CL in Goats: Caseous lymphadenitis

Caseous lymphadenitis, usually called CL, in goats is an incurable and highly contagious disease. I recently helped one of our Goats 365 members think through her options when several of her goats tested positive, and I discovered that eradication of this disease from a herd is not nearly as simple as the textbooks make it sound — emotionally or medically.

In this episode, Dr. Michael Pesato, an Assistant Clinical Professor at Mississippi State University's College of Veterinary Medicine, is talking about the symptoms, diagnosis, and treatment of CL.

Dr. Pesato says that although abscesses can be treated, CL cannot be cured. While some people think it's not a big deal, it can negatively affect a goat's overall health and even fertility. Kids born to infected moms may not be as healthy as those born to CL-negative does.

We talk about what CL is and how goats can get infected. Then we talk about your options if you have goats that test positive. If a pregnant goats tests positive, can her kids be born with it? Can they get it from her after birth? Do you cull the positive goat before or after kidding

We also talk about the fact that although there used to be a CL vaccine for goats, it is no longer available, and Dr. Pesato talks about why the sheep vaccine is not recommended for goats.

If you are buying goats — or sheep — it's important to educate yourself about this important disease and how you can bring it onto your farm.

See full show notes here >> https://thriftyhomesteader.com/cl-in-goats/

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Transcript

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  0:19 
Hello, everyone, and welcome to today's episode. This is going to be so interesting today, because we are talking about a subject that very few people think about, and one that I actually thought was really pretty simple and straightforward until one of my Goats 365 members contacted me about six weeks ago to tell me that she suddenly started seeing abscesses in her goats a few months ago. And then, she got a whole herd test for CL—which is short for Caseous lymphadenitis—and a bunch of them came back positive. And, when I started trying to help her work through all of her options and stuff, I discovered that this is not nearly as straightforward as the textbooks make it sound.

Deborah Niemann  1:06 
So, we are joined today by Dr. Michael Pesato, who is an assistant clinical professor at Mississippi State University's College of Veterinary Medicine. He's a board certified practitioner with the American Board of Veterinary Practitioners and specializes in Food Animal Practice. And you might recognize his name, because he's been with us before. So, welcome back to the show, Dr. Pesato!

Michael Pesato  1:27 
Thanks, Deborah. I'm always glad to be here, and excited to talk with you and your listeners.

Deborah Niemann  1:31 
This is really interesting, because when this person contacted me and said, "I don't know what to do," I said, "Oh, well, you know, most people cull the positive animals, and then they vaccinate the rest of the animals." And she said, "Well, my vets told me there's no vaccine." And that just confused me. I'm like, "But... But, that's what the textbooks say." So, I was very confused by that. And that's when I sent you an email and said, "I don't understand." And then you started explaining it to me. So first of all, like, just start at the very beginning, because I know a lot of people have no idea of what CL is, or that it even needs to be on the radar screen. So, can you talk about what it is?

Michael Pesato  2:11 
Absolutely. So CL, or Caseous lymphadenitis, basically it's a bacterial infection that comes from a contagious bacteria. So, it has to be brought on to a farm. The tricky thing, and the kind of thing that gets confusing, is that it's a very hardy bacteria, so it will last on farm for a very long time. But it is brought on to the farm by an infected animal, so you can't buy a property that's never had goats and then find that your goat develops a CL lesion, a Caseous lymphadenitis lesion. So, this bacteria, which is known as Corynebacterium pseudotuberculosis, it is a bacteria that will invade the body of the sheep or goat via wounds or breaks in the skin.

Michael Pesato  2:52 
And, one of the most common ways that it gets into the goats' system is via the mouth. So, what will happen is that they—as we know—goats are browsers. They eat a lot of brush; they eat a lot of coarse material. We call it "roughage" for a reason. So, when they're eating this roughage, it causes microabrasions—small cuts—in the mouth. And, when they consume this bacteria, when the bacteria comes in contact with them, it will enter in through the mouth—or, if they have a small scratch or something on their skin, enter the bloodstream—and then travel to the lymphatics.

Michael Pesato  3:20 
One of the trickiest things about it is that, like I said, it's a very hardy bacteria. So, once it enters into the environment, it can last for 8 months to a year to even maybe beyond that, especially in organic debris, which most barns and housing for our goats is made up of—wood, dirt, hay, straw, all that stuff. And the way it kind of gets into the environment is through pus. So, this pathogen has two words, obviously, that we use to describe it: "Caseous" and "lymphadenitis." the term "kay-see-us" or "KAY-shus"—it doesn't matter how you pronounce it—it means "cheesy." So, that cheesy description is very accurate, because the pus that comes out of a lesion that is associated with Caseous lymphadenitis is very thick, almost cottage-cheese-like. It often is a yellow to green color, and unique to this specific pathogen, it has no odor. So, there's no stinky, foul-smelling, watery pus that comes out of this abscess. And then, the "lymphadenitis" part is associated with where the lesions occur, and that's going to be the lymph nodes.

