Deworming Debunked


By Maddy Butcher

wormer2The days of deworming every other month are over.

Research shows that you do more harm than good when you order that variety pack and stuff worming paste down your horse’s throat indiscriminately.

Why?

Most horses don’t need wormer and by giving it to them anyway, you lower their resistance and compromise the good bacteria.

On average, just one horse in a herd of four hosts the majority of parasites. That horse should be identified and treated accordingly.
Today’s body of evidence points to the importance of doing annual or spring/fall fecal egg counts to pinpoint the specific horse, the specific parasites, and direct treatment. It’s been called “Targeted Deworming.”

“The object of targeted worming is to cut way back on the amount of worm medicine being used and so lessen the ability of the parasites to develop immunity to it.   It’s similar to human medicine where your doctor doesn’t want to give you antibiotics for every little infection,” writes Dr. Dave Jefferson of Maine Equine Associates.

wormThink about it: We wouldn’t give our kids amoxicillin every January just cuz. It would be absurd and harmful. That kind of pointless medication would eventually render amoxicillin useless because over time, the bacteria would morph into new amoxicillin-resistent bacteria.

Watch this excellent educational slideshow, called Parasites 101. It’s by Merial, the maker of Zimecterin.

Jefferson and many vets interviewed recommend fecal egg counts performed once or twice a year. Many practices do them in house. Some even do them during a farm visit.
Even with the cost per sample  (between $16-28), clients typically save money by not using wormers so often. And the horses are healthier for it.
Of course, there’s the added bonus of knowing exactly which horse has parasites and which parasites need targeting.

  • More information.
  • Less blind treatment.

equimaxSound good?

Additional Note:

Some vets recommend once-a-year worming for tape worms and/or bot fly eggs. (One typically sees bot fly eggs on horses’ legs). The most effective wormers in these cases are Zimecterin Gold and Equimax  as they contain a combination of the drugs ivermectin and praziquantel.

9 comments


  • Goldenwinds

    I have been following this practice for years but was warned this year by 2 vets that since it is impossible to see tape worms in the fecal count samples, that it is still a good idea to worm for tapes once a year.

    January 11, 2013
  • maddy

    Mail In Fecal Sample Counts are cheap and easy! Just google them and pay attention to what they are testing and what kind of results and support they offer. Most give folks good discounts for quantities.
    This is a FAR BETTER practice than injecting your horse with a drug that will only encourage parasitic resistance – that spells trouble for all horses, not just the ones you’re worming!

    January 10, 2013
  • Rick S,

    Follow the money. There’s more money for vets in fecal testing than in owners doing their own deworming.

    January 10, 2013
  • calico

    Good in theory but it doesn’t for for all stables. To do this, you’d need to do fecal egg counts on all the horses periodically. Some people can’t afford the $25-30 per horse our local vets charge per horse (plus dewormer for the highest egg burden horses)… vs $2 a tube per horse to worm the entire herd with generic ivermectin. For 10 horses that’s $300 + dewormer costs… versus $20 total. Ouch!

    I know in a perfect world money wouldn’t be a priority. But as long as vets charge so much to test it, the expense closes some people out.

    Also, in barns where horses are always going in and out to/from other places, a horse may not be there long enough to do 1-2 egg counts on and to see where his egg counts are. What do you do with that horse in the meantime, as he may or may not be shedding things into shared pastures?

    Combine the two, and you might see why it wouldn’t work for example at busy boarding barns where owners aren’t keen on $30/horse/test fees, where horses only stay a few months, and where old & new horses are always sharing pastures.

    All I’m saying is that how horses are managed depends on the individual situation. There is no right answer that works for every horse owner & ever horse. The plan needs to be tailored to the situation.

    January 10, 2013
    • catto

      Cannot afford $30 for a fecal exam?? Then how do these horse owners afford shipping, showing, lessoning, etc? Times are changing, there are going to be camps of people generally unwilling to learn new ways and adopt new schools of thought, but if you actually think about this method it is really for the better of us all and your horses. Rotational deworming practices bank on using a dewormer once every two months. So at the least that’s $2/month and you’re deworming blind – you have no idea what you’re treating for. If you continue to do this, problems are bound to arise if you have a horse with a high burden.

      If you have the type of attitud that you think it is the vet that is trying to win your money over promoting best practices then you shouldn’t be owning animals. Your vet should be someone you rely on to keep your animals healthy, right? So why the distrust in their motives? I’m sure you’d be calling them right quick if your horse started colicking. Trust comes in one flavor, all or none.

      January 10, 2013
  • Thanks for these great comments. Just a word about Aw Firestone’s comment. A composite sample is NOT effective. Research shows that one horse may be drastically different than others in terms of hosting parasites. He will not look any different, but his individual fecal sample will reveal that he hosts the majority of parasites while his herdmates may have next to none. Individual fecal samples are crucial.

    January 10, 2013
  • I’ve been going with this model for quite some time as it just makes sense. Just want to add after seeing the price to run a fecal, that if one has multiple animals a composite sample, taking a bit of each animal’s manure to create one sample will tell you what you need to know.

    January 10, 2013
    • calico

      Do NOT mix manure samples of multiple horses together. This make the test results worthless.

      The point of testing a horse is to see the egg count of THAT HORSE and only deworming enough to treat those with high egg counts. If you mix samples together, you have no way of knowing which horse was shedding and which wasn’t. You’re throwing your money away.

      January 10, 2013
  • After a through review of the research in this area and discussion with numerous vets, I have followed this procedure for years with great results. fecal egg counts have been low in all my horses and I can be confident that I am not contributing to the development of their immunity to these agents. I remember my initial amazement on learning that it was usually the horses treated with the regular dosing with various wormers who carried the largest parasite burden because they had developed immunity.

    January 09, 2013

Leave a comment


Name*

Email(will not be published)*

Website

Your comment*

Submit Comment

Copyright © Dandelion by Pexeto