Goat Worms: A Complete Guide to Winning the War in Your Pasture

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Since I bought my first goats in 2002, nothing has changed more than the diagnosis and treatment of worms in goats. Unfortunately, nothing online ever dies, so there is still tons of old information out there, which actually makes the problems worse.

The prevalence of gastrointestinal parasites in goats is pretty much 100% unless your goat has been living in a sterile room its entire life. As one vet said to me years ago, you will never get to zero parasites in an animal that eats off the ground.

That means your goat has worms, and it’s okay. This is a major shift in thinking from the 1990s when everyone thought that no one ever needed to lose another goat to internal parasites because we had so many great new drugs available.

This is a lot like the thinking about infectious disease 50 years ago. No one ever needs to die from an infection because we had invented so many great antibiotics. Unfortunately, in both cases, overuse of the drugs has led to resistance. Just as overuse of antibiotics has led to antimicrobial resistance, overuse of dewormers has led to dewormer resistance, which means worms survive exposure to dewormers.

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Does this mean we just give up and watch our goats die?

Absolutely not! And I say this as someone who did watch a lot of my goats die back in the early 2000s because the worms on our farm were resistant to all of the drugs. And I tried all the things that everyone told me would work, including herbs, garlic, apple cider vinegar, Basic H, essential oils, and more! None of it worked. This article explains why I don’t recommend herbal dewormers for goats.

Giving dewormers is short-sighted and although you might win the battle today, it’s a losing strategy in the long run. The answer to winning the war on worms in goats is to know your enemy and adjust your management.

Goats have worms

Before you get too upset about this idea, remember that 50 years ago, we thought it was a great idea to kill all the bacteria in our bodies. Today the sale of probiotics — healthy bacteria — is a multi-billion dollar business. They are especially popular for people who have recently taken antibiotics because they are trying to build up the healthy flora in their bodies again.

We have no idea how worms and other intestinal parasites might be helping goats, but since worms are species specific, worms like haemonchus contortus (barber pole worm) would not exist without goats and sheep. And it’s really not in the worms’ best interest to kill the goat because then they die without a host. Worms don’t crawl out of one dead goat’s body and find another host. So, there is some kind of symbiotic relationship there, and we need to get over the idea that we need to kill them all.

Most worms don’t hurt goats. I did an entire podcast episode on the common but unimportant worms in goats with Dr. Ann Zajac, Professor Emeritus of Parasitology at Virginia-Maryland College of Veterinary Medicine at Virginia Tech.

Roundworms in goats are a problem, which I covered in a podcast episode with Dr. Steve Hart from Langston University. The most infamous of the roundworms is the barber pole worm, which is the common name for haemonchus contortus. It kills more goats than any other worm because it’s a blood sucker. The other roundworms just eat the contents of the digestive tract, which can make for some very skinny goats, which is why one has the nickname “bankrupt worm” because skinny goats are unproductive and can bankrupt owners.

The other thing that makes barber pole so much worse is that a female can lay thousands of eggs per day, which means a pasture can become contaminated very quickly! Other roundworms only lay hundreds of eggs per day. This is a problem for your whole herd because when a goat poops, all of those thousands of eggs are being dumped on your pasture where other goats can become infected after the eggs hatch and mature into infective larvae.

How do goats get infected with worms?

Contrary to popular belief, eggs do NOT hatch inside the goat. Worm eggs hatch on pasture where they mature into infective larvae over the course of a few days. Then goats eat the larvae that is on short grass.

This is where management comes in. If goats don’t stay on the same pasture for too long, they can avoid consuming too much worm larvae. Rotational grazing is the key to maintaining a goat herd that’s not burdened by worms. There is no magic number when it comes to rotating them to fresh pasture because there are several things to keep in mind.

Larvae cannot crawl or swim, but they can float up on grass. This is why their range is limited to the lower four inches of grass when it’s wet. So, the more rain you have, the more mobile larvae can be. They can live on grass for a long time as long as they have water, and if it’s raining every day or two, they can live for months! But once it gets hot and dry, they start to die.

