Johne’s Disease in Goats

Episode 91
For the Love of Goats

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If you have goats, or if you are considering getting goats, you should be aware of Johnne’s disease. It is an infectious disease that is highly contagious, and there is no cure.

Today’s guest is Dr. Michael Pesato, an Assistant Clinical Professor of Food Animal Medicine and Surgery at Mississippi State University. He is a board certified practitioner with the American Board of Veterinary Practitioners specializing in Food Animal Practice.

We are talking about how Johne’s is transmitted, the symptoms, and diagnosis. We also discuss the different types of testing, as well as the efficacy of each one, and when it makes the most sense to do a blood test or a fecal test. And finally, we talk about what to do if you discover that you have Johne’s in your herd.

Other episodes with Dr. Michael Pesato

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Introduction 0:03
For the love of goats! We are talking about everything goat. Whether you’re a goat owner, a breeder, or just a fan of these wonderful creatures, we’ve got you covered. And now, here is Deborah Niemann.

Deborah Niemann 0:16
Hello, everyone. Welcome back. Today, we are going to be talking about a disease that is extremely interesting and extremely contagious. And, if you don’t know about it, you definitely need to listen in today so that you can learn as much as you can, so that you can protect your goats—as well as if you have sheep or cattle. Because, this is a disease that can happen with any of the ruminants. So, we are joined today by Dr. Michael Pesato, an Assistant Clinical Professor of Food Animal Medicine and Surgery at Mississippi State University. He’s board certified with the American Board of Veterinary Practitioners, specializing in Food Animal Practice, and he has joined us in the past for some other really great topics, like parasites. And, we’ll put links to those in the show notes. Welcome back, Dr. Pesato.

Deborah Niemann 0:20
Thank you for having me again! I love being a frequent flyer. This is a lot of fun.

Deborah Niemann 1:09
Good! So, it’s really kind of funny. When I got interested in goats, I learned about CAE pretty quickly. And then, one day, after—I think—I’d probably had goats a couple years, I was talking to my mentor. And she said, “You know, everybody’s just so concerned about CAE, but the thing that really scares me is Johne’s.” And I was like, “What’s Johne’s?” And so, she tells me about this horrible disease that can live on your pasture for, like, five years. And, you can’t have any more ruminants on your pasture for all those years, because they could get it. And, it’s a disease that has no cure. There’s no vaccine. There’s no treatment. So, that’s the bad news. And, she certainly had me convinced that I needed to be concerned about it after that brief conversation. So, if somebody’s not familiar with Johne’s, explain exactly what this disease is.

Michael Pesato 1:55
Yeah. Yeah. So, Johne’s is a very interesting disease. It’s endemic in the United States, meaning that we do have it very commonly in a lot of different species. As Deborah has already mentioned, it happens in multiple different ruminant species—sheep, goats and cattle. It’s caused by a bacteria called Mycobacterium avium subspecies paratuberculosis. And, I always tell my students, the way to remember that is M.A.P. So, this is the same genus as Mycobacterium bovis, which is the causative agent for tuberculosis in cattle. It’s the same genus as Mycobacterium tuberculosis, which is the causative agent for tuberculosis in people. It is not, however, tuberculosis, so don’t panic. I know it has “paratuberculosis” in the title; that does not mean that it is going to cause tuberculosis in animals.

Michael Pesato 2:43
And, the reason it’s endemic in the United States is because we haven’t found it important enough at this point to kind of eradicate, or to come up with a solution to get rid of it, because it’s one, either not affecting production as much as other diseases that we’ve run into, or two, it’s not causing an issue for human health. That being said, it is a very costly disease, if you have it on your farm. What’s kind of special about it is that, as Deborah said, it’s hardy. It’s hardy in the environment; it’s hardy in the animal.

Michael Pesato 3:13
So, this bacteria actually invades the animal when they’re very, very young. There’s a potential that it will be spread from mother to babyvia transplacental pathways. So, essentially, the mom can give it to baby in utero. Which, that really is a shame, because that means that all offspring from a positive animal could potentially have to be culled as well, or removed from the flock or herd as well. It is a pathogen that goes, essentially, to the distal part of the small intestine. So, the ileum is the most common location. And, it doesn’t come out and play until the animal is way older than when they were infected.

