapeworms, botflies bring bot larva

I agree - there is just no one-size-fits-all worming plan - each horse owner has to make their own decisions, but it would be a whole lot easier if up-to-date, accurate information was available from the people we are supposed to trust with our horse’s medical decisions (vets).

[Ghazzu]

@leheath

it would be a whole lot easier if up-to-date, accurate information was available from the people we are supposed to trust with our horse’s medical decisions (vets).

Not that I’m condoning it, but I wonder if the “lack of interest” on the part of DVMs wrt newer deworming protocols is at least partly due to the fact that they’re all OTC drugs now, so the DVM is somewhat out of the loop.

[leheath]

@Ghazzu

Not that I’m condoning it, but I wonder if the “lack of interest” on the part of DVMs wrt newer deworming protocols is at least partly due to the fact that they’re all OTC drugs now, so the DVM is somewhat out of the loop.

I guess that’s a possibility, although they could still be pushing for FECs…

[Ghazzu]

@leheath

I guess that’s a possibility, although they could still be pushing for FECs…

True, but I’m guessing a lot of clients would see that as just another attempt to lighten their wallets.

[trubandloki]

@Ghazzu

@leheath

I guess that’s a possibility, although they could still be pushing for FECs…

True, but I’m guessing a lot of clients would see that as just another attempt to lighten their wallets.

I do believe we have had threads here that have said exactly that.
Sometimes the poor vets can not win.

[leheath]

[quote=“trubandloki, post:49, topic:758671, full:true”]

@Ghazzu

@leheath

I guess that’s a possibility, although they could still be pushing for FECs…
[/quote]

True, but I’m guessing a lot of clients would see that as just another attempt to lighten their wallets.

I do believe we have had threads here that have said exactly that.
Sometimes the poor vets can not win.

Oh I totally agree - they are in a tough spot. In my ideal world, vets would be educated in reasonably up-to-date information regarding worming, offer the FEC service, and mention the DIY FEC service so clients can make informed decisions. Sadly, I doubt my ideal world matches very often with reality!

[Pippigirl]

Are DIY FEC only available in the US?

[Texarkana]

@Pippigirl

Are DIY FEC only available in the US?

I don’t know the answer re: mail in services. But it’s very easy to learn how to do your own FECs and not particularly expensive. Depending on how many horses you own, it will pay for itself.

[Pippigirl]

How did you teach yourself? Did you buy a basic kiddie microscope?

[Simkie]

@Pippigirl

Did you buy a basic kiddie microscope?

You can get a pretty nice microscope for a couple hundred bucks. Not sure a toy would do it for you.

There are great resources out there online that walk you through how to set it up and what eggs look like.

[Texarkana]

@Pippigirl

How did you teach yourself? Did you buy a basic kiddie microscope?

You need a little better than a kiddie microscope, but any basic microscope with 100x capabilities (a 10x objective + 10x eyepiece) will do the trick. You can buy a very simple student microscope for less than $100 that will work, although for about $200-300 you can get one that is more comfortable to use and rivals the quality you would find in any veterinary lab. You will also need a McMaster slide, but that is a small investment-- around $20.

I had a leg up because I used to work in veterinary medicine and learned though my job, but there are TONS of resources online to help you. It’s very big in the goat raising world to do your own fecal egg counts, and while the species of worms that infect horses v. goats are slightly different, the technique is identical and the eggs look similar enough to use their resources.

This website sells kits and provides support. I think their prices are a bit high, but having support is beneficial to anyone who may be intimidated: https://www.eggzamin.com/

[Pippigirl]

Thank you and Simkie for the information!