Michael Pesato  4:26 
So, the most common locations for goats will be lymph nodes around the face and the head. So, we're looking at submandibular lymph nodes. We're looking at parietal lymph nodes, kind of on the side of the face. We're looking at prescapular lymph nodes on the shoulder blades. And those are very, very common sites, but they can occur in any lymph node, any location, anywhere in the body. And the other unfortunate thing that this bacterium can cause is the internal form of Caseous lymphadenitis. More common in sheep, but also seen in goats, where it can affect any and all tissue that has lymphoid tissue inside of it—which is basically every part of the body, from the kidneys to the mammary glands to the lungs. There can be invasion of this bacteria in any of those tissues. So, it can hide out, basically, within the body, and we'd never even know the animal is affected by Caseous lymphadenitis.

Michael Pesato  5:19 
So, a lot of people would say like—like you already mentioned, Deborah—that it's very straightforward. It's an easy disease to diagnose. "Oh, you see an abscess?" You know, "Oh, we definitely know we have Caseous." That's not always true. And, we do say, one of the caveats of small ruminant practice: If it's an abscess, it is Caseous until proven otherwise. So, it's something that we as veterinarians, and I think most goat producers that have heard about this disease, are very, very leery about and kind of diligent about watching for it.

Deborah Niemann  5:47 
Yeah. I'm super paranoid about it. You know, if I... A couple years ago, I saw an abscess on my goat. And it was on her neck, of all places. And I just completely freaked out. It was in 2020. I'm like, "This is impossible. Nobody has been on this farm in months. How could this happen?" I was, like, on the phone; I had a vet out here, like, within hours. I'm like... You know, she took a culture; she sent it in, and it came back and said, "It's just normal skin bacteria."

Michael Pesato  6:18 
Yes.

Deborah Niemann  6:18 
She must've just stabbed herself right there on her neck, and I'm like, "Urgh."

Michael Pesato  6:23 
But, it's panic-inducing, you know? And I've had many clients that it is very panic-inducing. The only way to definitively diagnose it is what you just described, getting a culture. So, doing an aerobic culture. This is a Gram-positive facultative anaerobe, which basically means that it can survive in anaerobic environments with no oxygen, but it is able to be aerobic—which is great for us. It's easier to culture that pathogen, because you can actually take a swab or a sample from an open abscess that's been exposed to air, and you can get that submitted to the lab and get test results back, and get culture results back, that gives you a positive or a negative diagnosis.

Michael Pesato  7:00 
And I've had clients that will bring their animals to our facility, put them in quarantine, test them, see if they are positive, do a culture. Because, as you know, to collect that you might have to open up that abscess, and if you open the abscess, the pus enters the environment. So, I have had clients that have been so nervous about it that they actually have them brought to the facility—to our facilities—and they have us collect the samples. Or, I had one client who housed the goat in her home while we waited for test results to come back, so that it wasn't in her goats' environment. And unfortunately, that one did come back positive. So, we ended up having Caseous lymphadenitis in that case, and she kept the goat—it was pregnant. So, she kept the goat in her house until it was time for it to give birth and she could then cull that goat.

Michael Pesato  7:45 
And I... My client is like, "Oh man, maybe I'm being too paranoid." I don't think you can be. I think it's something that will be in your herd forever, if it gets into your herd. It's very, very, very hard to get rid of. So, I'm totally about that paranoia and diligence when it comes to watching for that bacteria, watching for that presentation.

Deborah Niemann  8:03 
So, you just mentioned somebody had a pregnant goat who had it. That actually happened to this other person, too. And that was one of her really challenging decisions to make was, do I cull the pregnant goats now? Or do I wait until they kid? You know, because there was the question of like, can they be born with it? You know, and all that kind of stuff. So, can you just talk a little bit about, like, if somebody does have a pregnant goat test positive for it, what does that look like in terms of trying to make that decision about when to cull?

Michael Pesato  8:34 
Yeah, absolutely. So, when it comes to the pregnant goat that has Caseous lymphadenitis, there's not been any documented proof that is kind of, like, uniformly accepted that they're going to pass the bacteria through their bloodstream to the fetus. And the reason for that is that the bacteria, it does travel through the bloodstream to get to the lymphatics. But, once it's in the lymphatics, it basically stays in the lymphatics. That's the, I guess, pro and con. It may not, you know, be transmitted via blood sharing, so sharing needles and sharing instruments and things like that, or passing it to their fetus. But, when it's in that lymphatic structure, it doesn't go away. It just travels to different lymph nodes, travels to different parts of the body. So, it's not necessarily a bacteria that's going to respond really well to systemic antibiotics, or to something where you can kind of easily get rid of it. So, with those pregnant animals, it's not, you know, "Okay, well, she's pregnant. She's definitely gonna pass it to her offspring."

