Copper Oxide as a Dewormer

Episode 30
For the Love of Goats

Whether you are facing resistance to chemical dewormers, or whether you prefer to use more natural remedies, copper oxide wire particles may be helpful in the fight against barber pole worm (haemonchus contortus) in goats and sheep. Joan Burke, Ph.D., has been studying the effects of copper oxide and other alternative dewormers on intestinal worms since the early 2000s. She has had multiple studies published in peer-reviewed journals, such as Veterinary Parasitology. In this episode, Dr. Burke talks about using copper oxide in goats, as well as her research on herbal dewormers.

Dr. Burke is also a member of the American Consortium for Small Ruminant Parasite Control, where you can find links to more than a decade’s worth of studies done on worms in goats, sheep, and camelids. 

Other episodes with Dr. Joan Burke

Episode 107 Red Cell for Goats

Episode 36 – Basics of Goat Research

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Other episodes on dewormers:

• Episode #114 – Goat Worms: Myths and Misunderstandings
• Episode #68 – New Goat Dewormer Guidelines
• Episode #24 – Using Dewormers Correctly
• Episode #6 – Natural Parasite Control with Lespedeza

Want to know what is the 5-point check for parasites, and how you can use it to determine when you need to use a dewormer? Check out this podcast episode.

If you have a worm problem with your goats, and rotational grazing is not an option, check out BioWorma for Goats. In this podcast episode, we are talking about how to get started, as well as what works and what doesn’t.

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TRANSCRIPT – Copper Oxide as a Dewormer

Deborah Niemann 0:18
Hello, everyone and welcome to another episode. I am very excited today to be joined by Joan Burke, PhD, an animal research scientist at the USDA Research Center in Booneville, Arkansas. Welcome to the show.

Joan Burke 0:34
Hey, Deborah, thanks for having me.

Deborah Niemann 0:36
The first thing before we get into the whole barber pole and copper oxide issue: Could you just tell us a little bit about how you initially got interested in studying copper oxide wire particles? Because that seems kind of out in left field.

Joan Burke 0:50
Sure. I started doing sheep research at USDA in… somewhere around ’99, 2000, looking at kind of various things, different breed types, organic research, and quickly learned that, you know, on our deworming schedule, our dewormers weren’t working. So, we had fecal egg counts of somewhere around 1,000 or 2,000; it should have gone down to 0 theoretically, and they shot up to 4,000 or 5,000 eggs per gram. And that is our best biomarker in looking at parasite infection. So that pointed to a need for alternatives to chemical dewormers or anthelmintics, because of dewormer resistance. Dewormer resistance is the inability of a dewormer to eliminate gastrointestinal nematodes or parasites, because the worm population develops resistance genetics or mechanisms to tolerate the dewormer. Also, I had an interest in organic livestock production, as I said, which states that approved dewormers in—originally, organic regulations allowed just ivermectin, but only during the maintenance phase of a dam or the first two thirds of pregnancy, but not during the last third of gestation or anytime in the lamb’s lifetime. So these dewormers could be used, but animals couldn’t be certified if they were used.

Joan Burke 2:21
Our flock is certified by Nature’s International Certification Service, and they allow the use of copper oxide wire particles as a dewormer as needed. This actually came about kind of after I started doing research, so pretty exciting. Copper oxide had been discovered to be effective against Haemonchus contortus, or barber pole worm, around 1990 by New Zealand researchers, and in 2002 by an Australian researcher. And even before that, some early researchers using copper oxide wire particles to treat copper deficiency in sheep accidentally discovered a reduction in parasites or reduction in fecal egg counts after using copper oxide wire particles. And my colleague from Louisiana State University, Jim Miller, approached me somewhere around 2002 about doing a dose titration study. And I had met Dr. Miller—he’s a veterinary parasitologist and he’s with The Consortium—I met him at an animal science meeting. And then we became good friends and collaborators from that study on, and that was about the time where all of our chemical dewormers at the station were failing. So, of course, I was interested in doing the project with him. And so that’s kind of a long answer to how I got started and why I was interested in using copper oxide wire particles.

Deborah Niemann 3:43
Oh, that’s really fascinating, though. Thanks for sharing that. So, why exactly did the barber pole worm become such a big problem for goats and sheep?