Michael Pesato 3:53
So, that baby animal can be infected either in utero, like I mentioned, or another common route is fecal-oral. So essentially, nursing on a mother who has the infection and is shedding the bacteria in her manure; if her teats are dirty, they can get it from her. And, that baby will be completely fine for anywhere from 1 to 8 years or more, and never show any clinical signs. And then, when a stressful event happens—that’s often kind of something that helps elicit this clinical sign of this disease—that is going to lead to the animal starting to develop some of the classic clinical signs. And so, that stressful event can be anything from parturition, which we tend to typically see in animals that are 2 years old, roughly, having their first offspring. It can be shipping; it can be moving an animal from one place to another. It could be intermingling with a new group of animals. It can be disease, other disease, kind of concurrent diseases that are happening. So, we classically associated this from about 2 to 7 years of age being the biggest timeframe for this to rear its ugly head. However, over 2 years old is what I tell people, and beyond. So, it can happen when they’re well into their geriatric years where it starts to develop.

Deborah Niemann 5:06
So, once an animal has this, they’re not necessarily going to be showing symptoms. So, this is always, like, my big example of like, why you should not buy animals at the sale barn. And, it even used to freak me out, like, when my daughters showed goats, and we would be, like, at fairs, where there’s just… There’s animal manure everywhere.

Michael Pesato 5:24

Deborah Niemann 5:25
You know, and you’re stepping in manure, and then you’re walking into your pen with your goats, and then what if your goat eats hay that fell on that manure that was on your shoe? And then, some people go, “Ugh. You’re just paranoid.” Like, is it really that easy to transmit it to your animals?

Michael Pesato 5:42
Unfortunately, yes. And, that’s what I love about you, Deborah; you’re always very cognizant of biosecurity. And, I think that’s something that is really great about this podcast, is that we do a lot of topics discussing biosecurity. Because, I think biosecurity is something that a lot of people don’t consider as a strong thing that they need to be aware of.

Michael Pesato 6:00
I have a lot of clients, for example, that they’ll tell me, “Oh, yeah, I purchased that goat the other day from somebody I never met before. And, I put them out in the pasture right away with my other animals.” And I’m like, “No, no. Let’s do some kind of screening. Some kind of,” you know, “a physical exam at a very least.” Letting me look and see what this animal’s got going on. Because, the reality is that these contagious diseases are indeed very contagious. And, there is the likelihood that you could easily get this from a show if you have an animal that’s there shedding this. You can get this from an animal that comes from a sale barn. You can get it from someone who has a flock or herd of animals that they don’t do any kind of testing or screening for, and you just don’t know any background.

Michael Pesato 6:40
I will say, the most common time that this is going to be contagious and heavily shed into the environment is when the animal is actually clinical—which, we’ll talk about clinical signs in just a second. But the other thing I want to say—which is kind of bad for goats—is that there are two different strains of this bacteria. So, there’s a strain S, which is for sheep, and strain C, which is for cattle, and fun fact: Goats get both. So, the unfortunate reality for goats is that they can easily pick up this disease from a cow or a sheep; it doesn’t matter. And then, they can continue to shed either strain into the environment, contaminating the environment, and possibly infecting other individuals. So, it is very contagious. And unfortunately, it is relatively common.

Michael Pesato 7:25
And oftentimes, the clinical signs indicate a tip-of-an-iceberg phenomenon. So basically, when you have an animal that’s clinical, that’s showing you clinical signs, you are going to most likely have layers of animals underneath that are going to be subclinically infected, that will still be potentially shedding low numbers, or have the risk of becoming clinical and shedding high levels of that bacteria into the environment.

Deborah Niemann 7:51
Yeah. So, a few weeks ago, we had someone here from Washington State Diagnostic Lab talking about the test for Johne’s. And, we were talking about the fact that, you know, just getting a single negative test on one animal is really not that helpful. That’s why it’s a good idea to buy animals from a herd where the whole herd has tested negative. And like, I don’t want to sound mean to new herds, but… Because, if you’re a new herd, and you bought all your animals from other herds that test, then you’ve got their history, you know. But, if you just, like, started a new herd, and you just picked up a goat here and a goat there from Craigslist and, you know, all these random places, from people who never tested, you’ve got quite a potpourri there of all kinds of bacteria and parasites and everything.

Michael Pesato 8:39

Deborah Niemann 8:40
And, that’s something I think a lot of people don’t think about, because with dogs and cats… There’s nothing comparable with dogs and cats, is there?