Michael Pesato  9:26 
Where it gets challenging is that once that baby is born, if mom has an active draining lesion, or there's risk of that baby being exposed to the bacteria from the environment from previously draining lesions, there's a lot of open spots for it to enter into a baby. So, one of those spots is the mouth, because they're cutting teeth. So, they have an obviously open area for that to enter into their mouth. The other location is, of course, their umbilical cord. So, they have, essentially, a hole in their abdomen at that time that they're born that will potentially allow for bacteria other than just Corynebacterium that causes Caseous, but other bacteria can get in there, as well. So, you kind of have to be very diligent about, again, kind of monitoring those babies. I do recommend, if someone says to me, "I do not—one-hundred percent do not—want my goat babies to get Caseous lymphadenitis," I recommend pulling them from that mom and bottle feeding. That's the only way that I can guarantee they're not going to have exposure in the environment that mother is living in, especially if she has an active draining lesion.

Michael Pesato  10:23 
The other thing that could happen—rare, but it could happen. If there are masses or abscesses within the mammary gland that are rupturing into the teat cistern or teat canal, and there's pus actually being fed in the milk, there's a chance that the babies can consume pus via that direction. Again, rare. I don't think that's going to happen. I think they're more at risk just being with mom, and staying with mom, and nursing on mom to being exposed to her shedding bacteria from her outside masses.

Michael Pesato  10:51 
So, what I generally recommend to people is, if you really, really, really do want to keep the babies, but, you know, you're concerned about them getting exposed, as soon as they're born—and I mean, like, you probably have to monitor them very closely. Because, you don't really want them jumping up and just being with mom for three days when you come back out to the barn. Try to pull them. Make sure that they get adequate colostrum replacer. And then, make sure that you're bottle-feeding them away from the mother, and then the mother can be culled from that. It seems cruel and harsh, and it's really sad.

Michael Pesato  11:18 
And the client that I had, who had the positive pregnant female, actually elected for a terminal C-section. So, we waited until the baby was as close as we could—she guesstimated kind of when the baby was gonna be due—and then we did a terminal C-section, because she was going to euthanize the mother anyway, because of the Caseous lymphadenitis. She didn't want to sell it, obviously, to someone else. She didn't want to keep it in her herd. And she felt like the best thing for her would be euthanasia. And, the mother wasn't the healthiest candidate anyway, so it wasn't necessarily, like, this beautiful goat. But we ended up doing that. And unfortunately, the baby was a little premature, and you can't be a little premature with goats. It really... To do a C-section appropriately, it has to be within, like, three days of giving birth, because 70% of fetal development happens in the last 6 weeks. So, if you do it too early, you cut that 70%, and you could be in trouble.

Michael Pesato  12:07 
But also, I have had experience where I feel like Caseous lymphadenitis does compromise pregnancies. It's an active bacterial infection. There's bacteria in the animal's body; they're being challenged daily by the bacteria. And so, I've seen kids that were born kind of unthrifty from these mothers. I've seen... This kid particularly, that we ended up doing the C-section on, had an adenomatous umbilical cord. And we couldn't figure out why. But, we were suspicious that he was fighting off not necessarily the Caseous, but his mother's compromised to begin with, so she could be fighting off other bacterial infections. So, you know, in my thought process with it, if you have a compromised mother, you could be dealing with compromised babies. And it doesn't have to just be Caseous. It could be other bacterial or viral infections that she's susceptible to, because she has a decreased immune function to begin with, because she's fighting this bacteria.

Michael Pesato  12:57 
So, when it comes to, "What do I do with a pregnant female?" If you want those babies, pull them as soon as they're born, as soon as you possibly can. Don't let them kind of interact with mother; they will be bottle-fed babies. Get rid of mom. Try not to put them back in the same environment. And then, I would say when they're probably about 6 months, maybe 6 to 9 months, go ahead and test them for it using a blood test—which we can discuss more about in a minute. And I know next week's podcast is gonna be great for talking about diagnostic testing for Caseous lymphadenitis.

Deborah Niemann  13:31 
Yeah. And in this person's case that I was talking to, she said that some of her goats did have abscesses on their udders. So, that would be really a big like, "Oh my gosh, yeah." Like, I mean, when kids are first born, they're, like, sucking on everything before they actually find the teat. So, the chances of those kids getting infected would actually be really high.

