The Truth About the "Pea Sized Blob" of Horse Paste De-Wormer

Okay, so how did this misinformation start? I see it everywhere, including a book, and some people say to use this "blob" for all types of de-worming pastes. So far I've seen it suggested for Safeguard and Panacur, Ivermectin, Zimectrin Gold, and Moxitectin. The only one I haven't seen is suggested for is pastes containing pyrantel pamoate (Strongid, Exodus, etc.).

How big is a pea sized amount?

From left to right:
Small = 10 ml = 10 mg
Medium = 25 ml = 25 mg
Large = 50 ml = 50 mg


From left to right:
Small = 0.1 ml = 1.87 mg ivermectin
Medium = 0.25 ml = 4.675 mg ivermectin
Large = 0.5 ml = 9.35 mg ivermectin
The blob above the grain of rice is 0.025 ml (0.4675 mg ivermectin)

Moxidectin Paste

Using the pictures posted in the previous post as a reference:

Small = 10 ml = 2 mg moxidectin
Medium = 25 ml = 5 mg moxidectin
Large = 50 ml = 10 mg moxidectin




QUEST GEL
Zoetis
(moxidectin)
NADA 141-087, Approved by FDA (for horses)
2% Equine Oral Gel
Contains 20 mg moxidectin/mL (2.0% w/v)

-Kathy

This was a question I had! I was reading up on gapeworms just in case my girl has that instead of a plain old respiratory ailment... I didn't see the goat liquid option in my local, but the horse paste was there. However...'pea-sized' amount seems like it could vary WIDELY. a mL amount is much more helpful. Thanks for posting!!

hooktontravel said:

This was a question I had! I was reading up on gapeworms just in case my girl has that instead of a plain old respiratory ailment... I didn't see the goat liquid option in my local, but the horse paste was there. However...'pea-sized' amount seems like it could vary WIDELY. a mL amount is much more helpful. Thanks for posting!!

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This is what this book recommends for gapes:

So that would be 0.14 ml (paste or liquid) per pound for 5 consecutive days


This is what many vets prescribe:


The above is for liquid or paste.

The use of the "pea sized" blob is extremely dangerous. It can be dangerous because it can vary in size 5-fold or more. It can be dangerous because you might underdose a medication that is critical to your animal. Or it might be dangerous because you might overdose a medication, causing side effects or even death. Even though most deworming medication has a fairly wide safety margin, I have seen severe side effects in about 25% of chickens when they were accidentally given 20 mg/lb (instead of 20 mg/kg) of Panacur for 5 days. Of those affected, about 40% of those died!

But it's not just the blob-size variability. There's a separate issue that might be even more important. These medications are made for a 1000 pound animal. Because they are made to be used in relatively large volumes, they aren't always mixed thoroughly enough to accurately predict the amount of medicine in a tiny volume.

Think of this like cooking. When I was a young girl I was "helping" my aunt bake a coffee cake. The recipe called for 1/4 teaspoon of vanilla to be mixed into a large amount of cake mix. I asked how such a small amount of vanilla could distribute into every drop of batter. My aunt said that it had to be mixed well enough to be sure that there was some vanilla in every bite, but that it didn't need to be mixed so thoroughly that there would be vanilla in every crumb. When we took a bite, we would taste the vanilla within that bite, even if there were a few crumbs that didn't have it thoroughly mixed in. That's why you just need to spend a few minutes mixing cake mix with a fork, not an hour mixing it with a blender on puree speed.

So applying that to medicated paste intended for large animals, the paste is mixed adequately such that there is a known amount of medicine in a horse-sized volume, comparable to a bite sized piece of coffee cake in the above example. However, it may not be mixed well enough to have a know amount of medicine in a bird-sized volume, comparable to the tiny crumb of coffee cake in the above example. Some pasty "crumbs" may have a high amount of medicine, some may have a low amount of medicine, and some may have no medication. When I lived in SC and GA years ago, several people I knew with large hunting dog packs wanted to economize on heartworm prevention. Instead of buying the appropriate heartworm prevention made for dogs, they did the math and gave the ivermectin horse paste to their dogs. Every month most of their dogs got enough medication, but some months a dog wouldn't get enough or any medication with their paste, and would get the parasite. The cost of treating just one dog for heartworms is more that it would cost to prevent the disease in 30 dogs for a year, so people quickly found out that it wasn't worth the risk. Theoretically, yes, it should work. But sometimes the practical details outrank theory.