Joan Burke 3:52
Well, I think it’s always been a big problem. But it just became worse with dewormer resistance. But barber pole worm—it’s a prolific worm. It’s a bloodsucker. That means that an animal will become anemic, can lose a lot of blood, with a severe infection. As most sheep and goat producers eventually find out, barber pole worm will eventually become a problem if animals are on grass pastures in warm, humid climates, which includes summers for a lot of the eastern states—southeastern U.S. we can find worms nearly year round—or on irrigated pastures in the western U.S. And they’ve been found in nearly every state in the U.S. and worldwide. So it’s a huge problem not just for us here in the U.S., but everywhere. As I said, it’s a prolific egg layer, sucks blood, as much as 200 microliters per day, so you get, you know, 100-200 worms, an animal can lose a lot of blood. And that’s both a developing larva that sucks blood and the adult worm. The worm has a short life cycle, which takes about five weeks to complete. So you can have multi generations of worms in one summer. And that’s why we can see dewormer resistance develop so quickly, because of that fast generation cycle. And veterinarians used short-sighted recommendations for years in advising farmers to treat, often with dewormers. They advised them to move to clean pastures, so deworm and move to a clean pasture, so the only thing surviving on that clean pasture would be resistant worms, worms that survived the treatment. They said deworm in the fall, which, that’s a bad idea, because there’s not a whole lot of worms. Anything that survives by spring is going to be resistant. So all of that didn’t consider refugia, or leaving worms in the animal or in the environment that were left untreated.

Joan Burke 5:47
So use of dewormers in this way, initially, that led to increased growth of animals. So the reason why it was so widely advised to use is because animals would grow better. And so this led to dewormers and resistance of multiple drug classes, which kind of happened pretty fast, especially in southern states, but now we can kind of see multi-drug resistance pretty much everywhere. And eventually many farms went out of business because they couldn’t keep their goats alive. And sometimes sheep. I said goats because they’re more susceptible to worms. And that’s, um, that’s why it’s such a big problem.

Deborah Niemann 6:22
Okay, so basically, as more and more ruminants have worms that are resistant to the chemical dewormers, we need some alternatives. And that’s where copper oxide wire particles come into the picture.

Joan Burke 6:33
Right, exactly.

Deborah Niemann 6:34
So, what exactly are copper oxide wire particles, and how do they work?

Joan Burke 6:39
Copper oxide wire particles—a lot of people are kind of seeing that they’re sold commercially. They can find them now as either Copasure or UltraCruz copper oxide, or they’re sold as boluses or gel capsules with little particles of copper oxide inside the capsules. They’re developed to alleviate copper deficiency in livestock, and yeah, I alluded to that earlier. So the particles, they’re about 500 micrometers in diameter, so they’re pretty small, and they have varying length. So what happens when you give an animal the capsule: It’s dissolved in the rumen, and the particles travel… make their way to the abomasum, or the true stomach. And that’s where Haemonchus, or barber pole, lives, in the true stomach. And then the particles lodge in the folds. So you can find particles somewhere between the rumen and the feces, but most of them stick around the abomasum for a couple or several weeks. And the pH of the abomasum is much lower than the rest of the digestive tract. It’s close to 1. And it’s thought that this acid environment causes slower release of copper to the animal. And that can have an indirect effect on the worm.

Joan Burke 7:48
And we see some evidence of that when we look at copper concentrations in the worm itself. We’ll find that it’s higher from animals treated with copper oxide. But it’s also thought that—we got some evidence from a student that worked with Dr. Miller—that copper oxide works directly on the adult worm, causing damage to the cuticle. So doing kind of an intricate study, where we removed the adult worm after copper oxide treatment, we found that the worm actually had some damage to it. But using it as an anthelmintic or a dewormer, it really only lasts about 72 hours. So even though you can find the particles in the abomasum for longer that, it only works as a dewormer for about 72 hours. Not really sure why, but that’s what seems to happen.

Deborah Niemann 8:37
Okay, and so how did you figure out how much copper was needed for parasite control in goats?

