Internal parasites in goats: Preventing infection

If fighting internal parasites with dewormers is ultimately a losing battle, what can you do to keep your goats healthy and productive? There are a number of environmental controls that can be utilized to eliminate parasite problems almost entirely. If goats needed dewormers to survive, they would have all become extinct before dewormers were invented. Many of the following ideas are not new, simply rediscovered from the era before drugs were developed. There was an old Scottish shepherd’s saying that one should “never let the church bell strike thrice on the same pasture,” meaning that sheep should be moved to new pasture at least every couple of weeks.

Pasture rotation

Pasture rotation is one of the most important management tools you have in preventing parasite problems. Worms and coccidia can contaminate a pasture and cause continual reinfestation of goats eating the grass. The shorter the time goats spend on pasture before being moved to fresh ground and the longer they stay off previously grazed pasture, the fewer parasite problems you will have. For example, if you could give goats a clean pasture every day and never put them back on any section for a full year, you would probably never have any parasite problems. Of course, few people have that much pasture or the time to rotate their goats every day, especially if they have a large herd, which may require the help of several people to move. Ideally, goats should be moved off a piece of grass within five to seven days and should not return to that spot for six weeks. However, the more often you can move them and the longer they can stay off of a piece of ground, the better.

Weather

Weather plays a big role in the rotation schedule. If temperatures are above 95°F and it is very dry, you will be able to leave goats on a piece of pasture much longer than if it is 70°F and raining every other day. You can usually let goats graze in a pasture until you get at least 1/2 inch of rain, which provides the perfect environment for larvae to thrive. When temperatures are in the upper 90s, you can probably let a pasture rest for as little as five or six weeks. However, keeping goats off pasture for at least three months in more moderate temperatures is necessary to help prevent ingestion of worm larvae left on the pasture during the previous grazing period.

Grass height

Height of grass is an important consideration when goats are on pasture. Because most larvae are on the lower 2 or 3 inches of grass, it is a good idea to move goats to the next pasture when the grass is about 5 or 6 inches tall in their current pasture and definitely by the time it is grazed down to 4 inches. Early in the grazing season, some varieties of grass may not get very tall, so you will have to move goats to fresh pasture sooner than you will have to later in the grazing season. This is one reason it is better to create many smaller paddocks and move goats more frequently. Goats in a very large pasture will completely ignore some areas and overgraze others, and the longer the goats are there, the worse the problem gets. Young grass is tender and sweet; taller grass begins to grow tough and becomes less appetizing. Sections of untouched grass can be mistaken for an abundance of grass in the pasture, but unfortunately, goats will keep going back to the grass that is extremely short and covered with infective larvae.

Mixing species

Integrating other species such as poultry, horses, cattle, or pigs into the pasture rotation can help you utilize pasture more effectively than if you only have one species. Grass is at its most nutritious about thirty days after it was last grazed or cut, but that is also when larvae tend to be at the most highly infective stage. However, horses, cattle, and pigs are not susceptible to worms that infect goats and are able to digest the larvae. In other words, cattle, horses, and pigs can clean up a pasture, making it safe for goats to graze sooner than would otherwise be safe. Using sheep, alpacas, or llamas is not effective, however, because some goat worms can also infect them.

Browse

Providing goats with areas to browse is also an effective tool for controlling parasites. Goats have a much harder time dealing with parasites than sheep and cattle because as mentioned earlier, goats have not been grazers throughout history, like sheep and cattle. Although goats will eat grass, they are browsers and prefer to eat small trees and shrubs, which have no parasite larvae on them.

Dry lot

It might be tempting to keep goats on a dry lot or in a barn to avoid grass and the inevitable parasites on it. However, when goats are kept inside, the bedding needs to be kept cleaner than you would expect, in order to avoid coccidiosis in kids. If a stall is too dirty for you to sit down in, it isn’t clean enough for kids. A dry lot needs to be large enough that there isn’t a build-up of manure in it. Even in a dry lot a goat can become infected when it sticks its head through the fence to eat the grass that has been infected by other goats pooping along the fence line. Also keep in mind that not all parasites need grass. Intestinal thread worm (Strongyloides papillosus) can hatch in bedding or soil and infect a goat through its skin, although it is not a common parasite.

