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Double dosing dewormers?

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    07-07-2011, 11:19 AM

I currently only deworm my horses twice per year. So he might not be due.
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    07-07-2011, 11:24 AM
Yes, MTG.

If he isn't wormy, then I really don't know what's going on.. He has been losing quite a bit of weight lately and he's still being fed the same amount. He gets 2 flakes of hay in the morning with a scoop of high-fat-high-fiber and a cup of beet pulp that has been soaked, and he gets that twice a day.
    07-07-2011, 11:38 AM
I would start with taking a fecal sample to to your vet.
    07-07-2011, 12:32 PM
I agree, a simple fecal sample would help and also a routine de-worming program that suits your location. It would keep you less confused by taking more of the guessing game out of "when" to use "what".

On the double dose note, it really depends "what" this previous owner double dosed with. It is certainly not as scary as it sounds (although, could be horribly mis-used I suppose) we give in-coming horses a three day double dose of safeguard and one tube of Ivermectrin three weeks later before droping them in with the herd. The rest of the herd is fecal tested twice yearly and de-wormed according to a schedule that I've had success with over the years.

Also, a handful of years back I had a Miniature gelding who was 29" tall and 250 pounds soaking wet. The plunger broke and he ended up with 1200 pounds of Zimectrin Gold. NOT recommended and boy was I in panic calling the vet at that time however he had no issues.
    07-07-2011, 01:01 PM
Originally Posted by New_image    
On the double dose note, it really depends "what" this previous owner double dosed with. It is certainly not as scary as it sounds
It certainly is! Unless a vet is consulted, double dosing is dangerous. And doing it again two weeks later is idiotic!!

Anyone ever consider that aside from the danger from the drug itself, that huge doses like that in such a short time can cause a quick die off of any worms present and colic the horse.

we give in-coming horses a three day double dose of safeguard and one tube of Ivermectrin three weeks later before droping them in with the herd.
I would not allow that done to my horses, and would want a statement from your vet stating his/her reccomendation for such a regimen and the reasons why.

Even then, I would likely opt out of having my horses dosed with 6 doses of ANY wormer in three days....

The way some of you are downplaying such extreme overuse of wormers makes me wonder if you are in the Twilight Zone.

PEOPLE WHO DO THIS ARE A BIG PART OF THE REASON WHY THESE WORMERS ARE LOSING THEIR EFFECTIVENESS..... overuse of the wormers are breeding resistance in the worms.

WISE UP..... Use them when you KNOW you need them (fecal egg count) not because you have a worm phobia!!!
    07-07-2011, 01:08 PM
That was worded wrong. I am by no means promoting blind double dosing whatever you'd like. Hence the suggestion for a fecal and a schedule. However there is a reason Safeguard sells FIVE day DOUBLE dose pacs. If this former owner double dosed with Safeguard then doubled again two weeks later, that's a really odd way to do it but not 'scary' considering they sell packs to double up for five days in a row.
    07-07-2011, 01:14 PM
Beau, double dosing of most deworming products it truly not dangerous. Some of them have the ability to be given in huge doses compared to what they are in those tubes with out any ill affect to the animal.

And giving higher doses close together is a good way to take care of some issues that can not be dealt with any other way. It is not idiotic at all.

Under dosing is far more likely to lead to resistance issues than over dosing.
    07-07-2011, 01:20 PM
Green Broke
Originally Posted by Alwaysbehind    
Under dosing is far more likely to lead to resistance issues than over dosing.
^^ THIS. Over-dosing of de-wormer does not cause resistance, under-dosing does.
    07-07-2011, 01:56 PM
Originally Posted by Indyhorse    
^^ THIS. Over-dosing of de-wormer does not cause resistance, under-dosing does.

That is a not true.

Worms are building up resistance for the same reason bacteria are building up resistance to antibiotics.....OVERUSE!!!!!!!!!

You might want to do some reading on this topic so you can be better informed.

Suggested reading:
In January 2010 the British vetinary association issued new guidelines which called for "the immediate cessation of blanket worming in all grazing animals, including horses. This is because of increasing drug resistance of the worms caused by overuse of wormer chemicals. Each time a wormer is used it increases the chance of the worms developing resistance against the wormer. There are no new wormers being made, we need to change to "targeted worming"
80% of the worm burden is usually found in 20% of the horses. This means the 80% are being wormed unecessarly, ingesting strong chemicals,wasting money and increasing the chance of resistance to wormers.

Worming - cobswallop

How bad is parasite resistance in horses today?
  • Entire classes of equine dewormers no longer work well against small strongyles.1,2,4,5
  • Small strongyles — the major target of parasite control in mature horses — have demonstrated widespread resistance to two of the three major dewormer classes (benzimidazole and pyrantel products).1,2,4,5
  • While products in the third class (macrocyclic lactones) still control small strongyles,2,3,6 resistance could develop from overuse.7,8,9,10

Parasite Resistance

Parasite resistance to equine dewormers

Drug resistance occurs by overexposing a pathogen to a medication. This overexposure gives the pathogen more opportunities to find a way to avoid the effects of the medication. Evidence has been presenting itself around the world that resistance of equine parasites to
current medications is already occurring.

Parasite resistance to equine dewormers - Equiworld -Horse and Pony Informationon the internet- Text Only

My point to all of this is that double dosing should be done ONLY on a vet's reccomendation, not done by people just because their horse is losing weight, itchy tail, becaue its 6 weeks are up or has a "grass belly", etc.

Let me be plain spoken: what I see on this thread is some posters advocating and engaging in (per their statements} gross MISUSE and OVERDOSING of wormers. While this may be a medical necessity in some rare vet endorsed cases, that is not what I am seeing here. I am seeing a bunch of worm phobic people going way above the reccomended dosage thinking that they are helping their horse, when all they are doing is breeding worm resistance that may some day come back on ALL horse owners, including themselves.

FYI, our vet recommends worming be done ONLY after a fecal test is done and worms found. She DOES NOT ENDORSE the routine six week worming.... nor do alot of boarding facilities around here.

And when people like Indy horse and AB say things like's downright scary how uninformed horse owners are to this threat.

I encourage BOTH of you and all horse owners to do some research on this topic. UNDERUSE is not the cause of worm resistance. INFORM some googling.....
    07-07-2011, 02:02 PM
My vet too says to do fecals and only deworm as needed (with 2x per year no matter what fecals says).

That does not make it not a fact that under dosing of dewormer has be a cause of resistance.

Just like only taking 2/3 of your antibiotics when they are prescribed. If you are guessing your horse's weight and you give them dewormer for 1000lbs and they really weight 1500lbs you have under dosed them. This leads to the parasites developing a resistance.

Over use is different than double dosing at one time. It has a very different affect. And of course double dosing should be something you discuss with your vet first. I think that has been said many times already.

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