Working to Eradicate CAE

Episode 28
For the Love of Goats

 

 

Caprine Arthritis Encephalitis, usually referred to as CAE, is a disease unique the goats and sheep, which has no cure. It spreads easily because goats in the early stages of the disease have no symptoms, and some may remain symptomatic forever. In the 1970s, it was discovered that most goat herds in the United States and many other countries had multiple goats that were infected.

CAE doesn’t kill goats directly. However, they can wind up dying from chronic mastitis or pneumonia, and some owners euthanize CAE-postive goats when they can no longer walk. Weight loss usually occurs because the goat doesn’t want to get up and graze or walk to the hayrack or feed pan.

Since the disease is spread by bodily fluids, including blood, milk, and mucus, it is easy to control the disease when you know a goat is infected, which means routine testing of all goats is key. After decades of taking kids away from their dams at birth, the number of goats with CAE has decreased dramatically. However, with the increase in the popularity of goats, I am hearing of more and more cases of CAE in the US. This is one reason I am not a fan of buying goats from sale barns and auctions, as that is where many of these goats are sold. 

In this episode I am joined by Dr. Sandra Baxendell, a goat vet in Australia, who talks about how her country has started to bring the disease under control, as well as how other countries have eradicated it completely.

The above photo shows one of the most common symptoms that goats may eventually present, which is swollen knees. 

 See complete transcript below.

For more information from Dr. Baxendell

Transcript

Deborah Niemann 0:00
Hello everyone, and welcome to another episode. I am really excited and honored today to be joined by Dr. Sandra Baxendell from Brisbane, Queensland, Australia, who is a goat vet, which is pretty exciting to me. It’s so hard to find vets who see goats, and she specializes in goats. And she came to my attention because she has a page on Facebook called “Let’s Eradicate CAE from Australian Goats.” And that is a super exciting idea to me. And so the first — as soon as I saw it, I thought, “Oh, my goodness, I have to get her on the podcast so we can talk about CAE.” So, welcome to the show today, Dr. Baxendell.

Dr. Sandra Baxendell 0:40
Yes. I’m pleased to be here.

Deborah Niemann 0:43
Thank you so much for joining us today. So, just to get started, I imagine we have some listeners who don’t know what CAE is or know why they should care about it. So could you just give us a, you know, let us know what is it and why should people care? And what does it do to your goats?

Dr. Sandra Baxendell 1:00
Well, first of all, CAE stands for “caprine arthritis encephalitis.” And, it used to be known by its common name, which was “big-knees.” And, as you can imagine, from the term, the most common clinical signs are just enlarged knees or arthritis. Or, it is actually a periarthritis. So it’s a bony outgrowth around the carpal joints or the knees. And then that develops into arthritis, spreads to other joints, causes wasting, and a range of other clinical signs. So it’s a virus, there is no treatment, and there is no vaccine. So that’s why it’s very important to try and eradicate it, both from your herds, and to follow the example of Norway and eradicate it from your country.

Deborah Niemann 2:03
That’s really exciting to know that Norway has been able to eradicate it. I know, and then, I think in the 1970s in the United States, it was… The majority of goats that were tested had it. And I think, from what I’ve read on your page, it sounds like Australia got in pretty much the same situation.

Dr. Sandra Baxendell 2:22
Yes, in the late 1970s, 1980s, it was rampant in the dairy goat population. And that’s because people didn’t know how it was spread. And so a lot of dairy goat farms removed the kids from their mothers and fed their kids on bottled milk. And that just meant if you had one carrier in your herd, you infected all the kids that year. And so that’s why it’s spread so rapidly.

Deborah Niemann 2:55
Wow. That’s terrible. And so, one of the other things too… Take a quick step back: Don’t goats also tend to have problems with their udder in the later stages of CAE?

