Discussion on Ivermectin/moxidectin resistance found in Canadian study
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| Author |
Message |
    
LL
Member
Username: frances
Post Number: 539
Registered: 3-2004
| | Posted on Tuesday, Nov 6, 2007 - 9:00 am: |   |
Hi DrO,
Have you seen this recent report on the above?
www.equinescienceupdate.co.uk/parascres.htm
There seems to be growing resistance to these pillars of our deworming programmes. I'm getting worried. |
Chris Doyle
Member
Username: christel
Post Number: 354
Registered: 8-2005
| | Posted on Tuesday, Nov 6, 2007 - 9:46 am: | |
LL- thanks for posting that. Holly sent me that study last week and I had a question, just didn't get around to posting it- will now.
DrO- my vets here tell me with my foals I should worm every 4 weeks, switching with ivermectin one time then anthelcide the next- do this until late in yearling year. They say that ivermectin is not effective against roundworms (which the foals will get immune to as yearlings) but the anthelcide is.
Is this the reason you recommend double dosing ivermectin in a foal every 4 weeks till their yearling year? Are you thinking the double dose will get the roundworms? Do you see a problem with the way my vets are recommending the anthelcide?
LL I agree this is scary.
Chris |
Robert N. Oglesby DVM
Moderator
Username: dro
Post Number: 19498
Registered: 1-1997
| | Posted on Tuesday, Nov 6, 2007 - 1:15 pm: | |
Unfortunately avermectins are the single pillar of all good deworming program, the question is how to administer it for maximum effectiveness and decreased the the development of resistance, which is the rationale behind our program.
In the past 5 years we have seen several reports like this on both single farms and some large surveys that detail decreased response to avermectins in foals particularly with adult roundworms response to ivermectin. As we have been reporting for some time now foal parasites in general do not respond as well as adults to ivermectin and several reasons have been hypothesized, for more see Horse Care » Worms, Deworming, Parasite Control » Overview of Deworming. This is the reason for our recommendation for the double dose every 4 weeks and using such a program, we have not seen any parasite breakthroughs. Then again most farms we manage use our regular program and so we hope the parasite problem is taken care of "up front". The above findings were also the stimulus for adding the year of daily pyrantel.
The most important part of any deworming program is monitoring efficacy through regular fecals and if problems with roundworms are found after following our recommendations adding Anthelcide to the program would be reasonable.
DrO |