Usually if you can move them to fresh grass about once a week, that works, as long as they don’t eat the grass down shorter than four inches during that time. If they eat the grass down within three or four days, then they need to be moved at that time.

They should not return to a pasture for at least a month, but longer is better, especially if it’s been raining a lot and it’s not too hot. Our front yard is reserved for kids and their moms in April, which is the beginning of grazing season for us. Until then, they are kept in the barn. Since there have been no goats on the front yard in 11 months, it is considered a clean pasture, so the kids are not immediately consuming a ton of worm larvae.

This article provides more info on exactly how to practice rotational grazing, and includes a video.

Worms in Goats: Symptoms of an overload

If we only give a dewormer to goats that are sick from worms, how do we know which ones have a problem?

The primary symptom of barber pole worm is anemia. You’ll know your goat is anemic by pulling down the lower eyelid and looking at the color. It should be bright pink or red. If it’s light pink or white, the goat is anemic. This only works on the eyelids (not gums) and is called their FAMACHA score.

Other symptoms of barber pole worms in goats are weight loss, a rough hair coat, and sometimes, bottle jaw, which is swelling under the jaw from the jawbone to the chin.

Other roundworm infections in goats do not cause anemia, but may cause a goat to be underweight and have a rough hair coat, as well as diarrhea.

Diarrhea in kids from 3 weeks to 5 months is usually caused by coccidiosis, which is a protozoa, not a worm. Dewormers do nothing to treat coccidiosis, so if a kid has diarrhea, you may need a fecal exam to determine whether it has a problem with coccidia or worms because different medications are needed.

How do you prevent worms in goats?

There is no magic pill. There are a number of strategies you can use to reduce the parasite burden on your goats. This list is a summary of my article on preventing internal parasites in goats, and it also includes links that give you more detailed information on some of these strategies:

  1. Pasture rotation, also called rotational grazing, is the ultimate tool for preventing worm problems in goats.
  2. Creating a dry lot is a good alternative for people who can’t rotate pastures. If there is no grass for the larvae to cling to, then infection is greatly minimized. Just be sure that the goats are not eating grass around the edge of the dry lot that could have incredibly high levels of larvae!
  3. Pay attention to grass height, and don’t let your goats eat grass that is less than 4 inches. Personally I play it safe and move them when it’s down to only 6 inches.
  4. Pay attention to the weather. When it’s especially wet and rainy, your goats may need to stay off pasture for a longer period of time than if it’s not so rainy.
  5. Mixed species grazing means that your goats are sharing pasture with species that do not have the same worms, such as horses and cows. When the horses and cows eat goat worm larvae, their body digests it because the worms can only survive inside goats and sheep.
  6. Provide more browse! I wanted to cry one day when someone emailed me that they had brush hogged all the brush in their pasture and wanted to know what kind of grass to plant for goats! Goats are browsers! There is an old saying that goats should never eat below their knees. There is no worm larvae on the leaves of small bushes and trees.
  7. Have goats give birth during the time of year when worm loads on pasture are lowest. In Illinois, that meant that we had goats kidding in January when all the grass was covered in snow.
  8. Breeding for resistance is probably the best long-term strategy. Some goats are simply more resistant to worms than other. There was an 11-year study on genetic resistance to worms. I know one vet who raises meat goats and said that the second time a goat needs a dewormer in its life, it goes into the freezer. Not everyone is willing to cull goats that have poor resistance to worms, but in my case, Mother Nature culled my herd for me. When the dewormers no longer worked, it was a real life case of survival of the fittest. Now I have a herd that has great resistance to worms.
  9. Plants with high tannins have been shown to reduce parasite loads in goats. This includes plants like sericea lespedeza, which we discussed at length in another podcast episode.

Deworming goats

Back when I got started with goats in 2002, people dewormed goats on a schedule. Some did it monthly or three or four times a year. Others did it before breeding season and before kidding or after kidding. And they dewormed every goat in the whole herd.