Michael Pesato 8:47
No, you know. I mean, the only thing would be, like, a very young dog or cat with, like, a parvo virus-type of thing, but that’s only a litter of animals. It’s not because you brought in a ton of animals. Now, I would say the only comparable thing is shelter medicine. Some of the diseases they deal with, with a shelter of animals, that are the same scenario, but these animals came from a hodgepodge of different places and different exposures coming into the same space. But, for ruminant species, you know, we have a lot of—as you mentioned—parasites and bacteria and viral diseases that comingling is the kind of impetus, the start, for this to all happen.

Michael Pesato 9:19
So, there’s really nothing that is—kind of off the top of my head—extremely comparable in small animals that we do regular biosecurity screening for or something like that, that’s really, really helpful, has been created to try to look for. In the small animal world, we’ve kind of jumped onto preventatives, where we give vaccinations to all animals in order to prevent them, and we do have that in sheep and goats as well. But unfortunately, as you mentioned earlier, Johne’s does not have a vaccine. So, there’s no real preventative, injectable, biological, anything that we can give them to prevent this, except for management, and that includes buying animals from known sources, buying animals from sources that test their animals, and then also, maintaining cleanliness in the environment, and trying to maintain an environment that doesn’t factor manure as a mainstay of their bedding, for example. So, all of that is, you know, important, and it does deviate us a little bit away from the small animal kind of component of things.

Deborah Niemann 10:17
Yeah, I think that’s the thing. Most people, you know, if they’re new to goats, a lot of times they’re the first livestock people buy. Their only experience is with dogs and cats, and there just isn’t anything comparable.

Michael Pesato 10:27

Deborah Niemann 10:28
They have no idea that you can buy goats that have no symptoms, and yet are walking around with a fatal disease that not only is going to kill them eventually, but is going to—not just infect your other animals—but infect your pasture.

Michael Pesato 10:43

Deborah Niemann 10:43
And your pature will now be infected for, like, five years, because that lives for so long in the environment.

Michael Pesato 10:51
Yeah, absolutely it does. You know, and that’s the thing with Johne’s. So, I want to touch real quick on clinical signs. I feel like I’ve been skirting around that. And, I just want to make sure we cover what to look for. So, I’m going to talk a little bit of cattle and a little bit about small ruminants. So, the clinical signs for cattle—if we’re going to start with cattle—they typically have a pipe stream diarrhea. That is kind of, like, classic Johne’s disease; they’re going to literally have water coming out of their rectum. They also lose weight and get very, very, very, very thin. So, they become skin and bones in the face of a great appetite. So, they continue to eat and eat and eat, but they’re just not able to put anything together.

Michael Pesato 11:27
Now, in the small ruminant side of things, there are some similarities, and the biggest similarity is that chronic wasting disease. So, they’re eating and eating and eating, but they’re getting thin, thin, thin, thin. And, what will happen often is, you’ll have an older doe, right? We talked about this being an older animal disease. So, you have an older doe. She’s, you know, 8, 9, 10 years old, and she starts losing weight. Well, there’s lots of things—and we’ve talked about Caseous lymphadenitis. We’ve talked about cancer. We’ve talked about elderly goats having other diseases, dental disease, things like that, that are going to cause them to lose weight over time. So, you may think, “Oh, it’s just she’s old,” you know? “She’s getting older. She’s losing weight.” And, what it could be is Johne’s. And, as Deborah mentioned, you know, she could be shedding. She’s now clinical, right? She’s losing weight. She’s getting thin. So, she is actually clinical for the disease. So, the volume of bacteria she’s shedding in her manure is higher, so she’s actually putting up more into your pasture space and into your environment.

Michael Pesato 12:18
Only 20% of the cases will actually develop diarrhea in small ruminants. So, where 100% of cattle develop that pipe stream liquid diarrhea, only about 20% of sheep and goats will develop that actual diarrhea. So, a lot of people—especially people that came from a cattle background or have any knowledge of Johne’s—the first thing they think about is diarrhea. And, if they don’t see diarrhea, they’re like, “Well, I don’t think my sheep or goat has Johne’s.” But, the reality of it is that most sheep and goats, 80% of them, do not even show any diarrhea. It’s just that thin, thin goat, that thin doe, that is eating like a champion, just not gaining any weight—typically anywhere from 3 to 7 years old or more.

