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Spinal Research



Worming - keep in or turn out


Posted by issyhotten on  Oct. 1, 2001

I understand that the original wormers caused the worms to be excreted live. And modern wormers actually kill the worms before they're excreted.  But if the horse eats the worms, surely they will be digested in the stomach acids (ok they can live in the gut, but not in the stomach?).

So a horse can't pick up worms from the excreted adult worms!.

And OK, maybe you don't want the local birds scoffing the worming chemicals inside the excreted worms, so that could be a good reason.  But you still muck-out onto the muckheap, so the birds can still get the chemicals?.

So why do people keep horses in after worming?.

Also some people don't exercise their horses after worming in case they get colic - this I can understand if the horse has a heavy worm burden and the little buggers all die off and start rotting in the gut at once - but with regularly, properly-wormed horses surely this isn't a problem?. OK - I wouldn't worm the day before a 3-day event, but is it necessary to keep the horse stabled for 24 or 48 hours - this could cause colic in itself.

Also, if you are worming between changing fields, it seems like a good idea to get the horse off field 1, worm it, wait for a day to make sure they're not excreting eggs and THEN turn out onto nice, clean field2.
Of course, with an unknown worming history I wouldn't ride for a couple of days - but I wouldn't want to keep the horse confined entirely to the stable either?

Ideas, Opinions welcome!. I'm quite willing to change my mind given a good enough argument!.

Posted by LizCobby on Oct. 1, 2001

I think it's because they excrete parasite eggs in their systems too. ( if they have them they come out anyway, as found in worm counts) but perhaps more than usual.
And the worms them lay eggs on the grass and so it goes on.
But if kept in, worms get put on muck heap.
(Hence reason not to use this year's muck heap for fertilising grazing land)

Checked with rep from Panacur re their 5 day Guard - he confirmed only need keep in for first 24 hours, as any excreted after that are non-viable- i.e. dead.

We time our worming to farrier's day, when they can stay in from night before to following evening. ( To make sure all caught and in with clean feet, whatever time he gets there)

 Posted by issyhotten 

But the eggs were put on the pasture the day before worming anyway?

Posted by JanetGeorge on 5:47 pm on Oct. 1, 2001

I think the reason is eggs - rather than the worms themselves.  Although most wormers will kill the worms, they do not kill all the eggs which would then be re-ingested and re-infect the horse

There is also the risk of dogs eating the dung of horses treated with Ivermectin (I think???) that is, I think it's Ivermectin that is lethal to dogs, but I stand to be corrected (the old memory is NOT doing too well today.)

I would agree re exercise.  I would tend to worm after exercise, the day before a rest day for choice, because IF the horse has a heavy infestation, you can get colic as a result of the wormer.

Posted by cervine 

yes, Ivermectin kills collies and collie crosses, and has been known to cause fatalities in other breeds. Don't let Woofums lick the worming syringe!

Posted by WelshFox

I didn't know that some horse wormers can be lethal to dogs!  You really do learn something new every day.

I'll put a notice up at the yard as there are a number of dogs that run around all the time.  Maybe they shouldn't be allowed to run loose when the horses are wormed.

Posted by Ros B 

We wormed Sadie when she arrived, of course - the five day one, and Chrissie told me to make sure that she didn't sweat up during those five days because the rise in body temperature would make the wormer less effective..... which would explain the 'no exercise' bit?

Posted by sunflower 

I used to be on a yard where the horse had to stay in for 48hrs after worming, which I hated doing as it was such a drastic change to the horses routine and diet.

Now, we worm and then turn them out into a different field the next day, clearing the old field within the next day or so.


Posted by sjm72 

The thing about not sweating is NOT relevant to worming - this is a vaccination thing!!! People do get confused - you can worm and exercise straight away if you want (within reason if it is a wormy looking bag of bones!)
You keep them in to allow any half dead worms (i.e. those that may also go on to develop resistance!) and eggs passed out to be passed out into the bedding so you can pick it up and put it on the muck heap - which is why you should never fertilise horse fields with horse muck - although if it is a correctly built muck heap or muck midden where you compact it down daily and keep it square it should get hot enough in the middle to 'cook' any parasites! The wormer will cause more eggs and worms to come out that would normally pass out.
We worm after a morning turnout (i.e. lunchtime) and then keep the horses in for two nights and let them out after exercise on the third day - so there is only one day when they are actually not turned out - but they are exercised.


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