Deborah Niemann  13:55 
And so, the main mode of transmission is the pus from the abscesses. Now, I know when I first got into this... I don't know how I got educated about biosecurity so early in my goat-owning days, because there was a lot of other really important information that I didn't get. I think maybe it was because my mentor, the person I bought my first three goats from, was very, very serious about biosecurity. And people would talk about, you know, like, the shoes you wear out to your barn should only be worn out to your barn. Because, if you wear those shoes to the feed store, somebody could have something on the bottom of their shoes, like CL or Johne's or something, that you're going to bring back to your farm. Do you feel like that's an overreaction, or do you think that's a good idea? To wear different shoes?

Michael Pesato  14:45 
So, you know, for me, I love that you were educated about biosecurity so early. I think it's such a hugely important aspect of animal agriculture to practice appropriate biosecurity. I think that having a specific pair of shoes that you wear into the barn, that is really just your barn shoes, an excellent idea. I see a lot of people... I work with a lot of students. I work with a lot of undergraduate students that are out on animal science farms. And, you know, we have a lot of facilities here. And they'll wear the same boots, that are their barn boots, but they also wear them home. And, if they have agricultural animals, if  they have livestock, I never recommend that. You know, I have a school boot and have a home boot. I think, you know, again, the risk of kind of picking up an accidental CL at the feed store might be rare, but it's not impossible. So I do agree, if you can have a pair of farm boots, or shoes, tennis shoes, whatever you want to wear in your barn, that you only really wear in your barn—or, you know, around your property—and then have your outside shoes, I think that's an excellent idea.

Michael Pesato  15:45 
This bacteria is so hearty. And especially if you are dealing with an outbreak of this, you should have a pair of shoes or boots that you can scrub and clean. You should wear gloves. If you're dealing with this, if you're going to lance an abscess, or if you have an open abscess that's draining, you're going to want to do that in an area... Take it away from your other goats. Because, the more you can try to prevent this bacteria from getting into your environment, the better you're going to be. Remember that things like bleach are inactivated by organic debris. So, you're gonna want to clean anything you have with soap and water first, and then you can sterilize with bleach. And, if you have a cement surface to kind of drain any abscesses or flush or clean any abscesses, that's even better, because it's much easier to disinfect versus a barn floor or a wood floor or something like that. So, when it comes to Caseous lymphadenitis, there's no such thing as over thinking the biosecurity component. It's very important.

Deborah Niemann  16:44 
And then, I also wanted to kind of take a step back to where you were talking about, like, a pregnant goat not being the healthiest animal in the world. Because, one of the things that I know I've read repeatedly is that an animal can be a carrier of CL and not get an abscess until they get stressed. And of course, pregnancy is stress; giving birth is stress.

Michael Pesato  17:07 
Yep.

Deborah Niemann  17:08 
So, you may actually see an abscess for the very first time when a goat is pregnant—or, like, a day or two after they give birth.

Michael Pesato  17:15 
Yes, absolutely. And where we see a challenge with Caseous lymphadenitis is that this is a kind of slow, insidious bacteria. So, it takes a while for it to present clinically; it can take 6 months or more for this animal, after they've been exposed to the bacteria, for it to even cause clinical signs. And of course, we know stressful events, anything stressful, is going to decrease your immune system; it's going to make your immune system a little bit less likely to be able to fend off some of the things and keep things in check. And so, it's not surprising if you see, after parturition, increased incidence of disease. And especially you may see these abscesses start to pop up a little bit.

Michael Pesato  17:56 
So, when it comes to Caseous lymphadenitis, it's really challenging to go out, and let's say you purchase a new goat, and you bring it to your farm and say, "Well, I'm going to quarantine it for two weeks. I'm going to quarantine it for a month." I typically recommend 30 days. But if you're going to quarantine it for a set period of time, this can take so long to present clinically that you may have them already mixed in and 8, 9 months later, that's when you notice that they're starting to develop abscess. Which makes me think of your friend. You know, that's probably what happened with her, is that everything's been fine, everything's great. And then, somebody was harboring this bacteria, it was traveling through the lymphatics, and it perfect storm event; we ended up having it start to pop up clinically.

Michael Pesato  18:35 
So, Caseous lymphadenitis-positive animals, to me, are not very valuable within a herd. And I know some people would argue with me about that, because there are—especially the meat goat industry. We see a good bit of Caseous lymphadenitis in the meat goat industry, to the point where it's kind of been accepted as just part of it. But, I think we have to work hard to try and eradicate it as much as possible. Because, it does impact things like your meat quality; it does impact how much you're going to get for the carcass, because if they have to cut out a lot of the meat because there's absolute contamination, or condemn the carcass altogether, you're not gonna make any money. So, it's not just a benign, "Oh, it's just CL. It doesn't matter." You know, "It's part of the game." It doesn't have to be, you know? And what it takes is kind of what we're discussing now. Biosecurity, proper, you know, diligence when it comes to paying attention to these lesions, knowing when to cull versus, you know, what you want to do next.

