For the Love of Goats
Steve Hart, Ph.D., of Langston University talks about roundworms in goats, including the infamous barber pole worm, which causes a lot of heartache and financial loss for goat owners every summer.
Did you know …?
- a barber pole worm can lay 2000-6000 eggs per day
- can consume a pint of blood per week from your goat
- the larvae survives on pasture by eating the e.coli in fecal pellets
- the larvae can survive on pasture for up to three months if temperatures are in the 50s
Dr. Hart explains why this worm is such a problem for goats and their owners, as well as what you can do about them. We also talk about other roundworms and how they cause different symptoms than the barber pole worm.
2:54 barber pole worm
9:50 risk factors for goats
10:55 dewormer resistance
12:14 integrated pest (parasite) management
15:11 5-point check
17:20 using dewormers
23:12 creating a parasite management plan
For more information on parasites in goats …
Listen right here by clicking on the player above, or on your favorite platform:
Deborah Niemann 0:18
Hello, everyone, and welcome back to another episode. Today I am talking to one of my favorite people who works in the world of goats and parasites, and that is Steve Hart, PhD, of Langston University. I am so excited to have you on the podcast today, Dr. Hart, thank you for being here.
Steve Hart 0:39
Thank you for inviting me, Deborah. I enjoy working with producers and look forward to visiting with them on this subject of parasites.
Deborah Niemann 0:48
This is one of the biggest problems that people have. I think if we didn’t have problems with parasites with goats, they would just be incredibly easy. Now, there are so many—well, not “so many.” There are a number of different parasites. And they basically, usually, fall into the category—when you’re talking internal parasites, usually, they’re going to fall into the category of either “worms” or “coccidia.” And when you look at the worms, one of the… The group that seems to cause the most problem are the roundworms. Now, everybody thinks of barber pole worm, and that is a roundworm, but there’s a couple others that we need to know about, too. So, can you give us a quick summary of the difference between the different roundworms that goats have?
Steve Hart 1:32
Okay, Deborah, although there’s more than a dozen different types of roundworms that affect goats. There are three major ones that we look at and monitor, most importantly. Although, you know, any one of the others under unique conditions can be a problem. But 98% of the conditions, we’re going to be looking at these three major species: the barber pole worm, also called Haemonchus contortus, which is our biggest problem. Tropical worm, likes it warm. And then probably our second most important one would be the black scour worm, called Trichostrongylus colubriformis, which is a temperate-species worm. Likes it cool, likes spring and fall. And then what’s called the brown stomach worm, or Teladorsagia circumcinta, or used to be called Ostertagia ostertagi, which is a cool-weather worm and probably our most cold-tolerant worm.
Debora Niemann 2:36
Okay. And barber pole worm causes a lot more damage than these other ones, because it’s got some unique qualities. Could you talk about why the barber pole worm causes so many more problems than the others?
Steve Hart 2:53
Okay, Deborah. The barber pole worm, if you look at a fresh one, will have a red and a white stripe spiraling down them. The reason why they’re given the name “barber pole worm.” The red stripe is the worm’s gut, full of your goat’s blood, and the white stripe is the uterus, full of eggs. And so basically, this worm is a blood-sucking, egg-laying machine capable of laying up to 6,000 eggs per day.
Deborah Niemann 3:24
Steve Hart 3:27
The protein in the eggs has to come from your goats’ blood. They may consume 1 to 5 drops of blood per day, a thousand of them is a pint of blood in a week. If you and I give blood, and we give a pint of blood, we’ve got eight weeks of rest. Your goat has to give another pint of blood next week.
Deborah Niemann 3:50
Oh, my goodness. The number—the 6,000 offspring from a single worm—is what just blows me away. Like, I’m always hesitant to quote the number, because it just always feels like, “No, no, that can’t be right. That’s just too big of a number.”
Steve Hart 4:06
That’s probably… An average is probably more like 2,000 to 3000, but we say—
Deborah Niemann 4:12
That still sounds crazy.
Steve Hart 4:14
Deborah Niemann 4:15
That’s a lot of babies.