Michael Pesato 12:57
Now, in terms of it going into the pasture, that’s absolutely correct. This is a hardy, hardy bacteria. It survives in sunlight. It survives in cold. It survives in organic debris. Most barns are made up of organic debris. We have wood. We have dirt. Very rarely you have a stainless steel wall and a concrete pad that you’re housing your animals on, right? And unfortunately, the organic debris, organic matter, is extremely hard to disinfect. So, we talked a little about cleanliness, and how that could be very helpful. Well, you can’t clean the pasture; it’s just not going to work. You can’t clean dirt. You can’t clean grass. So, you have to wait over time, and we know that this can survive in the environment for a minimum of a year. So, you could be hurting yourself, you know, if this is going to be in your environment.

Michael Pesato 13:44
And, like with other small ruminant diseases, there are some people that say, “Hey, once the area’s infected, that’s an endemic herd. That herd has it. It’s just part of its life.” And, you may not see a clinical animal once every 5 years, but you have it floating in your herd. So, for me, that’s a very scary concept to think about. That, as Deborah mentioned, like, you’ve got this animal walking around with a deadly disease that not only infects other animals, leads to its own death, but will impact your pasture as well. So, this disease, I would say, is tricky because of the iceberg effect, of the fact that we have all this subclinical going on. It’s so hardy.

Michael Pesato 14:21
And then, we’ve kind of brought up diagnostic testing. So, I love that a Washington Animal Diagnostic and Disease Laboratory, that they talked about how doing a one-off sample is not a good idea. I wholeheartedly agree. So, there are a couple options for testing for Johne’s. The options often include one of two samples. So, either a blood sample—which is what the WADDL lab will do. They’ll run a blood sample for you, and they do a test called an ELISA, or a fecal sample. And, there’s a couple of fecal sample options out there, or test options. First, you can do a culture. Cultures take a very long time, like 8 to 12 weeks, and I know that many of you out there wouldn’t have that much time, especially if you have an animal that’s kind of chronically wasting, getting worse and worse, and you just want to know what’s going on. The other option is a PCR. So PCR, fortunately, has about a one-week turnaround time.

Michael Pesato 15:11
Here’s the caveat with diagnostic testing: If the animal is not showing any clinical signs, I never trust a negative. Because, that negative is probably a false negative, potentially, because that animal could be shedding very low numbers of bacteria at that time. So, what we really like to do, what we encourage people to do, is make sure that you’re testing animals that are clinical. Now, you might say, “Well then, what’s the point of biosecurity screening?” Well, the point of biosecurity screening is that you kind of do it every year if you’re going to be up-to-date on everything, especially if you’re an open herd that brings in other animals from different places—even if it’s a buck that you’re just bringing in for 40 days to get your does bred. You should still do your biosecurity screening every year, because that Johne’s, the most valuable way to do that is to do it every year to catch the animals that you may not have noticed were losing condition, or may not have noticed that they were kind of lagging behind a little bit.

Michael Pesato 16:06
Because otherwise, you know, like WADDL already said, during that one-off testing of just, “Oh, I did it, and I’m done. And I did this animal, and they’re negative. I can sell it for that animal to be negative.” No, not true. If that animal is positive, however, there’s a pretty good chance that they’re actually positive. So, these tests have a better chance of telling you if they’re positive being correct. If they’re negative, we question.

Michael Pesato 16:28
I know there’s a lot information in one fell swoop. But, hopefully, that was a good kind of whew.

Deborah Niemann 16:33
Oh, yeah. That was great.

Deborah Niemann 16:34
So, if somebody is buying goats, it’s a good idea to buy from a herd that’s been doing testing, so that they’ve got this history of negative results behind them. And, for how many years would you say? Like, for five years? Or three years? Or 10 years? Or… Obviously, the longer the better. But.

Michael Pesato 16:56
Yeah, exactly. I know. But like, I mean, let’s be honest: How many people out there may have that—don’t get me wrong. There are some amazing goat producers out there who have these results for years and years and years and years, and have really jumped on the positive biosecurity screen. Which, I think, is something that, you know, podcasts like this and other educational opportunities are kind of opening up other people’s eyes that maybe didn’t know this existed, and hopefully kind of inspiring other people to pursue diagnostic testing like this, in order to make everybody’s lives safer, the goats safer, the pasture safer, the human safer.