Deborah Niemann  19:30 
Yeah. And a couple of weeks ago, we were talking about buck health and breeding. And I was talk—it was Dr. Jamie Stewart from Virginia Tech, and she was saying that a buck can have CL, and that is going to affect his fertility.

Michael Pesato  19:46 
Oh, absolutely. I have seen pictures—I haven't had a case myself—but of CL in the scrotum, basically, and this testicle with a giant abscess. I had a case, it was really sad. I had a farm that had endemic CL. So, the buck had it. And the buck spread it, essentially, to all the does. So, all the does had it. And I went there because they had a downed goat kid; it was about a 5-month-old goat kid. And I thought, "You know what, this looks like maybe caprine arthritis and encephalitis virus. Maybe this is the encephalitis form." We ended up having to euthanize the goat kid, and we took it back for necropsy. He had a Caseous lymphadenitis lesion in his spine. So, this can pop up anywhere. And it's not, again, it's... These are losses. You know, this is loss of fertility, means loss of kid crop, loss of your kids at 5, 6 months of age. That could be a lot of money down the drain. So, it's not something where it's like, "Oh, it's fine. We just deal with it." You know, it's something where you, kind of, best practice is to try and not have to deal with it.

Michael Pesato  20:46 
And so, you know, I'm sure that—and this might be your next question, Deborah—but a lot of people are like, "Well, how do I treat it?" You know, like, "If I have it, how do I treat it?" The unfortunate reality is that there are treatments, but there's no cure. So, treatment-wise, you can treat the individual lesion. If you've got, on your jaw line, you know, an abscess, you can lance it with a scalpel. You can flush it. You can get all the pus out. You can use hydrogen peroxide. There's even people who put formalin into these legions and say, "Oh, that's the treatment of choice. Formalin will kill it." You know, formalin is, like, a derivative of formaldehyde. That might get rid of the abscess, but it doesn't get rid of the actual bacteria in the system of the animal. So, it's gonna pop up again, somewhere else. So, people might tell you, "Well, that's the treatment. That's how you treat it." That's how you treat the lesion, not the whole disease. So, keep that in mind.

Michael Pesato  21:35 
And people say, "Well, how long do I need to wait before I put an animal that ruptured an abscess back in with my other animals?" It takes about a month for the skin to heal over that, and you want skin to heal. Because, even if there's just a little bit of pus draining down, that's all infected material. So, they can't go back in with those animals. And quite frankly, I would recommend not putting them back in with your animals, and either culling them, or starting a separate herd that has CL, and try to keep one herd that doesn't, if you can, if they're near and dear to your heart, and if they're very expensive, I understand. But ,that's what you have to kind of grapple with yourself about what you want to do next.

Deborah Niemann  22:10 
I started chuckling when you were talking about treatments, because I recently posted something about CL on Facebook, and somebody said, "Oh, it's not a big deal. You just spray WD-40 on it, and that'll take care of it." And I... You know, there are some comments, like, I'm not even going to argue. I'm just going to delete your comment.

Michael Pesato  22:29 
Right? Yeah.

Deborah Niemann  22:30 
Like, I was just like...

Michael Pesato  22:32 
Yeah.

Deborah Niemann  22:34 
WD-40? Really?

Michael Pesato  22:36 
You know, it reminds me of... I mean, I've had people, you know, talk about spraying diesel fuel on their animals for fly control. I had a man who told me they accidentally caught their cow on fire when they used the hotshot on her after spraying her with diesel fuel. Yeah. So, you know, these kind of old-fashioned old farmer tricks, I don't recommend them. I typically don't recommend using chemicals that might be, you know, aggravating to the animal to treat.

Deborah Niemann  23:07 
Yeah, exactly. I know. It's like, there are people who say to give a goat Tide laundry detergent when it has bloat. And I'm just like, "You know, I don't usually tell people to go to Google. But, if you go to Google, you'll find out that something like 15,000 children a year wind up in the emergency room because they accidentally ingested laundry detergent."

Michael Pesato  23:25 
Right.

Deborah Niemann  23:25 
Why would you give that to your sick goat?

Michael Pesato  23:28 
Right. And I think that, you know, that obviously comes from, we use something called poloxalene, which is a kind of detergent derivative. Honestly, if I was going to use any kind of over-the-counter detergent, I use Dawn dish soap; it's very safe for the bloat. What it does is it breaks up bubbles. But Tide laundry detergent may not be the safest option. You know, so use the safest thing possible for your animals. You know, that's what you really should focus on.