Breeding for resistance

Selecting goats for parasite resistance is one of the most sustainable ways to deal with parasites. Some goats are clearly more parasite resistant than others, and research is under way to see if some breeds are more resistant than others. In the meantime, some researchers and veterinarians are encouraging breeders to cull animals that have an unusually hard time with parasites. By eliminating goats from your herd that need multiple dewormings, you reduce your dependency on dewormers. I know one vet who raises goats and will cull an animal the second time it needs a dewormer. In my own herd, I breed goats with mediocre parasite resistance to goats with high parasite resistance.

Seasonal birthing

It has been a common practice for many years for goat breeders to give a chemical dewormer to every doe as soon as she kids. An increase in worm load is thought to be a normal part of freshening, and the dose of dewormer at that time has been considered unavoidable. However, some breeders are starting to question this practice and are waiting to deworm until they see that a doe truly needs it. There is no doubt that some does have an increase in parasite load after kidding and they do require a chemical dewormer. There are alternatives for some goats, though.

Most of my goats do not require dewormer after kidding if they give birth in January or February when parasites on the pasture are frozen or in late summer or early fall. If they give birth between March and June, however, the odds are not in their favor. July is variable based upon whether it is a dry or rainy summer. A number of breeders and researchers have begun to make similar observations about avoiding dewormers by timing kidding so that does are not freshening when parasites are at their highest level on the pasture. Keep in mind that the ideal time for kidding can vary from one location to another, depending upon your weather.

Tannin plants

In addition to traditional herbs, there are a variety of tannin-producing plants such as sericea lespedeza, birdsfoot trefoil, and chicory that have been shown to reduce parasite loads. These are plants that grow wild in many places but can also be planted in your pasture. However, it is not as simple as seeing a few of these plants growing in the pasture and assuming that you don’t have to worry about parasites. Sericea lespedeza is the most studied of the natural anthelmintics, and it has been shown to reduce parasite levels at varying degrees. Goats grazing on fields of lespedeza daily have been shown to have no parasite problems. However, as their grazing time decreases, the parasite problems increase. There are currently no solid recommendations for how much lespedeza goats need to consume to control parasites.

As you have probably realized by now, there is no magic bullet. Controlling parasites has to be a multipronged approach. And just when you think you have it figured out, things can change. This is why it is important that you understand the life cycle of the parasites, rather than simply memorizing a particular deworming protocol. An unusually mild winter or wet spring can make problems worse by providing the perfect environment for larvae to survive on pasture for an extended period of time. A drought may improve the problem by drying up the larvae on pasture. Raising goats sustainably doesn’t mean substituting a natural dewormer for a chemical one. It means creating a management plan and an environment in which goats can thrive with the fewest external inputs from humans.

This is an excerpt from Raising Goats Naturally: The Complete Guide to Milk, Meat, and More by Deborah Niemann. 

To learn more, read my post about dewormer resistance.

31 thoughts on “Internal parasites in goats: Preventing infection”

  1. I only worm my goats if their eyelids tell me they need it. A couple of weeks ago, they didn’t need worming but it recently rained and their eyes have paled. I just wormed my male goats but my doe has been bred a few days ago. Is it safe to use Panacur on her? (I don’t have access to herbal wormers…as those websites don’t deliver where I live)

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  2. Thanks for your reply. Some people are telling me that Panacur will cause abortion in the first 30,days? I knew this about Valbazen but not Panacur. Is this statement valid?

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    • Levamisole and Valbazen are the only two dewormers to be avoided during pregnancy. Panacur is actually the safest dewormer out there. It has a huge margin of safety. Maybe they are confused by the fact that it is white like Valbazen?

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  3. Yes…now that you mention it. This was the first time I heard of such a claim. And I think that its more important to keep the doe healthy during pregnancy; instead of worrying about possible abortion. A wormy pregnant goat is in a dangerous situation. Thank you:)

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    • Well, I would NOT give levamisole or Valbazen because they do have documented history of causing birth defects or abortions. But other dewormers are totally safe for pregnancy. In fact I had a doe treated with Panacur for meningeal worm, which is a HUGE dose (about 10x the regular dose), when she was pregnant, and she went through pregnancy and gave birth to healthy kids.

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    • It will help if barber pole is the one causing most of the trouble. It doesn’t help with other types of worms though.