Michael Pesato 16:56
Yeah, I would recommend, at a minimum… Now, if it’s a new person who just got started, and they have only one year of results, that’s great that they took the initiative to do that. And, I would say I trust—especially if you talk to them, and get to know that person, and they say, “Yes, this is something that I’m going to be doing. I already did this on my goats. It’s something I’m going to continue, you know, doing every year.” I would be comfortable. Especially if you plan to do biosecurity screening, maybe going ahead and getting that animal.

Michael Pesato 17:56
Ideally, I’d say at least two years. And, I would say I would really want to see some of the results on their older animals. For example, if they say, “Oh, here’s all my results on my 6 month old.” That’s not enough time for Johne’s to take hold. In fact, I would recommend that you don’t test the 6 month old. I would wait until they’re at least 18 months old to do your initial Johne’s test. Doing them young like that is probably a little bit of a waste of money, because they’re not going to be shedding any high volume of that bacteria at that point. So, buying a doe from a person who is testing, if it’s a 2-year-old doe that came back negative, I would say, “Hey, you know, it looks like you’ve got a lot of other does on this property. Do you mind if I see your herd record?” You know, and if I look at this doe that’s 8 years old and see what she looks like, because if she’s negative, then likely, that’s where it’s going to start, right? That’s who’s going to be at the tip of the iceberg.

Michael Pesato 18:45
So, I think there’s ways, and I think it all ties back to communication. We have to be able to communicate with the people we’re buying animals from. And, if they don’t want to communicate with you, you might want to consider going somewhere else. That seems a little shady to me, because they should want to brag about this stuff. This is stuff that makes their animals more marketable and allows them to really kind of showcase how high-quality they are as a producer. So, if they’re being kind of dicey, and they’re like, “Oh, well, why do you want to see her results? I’m not telling you her.” You might want to say, “Okay, that’s a little bit of a red flag for me. What are you trying to hide?” Maybe that’s paranoia, but I feel like that that’s how I would feel.

Deborah Niemann 19:20
Yeah, no, I totally agree with you. Like, I mean, you know, when you have negative results, you want to tell the world. You see people on Facebook all the time saying, “Hey, we just got our whole herd tests back for CAE, CL, and Johne’s. We’re negative for everything for the ninth straight year!” Whatever, you know?

Michael Pesato 19:37
It’s a point of pride.

Deborah Niemann 19:39
Yeah, exactly. So, I think if somebody is starting a herd, and they buy all of their animals from a herd or two that’s had all negative results for a number of years… And I mean, I just really think it’s a good idea, anyway, when you’re starting, to, like, buy from established bloodlines and stuff. That’s kind of what I did. It’s funny. I started In 2002, and I pretty much built my herd on the culls of the best herds in the country.

Michael Pesato 20:05
Yeah. Which, I mean, are amazing animals.

Deborah Niemann 20:08
Yeah. Because I’m like, “Okay, so this is their cull that they’re selling, you know, as a yearling, because her udder is not good enough for their show string.”

Michael Pesato 20:18

Deborah Niemann 20:19
But, she’s gonna be better than, you know, 95% of the other goats out there—

Michael Pesato 20:25

Deborah Niemann 20:25
—from herds that are not trying as hard or not as well-established. And, I think the same thing is true with the testing for disease, too. That when people have been around for a while, and they’ve been doing tests for years and years, and you buy your goats from them, then that’s a selling point for you. Even if, like, this is just your first year, and so you just did your first round of tests, you can still say, “But all of my foundation herd came from these herds that all have a long history of negative tests.”

Michael Pesato 20:55
I 100% agree. I think just establishing a herd that has that history is enough for you, as a beginner, to kind of show that you’re not just going to the sale barn and buying a bunch of goats that, you know, came off of the back of someone’s truck. And sale barns are great. They’re great for certain things. They’re not great to build a foundation herd. I’ve had so many clients that are like, “I got this goat for 30 bucks.” And I’m like, “Oh, boy, here we go. Let’s see how many veterinary medicine charges I’m going to have to put into this animal, because it’s sick.” And that’s the problem. These cheap goats, they look, you know, glossy on the outside; they’re gilded, right? They look shiny on the outside, but inside they’re kind of rotten. So, I would definitely recommend not building a foundation herd from Craigslist, or from a sale barn. Getting a string of goats from a well-managed herd that has documented proof their animals have been healthy, that is, I think, super, super helpful just starting out the gate.

Deborah Niemann 21:54
So, we already kind of spilled the beans on how the story ends: There is no treatment. They die.