Deborah Niemann  23:52 
Yeah. There's so many things, so many ingredients—

Michael Pesato  23:56 
Oh, yeah.

Deborah Niemann  23:57 
—that, like, burn the esophagus and all this kind of stuff. Like, it's just really bad.

Michael Pesato  24:03 
Yeah, absolutely. I mean, you have to think about that stuff, because that has lasting effects, you know? It can have lasting effects on your animals.

Deborah Niemann  24:09 
Yeah, I agree. So, when this person asked me about what she should do with her herd, and I said, "Well, the textbooks just say, 'Cull all your positive animals, and then vaccinate everybody else,' she said that her vets told her there was no vaccine for goats. Which is when I contacted you and said, "What do you mean there's...? Like, I don't understand. Like, the textbooks say 'vaccinate.' This is what the textbooks say." Can you explain the disconnect there?

Michael Pesato  24:35 
Yeah, yeah, for sure. So, first thing I want to say is, you know, cull all the positives. So, that is based on the blood test. Essentially, it's a blood test that's called a "synergistic hemolysis-inhibition test." So, S-H-I test. For my students, I always say it's a bad word, S-H-I-T when it's put together, and they always get a kick out of that and it helps them remember. But, that test is something that is... I pretty much exclusively use Washington State's Animal Diseases Diagnostic Laboratory; it's a great lab, and they run that test there at the lab. And I trust them. I trust their results. And so, you know, it says "Cull the positives." That is very true if you have, like, an ongoing outbreak and you're running a herd-based test. It's tough to say "cull the individual." Like, let's say only one animal you test comes out positive. Even their website will recommend being careful, cautious, not to cull individuals based on this. But ,when you have a herd that you're running the tests on, it's a little bit more helpful, because it gives you an idea of how many of those animals were technically exposed, and how many of them may have circulating bacteria.

Michael Pesato  25:34 
What that test looks for is actually the toxin from Corynebacterium. So, it's looking for the toxin produced by the bacteria, meaning that these animals may... It's not an antibody test or anything like that, where, you know, "Oh, it's been exposed, and they've developed antibodies." No, it's looking specifically for the toxin from that bacterium. So when, you know, the testing is done, and you've found your positives, you're gonna cull, yeah, the next most logical step is, "What's our preventative? How do we keep this from affecting the rest of the herd?" And you're going to want to reach for the vaccine. 

Michael Pesato  26:02  
Now, about maybe five years ago, maybe even less than that, we had access to a sheep and a goat vaccine. The sheep vaccine was from Colorado Serum. Still exists. And the sheep vaccination is labeled for sheep. And so, we generally do not recommend that for using goats. And, the reason for that, is that the sheep vaccination tends to create a very large reaction site at the site where you give it. It also it can lead to systemic effects on the animals. So, you could find that they develop a fever, or they become lethargic, you know? You get some kind of systemic vaccination reactions. It also has different withholding times than what the goat vaccine had. It's labeled to start giving the sheep vaccine at a different age than what you would give the goat vaccination. So, there are some big differences. So, we typically said avoid sheep vaccine for goats. 

Michael Pesato  26:51  
Well, the goat vaccine was put out by a company called Texas Vet Lab, Incorporated. It had gotten approval by the mid 2000s for use across the United States. And it was amazing, because it was the goat-specific vaccine. We never had that. That was perfect. It was excellent. Well, that lab, unfortunately, was bought out by a company called Bimeda Biologicals. And so, that's one of the products that got cut from the commercial aspect. And there's no longer a commercially available approved vaccination for goats in the United States. So, that's kind of where, you know, the texts—and even articles and things that would have been published within the last, you know, 4 or 5 years—they're going to recommend "vaccinate, vaccinate, vaccinate," but that goat vaccination is no longer on the market. So, we have people reaching for the sheep vaccine. Which when in, you know, a panic mode, I don't think that's the worst idea. But know the risks. 

Michael Pesato  27:44  
The other thing about the vaccine is, even the goat vaccine that we used to have: It does not actually prevent them from becoming infected. So, there's nothing that's going to prevent them from becoming infected except getting rid of the infection from the farm. That's the only thing that's really going to stop your animals from becoming infected. If, you know, you use the vaccine, what it does is it decreases the incidence and severity of disease. So, essentially, it's going to stretch the timeframe from an initial introduction of the bacteria into the body to when you see clinical signs of disease. So, it's going to take that 6-month period of incubation, and it might make it, you know, that you won't see lesions for a year. But eventually, you're gonna see lesions, and it decreases the severity. So, the lesions may not be as large as what they would be when we would see a non-vaccinated animal developing an abscess in their lymph node. 