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  4. Can I use mulch to create a dry lot around the goat shed and their milking shed which is also where their water is? I’m also planning to start rotation. Are there any ideas on housing to have in the individual paddock? We are also planning to get a calf to grow out so I’m guessing they would need housing as well, but maybe not as much as goats since they don’t mind rain.

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    • My only concern about mulch is that some of it is cut really rough, and I’d worry about them getting splinters in their hooves. But if it’s a nicely cut mulch without a lot of jagged edges, that might work. One woman I know who raises kikos put down road felt with gravel on top.

      If the goats are only outside during the day, or if it’s bucks, a 3-sided shelter is fine.

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  5. I have five does in a 50×50 lot with no grass. They never graze because there is nothing to graze on maybe some leaves. Does this mean my goats will not have a huge problem for internal parasites. Its a pretty big lot. 90 percent of it is dirt.

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    • If there is literally zero grass, then they should not have parasite problems. However, if there is grass around the edge of the pen, that might be enough to cause a problem if enough poop winds up there. One researcher told me about a herd that had a parasite problem because they were on concrete, and the rain would wash all of the poop to the edge of the concrete. There was grass there; the eggs in the poop hatched; and the larvae wound up on that grass. The goats ate it and had big problems. They tested the grass and said that the weight of the larvae was more than the actual grass itself because all of the poop was being concentrated on the edges of the pen. So don’t make any assumptions to start. Pay attention to body condition and FAMACHA scores. Every situation is slightly different, so watch your goats. They’ll let you know what they need.

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  6. Do you have any information on whether the buck or doe contributes most to parasite resistance, healthy hooves, and number of babies?

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    • I have never actually looked into that for parasite resistance or hooves. Both are definitely heritable, but I would never use a buck that is not as close to perfect as I can find. If he has bad hooves, he’s castrated. If he has poor parasite resistance, he’s castrated. I only keep bucks out of does with excellent parasite resistance and moms who are excellent milkers. We need so few bucks in the world that it’s just not worth keeping one if he’s not excellent in every way. I would not keep a buck whose dam did not have excellent parasite resistance.

      I’ve only had one doe with bad hooves. She gave them to her daughter, and then they were gone. I’ve kept multiple generations out of that doe, and no one has the terrible hooves her mother had — which were always on the verge of hoof rot.

      As for number of kids … having high multiples on either side of the pedigree can mean you can wind up with high multiples. It’s all about how many eggs the doe is releasing. High multiples came into my herd through two bucks. And I didn’t realize until recently that all of the births of five or more kids have had both of those bucks in the pedigree, except one, which was a doe I bought so long ago (2003) that I don’t know what was in her pedigree in terms of multiples. I really don’t like more than triplets, so I have been retiring does that have more than four. If you have does that have single a lot, keep in mind that it could be caused by selenium and/or copper deficiency.

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  7. I find your article very interesting. Thank you for taking the time to help others with this problem. My question is we live in south central Iowa where the summer is very unpredictable as far as wether goes. We have got to thinking about where you talk about how the taller the grass lowers the chance of getting worms. We have some bottom ground that is full of slou grass and didn’t know if it is a good place for the goats to graze as long as they don’t eat it down to low. I also was wanting to now is there a pesticide that can be spread on the pasture to help with the issue of worms. Thanks for your time.

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    • There has been no positive research on pasture treatment with chemicals or even fire. You really just need to rotate and let Mother Nature kills the worm larvae.

      I’m not familiar with slou grass, but with any pasture you should not let the goats graze it any shorter than 4-6″. Research specifies 4″, but I prefer to move them when it’s less than 6 just to be safe.

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  8. Thanks again for sharing your expertise! A question… if one were to keep birds with the goats, which would be the best kind to eat the larvae and worms and to cohabitate with the goats? I keep my chickens in pens and house separate from the goats’. I just really don’t like having the messy bird droppings all over while goats’ droppings are so “clean”, but I’d be open to keeping a few birds with the goats if it were to be very helpful for parasite management. Thank you.

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    • Keeping chickens with your goats will not help with goat worms, which are microscopic. Chickens are great with cattle because cows poop big messy cow pies, and flies lay eggs in those cow pies, and chickens eat the larvae (maggots) after the eggs hatch. Goats don’t have the fly problems that cows do because their poop is dry little berries.

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