How would you interpret these instructions?

[danacat]

My horse with CVID is doing well but he’s not handling worms like a normal horse would. His fecal count for strongyles was 235 (low shedder) 60 days ago but that has shot up to 1275. Typical and frustrating issue with CVID horses.

Can’t use Quest due to high worm burden and because his BCS is a 2 (if you just score his top line which is skeletal) so not enough body fat.

Vet has recommended a Panacur Power Pac: These are her instructions: Double dose (foal and Larvicidal dose) for 5 days.

Looking at the dosing syringe the foal and larvicidal amounts are more per pound than the standard adult dose, but doubling it means that I will be giving him the same amount that a big draft horse would get – in one shot for 5 days – which is kind of freaking me out.

Am I reading her instructions correctly? Of course it’s the weekend and I doubt I’ll be able to get in touch with her to clarify, but what she said does seem pretty clear – yes?

She initially did prescribe Quest Plus and I had to remind her that my horse is too thin to safely use it, and that impaction colic is a real possiblility due to the massive worm die off Quest could cause. Because of my having to remind her of my horse’s fragile condition I don’t think I’m wrong in being wary of this double dose idea…

… so I’m wondering how dangerous Panacur Power Pac is at high doses.

Thoughts? Experience with this wormer? I’ve never used it before.

[Simkie]

The issue with quest and thin horses isn’t a die off–it’s an overdose of the drug because there’s not enough body fat to absorb it.

Panacur is so safe. It’s really pretty impossible to overdose. I hear your concerns, especially with this guy who is fragile, and you should 100% discuss with your team if you have worries.

But you’re not really even targeting encysteds here, right? They don’t show on a fecal. You’re targeting just straight up active strongyles. I’m not sure how that changes your approach, given your horse’s diagnosis, but it’s maybe worth the question?

[Montanas_Girl]

@danacat

Looking at the dosing syringe the foal and larvicidal amounts are less per pound than the standard adult dose,

I don’t think you are reading the package label correctly. The foal dose of fenbendazole is twice that of adult horse, as far as mg of drug per lb. of body weight goes.

ETA: I’m also surprised your vet recommended fenbendazole rather than ivermectin to treat small strongyles in an adult horse. Have you performed a FECRT to confirm that fenbendazole is effective in your herd? The last research I saw on the subjected indicated an estimated 95% resistance rate in this country.

[danacat]

Not targeting encysteds. Just active. Happy to hear Panacur is safe.

[danacat]

Yes – I mistakenly typed less per lb. instead of more. Thanks for catching that! We used Ivermectrin the last two wormings. And my vet did mention that the Panacur is not as effective as Quest, but we can’t use Quest on this horse.

[Montanas_Girl]

Using ivermectin twice in the recent past does not mean you need to use a different drug now, as long as his FEC did reduce sufficiently following deworming. I can’t quite understand your vet’s logic in recommending a less effective drug if the one you’ve been using has been working well. If you do use fenbendazole this time, I’d for sure want to do a FECRT to know if it did any good at all.

[Disclaimer: I am not a vet.]

[danacat]

I can’t understand logic either. The Ivermectin reduced fecal count from 700 (high shedder) back in March to 235 (low shedder) in June fecal. Maybe this recent extreme jump to 1275 along with his diagnosis of CVID prompted her to switch wormers. CVID is tricky when it comes to worms.

I contacted the CVID specialist at Cornell who diagnosed my horse (through bloodtest and review of his history) and asked her about best worming protocol – haven’t heard back from her.

[Montanas_Girl]

Good luck with your guy! Hopefully the specialist will get back to you and provide some clarity.

[JB]

@danacat

235 (low shedder)

technically moderate, but close enough to 200 to consider it low

@danacat

Can’t use Quest due to high worm burden and because his BCS is a 2

1275 isn’t too high for moxidectin at all, but BCS 2 is definitely a no-go. Moxidectin works a bit slowly over time, so unless you’ve got an enormously high count, an impaction at this level is highly unlikely. i wouldn’t have a problem with Quest with a 3000 FEC

@danacat

Vet has recommended a Panacur Power Pac: These are her instructions: Double dose (foal and Larvicidal dose) for 5 days.

The odds of fenbendazole being effective on strongyles is fairly low. Ivermectin would be much more useful.

That said, you wouldn’t need a whole PP for this, just a single dose of fenbendazole. Then in 10-14 days you NEED to do another FEC to see what the reduction was. If it was high enough (90% or more) then great, it’s effective on your farm and it’s a non-macrocyclic lactone option for an extra deworming if someone needs it. If not, try Strongid 9pyramten pamoate) and do the same - FEC in 10-14 days to see if it was effective enough. If so, great. If not, then you cannot use either of those on your farm, you’re left with moi/ivermectin

@danacat

Looking at the dosing syringe the foal and larvicidal amounts are more per pound than the standard adult dose, but doubling it means that I will be giving him the same amount that a big draft horse would get – in one shot for 5 days – which is kind of freaking me out.

100% safe (as safe as any dewormer is). That’s simply the amount needed, for the days needed, for encysted strongyles. It is not needed for adult strongyles. And a single double-dose is all that’s needed for ascarids.