Liquid medication made for large animals, either solution or suspension that is very thoroughly shaken, is a different story. Those medications should be adequately mixed to measure down to a chicken-appropriate volume.

I'm sorry, but where do you come up with this theory about a lack of mixing in commercial horse vermifuge? Any company that would produce such a thing would go out of business faster than Donald Trump! Not to mention the regulatory problems and veterinarians who would drive any outfit producing such a product over a cliff, PDQ.

With all due respect, barring you providing some kind, or even any, actual evidence for what you say above, I will disregard your anecdotal and quite likely misleading observations.

edit: I forgot to again thank you casportpony for your diligent efforts at making deworming our birds so much less of a daunting task. Your math is spot on and advice worth it's weight in Zimectrin Gold! (Called Eqvalan Gold up here on the northern fringes of the civilized world)

Northern Flights, you are certainly free to disregard logic all you like. However, the manufacturer does not label these products for chickens, or dogs, or even small ruminants. They are only labeled for very large animals. And they work great for the species that they are labeled for, and off label for others of similar size. Therefore, there is no risk that they will be driven out of business, or that there will be regulatory problems. There is no regulation that a medication has to be appropriately mixed for an animal that it is not intended to treat. My "actual evidence" comes from the information received from the veterinarians that work in the technical support departments at the manufacturing companies. The information received from them has been consistent when these "adverse events" have been reported. My anecdotal experience may not be scientific proof, but it involved more than 50 animals that had to be treated for heartworms over the years while taking these products. Most reasonable people do learn from experience.

I apologize since I know this is an old thread, but since others have revived it...

I see what @Sydney Acres is saying. My problem with the theory is that it's not like someone is individually making each syringe and forgetting to stir it. They're made in large quantity and they have to insure that each syringe is identical, unless the whole solution was well mixed then you would get syringes that are each different. This is quality control.

It's also worth pointing out that while a full grown horse will get a whole tube, ponies, mini's, yearlings, etc are only getting partial tubes. That's why there are weight markers. So I do believe that paste for equines is well mixed.

RumneyRoost said:

I apologize since I know this is an old thread, but since others have revived it...

I see what @Sydney Acres is saying. My problem with the theory is that it's not like someone is individually making each syringe and forgetting to stir it. They're made in large quantity and they have to insure that each syringe is identical, unless the whole solution was well mixed then you would get syringes that are each different. This is quality control.

It's also worth pointing out that while a full grown horse will get a whole tube, ponies, mini's, yearlings, etc are only getting partial tubes. That's why there are weight markers. So I do believe that paste for equines is well mixed.

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Sydney Acres, my apologies if I have insulted you, but I believe it is very important not to mince words on the subject of animal health.

Thank your considered and wise comment RumneyRoost. Fortunately we don't have to "believe" that these anthelmintics are therapeutic, even "unmixed" and as dispensed in small doses from the same tube. Happily all these products are tightly and strictly regulated in myriad ways, which for me carries vastly more weight than any unsupported, unattributed and quite frankly unhelpful observations at a website. Alone your common sense reasoning about the size of the batches and the regular inclusion on the syringe of a dosage limiter of some kind is elegant and convincing. I wish I were clever enough to have thought of it myself.

In a world seemingly swimming in disinformation, there is still veterinary medicine—which is fortunately and by its very nature firmly rooted in reality. I may not have access to 50+ vets and hundreds of vet techs, but the two I do know just about coughed up a lung when I mentioned this poor mixing hypothesis. Yes, I went out of my way to ask about it, because it concerned me quite a lot. Very wrongly I must add. It is the very reason I originally responded so firmly.

I will closely paraphrase one vet's comment: "Deworming is already a tricky prospect for far too many (me included) and treatment is often ignored out of misplaced fear and anxiety—much to the cost of the infected animal. Adding ill-informed speculation about product safety is at best unhelpful and at worst ...

I'll stop there. I think I have said enough.