My horse has been having recurrent colic episodes for the last two months. We had him scoped and treated him for ulcers with Gastrogard. He is on his last week now. I just go the FEC results and he tested positive for strongyles at 200 eggs per gram. I have been searching here. My vet doesnt seem to know much about proper deworming. Is Equimax my safest bet?
We are going to a vet specialist hospital next week Monday for further investigation via abdominal ultrasound.
Most, if not all dewormers will take care of adult strongyles. Moxidectin kills encysted small strongyles (if your horse has small and not large strongyles). A fenbendazole power pack (Panacur) will take care of encysted worms as well. Your vet should know about dewormers. What does “proper” deworming mean?
200 is right on the edge between a low and a moderate shedder. It is also the time of year when you’d be treating for strongyles and tapeworms anyway.
What you used last, and when, may impact what you do now. But assuming you have not dewormed for tapes in the last 6 months or so, and it will be a good month or more before you expect a hard freeze, then Equimax would be the best option right now. If your first hard freeze is within a few weeks, I’d wait until after that. 200 is not a dire “deworm now!” situation, but I also wouldn’t wait 2 months. The reason for the hard freeze timeline is that will kill all/most of the botflies, so you can kill whatever is in the horse without a significant reinfection risk (assuming you also make sure the eggs are off).
Fenbendazole, pyrantel pamoate, and oxibendazole are highly INeffective in single doses. They have been for many years now.
Moxidectin kills encysted small strongyles (if your horse has small and not large strongyles).
Moxidectin kills all adult strongyles, large and small, It kills all but 1 stage of encysted strongyles, but a stage that is likely to be a relatively low % of the total EL population.
A fenbendazole power pack (Panacur) will take care of encysted worms as well.
Unless you’re in a growing segment where the EL are also resistant to fenbendazole. As well, the Power Pack (5 consecutive days of double-dosing fenbendazole) kills in place, where the larva decay and cause ulcerations. This can cause colicky issues in some horses. Moxidectin is a much kinder method
Your vet should know about dewormers.
Most vets know far too little about any deworming information that’s new in the last 15+ years. Most seem to be unaware of resistance issues. Most seem to be unaware of much of anything outside of deworming every 8 weeks, and alternating each time. Too many don’t even know what chemicals kill which worms 
That would explain why my vet recommends double doses of pyrantel pamoate. Honestly I haven’t looked into resistance issues because when my mare was at a place that did regular egg counts she was always low (50-100 eggs/g) so I went ahead with whatever I knew I didn’t use last time. And that was where 70% of the horses were “dewormed” with Worm-Check, which is garlic and clove oil. I did do some research on lungworms as there were donkeys in the herds. My pony club days may be rolling in their grave over my lack of record keeping.
Apparently continuing education is dead. Which is to bad as new science is interesting.
ETA: Apparently small strongyles are showing resistance to ivermectin now too.
That will get tapeworms, but still not guaranteed to get strongyles. So just that is almost useless, as it won’t kill any bots. It’s a GREAT alternative IF it’s proven, through FECs and FECRTs, to be effective enough on a given farm, for the horses who need an extra deworming so you don’t have to use ivermectin again. But it should be proven.
Honestly I haven’t looked into resistance issues because when my mare was at a place that did regular egg counts she was always low (50-100 eggs/g) so I went ahead with whatever I knew I didn’t use last time.
But unless you’re sticking with ivermectin and moxidectin, you may have been using something that had resistance, or didn’t even target bots.
And that was where 70% of the horses were “dewormed” with Worm-Check, which is garlic and clove oil. I did do some research on lungworms as there were donkeys in the herds. My pony club days may be rolling in their grave over my lack of record keeping.
And that just proves that most horses do a pretty good job most of the time of keeping the things they can develop immunity for, in check.
Apparently continuing education is dead. Which is to bad as new science is interesting.
I don’t expect most vets to keep up with a lot of newer research on everything - they don’t have time. But this, I absolutely do expect it, because it’s not that hard to stay up on, it’s not changing rapidly, and IMHO, parasite management should be something they are on top of because it directly affects the health of their clients’ horses.
I don’t hold it against them if they don’t, because I need them for things I can’t do, much more than I need them for this (or nutrition)
ETA: Apparently small strongyles are showing resistance to ivermectin now too.
Link to a study?
The “resistance” I have seen is in the ERP, which on a few farms has gone from 8 weeks to 4. Moxidectin too, going from 12 weeks to 8.
And that’s exactly why we need to STOP over-deworming with the macrycyclic lactones. Until you need to kill bots (twice a year most places in the US), then don’t use them IF you can prove that either fenbendazole or, more likely, pyrantel pamoate is effective enough against strongyles, and then use whichever one does work well enough, when you only need to kill strongyles.
Thank you very much for your thorough replies! I will go for the Equimax.