Joan Burke 8:45
Well, initially, we did dose titration studies in sheep. And let me just say, some of our later studies that we did with Fort Valley State University, really, we get the same response of copper oxide wire particles in sheep and goats. So I think it’s safe, you know, anytime that I talk about a lamb or a sheep study, we’re really going to see pretty similar things in the goat. So initially, we had a dose titration study where we gave no copper wire to 4 or 6 grams per animal. And, generally, experimental doses published in the literature were higher than 2 grams. But our aim was to minimize the risk of copper toxicity. Some studies were as high as 20 grams. But if we want to use this as a dewormer, and we know that copper can potentially be toxic to both sheep and goats, we want to go with the lowest dose so that we can use it multiple times in summer. And then we did another dose titration study in weaned lambs later, and we went as low as a half gram or one gram, and both worked the same. So we can actually go as low as a half gram. And we basically now recommend, anything less than a year of age, to give half or one gram. If you’re not sure of copper status, go with a half gram. And I just want to say (this is not part of the dose titration), but I’ve heard this recommendation—I’ve seen it in writing and I’ve seen it on Facebook and on the web—this recommendation of giving 1 gram per 22 pounds of body weight. I’m not sure where that came from. But we do not, for use as a dewormer, we don’t recommend that, because that ends up being a lot of copper. And if you have a truly copper-deficient animal, that might be okay, and that’s your only reason to give the copper. But if you’re using it as a dewormer, there’s no reason to go that high. If you’re, I mean, you’re wasting it. And, again, if you’re copper deficient, and you also have worms, you’re still going to give the copper at another time with that. So, we really do a lot of studies on safety of getting it, because we know that, like, again, we know that sheep and goats are susceptible to copper toxicity.

Deborah Niemann 11:12
Okay. Um, it’s funny, I actually know where the 22 grams—the 1 gram per 22 pounds comes from.

Joan Burke 11:20
Yeah.

Deborah Niemann 11:21
Because we had a problem with copper deficiency like 15 years ago, which is how I found your research, because so many people were saying, “Oh, you can’t give them copper. You’re gonna kill them,” including vets. Even though I had a goat who had a liver level of 4 ppm copper on necropsy. And it is from… Many years ago, there was a website called Saanendoah that was done by this woman in California who had a severe problem with copper deficiency. And she had a very long list of studies and citations and stuff with University of California, Davis. And she’s the one that, like, everybody was quoting 15 years ago or so when it came to copper—the only source of copper in the literature, other than the stuff I found with your parasite research back then. And so, and that is definitely for copper deficiency, not for, you know, parasites, because of course, if they just have parasites, like you said, you’re wasting it if you give them more than what they actually need to kill the parasites.

Joan Burke 12:31
Right.

Deborah Niemann 12:31
So, it’s two completely different dosages for two completely different issues. So assuming somebody is giving their goat—and this is actually a really good time to talk about this, because what I’m going to ask is, like, how often is it safe to give copper at the levels that you’re giving it in your research for parasites specifically?

Joan Burke 12:55
That is a really good question. So, kind of early on, we wanted to look to see how long the copper oxide was going to be effective in keeping fecal egg counts low. For people who don’t know, fecal egg count is kind of our standard measure to know how, in fact, the animal is. So, we generally want to see… We don’t want to see zeros, because we want the animal to have some worm infection, because it stimulates the immune system. If an animal is—I’m getting off topic a little bit—but if an animal is without worms, and all of a sudden faces them, they could have a huge crash immunologically speaking. But anyway, so we wanted to see how long the copper would last. And we conducted a study with young goat kids, so they were just weaned. The pasture we were using was overstocked. So, we used conditions that we don’t recommend for good production. So these goats, of course, were being weaned, they were stressed, they were susceptible to parasites. We gave a dose of copper oxide wire particles, and it brought the fecal egg counts down nicely, but, within three weeks, fecal egg counts were high again. And that’s not unusual if you’re overstocked, they’re picking up more larva from the pasture, and the animals became anemic. And so we treated them again. And that again, brought fecal egg counts down. So that study we just did two treatments every three weeks.