If a goat had a parasite overload and got sick, they’d give them a dewormer multiple times, and they’d give it to every goat in the herd. The incorrect thinking was that if one goat had worms, they all did!

For more than 10 years now, research has told us that all of those old practices simply created a problem with dewormer resistance. We’ve also learned that typically only about 10-20% of the goats on a farm are carrying about 80% of the worms.

So, the #1 rule of using dewormers in goats is to only give it to goats that are showing symptoms of a worm overload.

What is the best goat dewormer?

People ask me this question so often! And the answer is … the best dewormer for your goats is the one that works on your farm! If you’ve never used a dewormer and you’ve had your goats at least a couple of years, then all of the dewormers should work as long as you use it at the correct dosage. If you’ve bought your goats within the last few months, you should ask the seller what dewormers they have used on their farm, how often, and on what percentage of their herd.

Maybe you’ve heard that dewormer X or Y doesn’t work. If X or Y doesn’t work for Farmer Z, it’s because they’ve used it too often or used it incorrectly. All of the dewormers work when they are given at the correct dosage to goats that are carrying worms that have never been exposed to that dewormer.

Dewormers should also be stored at room temperature, never refrigerated or frozen, and they should not be used after their expiration date. They start to lose potency after their expiration date, so it’s like underdosing when you use expired dewormers, which means more worms will survive, and they will be resistant to that dewormer now.

Because dewormers are not labeled correctly for goats, many people underdose, which means that a lot of worms survive exposure to the drug. Sheep drenches (except levamisole) should be given to goats at twice the sheep dosage, and levamisole should be given at 1.5 times the sheep dosage. Even the Safeguard that is labeled for goats should be given to goats at twice the dosage on the bottle. Every worm that survives a dewormer is now resistant to the dewormer and will have baby worms that are resistant to that dewormer.

How to deworm a goat

Goats should always be given dewormers orally. This is a recommendation that I have seen come full circle since I started in 2002. There was a brief period of time when injectable dewormers were recommended, but there are two excellent reasons why they are a bad idea for goats.

First, injectable dewormers are “long tail,” which means they stay in the goat’s body for a very long times at a very low level. That means that for weeks, every worm in that goat’s body will be exposed to the dewormer at a level that is low enough for the worm to easily survive, so all of its offspring will be resistant to that dewormer. Basically, if you use injectable dewormers, you are on the fast track to dewormer resistance.

Second, if you have dairy goats, you will be consuming dewormer residue in the milk. You have clearly ignored the label warning to NOT use it in dairy animals, and you’ve probably believed someone who said to just wait a couple of weeks and it’ll be fine.

Some people incorrectly assume that the warning on the label just means that a withdrawal time has not been established, but they are so very wrong! It has been studied, and the warning is on the label because who wants to milk a goat and dump their milk for 2 to 4 MONTHS?! Yes, there is dewormer residue in the milk for 2 to 4 months (depending upon which drug) when dewormers are injected. When those same drugs are given orally, the milk withdrawal time is only 2 to 3 weeks. This article goes into more details about milk and meat withdrawal in goats following drug use.

There is a social media myth that oral dewormers will kill a goat with a bad load of worms because all of the worms that were sucking blood will die and let go at once, and the goat will bleed to death. This is incorrect because the worms are not attached to the inside of the goat’s stomach like a leech. They scratch the lining of the stomach and suck the blood that’s released.

But someone told you that they gave their goat an oral dewormer and it died! This does not mean the dewormer killed the goat. When a goat has a bad case of barber pole and is severely anemic, it may need more than just a dewormer to recover. If a goat’s PCV is low enough, its only chance of survival may be a blood transfusion.

Or maybe the worms on the farm are resistant to the dewormer, so it only killed about half of the worms, which was not enough to help the goat to recover. There are many reasons why a goat might die, even though you gave it a dewormer. A lot of goats with worms might wind up dying from dehydration because they are simply too weak to walk to the water trough — especially when it’s extremely hot out.

Do pour-on dewormers work for goats?