Steve Hart 4:17
It sure is.
Deborah Niemann 4:20
So, it’s easy to see—because so many people will say, like, “Well, she was fine yesterday!” You know, you go out there, and you’ve got a goat that just all of a sudden, today, she looks like she’s lost several pounds. She’s anemic. She’s got diarrhea. That is how it happens so fast, because the barber pole can reproduce so fast. So then there all of a sudden you’ve got tens of thousands or hundreds of thousands of these worms, sucking the blood from this poor goat. Can you tell us a little bit about the life cycle of the barber pole worm?
Steve Hart 4:55
Yes, Deborah, and it’s kind of a long description. And basically, we start with the egg being in the fecal pellet laying on the ground. And it hatches, assuming the temperature is higher than 50 degrees; it really likes temperature close… around 80 to 90 degrees Fahrenheit to hatch. So, it hatches in 1 to 5 days depending on temperature. The egg hatches to what we call a first-stage larva. And this larva wanders through the fecal pellet eating E. coli bacteria, kind of like a slider. And so that’s how they grow up, is eating E coli. So, it gets big enough that he then molts to a second stage larva, and he kind of sheds his skin like a snake would shed their skin. Then he becomes a second-stage larva. Both the first- and second-stage larva can be killed in the pellet by drying out, and especially if, like, a chicken were to pick pellet open and the pellet dries out. Also, a hot, dry climate can cause these first- and second-stage larva to dry out. So, the second-stage larva wanders through the fecal pellet, then, eating E. coli, and grows up to where he’s going to become a third-stage larva.
Steve Hart 6:31
However, this molt is what is called an “incomplete molt.” The skin, instead of coming off, just slides up. Okay? The good part is it gives him two jackets, then, that make him resistant to drying out. The bad news is it slipped up over his mouth, and covers his mouth where he cannot eat. So, this means that he has to live off the fat on his back until he gets into your goat. If he runs out of that, he’ll die. And that is dependent on temperature—how fast he burns his fat up. Since he’s cold-blooded, then his metabolism reflects the ambient temperature. If it’s 95 degrees, his metabolism goes fast. He burns up fat stores faster, and he may only live 30 to 40 days. Whereas if the temperature is 50 degrees, he may live in excess of 100 days. And this is how hot weather helps to clean pastures. So, the question about how long do you need animals off the pasture before most of the worms—or infective larvae—are dead depends on temperature. Hot temperatures, shorter period of time. This third-stage larva is the infective larva. He’s got to get out of the pellet to infect your goats, since goats don’t go around eating fecal pellets. The pellet has a hard shell, and so the larva can’t penetrate that. That shell has to be opened, or broken up, by rain—several days of heavy-duty. But we say two weeks of rain in a month’s time is adequate to break the pellet open. And that third-stage larva has no swimming organs; he is like a canoe without a paddle going to where the rain takes him. And he hopes it takes him several inches up on the grass, so that the goat will eat the grass—eat low enough on the grass to consume him, also. When the goat consumes the larva, the larva—when he gets to rumen—immediately molts to a fourth-stage larva. This fourth-stage larva can either continue developing to a fifth-stage larva adolescent and a mature adult that mates and lays eggs, or the fourth-stage larva can become what’s called an “arrested” fourth-stage larva or “inhibited.” And what he does, he just kind of hibernates—nestles down in the stomach glands. And this is an important mechanism for overwinter. And then, in the spring with kidding or lactation, green grass, he wakes up and then becomes an adult to infect the kids. So, like we said, it’s an overwintering mechanism. So this completes our life cycle, then, of the worm.
Deborah Niemann 9:50
And then what are the risk factors for goats in terms of barber pole worm?