Joan Burke 14:29
So, if you were to treat every three weeks… So let’s say you’ve got poor management and you treat every three weeks if you’re using a low dose, such as a half-gram, and you’re in a copper deficient area—so what you saw, you had copper deficient goats. And our sheep tend to be copper deficient here in Arkansas. So we have lower levels of copper in the liver and in the blood. So, if you’re in that type of environment, you might be able to get away with treating up to 10 times within a summer, so that would be 10 times a half-gram would be 5 grams. And that’s probably relatively safe, for goats anyway. Maybe or maybe not for sheep, it just depends. So, the animal might not be at risk for copper toxicity in that case. But, if your animals are exposed to a lot of copper, which does happen in soils, forage, feed, water from copper pipes, you know, there’s all kinds of ways that animals can get copper, then the risk of copper toxicity greatly increases. And let me just say, like you said, we knew animals were copper deficient, because we did tests in the liver. And if you want to do tests on a live animal, you can pull a blood sample and submit it to diagnostic lab. It’s not as good as the liver measure, but it’s still pretty good. We did another study in lambs. We tested how often we could give it in lambs. And so we gave it six weeks apart, and we gave four treatments, and we gave either a half-gram or one gram. And, we did increase the copper in the liver over time. But for those four treatments, we were still well within the safe zone. So none of them were at risk for copper toxicity.

Joan Burke 16:17
Something to keep in mind—and it just reminds me in this study—so although we treated four times, the last two treatments that we gave weren’t necessary, we actually had more non-barber-pole worm species showing up, which is not uncommon. So you take away barber pole worm, then you’re going, of course, you know, the proportion of other worms is going to go up. Those other worms are not susceptible to the copper oxide. In other words, the copper oxide targets barber pole, but not others, like Trichostrongylus colubriformis, or Oesophagostomum, some some of the others. And so, when you give copper wire, the fecal egg count actually doesn’t seem to go down in that case. So keep in mind that when worms that are in the intestine, or the hindgut, may not… They don’t cause the same kind of problems as barber pole worm, but you might see some reduced weight gain or… Those reduce weight gain, and that’s one of the problems with the worms. And it happens with cattle too, You can’t really see that they’re not gaining weight, because there’s lots of different reasons why they’re not gaining weight.

Deborah Niemann 17:25
And then, since the copper oxide wire particles are specifically for barber pole worm, which is a bloodsucker and causes anemia, we should also see improvement in the anemia status of the animals, so that breeders and owners can keep track of how they’re doing by checking FAMACHA scores, like before and after they give copper oxide, right?

Joan Burke 17:48
Right, kind of in general. So copper oxide wire particles will only improve anemia of the animal, like I just said, if it’s, in fact, barber pole worm. So if the animal has diarrhea, kind of looks unthrifty, not gaining, that could be other worms. And, like you said, the FAMACHA scores aren’t going to suffer so much with the other worms. So, if you’ve got mostly Haemonchus, and you look at the animal, and you’ve got FAMACHA scores of four or five, so they’re very pale, you give the copper oxide… Within two weeks or so, you should see an improvement.

Deborah Niemann 18:30
You’ve also compared the effects of copper oxide wire particles when it’s mixed into feed, or given as a bolus, because I know a lot of people think that you have to bolus it. But you actually did a study where you compared groups that, where it was mixed into feed, or bolus. Can you talk about what that study showed?

Joan Burke 18:51
Yeah. So we can incorporate copper oxide wire particles in the feed, or we can give it as gel capsules, and we see a similar efficacy with either method. So, you know, a lot of people ask, “If I give the bolus in the mouth, and they chew it, is it still gonna be effective?” And the answer is “yes.” And we’ve actually made those notes and then looked at the fecal egg count reduction. And so, whether the animal chews it, whether it’s in the feed, or they accidentally chew the capsule, it still works pretty well. However, if you think about it, there’s more of a chance of not thoroughly mixing the small particles to distribute evenly so that all animals get the same amount. And that can be a big concern, if you’ve got some animals that really don’t need the worm treatment and others that do. So, it’s fine if you’re feeding one animal at a time. So if you mix the particles in a ration, and you’ve got dairy goats, so the dairy goat comes to milk and you’re given her a little bit of feed with a copper oxide. And so that’s fine, but if you’re feeding 10, 20, or more animals, there’s always a chance that one will get too much. And another not enough.