Michael Pesato  28:35  
So, the vaccine, I only recommend it for use in endemic herds, where you are either unable to, or you just simply don't want to, get rid of actively infected animals. And in this case, now that the Texas Vet Lab's vaccination is no longer available, the only option you would have is the sheep vaccine, with no proof that it's even going to do what I just explained, because it's not labeled for goats. And it's going to potentially cause side effects that may not be worth the benefit that you think would come from vaccinating. So, it's an unfortunate reality that we don't have a commercially available vaccine. 

Michael Pesato  29:12  
Now. What we do have as an option, and it's available through this company, this Bimeda Biologicals—and I don't work for any of these companies. So, I'm not trying to push any of them. I'm just... This is just where they're commercially out of. They give the option of what's called an "autogenous" vaccine. Autogenous vaccinations are created by taking the bacteria from the animals affected, so from your farm, and creating a vaccine against that bacteria that they got from your farm. It sounds great. Sounds amazing, right? But it's expensive, generally, and I'm not sure what the breakdown is through this company, but you generally have to order a large volume of doses. So, if you have a goat farm with 20 goats, you may have to order in hundreds to thousands of doses, and you are never going to use that many. They're going to expire before you get a chance to use them. So, for many people, that autogenous vaccine is not practical. Financially, it's not practical. You know, it really isn't something that I would choose to use in a small-scale operation. But, that is an option presented by this company. So, instead of having that commercially available vaccine, they give the option of an autogenous vaccination.

Michael Pesato  30:21  
But yeah, so it's sad and a little frustrating that we don't have the available preventative that we used to have. But then, I also asked the question of, "Because it doesn't actually prevent these goats from getting the bacteria., what is your end goal?" That's gonna be the question to ask yourself. Is your end goal to get rid of this bacteria in your herd or flock? Well, then vaccination is not going to be your answer. Heavy culling is going to be your answer, and testing and picking out the animals that you want to keep. Now, here's the other thing: That vaccine makes the blood test unable to happen, because it makes all of them positive. So, if you vaccinate the whole herd, you take away the ability for you to test annually to make sure that you're not seeing new cases starting to pop up. So, I caution you when it comes to choosing to use that vaccination, because it does take away a diagnostic capacity for you to do to try and monitor the status; everyone will come back positive. So, don't vaccinate then test, because then you're gonna freak out. Everyone gonna be positive. So, keep that in mind when it comes to choosing whether you need a vaccine or not. You are taking away your ability to diagnostically see who might be positive or not from that SHI test.

Deborah Niemann  31:30  
Yeah. So right now, if you have a herd, and you have a lot of animals testing positive, your only real option right now is just to cull the animals that are positive.

Michael Pesato  31:40  
If you want to eradicate it from the herd, that's it.

Deborah Niemann  31:43  
And so... Because, I know one of the things this person was looking at, she's like, "Well, some of the goats that tested positive on blood have never had an abscess, but some of the goats that have had abscesses tested negative." So, should I cull everybody"—

Michael Pesato  31:57  
Mm-hmm. Mm-hmm. 

Deborah Niemann  31:58  
—"you know, that had one, or that had one or the other?"

Michael Pesato  32:03  
Yeah, yeah. That's a great question. And that's the challenge. You know, unfortunately, there's no such thing as 100% in science. It's just a reality. I like to tell my students, "Biology has no rules, just guidelines." Because, you know, there's these things that make sense, and that always happen, and there's outliers. So, there is a chance that you'll do that SHI test and literally—and I've had it before. You do it on an animal that has a clinical abscess that you culture; the bacteria from it comes back negative. I would cull anyone with an abscess—anyone with an abscess that is confirmed—because we just talked about your goat that had the abscess in the neck that came back as a skin bacteria. Don't just cull because of an abscess. Make sure you get a culture. Get a definitive diagnosis. And I would cull those animals. 

Michael Pesato  32:46  
And then, anyone positive, you have two options. One: Monitor closely. Because, if you read the fine print, even on the Lab—the Washington Diagnostic Lab website—it'll say that these animals aren't necessarily positive, in the sense that they have active lesions where they have the ability to become positive. It'll say that they've been exposed; they've had the bacteria in their system before. And then, I hate the end of it, because it says "recovered." I don't ever think they actually recover. It's hiding in their lymphatics and waiting to come out. So, I kind of disagree with the "recovered" statement. But, I think those animals are always going to be at risk of developing lesions, and they should be the ones you watch like a hawk. And, if you don't want to do that, they can leave. They're not going to benefit you in any way, especially if you don't have the patience to sit there and watch ticking time bombs.

