Deworrners and horse weight- How many pay attention?

[kcmel]

[QUOTE=Mosey_2003;8277437]
I always overdosed ivermectin and fenbendazole. Never Quest, I tried to be within 100lbs when using Quest. But, on my stock horses I had that were both 900lbs or less, they always got the full 1,200lb tube. The pony I deworm for my friend gets 600lbs worth usually. My big guy got a tube and a half (the other half convenient for the pony ;)) I’d rather overdose than under, but I won’t personally give anything smaller than a small horse Quest. It makes me nervous.[/QUOTE]

When I first got my draft x his fecal count was really high. I gave him 1 tube of Quest, which seemed right based on his weight tape. 10 weeks later his fecal count was just as high. My vet looked at the horse and thought he probably was between 1300-1400 lbs. So I gave him 1.5 tubes of Quest and his next fecal was clean. My point being you have to be careful about under-dosing with Quest, as well as over-dosing.

[JB]

No wormer - absolutely none of them - should ever be under-dosed.

I makes me utterly insane to hear vets!!! telling clients to use half doses of any chemical “to kill things slowly”

::headdesk::

[Mosey_2003]

[QUOTE=kcmel;8278850]

<snip>
My point being you have to be careful about under-dosing with Quest, as well as over-dosing.[/QUOTE]
Very true. I never purposely under-dosed, I dosed to the weight tape. What I meant/should have said clearly was that I was careful to never over-dose Quest

[Simkie]

Keep in mind that the margin of safety with moxidectin is smaller than with other wormers, but it’s still pretty broad:

http://www.fda.gov/AnimalVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/ucm117065.htm

No problems giving adult horses 3x a normal dose. Guessing high by a few hundred pounds when dosing with Quest isn’t going to be a problem for your average 1100-1200 ish pound critter. More care is warranted with foals or little horses…

[merrygoround]

[QUOTE=Texarkana;8278176]
I’ve been very polite in this discussion. Everyone in disagreement has been very polite. Perhaps you should follow suit?

If you don’t get it, you don’t get it. You’re not the only one. Which is part of the reason we have resistance and tolerance issues across the board-- with anthelmintics, antibiotics, antiprotozoals, antifungals… it’s hard to shake the notion that “more” does not always equate to “better for the long term.”[/QUOTE]

I would be very interested in reading any peer reviewed scientific studies in support of your statement that overdosing creates resistance.

[Texarkana]

[QUOTE=merrygoround;8279049]
I would be very interested in reading any peer reviewed scientific studies in support of your statement that overdosing creates resistance.[/QUOTE]

They cite this guy a whole lot.

In all seriousness, it’s just natural selection. By giving a higher dose, you create selective pressure that is going to allow the individuals resistant to the higher dose to continue to reproduce. Since they are the only ones remaining, they are going to have a more significant impact on the population over time than if they were just a small percentage of the original population.

There are literally millions of studies on this phenomenon in antibiotics and the creation of “superbugs.” While the organism is different, the evolutionary mechanisms are along the same lines. Any time we use a drug to kill organisms, there is the potential for resistance to develop over time. That’s why it’s so important to use them correctly and only when needed.

[kcmel]

[QUOTE=Simkie;8279042]
Keep in mind that the margin of safety with moxidectin is smaller than with other wormers, but it’s still pretty broad:

http://www.fda.gov/AnimalVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/ucm117065.htm

No problems giving adult horses 3x a normal dose. Guessing high by a few hundred pounds when dosing with Quest isn’t going to be a problem for your average 1100-1200 ish pound critter. More care is warranted with foals or little horses…[/QUOTE]

Yes, that is what I learned from my experience. My vet said 2x dosing of Quest is safe.

[AKB]

Texarkana, I also would like to see something from the scientific literature. In children with ear infections for example, antibiotic amoxicillin dosing recommendations are now for an increased dose, in order to prevent resistance.

Sometimes it is hard to know if all of the wormer is swallowed, or how much is left on the lips or tongue. I would rather weigh my horses on a scale periodically and then give an extra 100lbs of wormer over the recommended dose, to be sure they got enough.

[merrygoround]

Sorry your line of reasoning is fallacious.

The correct antibiotic used in significant doses for the correct length of time for the correct reason will not even in the case of overdose cause resistance. Deworrmers are the same.

I am gone.

[Texarkana]

[QUOTE=AKB;8279178]
Texarkana, I also would like to see something from the scientific literature. In children with ear infections for example, antibiotic amoxicillin dosing recommendations are now for an increased dose, in order to prevent resistance.

Sometimes it is hard to know if all of the wormer is swallowed, or how much is left on the lips or tongue. I would rather weigh my horses on a scale periodically and then give an extra 100lbs of wormer over the recommended dose, to be sure they got enough.[/QUOTE]

Be careful with your wording. Doses are increased to address the current population of resistant bacteria, to prevent them from establishing a “foothold” so to speak. Increasing the dose does not necessarily stop the potential for resistance over time. Organisms are constantly adapting.

I do the exact same thing as you with dewormer. I just made the mistake of pointing out that dosing too high over the measured weight is not a good idea if we all want to preserve anthelmintic effectiveness in the long term.

I am also done. I’m clearly not communicating well. You win some you lose some. :lol:

[Mosey_2003]

I’m a little confused as well.

If those superbugs that aren’t being killed with, say, the 1.5 dose (which I don’t dispute) are sticking around and reproducing, those same ones would still be present after the appropriate dose, no? Obviously, if they can withstand 1.5x, they can withstand 1x. If that stands to reason, it would seem not to matter whether they survived 1x or 1.5x, as they will survive and reproduce anyway. Is this where I’m wrong?

[Texarkana]

[QUOTE=Mosey_2003;8279243]
I’m a little confused as well.

If those superbugs that aren’t being killed with, say, the 1.5 dose (which I don’t dispute) are sticking around and reproducing, those same ones would still be present after the appropriate dose, no? Obviously, if they can withstand 1.5x, they can withstand 1x. If that stands to reason, it would seem not to matter whether they survived 1x or 1.5x, as they will survive and reproduce anyway. Is this where I’m wrong?[/QUOTE]

You’re not wrong. And I think your confusion is the same as everyone else’s.

It’s about selective pressure. Yes, those bugs would be there either way. But they would be a smaller percentage of the remaining population at 1x the dose. It would take a longer period of time (maybe never) for them to significantly impact the breeding population.

But when only those bugs that survive the higher dose remain to reproduce, if the conditions are right (like in the case of parasites where we have extremely high resistance), they are going to reproduce their ability to survive that higher dose. There is to potential to create a little “breeding farm” for those more resistant bugs. You will end up with an increasing percentage of bugs who can withstand the higher dose over many generations.

But I really am done now. I have derailed the original conversation so badly by this point, it’s completely moot. :lol: The take away message is to use your dewormer correctly, which I think we can all agree with.

[Mosey_2003]

OH!

So, what you’re saying, is that it is beneficial to leave the bugs that could survive 1x, but NOT 1.5x, because then they would be breeding with the superbugs, and thus slowing down the superbugs’ world domination?

[Texarkana]

[QUOTE=Mosey_2003;8279291]
OH!

So, what you’re saying, is that it is beneficial to leave the bugs that could survive 1x, but NOT 1.5x, because then they would be breeding with the superbugs, and thus slowing down the superbugs’ world domination?[/QUOTE]

:lol: All I can think of is superbugs now.

The word “beneficial” is going to get me in trouble.