Dr. Sandra Baxendell 3:07
Yes, so there’s a range of clinical signs. So the clinical signs, most commonly, are the arthritis or the big knees; they also have wasting, they get very, very skinny; they have what’s called “hard udder.” Now, it’s a very specific form of mastitis. It occurs from the first lactation, and these goats look like they’ve got a lot of milk. But when you feel the udder, the udder feels like two smooth rocks inside this skin-like bag. And the only areas of the udder that aren’t rock hard are the teats. And the milk production is measured in teaspoonfuls. So very, very severe mastitis. The other form that you can get is the pneumonia form. And so this is where the lungs just almost become solid. And these poor animals have such great difficulty breathing that they spend all their effort breathing and they just waste away, because they can’t really eat properly, because they’re just concentrating on breathing. So they have to be destroyed once they get to that stage. The other thing that you can find sometimes is enlarged bursae, either around the carpal joint or the knees, but also at the back of the head and on top of the shoulders. There’s a little bursa there that helps the tendon smooth over bone and they can be enlarged. So they’re the clinical signs. There’s the encephalitic form, which is basically more common in kids, though it has been recorded in adults. And this, it’s a whole range of nervous signs. And these animals have to be destroyed within weeks, because they’re just too bad.

Deborah Niemann 5:12
Wow, that’s… This is — it’s such a sad disease, because for the most part, it’s not going to just kill the animals, it’s just going to make them so sick and debilitated and everything. Like, as you’ve mentioned several times, that basically the owners ultimately wind up just putting down the animals because they’re in such bad shape.

Dr. Sandra Baxendell 5:34
Yeah, not all animals will develop clinical signs; they estimate somewhere between a half and a third of positive animals that have the virus will have clinical signs. But it depends on the viral load, both the virus numbers within the particular goat, and also the virus numbers within the herd. And what we saw in the 1970s, 1980s is the herds would just get so many carriers, and have such large amounts of virus circulating, that they basically crashed. So, you’d see a whole range of clinical signs, the wasting, a few lung conditions, a few hard udders, and the majority of animals after their first lactation would be developing the enlarged carpal joints. So it’s a function both of how long the goat lives before it shows signs, and also the amount of virus both within that goat and also within the herd.

Deborah Niemann 6:42
So even though not all of your animals are going to die from it, or even show symptoms, the the big problem is that those asymptomatic animals can be infecting all of their kids and any kid who tries to nurse off of them, and…

Dr. Sandra Baxendell 6:57
And not only nursing. The the virus itself is actually in the monocytes and in the macrophages, which are types of white blood cells. So it’s not just milk — milk and colostrum are full of white blood cells. But so is vaginal mucus, that estrus; so is the blood that’s discharged after kidding; the saliva has amounts of white blood cells in it; the respiratory secretions have white blood cells in it. So these are all methods of spread. You can actually spread it if you’re using, say, an automatic vaccination gun and spreading it via the needle — poking it under the skin of one animal and then going to the next to vaccinate them. Tattoo pliers can also spread it, because they can get blood on the tattoo pliers. So there’s all different ways that CAE can be spread.

Deborah Niemann 8:00
Okay, so if you have a goat that is just walking around out there in the pasture and surprises you by giving birth, and if other goats come over and start licking off her kid, they’re ingesting blood and mucus and everything that can infect them.

Dr. Sandra Baxendell 8:15
That’s right.

Deborah Niemann 8:16
Okay.

Dr. Sandra Baxendell 8:17
So to keep animals… If you’ve got some carrier animals which have tested positive, you’ve got to keep them behind two fences or a solid wall. So the majority of herds in the 1970s and 1980s, they managed their CAE, managed to eradicate it, by snatch-birthing the kids. So they did things like putting T-shirts on the goats with their hind legs through the armholes, and tying the T-shirt at the front of the goat’s brisket. Or they put gaffa tape or Elastoplast on the teats to make sure, even if they missed the kidding, the kids weren’t going to get a drink. So they did all these things. And then they raised those kids in isolation. And they have to be behind a double fence or a solid wall. And that’s to protect them what we call the “sneeze distance.” So two meters is what most people used. Though, in the UK, they recommend three meters, because goats have longer necks than sheep. So for sheep, it’s two meters, and goats, three meters. And so long as they can’t sneeze on each other, you’re pretty safe.

Deborah Niemann 9:37
So the first thing that people need to do, then, is to test all of their goats to see if they’re positive, correct?

Dr. Sandra Baxendell 9:45
That’s correct. So most people use the ELISA Test. In America, I’d recommend that you only use a government or a university lab. In Australia, all laboratories must be accredited. And that’s done by sending out blood samples, and they have to get the answers correct in order to be allowed to offer that blood test. But in other parts of the world, anybody can just start up lab and say they will test animals for disease. But because agriculture is a big part of Australia’s economy, they only allow veterinary laboratories to offer services if they are accredited and pass proficiency tests.