Deborah Niemann 20:04
Yeah, I could definitely see that if you’re feeding it in a group. One of the things we do, because we have dairy goats, and so we do give it to the milkers on the milk stand. And what we do with the other goats, like our bucks and stuff, is that we do it on “spa day.” Basically when they’re getting their hooves trimmed, and we’re checking their eyelids, and everything, that’s when we give them copper if they need it. And we initially just give it to them with a little tiny bit of feed, so that they’re more likely to lick it up. Like, if they want that tiny little bit of feed, they have to lick up the copper to get it.

Joan Burke 20:37
Yeah.

Deborah Niemann 20:38
So in another one of your studies, you combined the copper with Valbazen, and I don’t mean like “together,” I mean, like, you gave them copper, and then you gave them Valbazen. Can you talk about how that turned out?

Joan Burke 20:50
Yep. So we had three different treatments. We gave—actually we had four different treatments—we had a treatment of nothing; or we gave copper oxide alone; or Valbazen, another name for Valbazen is “albendazole,” we gave that alone; or we gave the two in combination. And we had a mixed population of Haemonchus contortus, or barber pole worm, and we also had Trichostrongylus, Cooperia, and Oesophagostomum. So those are other intestinal or hindgut worms. Like I said, sometimes these worms in large numbers can cause problems, and sometimes in low numbers they’re really not pathogenic. And remember, copper oxide alone only targets barber pole worm. And we knew, so we’d done the DrenchRite test. And a DrenchRite test is basically a fecal egg count reduction test. But it was done at the University of Georgia, where we submitted a fecal sample with lots of eggs, and the larvae were hatched. And those larvae were tested and found to be resistant to benzimidazoles. And the benzimidazoles include albendazole. So we knew we had pretty good resistance to that dewormer, which not uncommon in the southeast. So in this study, there was only a 20% reduction by Day 7, and a 46% reduction by Day 14, with Valbazen alone. So, if that was our only dewormer, and we had wormy animals, the animals will be in trouble. You might find some improvement immediately, but within two weeks, the worms could become a problem. Now, the copper oxide by itself led to either a 12% or 1% reduction. And that’s because of our mixed population. If we… So we had cultured the feces, so we knew how much Haemonchus was in there. When we consider only the effect on the Haemonchus, we had close to an 80% reduction. So sometimes the copper oxide doesn’t reduce all of the worms, but the combination—so the copper oxide and the dewormer—led to a 90% to 99% reduction by Day 14. This is really exciting, because our dewormer didn’t work very well on the worms. So it suggests that when using a combination of the two products, we get the benefit of both, and both treatments improve, both products improve. So now, in our flock, whenever we see high FAMACHA scores of four or five, so we see really pale animals, we use copper oxide wire particles in combination with dewormers. And, if we see FAMACHA—and this is just our general recommendation for our flock—if we see FAMACHA scores of three, we’ll just give the copper oxide by itself. And we have also seen the same phenomenon with levamisole. But we don’t have enough data yet.

Deborah Niemann 23:46
That’s really great news. Because so many flocks or herds do have a problem with dewormer resistance now. And so, it’s really like you’ve got a fourth dewormer out there, or a fourth category of dewormer, because they’ve… I know researchers have been talking about combining dewormers from different categories for quite a few years now. And this actually just gives you another option if you’re having problems finding something that works, which is really exciting. One of the other things that I’ve heard people talk about, especially, and it’s mostly some older books and older sources of information, is that copper sulfate can help with worms. And, I think you may have studied that also, and compared it to copper oxide. What have you… How does copper sulfate compare to copper oxide in terms of treating parasites?