Steve Hart 9:57
Okay, Deborah. If the ambient temperature is greater than 50 degrees, you have temperatures high enough for those eggs to hatch and develop. For getting greater than 2 inches of rainfall in a month, we’ll have enough rain to break those pellets open and release the infective larva. Grazing pasture short is another risk factor. We’re getting down there and consuming those infective larva that are in the lower part of the grass. Then animals—because that reflects poor nutrition, which depresses the immune system. Animals in lactation, their immune system is depressed somewhat, so they’re very susceptible, as are young animals. Also, grazing a long time on the same pasture, you have an accumulation of a lot of infective larvae. So, these are the major risk factors that we see.
Debora Niemann 10:55
A lot of people are starting to have trouble, when their goats do get worms, that the dewormers are not working so well anymore. What happened to cause the dewormers to stop working?
Steve Hart 11:07
Okay, Deborah. The dewormers have stopped working because we have basically killed all the susceptible worms with our dewormers. The worm genome, or their DNA, is what’s called a “loose genome.” This means that there are generally a lot of mutations. There may be as much genetic difference between two worms as there are between man and monkey. This means that, in a million worms, you will have two or three that have mutations that would render them resistant to a dewormer. And so, to simplify these million worms, we will kill off the susceptible worms with repeated deworming, and so the resistant ones are the only ones that multiply, then, to replace them. So, when the resistant worms make up about half of our population, we say our dewormer’s not working, because every time we deworm we only get rid of half of the worms or less.
Deborah Niemann 12:14
So, since the dewormers are not working for everyone anymore, obviously we have to do something differently. Dewormers shouldn’t—you shouldn’t look to that as your only answer. So, can you talk a little bit about integrated pest management, and how to use management as your main control strategy?
Steve Hart 12:35
Yes, Deborah. Integrated Pest Management was a concept borrowed from the agronomist who had to cope with a bug resistant to insecticides, fungus that were resistant to fungicides. So, we have borrowed their concept, then. The big thing is to understand what kind of pest you’re dealing with, their life cycle, and management that you can do to discourage the worm. Such things as rotational grazing with a long rest period, not grazing close to the ground. And so, we apply these management practices. We monitor our animals with things like FAMACHA Five Point Check to make sure that management is adequately controlling the parasites. When management is not controlling the parasites, or levels of worms get high enough to cause us a problem, we use a conventional dewormer on those individuals that need it. And we learn from watching our results this year; we make changes in our management for the next year, and, hopefully, do a better job. Get rid of some of our animals that are most susceptible.
Deborah Niemann 13:55
I think you mentioned FAMACHA in this picture, and the Five Point Check. And, how do we… What is the best way to just, like—because people are always wondering, like, when do you deworm your goats? And does it have to do with a fecal or FAMACHA or something else? How does that all work together on a regular farm?
Steve Hart 14:21
Okay. You know, fecal egg counts are wonderful for determining when to deworm animals. However, most people don’t have the time to do fecal egg counts, but they are probably the best mechanism that we have. FAMACHA certainly is a lot quicker and easier to do. FAMACHA basically is a determination of anemia, then, that’s caused by the barber pole wormer. Anemia can also be caused by other things, such as your liver flukes, coccidia, or a bad case of lice, especially on young animals. But it only monitors the barber pole worm. We said there are two other major worms that causes problems. They cause diarrhea, as well as poor growth. And so, we check the animal for diarrhea; we check the animal for bottle jaw, which looks like a double chin in the animal; we look at their body condition score, because the worms suppress the animal’s wellbeing. We also look at their hair coat, then. So that’s the five points, then, that we look at so that we can monitor our animals, not only for the barber pole worms, but for these others worm species that don’t cost anemia.
Deborah Niemann 15:53
And I think it’s really important for people to know that, like, if you’ve got two or three goats, it might be easy to take fecals to the vet, and might not be cost-prohibitive. But if you have twenty, like, do you really want to be out there waiting to catch poop, or even getting poop, from all those goats, and then paying for all those fecals, or doing all those fecals? Because I think one of the things—like, sometimes I’ve heard people say, oh, well, they’ll just get samples from a few of them and mix them together. And what usually follows after that is, “Oh, if it’s high, we’ll deworm the whole herd.” And you really, really don’t want to do that. I always tell people that you should think of dewormers like you think of antibiotics. You only use—you only give them to a sick goat. You wouldn’t want to give them to everybody. You know, just because one goat has pneumonia, you don’t give a shot of penicillin to everybody.