Research has shown that they only kill about 50% of worms, meaning that you are again on the fast track to dewormer resistance because so many worms are surviving exposure to the drug. Plus, you haven’t really killed enough worms to make a really sick animal improve. Pour-on dewormers can work for lice and some types of mites in goats.

Want to know more about dewormers? This article goes into the specifics about using dewormers, the classes of dewormers, as well as using combination dewormers. It also explains what extra-label drug use means — and what it doesn’t.

FAQs about worms in goats

Does this information apply to meningeal worm or deer worm?

No. This post specifically addresses gastrointestinal worms in goats. Meningeal worm, also known as deer worm because it’s normally found in deer, and also known as brain worm because it can wind up in a goat’s brain or brain stem, is completely different. You can learn more about this devastating parasite in this article and this podcast interview.

What are the worms in my goat’s head — or udder or leg or …

The first time I got this question I was so confused! There are no worms that you can see in your goat’s head or udder or any other external body part. I walked into the other room and told my husband about the email I had just received, and he immediately said, “If someone has never seen maggots before, they do look like worms.” Yes!

If you ever see a bunch of worms waving at you from your goat’s udder or head or other skin, it’s most likely due to flies laying their eggs in an open wound. Fly eggs first hatch into maggots, which then grow up to become flies. In the livestock world, this is called “fly strike,” and some people refer to the maggots as “screw worms,” and I’d be oh-so-happy to never see another case in my life.

The first time we dealt with this, it was in a lamb, and we spent hours picking them out with tweezers. You can buy insecticidal sprays like this one to prevent flies from laying their eggs in a wound or to kill the maggots once an infestation has occurred.

What are the worms I see in my goat’s poop?

The only intestinal parasite in goats that is visible to the naked eye is tapeworms. They are usually dead when passed, so they look like rice or noodles. One vet I know says that they are worse for the mental health of the owner than the physical health of the goat. In other words, they don’t make goats sick, although they sure look scary to the owner!

Tapeworms were one of the common but unimportant worms I discussed in a podcast episode with Dr. Ann Zajac, Professor Emeritus of Parasitology at Virginia-Maryland College of Veterinary Medicine at Virginia Tech.

Can I give a dewormer to a pregnant goat?

It is safe to use ivermectin, Cydectin (moxidectin), and Safeguard or Pancur (fenbendazole) in pregnant goats. Valbazen is not safe in the first three months of pregnancy, but most people avoid it throughout pregnancy just to be on the safe side. There is also anecdotal evidence that levamisole is not safe to use towards the end of pregnancy.

Can I give a dewormer to a nursing goat?

Yes. All dewormers are safe for nursing does and their kids. There will be residue in the milk, but it won’t hurt the kids. It is also important to note that the residue is at a very low level, so the kids are not being dewormed, as I’ve heard some people assume. Yes, this could technically create some dewormer resistant worms in the kids, but ideally the kids have such a low worm count that it would be insignificant.

How many days do you give Safeguard to goats?

Safeguard is only given one time for roundworms, which includes barber pole. If a goat has tapeworms, it has to be given three days in a row, but remember that tapeworms don’t usually make goats sick, so do you really want to expose the roundworms to the Safeguard to kill worms that are not a problem? If you use dewormers on less than 10% of your herd annually, then it’s probably not a big deal. But if you have a problem with roundworms, then you might want to avoid treating your goats for tapeworms and reserve dewormers for when they are really needed.

How often should I deworm my goats?

Never! That would be the ideal, but life isn’t perfect and neither are all of our goats. After a decade of seriously managing internal parasites on my farm, most of my goats have never had a dewormer in their entire lives. Typically the only ones that do need a dewormer are first freshening yearlings after kidding because their immune system is not mature yet.

Also, I don’t expect my mature does to feed more than three kids, which definitely helps them maintain their body condition. Research has shown that does feeding multiples or who are high producers will have more trouble handling intestinal parasites than does feeding twins and not producing as much milk.

Bottom line — there is no best schedule for deworming goats because it should never be done according to any calendar or any type of schedule. Dewormers are drugs that should only be given to sick animals.

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