# Noromectin Pour-On



## CowboyRam (Dec 13, 2015)

I have heard that cattle get a resistance to Noromectin, and therefore one should switch out every few years with Ivomec pour-on. Have any of you guys heard this? Opinions?


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## Rrueda (Jan 10, 2019)

Yes. In fact it is not cattle but parasites that end up being resistant to whatever you use. Better use a different molecule every time.

If you are running a cow calf operation I would strongly suggest selection against that trait.


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## CowboyRam (Dec 13, 2015)

Rrueda said:


> Yes. In fact it is not cattle but parasites that end up being resistant to whatever you use. Better use a different molecule every time.
> 
> If you are running a cow calf operation I would strongly suggest selection against that trait.


Last year I did use Noromectin, and yes I should of said parasites. I guess I should change to Ivomec for this year. It just cost more.


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## Edd in KY (Jul 16, 2009)

Isn't the main ingredient the same in both? If so it will not change the resistance problem on your property.


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## CowboyRam (Dec 13, 2015)

Edd in KY said:


> Isn't the main ingredient the same in both? If so it will not change the resistance problem on your property.


That I don't know. I will have to take a look at that.


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## Trillium Farm (Dec 18, 2014)

CowboyRam said:


> That I don't know. I will have to take a look at that.


Anything ending with .....mectin is the same ingredient.


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## Hayjosh (Mar 24, 2016)

They're both ivermectin. You're changing who you are giving your money to, but not the drug. You need to change the active ingredient, and more frequently than every few years.


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## Rrueda (Jan 10, 2019)

Trillium Farm said:


> Anything ending with .....mectin is the same ingredient.


Not really. Ivermectin, doramectin and noramectin are different molecules.


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## Markpnw (Dec 27, 2019)

Rrueda said:


> Not really. Ivermectin, doramectin and noramectin are different molecules.


They are the same active ingredient. Doramectin is a derivative of ivermectin which means it’s the same stuff. If the parasites are resistant to ivermectin they’ll be resistant to doramectin and noramectin. Has anybody used amitraz to treat cattle?


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## Rrueda (Jan 10, 2019)

Markpnw said:


> If the parasites are resistant to ivermectin they’ll be resistant to doramectin and noramectin.


As far as I know, there is no scientific research available to back up that claim. Moxidectin is yet another option for the OP, it works for internal and external parasites and has less environmental impact. If money is not an obstacle, get Eprinomectin which is an extended release molecule and lasts for 150 days.

As for Amitraz, it works only for external parasites.


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## Markpnw (Dec 27, 2019)

Rrueda said:


> As far as I know, there is no scientific research available to back up that claim. Moxidectin is yet another option for the OP, it works for internal and external parasites and has less environmental impact. If money is not an obstacle, get Eprinomectin which is an extended release molecule and lasts for 150 days.
> 
> As for Amitraz, it works only for external parasites.


There really isn’t a lot of research papers in general about agricultural parasites. I’ve done plenty of research and if a certain parasite is resistant to a chemical ivermectin anything else that is a derivative will or is already resistant. If the parasite became resistant to ivermectin how is doramectin going to be better when it’s a derivative of the same thing. Slow release stuff is even worse because the parasite has more time to adapt to it.


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## Hayjosh (Mar 24, 2016)

Markpnw said:


> There really isn’t a lot of research papers in general about agricultural parasites. I’ve done plenty of research and if a certain parasite is resistant to a chemical ivermectin anything else that is a derivative will or is already resistant. If the parasite became resistant to ivermectin how is doramectin going to be better when it’s a derivative of the same thing. Slow release stuff is even worse because the parasite has more time to adapt to it.


I agree in general, however there is a trove of research available. Parasiticides are a very big industry $$.


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## jr in va (Apr 15, 2015)

I've heard you really need to take fecal samples for a vet to check to see what worms you need to target and use what works best. Also stay with an Ivomec type product until it shows resistance then switch to one of the white drench dewormers. Makes sense.


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## Trillium Farm (Dec 18, 2014)

jr in va said:


> I've heard you really need to take fecal samples for a vet to check to see what worms you need to target and use what works best. Also stay with an Ivomec type product until it shows resistance then switch to one of the white drench dewormers. Makes sense.


I was always told to rotate type as once resistance is established it cannot be undone!
Rotation is supposed to stop resistance, for rotation is meant every use with a different type at the very least in alternation, but if not possible not more than 2 or 3 in sequence of the same type.


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## Markpnw (Dec 27, 2019)

Trillium Farm said:


> I was always told to rotate type as once resistance is established it cannot be undone!
> Rotation is supposed to stop resistance, for rotation is meant every use with a different type at the very least in alternation, but if not possible not more than 2 or 3 in sequence of the same type.


Rotation is the best bet.


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## jr in va (Apr 15, 2015)

I've also read that you should use one type of dewormer until it isn't effective then switch. A simple rotation may cause resistance to both types. ?


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## Ray 54 (Aug 2, 2014)

jr in va said:


> I've also read that you should use one type of dewormer until it isn't effective then switch. A simple rotation may cause resistance to both types. ?


I cannot say I have asked about official about the wormer, but situations like with weeds and fungicides killing mold and mildew I have sat through many grower meeting with chemical company , and university professors all saying change every time . With luck using different chemistry it kills those that had immunity to what you used last time. So it was change fast and often. So I would think this is the same.


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## Trillium Farm (Dec 18, 2014)

jr in va said:


> I've also read that you should use one type of dewormer until it isn't effective then switch. A simple rotation may cause resistance to both types. ?


NO, one ought to use a different "KIND" not just a different name EVERY time.
If you wait till one type is no longer effective, the parasite have developed a defense against it and all future generations will be resistant, by changing type every-time the parasite does not have the time to develop and adapt.


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## Hayjosh (Mar 24, 2016)

jr in va said:


> I've also read that you should use one type of dewormer until it isn't effective then switch. A simple rotation may cause resistance to both types. ?


Why on earth would you establish resistance and THEN switch? You'll never be able to use that parasiticide again.


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## Trillium Farm (Dec 18, 2014)

Hayjosh said:


> Why on earth would you establish resistance and THEN switch? You'll never be able to use that parasiticide again.


EXACTLY !!!!


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## Hayjosh (Mar 24, 2016)

jr in va said:


> I've heard you really need to take fecal samples for a vet to check to see what worms you need to target and use what works best.


Yes x 1 million. Especially for horses, which if a closed herd, probably don't have ANY worms and probably don't need anything. My horses haven't had dewormer in years.



> Also stay with an Ivomec type product until it shows resistance then switch to one of the white drench dewormers. Makes sense.


NO x 1 million. It makes ZERO sense unless you're trying to keep me employed forever.


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