Steve Hart 16:50
Yes, Deborah. And, you know, just because you had pneumonia in February doesn’t mean this February you go give everyone in your herd a shot of LA-200.
Deborah Niemann 17:00
So, using FAMACHA and all these other things—checking the body condition—just makes so much more sense when, you know, you’ve got a herd that, you know, gets to be beyond just a couple of pets. Can you talk a little bit about how to use dewormers? Because there’s not really too many dewormers out there that are labeled for goats. And this is where I think a lot of people also run into trouble with dewormer resistance is they’re under-dosing right from the beginning. So, how are people supposed to use dewormers with their goats?
Steve Hart 17:34
Okay, Deborah. And you mentioned under-dosing. Under-dosing really increases the rate of dewormer resistance rapidly. And so, basically, we talk about needing a higher dose of dewormer for use in our goats. This is because the goat has a larger liver—it’s a percent of body weight. And so it can metabolize those dewormers away. And they also have a pasturated passage in the gastrointestinal tract which will move those dewormers through the gastrointestinal tract faster. So, we talked about needing double the dose of dewormers as compared to cattle or the sheep dose that’s listed on the dewormer to get our concentrations up in the effective range that we need to kill worms.
Deborah Niemann 18:25
And if somebody wants to incorporate some more natural control methods in terms of prevention or treatment, can you talk a little bit about some of those things that have been—because there’s so much stuff out there that has not proven to work. And so, I really just like to encourage people to try things that have been proven to work by—you know, according to the research. What are some of the natural things people can use when it comes to deworming?
Steve Hart 18:54
Well, I’ll touch base on herbals. Sometimes they work. They tend to be unpredictable, just because the active ingredient in the herb can vary so widely in concentrations because of where the plant’s grown, the way it’s processed, the stage that it’s harvested, etc.. If you insist on using herbals, do the Five Point Check regularly, and use a conventional dewormer if you’re getting in trouble on your animals. Some of the natural dewormers: the first would be sericea lespedeza. And I should point out there’s other plants such as birdsfoot trefoil in some areas, chicory, and sainfoin that all have a chemical called “tannins” that are effective against worms. Sericea lespedeza, which we were the first ones and have done quite a bit of work with it, works very well; it reduces fecal egg count by 60% or more. It interferes with the hatching and development of the larva in the fecal pellet. We’ve grazed goats the whole summer on it without needing deworming. One study showed that it might depress molybdenum absorption, and so that may be a consideration in animals that are on it too long. But we’ve had positive results, and many others have had positive results with it. The tannins in oats are not effective as a dewormer. There are likely other plants that have the dewormer effect, but we haven’t done the research on them. Other things that can work well are copper oxide wire particles; they are effective only against the barber pole worm. We don’t really understand how they work, but it seems to be fairly effective. They don’t seem to work for just weaned animals—one of the caveats. The correct doses 4 grams for an adult and 2 grams for those weighing less than 50 pounds; you probably need to limit it to three times in the summer, unless you have high levels of copper in the diet or high liver levels of copper, and you need to reduce that number. When you have an animal mortality, you should freeze a piece of liver as big as two fingers and have it submitted to the Michigan State diagnostic lab for analysis. This can not only tell you your level of copper, but tell you a lot about other minerals in your nutrition program and how you’re doing. BioWorma is another natural factor that we can use; it’s for sale by Premier1. It’s a fungus that parasitizes developing larva in the fecal pellet. It’s very effective. There’s been work done here in the U.S. It must be fed every day, and it’s currently pricey, but for those that have more goats than they have land, it may be the only way that they can really control pasture contamination. And so those are our major natural dewormers that are available.
Deborah Niemann 22:13
The way that the BioWorma works is that it keeps the eggs from hatching in the goat poop once it’s on the pasture, or it does something to the larva?