Deborah Niemann 10:37
That’s a really good point. I usually recommend that people use Washington State Diagnostic Lab, because they… From them, you can — one tube of blood, they can run a test for CAE, CL, Johne’s, and brucellosis. They call it their biosecurity screen.

Dr. Sandra Baxendell 10:54
Yeah. So you’re pretty safe with a government or university lab because they have their own internal quality controls.

Deborah Niemann 11:02
And then, once you test, how often do you recommend that people test again?

Dr. Sandra Baxendell 11:08
So initially, they should test once, and then every six months, then stretch it out to a year. We have an accreditation program. So herds agree to abide by the rules. The veterinarian inspects their property, makes sure they have a quarantine area, makes sure their fences are up to scratch. And then they sign to say that they will obey the rules. Then, they have to have — to join the scheme — they have to have two negative tests, 6 to 12 months apart, then they go on annual tests, then they go on every two years, then they go every three years. And so long as a vet inspects the herd, makes sure that there’s no clinical signs in that herd, the fences are still up to scratch, and they have obeyed the rules, then they remain accredited.

Deborah Niemann 12:06
So when those people buy goats from other herds, do they have to buy them from other accredited herds to maintain their status?

Dr. Sandra Baxendell 12:13
They either have to buy from an accredited herd, or they have to keep the new goat in isolation for six months, until it’s had two negative tests.

Deborah Niemann 12:24
Wow, that’s great advice for anybody, even if you’re not, you know, if you’re not in Australia, that is a really good way to make sure that you’re not gonna bring CAE on to your farm.

Dr. Sandra Baxendell 12:36
That’s right. Because a blood test is only looking at the antibodies from exposure that was six weeks prior to that. And we do know with CAE that it can take a long time — 6 to 12 months — for the antibodies to become positive on the blood test. So one test is not good enough. And if you’re buying in goats, there’s no point in just testing the goats you’re going to buy in, you must test — must have the test results from all the animals in that herd. Because the animal that you’re buying in could have been exposed to blood or milk just the day before you took the blood test, in which case is not going to show up. So it must have a record of regular negative tests and good biosecurity in between. There’s no point in just testing if you’re going to go out and buy goats at an auctions, or show goats and mix them up with goats that are untested, because you’re just spreading potential diseases such as CAE. So in my state, Queensland, in order to be counted for what’s called “the dairy goat of the year” (and so people get points for being first, second, or third in a class; they get points for championships; and things like that), in order to those points to be given out, then that show must be CAE-accredited. And so only animals, dairy goats, that have come from an accredited herd can attend that show.

Deborah Niemann 14:27
Wow, that’s awesome. So, a quick question about using cow’s milk, because you mentioned using cow’s milk to raise kids as one of the possibilities. Would you be concerned about Johne’s?

Dr. Sandra Baxendell 14:41
Yes, certainly, I would be very concerned about Johne’s. My state actually was regarded as Johne’s-free for dairy cattle. That’s no longer the case, because they’ve opened up the borders and anyone can introduced cattle from other states. But at the time, when we’re busy using cow’s colostrum for raising the CAE-free kids, cows in my state were Johne’s-free. And if it was ever found, that herd was quarantined, and could only sell their dairy cows to slaughter.

Deborah Niemann 15:17
So what should someone do if they have a goat, or two or three, come back with a positive test?

Dr. Sandra Baxendell 15:26
Then you must immediately try and work out how that occurred. Now, if these, for example, were newly introduced goats, you’d use them a little bit differently. So I’d gather them up, and I’d put them in isolation behind a double fence or solid walls, so that they could no longer mix with the other goats. Now, if they had been kidding in the paddocks, if their milk was used to raise that year’s batch of kids, then you might have to change that. And you might have to say the whole herd is now potentially positive, and start removing all the kids from this point in time, and snatch-birthing them, and raising them on pasteurized goat’s milk or cow’s milk or artificial powdered colostrum.

Deborah Niemann 16:22
So when you’re… It’s kind of like working with two different herds. You’ve got all your goats over here that tested negative, and then a couple over here who tested positive. Do you need to be concerned about having shoe covers or changing your shoes when going between them? Like, is casual contact like that going to be a problem?