Joan Burke 24:39
Yeah, so, Dr. Miller and I published a study in 2008, where we looked at giving goats copper sulfate, either in the mineral, which was a suggestion by an Australian non-peer-reviewed publication, or we gave it in the feed, and there was no reduction in fecal egg count. In fact, we saw that the growth rate of the goats tended to be reduced in goats that got copper sulfate, which, that could be a concern. Similarly, Dr. Miller conducted a study at LSU, where he gave copper sulfate drench to lambs, and again, there was no reduction in fecal egg count. And I think, years ago, before we had multiple classes of anthelmintics, I think they would combine the copper sulfate with other things, like tobacco or toxic compounds. And it might be, you know, when you combine it with other things, it works better. We also used an industrial copper oxide wire particle, so not what you’d get with Copasure or UltraCruz, but one that we use in a lab diagnostic equipment. And we didn’t get the same reduction in fecal egg count, like we see with the Copasure or UltraCruz. So it’s important that you use the right form of copper. And again, with copper sulfate, it’s relatively easily absorbed, so I think you can run into problems a lot quicker with copper sulfate, especially if you’re giving it over multiple days. If you’re giving it just once, then, you know, you’re less likely to get in trouble, except it’s not really going to work to kill the worms.

Deborah Niemann 26:14
Right.

Joan Burke 26:15
We did a study a number of years ago, where we looked at a combination of Duddingtonia flagrans, which is a nematode-trapping fungus, and copper oxide wire particles. So that was 20-plus years ago. Companies were trying to get Duddingtonia flagrans on the market for control of parasites on pasture for a number of years, and it finally just happened last year. So this is a nematode-trapping fungus. It’s now available in the U.S. as BioWorma; manufactured in Australia and sold by Premier; and veterinarians can get ahold of it and sell it as well. It’s the only product on the market that targets a reduction of parasites on pasture. So it’s pretty exciting for someone who is considering, you know, regenerative agriculture, reducing chemicals. But anyway, so in that early study, looking at the the interaction of copper and the fungus, we found that we could safely still feed the fungus and give copper oxide, and the copper didn’t harm the fungus. So, just as an aside, the way the fungus works is we feed the spores of the fungus of the animal, the spores go through pretty much untouched, but when they come out in the feces along with the eggs, both the spores and the eggs develop. And if the eggs develop into larvae, the fungus develops in it; it actually forms these structures that trap the larva and kill it. And so, to me, that’s a really exciting way that we can control parasites. It is a little bit expensive. So we want… Some of our research that we’re doing now is trying to find ways to economically feed it. So we want to be able to provide recommendations for the most economical bang for your buck.

Deborah Niemann 28:03
Oh, that’s a great thing to add, because people are… I’m getting a lot of questions about that now. And not just about the Duddingtonia flagrans, but just in the, on the pasture in general. You know, I have people asking me about things like, “If I burn my pasture, will that help?” Or, “If I sprinkled D.E. all over my pasture, will, that…?” I mean, all kinds of questions that people have. You know, when they have a really serious problem, they’re grasping at straws. So it’s really great that we do have something now that will help to reduce the number of eggs and larvae on the pasture.

Joan Burke 28:37
Yeah, and I would say, anyone who has named animals should get this product. I used to tell people, “Anyone who has named goats or sheep should keep them on concrete away from the worms.” But this allows them to go out on pasture and be relatively safe out there. It’s not instantaneous, because it does nothing for the worms in animals. But over time, it gets… the load of worms on pasture gets lighter and lighter.

Deborah Niemann 29:04
That’s awesome. And one last topic before we go: This isn’t about copper, but I also get questions from people about using herbal dewormers, and I know you have done at least one study that I’m aware of with an herbal dewormer. And can you just talk about the results of that?

Joan Burke 29:23
Yeah, just real quick. We did a study at Heifer International—Heifer Ranch, Heifer International—on goats. And so we fed the Molly’s Herbals dewormer according to the package recommendations, followed it exactly, and there was no reduction in fecal egg counts in these goats. And there was a similar study done at North Carolina State University, Jean-Marie Luginbuhl did that, and found similar non-control using, I believe it was a Hoeggers herbal product.

Deborah Niemann 29:54
Right? Yeah, and I found the same thing, too, back 15 years ago, 10 years ago, when we had problems with dewormer resistance. I tried everything that everyone said, or anyone said, might work. And I was doing before and after fecals, and there was not a difference in the fecal egg counts before and after using those two dewormers, as well as another popular one at the time.

Deborah Niemann 30:20
Well, it has been really wonderful having you here today. And I think you’ve provided a lot of really valuable information that is going to be helpful for people who have parasite problems. And thank you so much for coming!

Joan Burke 30:33
You’re welcome. Thanks, Deborah, for having me.