Deworming

Deworming

WORMING:
A Simple Approach to Success

Sue Reith
Carmelita Toggs
Bainbridge, WA

printed here with kind permission of Sue Reith

Jasper Farm –  We have actually experienced a resistance on our farm to Ivomec, and in most recent years have had good success with Valbazen.  We have not experienced a problem with liver fluke.  What’s so important about this article is to understand HOW to deworm effectively and WHY you do it.  Don’t get hung up on the brand/type of dewormer, other than that you need to use something that is effective for your animals.

Resistance to wormers is a ‘catch all’ term that’s very popular these days.  What’s really happening is a failure to understand the proper approach to worming.

The directions on any wormer package invariably say it wipes out ONLY the ADULT worms.  (Well, some claim to wipe out ‘4th stage larvae as well, but they’re only a day away from adulthood by then so the wormer will still be in the system to get them the next day.)

The time it takes for the average worm egg to pass thru the larval stage, and mature to lay its own eggs, is only about 14 days.  If your goats have a pretty serious worm problem and you worm them once, and then check a fecal sample a month later, you’re still going to find a bunch of worm eggs on the slide.  And it’ll be quickly determined that your goat is ‘resistant’ to the wormer.  But the catch is that the eggs on the slide this time aren’t from those original worms, which most definitely are long dead. Instead, they’re being produced by new adult worms that were just eggs and larvae when the previous worming was done, so were not affected by it. Now they’re adults themselves, producing their own eggs!

To avoid that confusion (and to be sure you’ve actually reached your goal of wiping out a serious worm load as well) proper worming must be done 3X in a row, allowing about 10 days between each dose, to destroy as many newly matured adults as possible before they start producing eggs of their own to start yet another worm cycle.

After doing all that you should be able to do another fecal check and find that lo and behold, these worms assumed to be ‘resistant’ have all but disappeared entirely!  (BTW: It’s important to recognize that the body needs to maintain a very low level of worms, not even enough to show up on the slide in most cases, so the immune system will have something against which to continue developing antibodies.)

There’s one big exception to that, and it’s the existence of the Liver fluke.  This is a highly lethal, difficult to eradicate worm that can only be done-in sufficiently by using that 3X worming regimen.  The Liver fluke eggs closely resemble those of the Haemonchus contortus (barberpole worm).  But unfortunately for goat owners, while Haemonchus contortus responds well to general wormers, the Liver fluke does not.  It will, however, respond readily to a relatively new product, Ivomec PLUS.  The PLUS part is clorsulon, specific to Liver fluke eradication.

This is where (albeit unintentionally) the problem falls squarely on the shoulders of the veterinary community, in the form of misidentification of worm eggs.  However, that was not always the case. Early on there was excellent photo reference material available for microscopic ID of eggs /oocysts in a book entitled Veterinary Clinical Parasitology, by Sloss and Kemp.  But following the release of the 5th Edition in 1982 the publishers, Iowa State University Press, changed the format entirely, ruining it for parasite egg /oocyst ID.  Unfortunately for us all, to date they haven’t seen the need to re-issue the 5th Ed., and while a few others have tried unsuccessfully to replicate the quality of that book for use in microscopic ID of parasites, no one has yet succeeded.  Idealized artists’ renditions have been made available in the hope they’ll ‘fill the gap’, but they simply aren’t useful for making those crucial, accurate ID’s out here in the real-world.  So unless / until someone else successfully takes on this important challenge, the fact is that Veterinary offices don’t have access to good photos for accurate ID of the eggs / oocysts seen on slides that would enable them to make that vital distinction between the egg of a Liver fluke and that of a Haemonchus contortus.

And many years of ongoing mistakes in ID have now fostered a shocking veterinary protocol wherein it’s assumed that all eggs ‘looking like’ Haemonchus contortus ARE Haemonchus contortus, thus failure to wipe them out, despite the vet’s recommendation that the owner increase the doses of the wormer he has initially recommended caused the vet to automatically assume that the worms have become resistant to worming, period. So the vets began recommending to their clients the use of larger and larger amounts of the wormers they recommended, but to no avail!  The conclusion, then, is that the only practical method of control is to destroy the animals harboring these worms as a means to prevent further spread.  This is interesting, an approach that ignores information in the Merck Veterinary Manual, which is NOT text used in vet school, but instead is a vet text that’s available to Veterinarians in practice, and lay persons like myself.  (In the 6th Ed. Pp.210-211, it states that “Fasciola hepatic, the most important trematode of domestic ruminants, is the common cause of Liver Fluke disease in the USA and other temperate areas of the world. It’s endemic along the Gulf Coast, the West Coast, the Rocky Mountain Region, and other areas.  It is present in Eastern Canada, British Columbia, and South America… etc and so forth.. They have even found it in Europe, Australia,in New Zealand, Africa and Asia, and it’s been reported in Hawaii as well.”

Thus the reality is, in fact, is that the eggs that are not responding to treatment for Haemonchus contortus are actually those of the Liver fluke instead, a worm that doesn’t respond to any of the goat wormers they’re using, but can be eradicated if just treated with the proper wormer!   A pathetic situation, I must say.

Having said that, in my view the easiest way to overcome this whole problem of egg misidentification and get the job done right once and for all is to use only Ivomec Plus (at a regular dose of 1cc / 100lbs, SQ), and to repeat the wormings 3X in a row with 10 days’ lapse between each one, for ALL general worming.  The result will be an excellent broad-spectrum worming, and the only worms you won’t be able to wipe out by that method are tapeworm (easily recognized by little flat white segments in the feces, and treated effectively with Praziquantal) , and pinworms (easily recognized by tiny, hairlike, wiggly white worms in the anal opening, and treated effectively by repeated daily doses of any of the benzamidazoles.)

I raise Toggenburgs. .. After having been continuously on the ‘show circuit’ for about 25 years, I’ve now retired.  My goats, housed in their lovely ‘Goatie Condo’, are no longer being exposed to worms from outside goats.  Every now and then (If I’m lucky enough to be in the right place at the right time) I scoop up a few ‘nanny berries’ from specific animals and run a fecal check on them right here in my office… And I have to tell you, I have not seen a worm egg in any of my goats for 4 years now!

I don’t necessarily recommend that you close your herd, but I do want you to know that if, when you do worm, you worm appropriately, you really can keep your animals worm-free.

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