Steve Hart 22:23
What it does is, the fungus actually puts out loops, kind of like lariats, and as the infective larvae are moving through the pellet eating the E. coli, they will go into the loop and get caught, and so the fungus, then, uses the larvae—or infects the larvae, and it uses it to reproduce itself, then. So basically, the parasite is parasitized by the fungus.
Deborah Niemann 22:59
Oh, that’s perfect. So, I think we’ve kind of covered a bunch of different bases here. And so, how does somebody put all of this stuff together? Like, how does this look for just your average goat owner who says, “I just want to make sure my goats are healthy and don’t have worm problems?”
Steve Hart 23:16
Okay. It requires putting together a plan. And one thing is to determine some things that you can use as far as management to prevent worms. And we haven’t covered—we’ve just touched base on a few things. Rotational grazing is one of the probably best things you can do. Avoiding grazing down close to the ground. Making hay out of a pasture. The use of horses or cattle, which clean up pastures. So, determine what management practices are applicable in your farm situation. And use those. And then, every two weeks, you need to monitor your animals for the Five Point Check of individual animals; deworm the ones that need it; cull those that need it the most—this is probably the single most important thing that you can do for controlling parasites is get rid of those 20% of the animals that are producing 50% of the worms or more.
Deborah Niemann 24:26
Right. That’s really important for people to understand, that just—because that’s one of those old things, you know, that you used to hear, like, “Well, if one’s got worms, they all have worms”—is that research has actually shown that’s not true. That parasites are much worse for some goats than others.
Steve Hart 24:44
Yes. One parasitologist said, “It’s like money; it’s not equally distributed to all individuals.”
Deborah Niemann 24:51
That’s good. I’ll have to remember that. So, I know that is what happened with me, because we had complete dewormer resistance a long time ago, and, basically, Mother Nature culled my herd for me. So, we actually have very little trouble with parasites now. I mean, maybe I’ll have 2 or 3 goats every year that need a dewormer, one time, and that’s it. Most of them it’s, like, a yearling right after she freshens or something like that.
Steve Hart 25:23
Yes, that is the most animals that are susceptible.
Deborah Niemann 25:27
Thank you so much for talking with us today. I know you’ve been working in this field for so many years—like, since the 90s, right, was when you started studying goats and parasites?
Steve Hart 25:40
Yes, that’s correct, Deborah.
Deborah Niemann 25:44
So, you have seen a lot of changes, which is another thing I love talking to you about, too, sometimes, you know, like, the history of it all, and how much it has changed. And so that’s why, you know, people see so much different information across the internet, because the stuff that was put out there 20 years ago is still there. And, you know, current research has shown that a lot of the stuff we did back in the 90s was not a good idea.
Steve Hart 26:09
And one of those things was rotating dewormers.
Deborah Niemann 26:12
Yes, that’s right. So, we know now that you’re not supposed to rotate the dewormers; you should just continue to use one until it no longer works.
Steve Hart 26:21
Deborah Niemann 26:23
And the thing is, if you’re only giving it to a single goat when that single goat needs it, they really should not need it. Like I said, I have goats that have never had a dewormer in their life, or some that have only had it once. Like, this is not something that you should have to do on a regular basis. And if you do, then there’s a lot of other management things that you probably need to start incorporating into your farm.
Steve Hart 26:50
Deborah Niemann 26:52
Thank you so much for joining us today! I think that a lot of people are going to find this really interesting and helpful. And I hope you’ll join us again sometime to talk about more of this.
Steve Hart 27:05
I hope so, Deborah. I really appreciate the invitation and the time to visit with producers about this very important subject.
Deborah Niemann 27:16
Thank you so much.
Deborah Niemann 27:19
And that’s it for this week. Next week we are going to be talking about goat law. Yes, law. Be sure to subscribe, so you don’t miss it, or any other episode. If you want to see the show notes. Be sure to visit ForTheLoveOfGoats.com. You can also find us on Facebook at Facebook.com/LoveGoatsPodcast. And, if you’ve got a moment, we would love it if you could leave us a review. Thanks so much! See you next time. Bye.
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