Michael Pesato 21:59

Deborah Niemann 22:00
Is there really anything else to say about that? Like, they just, they get sick, they start losing weight, there’s nothing you can do?

Michael Pesato 22:06
Yeah. The unfortunate reality is, we can only support them. So essentially, it’s going to be hospice care. What I will tell you is, if you notice that you have a clinical animal, you test that animal, and they come back positive, it’s best to cull them. It’s best to get rid of them. Euthanize them. I wouldn’t send them to a sale barn or anything like that. I would either, you know, have your veterinarian euthanize them, or perform humane euthanasia yourself. You know, it is an AVMA acceptable thing to use a firearm to euthanize an animal. I will say, keeping them around, you only risk infecting other animals.

Michael Pesato 22:39
So, when it comes to treatment options, since there is none, it’s probably best just to make the fastest move to get that animal off of your property. Try to disinfect the best you can. Remember, with any disinfection, clean with soap and water first, before you use the disinfectant. Many people I talk to, they’re like, “I just want to bleach it all.” Bleach is inactivated by organic debris. So, try to clean with soap and water, scrub the best you can, then go in with your bleach disinfectant or, you know, whatever disinfectant that you’re going to use. The animals that are clinical, it’s kind of the end of their line for them. So yes, I would say, you know, there’s not much more we can say.

Michael Pesato 23:15
One thing I will warn you all about—and I found this very interesting. I’ve had two cases in my career so far that they were losing weight, they were older does, and then they very acutely got very, very sick. Their abdomen started to distend, and they died. And, on necropsy—or autopsy—they found that their small intestine had perforated, and they were able to find Johne’s kind of in that perforation when they cultured it. So, it’s a rare possibility for goats with this condition. But, if you have an acute death on an animal that you’re like, “Wow, she was looking thin, and then all of a sudden they came out and—” Not bloat. She’s not bloated, okay? So, I’m not trying to say her left side of her abdomen is huge with gas; her belly is full of fluid. That’s from the rupture of the intestine. I would definitely recommend trying to get that to a pathologist or veterinarian to do a necropsy on them, just to kind of check out what’s going on and submit some samples. So, I thought that was a very strange presentation.

Michael Pesato 24:10
And of course, they had some of the classic signs, like that losing weight, but it was so acute to death, whereas an animal with Johne’s will take lots of time, if you keep them around, to go. Because, they’re going to just dehydrate, dehydrate, dehydrate, dehydrate until they get so weak, they can’t stand any further. And then, that’s when they often either expire themselves or be euthanized. So. Yeah. Unfortunately, no silver bullet treatment, except for maybe a silver bullet.

Deborah Niemann 24:36

Michael Pesato 24:37
As horrible as that sounds. But.

Deborah Niemann 24:38
Yeah. So, a year or two ago, I was talking to somebody who had had some goats tests positive for Johne’s. So, they culled those goats immediately. But, she didn’t want to cull the whole herd. So, she thought that like, well, they would just keep testing and then culling positive animals, which, to me, kind of sounds like you got a hole in your boat and you’re trying to bail the water out.

Michael Pesato 25:08
Yep. Yeah.

Deborah Niemann 25:09
This boat’s gonna sink eventually.

Michael Pesato 25:11
Sure. Yeah. I think the challenge there is that obviously, if it’s somebody who has, you know, this herd of beloved goats, they don’t want to cull the entire herd—and I understand that. It’s always an option to depopulate and restart fresh. We do typically recommend—if the person does not want to go ahead and depopulate, and they want to continue to do annual testing. The other thing we recommend, though, even before that, is to cull all offspring.

Michael Pesato 25:34
So, if this was a 8-year-old doe who had four kiddings while she was with you, and you have five of her daughters, it’s probably best just to go ahead and cull her daughters, because likely, they got it either in utero from her, or they nursed on her and got colostrum from her. And, as they did, there was contamination, potentially, in the environment. Obviously, she would have shedded her Johne’s more when she was stressed. So, there’s a chance that she has put it into the environment before we even knew that she was going to become clinical. So, you know, we typically recommend, if you’re going to be heavy on your culling, go ahead and cull—and it’s really sad—but that ends up being, like, a bloodline, you know? Because, it’s the mother and the daughter, or the grandmother and the mother and the daughters. That would kind of be the first place to start. And then, moving those animals off of that environment where the positive animal was, and testing annually with culling.