I’m with y’all in agreeing that the vet should know more details about dewormers, but the local one does not. We don’t have access to the top vets locally. I have to drive 2 hours to really get an expert.
Ok, so the article talks about ivermectin resistance with ascarids, which I had not mentioned, slipping my mind since we weren’t talking about foals direclty. Yes, that’s been around quite a while now. It’s still very effective against strongyles and bots. Horses under 3 need regular double doses of either fenbendazole, or pyrantel pamoate, to kill insure effectively killing ascarids. By 3 or so, they develop immunity, and we don’t need to be concerned about being proactive in killing them. They will show up on a FEC, and it’s the rare horse who ends up having a problem. Usually they had poor deworming as young horses and got overloaded and damaged, or older age or illness has compromised their immune system. But they do show up, so we can kill them if they do.
I do see it’s referencing a resistance of ascarids to pyrantel pamoate, but I can’t find enough right now to see if that’s in a single dose, or a double dose, though it does appear to be pretty small pockets at the moment.
Hope this isn’t off topic for the OP but can I also ask a question?
After a lot of effort we’re finally down to a once a year de-worming program in the late fall, with one or two floats in between. My vet seems to think sticking to Quest Plus yearly will not develop resistance. But she wasn’t firm on that so do you think we should continue to rotate with ivermectin?
Also, I remember a caution regarding dung beetles. Was that a spring thing?
Thanks!
Ivermectin kills dung beetles, and since they are most active in Spring and early Summer (all else equal) I always recommend avoiding ivermectin if at all possible.
Anything used to exclusion increases the risk of resistance. The less frequent the use, the longer resistance will take. Avoiding deworming at inappropriate times will help reduce resistance risk.
Moxidectin and ivermectin are both macrocyclic lactones, with slightly different mechanism. If you ever have a FEC > 200, the higher the better, for a horse who’s been on your farm long enough, it’s worth doing FECRTs to see if fenbendazole and/or pyrantel pamoate are effective enough. If pp is (the more likely of the 2), then you could use a double dose to kill strongyles and tapeworms, but you’ll still need a yearly boticide of one of the MLs, so you can’t really avoid either of them totally.
@JB, down towards the end.
Nevertheless, there have now been several reports of reduced strongyle egg ERP after ivermectin or moxidectin administration in a number of countries (von Samson-Himmelstjerna et al., 2007, Molento et al., 2008, Lyons et al., 2009, Lyons et al., 2010, Rossano et al., 2010, Lyons et al., 2011, Lyons and Tolliver, 2013, Canever et al., 2013, Relf et al., 2014). Reduced ERP is believed to provide an early indicator of a shift in a nematode population’s sensitivity towards resistance (Sangster, 2001) and so this provides a warning as to the likely long-term effect of macrocyclic lactone compounds in horses.
Nevertheless, there have now been several reports of reduced strongyle egg ERP after ivermectin or moxidectin administration in a number of countries (von Samson-Himmelstjerna et al., 2007, Molento et al., 2008, Lyons et al., 2009, Lyons et al., 2010, Rossano et al., 2010, Lyons et al., 2011, Lyons and Tolliver, 2013, Canever et al., 2013, Relf et al., 2014). Reduced ERP is believed to provide an early indicator of a shift in a nematode population’s sensitivity towards resistance (Sangster, 2001) and so this provides a warning as to the likely long-term effect of macrocyclic lactone compounds in horses.
@JB It looks to be one main research group in the US.
Yes - reduced ERP with strongyles on some farms.
Thx for the info JB! Very helpful 
Another point to keep well in mind is the size-weight of your horse. I have seen, people, who up til then , I had considered an intelligent horse owner, give an obviously 16.3h WB, weighing close to 1600 lbs, a single tube of dewormer. It made me wonder about the rest of their horses.
Yep, most people under-estimate how much their horse weighs. Weight tapes can be as much as 200lb UNDER-reporting. These dewormers don’t have such a narrow range of safety that you can’t tack on 10-20% above what a weight tape says.
Better yet, use the calculation
https://thehorse.com/tools/adult-horse-weight-calculator/
and then add 10% to that.
BTW - I want to see a 16.3 horse who weighs 1600lb LOL Mine is 17h, not a dainty creature, and is still a bit under 1500lb.
First of all, I’m very sorry about your horse. Have you heard of liposome? More information are on http://healthcare.evonik.com/. Try it out for yourself.
Reported.
But just in case you’re actually asking about the thread - strongyles aren’t a disease, they are a worm/parasite, and they have been here forever. And no, natural ingredients does not automatically equate to safe or free you from worry.
Your vet does NOT know about proper deworming!!! Yet scoped your horse?? Any ivermectin should kill the adult strongyles but there may be other parasites that do not show on fecals and there are probably some encysted ones…I would NOT ultrasound the horse until it has been dewormed and would recommend he be examined and dewormed by the horsepital.
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