Deborah Niemann  33:35  
Yeah, exactly. And I think the really important thing for everybody to understand is how important it is to... During that quarantine period, when you bring in new animals, like, the first thing you should do is blood testing to make sure that they're not carrying anything. And then to do regular testing. And, like, like you mentioned, next week, we're gonna be talking with somebody from Washington State about doing the biosecurity screening. And I'm just such a huge believer in that. And I'll talk more about my experience later. But, like, I've had closed herds since 2005; I've not bought a doe since 2005, and I've only brought in a few bucks. And they've all come from herds that have consistently tested negative year after year after year after year—for like 15 to 20 years—for all of the diseases. You know, and that's just so important, to make sure that these things don't sneak into your herd. Because this person that I started out talking about in this episode, she has had goats for 4 years, and she bought all of them from herds that had tested negative. But, there are other ways that it can come on to your farm. 

Deborah Niemann  34:43  
And the other thing was, she has sheep. And I have noticed this, because I have sheep too. I mean, I feel like goat people these days don't test nearly as much as they did 20 years ago when I got into this, and sheep people are like, "Diseases? CL? What's that? Johne's? What's that? OPP?" Like—

Michael Pesato  35:04  
Right.

Deborah Niemann  35:04  
—there's gotta be some sheep breeders out there who are testing. I just haven't met them, you know? So, when she told me that she had sheep, I said, "Oh, I bet your sheep brought it onto your farm."

Michael Pesato  35:16  
It's very, very possible. Caseous lymphadenitis can cross between sheep and goat species. So, it's incredibly possible that's what happened. And I agree with Deborah. I'm totally pro biosecurity testing. The most bang for your buck is going to be to do it consistently every year, because a one-off test on your animals may not be the best option, because you're not going to see patterns with that one test. So, when you get a new animal, I 100% agree with doing a biosecurity screen on that animal. And then, that animal should be added to your herd when your quarantine period is up, and you test your entire herd every single year. That's how you get that, you know, "I'm a negative status" person; not just from one year of doing biosecurity screen, because we can miss diseases that way. Again, no test is 100%. So, the more you do it every year, the better. And I think it's... Frankly, I think it's worth the money to test it, because you do have, one, peace of mind, and two, the opportunity to tell and market yourself as a disease-free herd. And that's very valuable. You know, and I agree. I mean, I think I see more goat people doing biosecurity screen testing than I have of my sheep producers. And I'm not sure why, to be honest. But, I think I've seen more goat people—because I think a lot of goat producers and people that have production or pet goats, that's a huge sell for them. When they purchase goats, when they look to work with another farm, they want something that is clean, and proven clean and free of disease. 

Michael Pesato  36:41  
And I think the fact that Deborah's gonna have Washington State on here is an amazing thing, because there's lots of labs out there. And I think you should use a very well-respected lab to get your results, because, unfortunately, what can happen—and what could have happened with your friend—is that the people she bought negative goats from may have been using a lab that didn't do the most up-to-date testing. So, there could have been some false negatives in that grouping. So, I love that you're gonna have Washington State, because like I said, I sing their praises.

Deborah Niemann  37:07  
Yeah, exactly. When I first got into goats, that was the only lab that was doing the ELISA for CAE, which is how I started using them. And then, I just kept using them ever since, so. 

Michael Pesato  37:18  
Yeah. 

Deborah Niemann  37:20  
Well, thank you so much for being on today! This has been really helpful. And thank you for simplifying something that I recently discovered was not nearly as simple as I thought it was. Is there anything else that you feel like we need to cover?

Michael Pesato  37:33  
No, I think we covered everything, really. Well, you know, I mean, I think again, this is a bit of a controversial topic. And I'm sure that some of you may be like, "I don't really worry too much about that disease. It doesn't bother me one bit." And I can't encourage you enough... You know, one: buyer beware. When you buy your goats from anyone, just know that there's a potential that you're going to enter in... I've had several clients that are thinking they're getting healthy animals, and they get an abscess, and they talked to the person, they're like, "I told you I wanted healthy animals." And the person says, "It's just CL." That doesn't mean it's a healthy animal! So, buyer beware, and those of you that have, you know, active CL, and you don't think it's a big deal, just remember that there are people who do. So, you know, do the best you can to have as healthy of a herd as possible, because it's going to benefit you, and it's going to benefit people you sell goats to. 

Michael Pesato  38:22  
And of course, if you have any questions or comments or concerns, you can always reach out to Deborah or myself. And we can direct you for more information.

Deborah Niemann  38:28  
Thanks so much for being with us today.

Michael Pesato  38:31  
No problem. Thank you for having me.

Deborah Niemann  38:33  
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 ForTheLoveOfGoats.com, and you can follow us on Facebook at Facebook.com/LoveGoatsPodcast. See you again next time. Bye for now!

Transcribed by https://otter.ai