Michael Pesato 26:27
But, you’re right; it is a little bit like trying to bail out a boat with a hole in it. And, I think you just have to accept that as your future for this herd. And, if you don’t want to accept that as your future, then it’s completely acceptable to say, “I’m gonna go ahead and depopulate and restart, because I know that this is a disease I don’t want to deal with, and I don’t want to have my facility diseased.” You know, but that, I often find that people don’t have the time to do that. Because, you have to let your property sit for a minimum of a year if you can’t disinfect it, you know?

Michael Pesato 26:56
So, this goes back to our initial, first thing out of the gate, how challenging this disease is to manage, to handle, to deal with, because it’s not something that’s just like, “Oh, I had it, and I don’t have it anymore.” No. Likely you’re gonna fight this for years if you have it in your herd. And, I think it all kind of ties back to proper communication with where your goats are coming from, making sure that they come from areas and people that have tested before and have some results for you.

Deborah Niemann 27:23
Yeah. So, you said a minimum of a year to even think about putting ruminants back on the pasture. So, like, years ago, I had heard that it could live on pasture for up to 5 years. Have they since realized it doesn’t really last that long? Or, what’s the latest thinking on how long it can survive on pasture? If you want to be really careful?

Michael Pesato 27:43
Yeah. Yeah, that’s a great question. You know, I think it’s hard to kind of give a solid answer on that, because I think it really does depend on a lot of things. The bacterium we know is so extremely hardy, it’s really resistant to things like frost and freeze and desiccation by sunlight. And so, it’s not like, “Oh, I live in Montana, or Minnesota, and I get a lot of snow, so I’m probably never going to deal with the Johne’s.” No, it’s… It can survive through that.

Michael Pesato 28:06
So, I tend to tell my clients that I would expect that that bacteria is so hardy, it can live for a minimum of a year, but I wouldn’t be surprised, in the right conditions, that it could survive longer. So, that really nice soft spot in the dirt, underneath the, you know, wall that has a little hole in it, that the, you know, goat poop fell into, and now it’s just sitting there, in a perfect temperature—that could stay there for years. And it would be impossible to know that it was there, until you decided to clean out your barn for the next set of animals that came in, and you stirred it up, and, it got into other areas in the barn. So, I wish I could say, you know, “Yes, if you definitely hold them off for 5 years, it’ll be gone.” I would say 5 years, it will probably be gone. Just by the things that happen in life over 5 years, and what happens on a farm in over 5 years. But, I typically say it can last for a minimum of about a year.

Deborah Niemann 28:58
Okay. So, this has been really interesting. And hopefully, a lot of people have a better understanding now of just how devastating this disease can be, and why they should be concerned when they’re buying new animals. Is there anything else that people need to keep in mind about this?

Michael Pesato 29:15
I think the biggest takeaways, hopefully, that everyone has kind of gleaned from this is: Keep a close eye on your animals. Know where your animals come from. If you notice that your animal is starting to lose weight, especially over time, and it’s an older animal—and I know we’ve had several talks about different diseases that can cause these things—call your veterinarian. That’s gonna be the best time to test. Even if you did screenings earlier in the year, and now it’s been 6, 8 months, and you feel like there’s an animal that’s been losing weight over time but has a great appetite, just do one, just to test that animal. I would recommend typically doing both a PCR and an ELISA, just to make sure, because if it does come back positive—one of those comes back positive—then you’re gonna say, “Yes, I have to deal with this.”

Michael Pesato 29:57
So, the biggest thing is just keep an eye on those animals, and if you’re concerned to call your veterinarian, have them come out and have a look, collect a sample, and get that testing done, so that you can try to avoid this becoming a problem in your herd and be as proactive as possible. And then, I hate say it, but don’t try to save these animals. They do not have long to live, and they’re only going to infect your pasture, infect your other animals, faster. So, cull as soon as you figure out an animal is positive.

Deborah Niemann 30:23
Great, thank you so much. This has been really informative.

Michael Pesato 30:27
No problem. Thank you for having me! And I’m sorry to leave on a such a sad note of “cull the animal,” but I really appreciate you having me. And, as always, if you have any questions, comments, concerns, you know, I am always happy to answer any.

Deborah Niemann 30:38
And that’s it for today’s show. If you haven’t already done so, be sure to hit the “subscribe” button so that you don’t miss any episodes. To see show notes, you can always visit, and you can follow us on Facebook at See you again next time. Bye for now!