[danacat]

Interestingly, when same vet sent me the FEC results in June (235 count) she recommended worming with Equimax in August.

So we’ve gone from Equimax to using Quest Plus (I said no) to Panacur Power Pac. No mention of using Ivermectin again even though he responded well to it with good reduction. I’m kind of disppointed in this vet being all over the place and somewhat off-hand about it – no clear explanations as to ‘why’ she recommends a particular wormer.

I think I’m just going to go with Ivermectin. Certainly my boy isn’t going to die from worms. With CVID it will be an infection like meningitis that will turn the tide.

[JB]

@danacat

Interestingly, when same vet sent me the FEC results in June (235 count) she recommended worming with Equimax in August.

Where are you? Generally, you deworm in Fall after the horse comes off grass or the grass is on its way to becoming fairly dormant, or about 6 months after the Spring deworming if you don’t get that grass transition. For some, August IS when grass is pretty toast, but not for most of the country

@danacat

So we’ve gone from Equimax to using Quest Plus (I said no) to Panacur Power Pac. No mention of using Ivermectin again even though he responded well to it with good reduction. I’m kind of disppointed in this vet being all over the place and somewhat off-hand about it – no clear explanations as to ‘why’ she recommends a particular wormer.

I was just having a conversation about this and nutrition in another group. Vets in general are not well-versed on either of these topics, though parasite control seems to be a bit better understood. So, your experience doesn’t surprise me

Ivermectin is a reasonable approach, unless you really want to go through the task of figuring out of either fen or pyrantel are effective on your farm. If there are enough other horses there it might be worth it

[danacat]

Since my horse has CVID his immune system isn’t able to ‘process’ (for lack of a better word) worms like a normal horse can, thus more frequent worming and FEC’s are advised – regular worm schedule (fall etc.) does not apply.

[JB]

@danacat

more frequent worming and FEC’s are advised – regular worm schedule (fall etc.) does not apply.

you still follow the same protocols though. FEC in late Winter and late Summer to see how the horse faired over Winter and Summer, but deworm anyway to target bots and tapeworms. After the egg reappearance period (ERP) for the drug used, FEC again for the moderate and high shedder to see if he needs to be dewormed again

For those who pove they’re a moderate or high shedder, then you can regularly do a 3rd and 4th deworming, respectively, and re-check status every couple of years to see if things change

A single or even a couple of moderate or high FECs doesn’t mean he’s always that, as seen here with his 235.

[danacat]

No, with CVID you don’t follow the same worming protocols as with normal horses. Here are a few snippets from an article that Cornell sent me when they diagnosed my horse:

"The most common clinical presentations in horses diagnosed with CVID were recurrent upper and/or lower respiratory infections, meningitis and/or ataxia, cholangiohepatitis, infectious colitis, infec- tious dermatitis and severe gastrointestinal parasitism…

…enteritis and intestinal nematodiasis; evidence of parasite migration in the liver and lungs. Frequent deworming was used based on faecal flotation test results."

Other case studies of individual horses with CVID revealed that fecals were done every two months – horses wormed accordingly.

The reason my horse was at 235 on 6/5 was because I had just wormed him in April due to a fecal that was 700 for strongyles. However, in just two months, his fecal jumped from 235 to over 1200 for strongyles.

[JB]

I think you missed the intent of my comment. Just because he’s currently struggling doesn’t mean he always will be. Currently, he does need more deworming. That doesn’t mean he always will. So keep doing FECs here and there to check on things. Situations change. I never said he only needs Spring and Fall deworming.

In his case, I absolutely would do some FECRTs to see if either fenbendazole (start there since it’s the most likely to be the least effective) or pyrantel pamoate are effective enough on your farm. It’s a very good idea to see if there’s a non-macrocyclic lactone you can use. If you use ivermectin every 2 months, you’re likely going to cause some resistance issues sooner rather than later. If you could use moxidectin, it would at least slow that down, but since you can’t, you’re left with ivermectin unless you can prove one of the others work.

[Simkie]

@JB

Currently, he does need more deworming. That doesn’t mean he always will.

This horse has an immune deficiency. Yes, that means he will always need more deworming.

Our current research on CVID in horses

[JB]

More frequent deworming may be necessary to control gastro-intestinal parasites.
(bold is mine)

Clinical management of immunodeficient patients

Please understand I have never said “always” or “never”. The entirety fo the immune system isn’t that black and white.

I’ve said “may” as does that article. THIS horse may always need 4 or more dewormings a year.

[danacat]

Purely for informational purposes:

The entirety to my horse’s immune system is black and white – CVID horses don’t just have an immunity deficit like horses that didn’t get enough colostrum when they were foals for example.

CVID is a gene defect – doesn’t get better or wax and wane, nor is it treatable. In affected horses, serum IgG concentrations are often below 800 mg/dL with > 1000 being protective. My horses is currently at 400 and eventually his IgG will fall below detectable ranges.

All I can do now is keep him happy and comfortable and not riddled with worms until such time as putting him down becomes a reality.

[NaturallyHappy]

I’m so, so sorry. That must be heartbreaking and so incredibly difficult. Thank you for teaching us about something new…to me, anyway.

[danacat]

It was new to me too – to most people infact. It’s very rare.