Understanding Johne's Disease in Goats

14 thoughts on “Johne’s Disease in Goats”

  1. Thank you for sharing this information. Currently our herd all tested negative for CAE/CL/Johnes. We will be testing yearly and careful to adding to our herd. On our site at this present were covering CAE because of a need to educate in our area. Have a blessed day.

  2. Johnes is an issue for all ruminants’ and like Menengeal worms, can be introduced through roaming deer. It does not affect horses as they are not ruminants.
    I found this out the hard way. While large pasture can be good from the parasite perspective, there is more likely to encourage deer.

  3. I thought Johnes disease, Mycobacterium avium subsp. paratuberculosis is a bacterium. Your statement above, ” An animal can be carrying Johne’s and shedding the virus in feces…” is a little confusing. Can you clarify please? Also, thanks for the article and info.

  4. Could my goat have been infected with Menengeal worm from hay harvested on a field where deer and antelope are frequently found?

    • Antelope, no. And it is ONLY white-tail deer that carry meningeal worm. Other deer do not have it. Also, you have to have snails or slugs in the field because they are the intermediary host. Since snails and slugs are usually in wet areas, and that’s not compatible with a hay field, the odds of goats getting m-worm from hay is nearly impossible.

  5. If the only visible symptom of Johnes disease is weight loss, why is it so devastating? Not to belittle the informative article; maybe because it’s an excerpt I didn’t get the full impact.

    • My neighbor had a herd full of Johnes infected goats. The goats had good appetites, but the goats wasted away and died because the bacterium blocks the transfer of nutrients from the intestine to the body. I cleaned my boots every time I went over there to trim hooves, so as not to bring it back to my own goats! I’ve gotten negative tests on my herd every year. One doeling I sold got Johnes from the raw cow milk from a local dairy (as far as we can tell).

    • It is called “a wasting disease” because animals literally waste away to nothing. What happens when you just keep losing weight? You die. And transmission is fecal-oral meaning that wherever the animal has pooped, they have spread the disease, so all of your other ruminants (goats, sheep, and cows) will get it, and you will watch them all waste away and die.

  6. I have two new 2 and 3 month old goats that I bought from registered breeders. I am quarantining them and plan to add to our herd once cleared. I have been reading all about CAE, CL, and Johnes I’m just wondering at what point I should test them and if the tests aren’t always reliable when can I feel safe introducing them to our herd? Thank you for any direction! 🙂

    • Ideally, they came from a herd that has been testing for those diseases for years or is a closed herd (no showing or buying new does and only buys a buck every few years) that had a long history of negative tests after becoming a closed herd. For CAE, a pathologist at WADDL told me that you can’t get a reliable test on a goat until six months after it has been weaned (stopped receiving milk from its dam). Unfortunately the Johnes blood test has a pretty high rate of false negatives, which is why the history of whole herd negative tests is important. If the breeder has not done Johnes testing, then you might feel fairly safe if they have not brought in any new goats (other than a buck or two from a Johnes-free herd) in the last five years.

  7. Thank you for this article! This is a topic I believe needs to be discussed much for frequently! Is there one test with a higher reliability rate (ELISA, PCR, or culture)? If one was to receive a positive on an ELISA and a negative on a fecal PCR, it seems Dr. Pesato would encourage us to trust the positive blood test ELISA?

    • The fecal culture is a PCR for Johnes, and it’s the most reliable. I never say anything is impossible, but I think that’s an unlikely scenario for Johnes because the ELISA for that test is not as sensitive as the one for CAE where you do get false positives once in a blue moon (probably 1% or less). I don’t think there is a simple answer to your question. If you have a closed herd and you’re doing the ELISA blood test as a biosecurity screen, and you got a single positive after lots of years of all negatives, I would look at the history of that goat. If it was the third generation born on your farm and had not spent any time on another farm, and you had not brought in any new animals (goat, sheep, or cattle), then a false positive seems probable, although I have not actually heard of any false positive ELISAs for Johnes. Not saying it can’t happen, but then I just don’t think this scenario is something that we need to worry about. Also remember that repeating a test is always my recommended first step when you get a positive result. There is also a risk of a lab error, which happens in human medicine too. So no one should be culling based on a single test. And seriously, if it’s Johnes, you’ve got a herd-wide problem, so just quarantine that one animal while you’re doing follow-up testing.


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