Dr. Sandra Baxendell 16:41
It could be a problem for Johne’s, but not really a problem for CAE. For CAE, you can actually use the same milking parlors for both the positive and the negative herds, as long as you milk the negative herd first, and then wash out and clean down the milking parlor after the positive herd has been through and been milked. But you have to be very careful in regard to vaccinations. I only ever use sterile needles for each individual goat. For tattoo pliers, the tattoo letters and numbers must be boiled or soaked in methylated spirits. So you have to use good common sense. The CAE virus is easily destroyed with disinfectants. It’s not like Johne’s disease, which is very, very difficult to destroy with disinfectants, and also is resistant to heat, even pasteurization.

Deborah Niemann 17:48
So, the smart thing for people to do basically, then, is to only buy from other herds that have tested negative for this. And, so in the US where we don’t have an accredited program like this, how long would you want to know that a herd had tested negative for CAE before you would feel comfortable bringing goats into your herd from them?

Dr. Sandra Baxendell 18:11
At least a couple of years. And I’d actually want to see the lab test results. And I want to see what lab they were tested from. And I want to know, what’s the level of biosecurity in between those tests? So for any livestock diseases, there’s some basic points for controlling it. The first one is to find out if you’ve got it, and if you don’t, then you’ve got a chance to keep it out by having good biosecurity, and only buying from herds which have a long history of negative tests and good biosecurity in between. The next step is to find it fast. So, if you are unfortunate enough to have it, it’s best to find out that you’ve got it before it spreads within your herd, then you need to stop spreading. So you need to take basic precautions, such as only ever using sterile needles when you’re injecting your goats. Never ever feed pooled goat’s milk to kids. It’s just too dangerous, not only for CAE, but also for Johne’s, and also for mycoplasma. And then you need to try and eradicate it. There’s two methods that you can use for eradication. One is testing and culling. So that’s basically testing frequently, so for example, every three months, and culling any positives. Now obviously, if you’ve got very large percentage of your goats that are positive, you’re culling a lot of animals. And that’s why you might go then to snatch-birthing — removing the kids at birth, testing them between 3 and 6 months, in case some did sneak either a drink from their mother, or they got contaminated with blood during the birth process. So you’re weeding those out quickly before they can spread it. And the spread between dry goats — so this is young kids — is minimal. You have to wait until the goats are adult, so they’re producing estrus mucus, they’re producing milk, which has got very high numbers of white blood cells, and therefore potentially very large numbers of the CAE virus. So snatch-birthing the kids, testing them, and always keeping them permanently separated from any positive goats. So they’re the methods you can use. Australia’s got a national kid-rearing plan that people can read, do a search for and read. And that has been successful in eradicating CAE. And we’ve now had herds which have been accredited for 20 to 30 years.

Deborah Niemann 21:10
Wow, that’s wonderful. I had no idea that the program had been around for so long. I feel like we’re way behind here.

Dr. Sandra Baxendell 21:18
So, I think I’ve got a picture on my Facebook page of a lady’s wall, where she’s got a whole range of her CAE accreditation certificates.

Deborah Niemann 21:28
Mm hmm. Yeah, and you also, you have so much good information on your Eradicate CAE from Australian Goat page. You’ve also got, like, your picture up at the top there with the goat with the swollen knees, so people can get an idea of what that looks like. And just so many great articles here about what’s happening in other countries and around the world — countries who are doing a great job, as well as those who are just kind of ignoring it. And it’s getting worse in those countries.

Dr. Sandra Baxendell 21:59
Yes. And it has a significant economic effect. Norway found that when they instituted snatch-birthing and rearing those kids in isolation, and then in two years time, they got rid of all the old goats and replaced them with a new young, healthy goats, that process eradicated both CAE, Johne’s disease, and caseous lymphadenitis. And they found that the new herds had a 20% increase in milk production, just by eradicating those diseases.

Deborah Niemann 22:37
Oh, yeah.

Dr. Sandra Baxendell 22:38
Switzerland is another country which has eradicated it. There’s no clinical CAE anymore in Switzerland. They have a problem, because they’ve got some maedi-visna, which is a very similar disease in sheep. So they haven’t quite eradicated it yet. But they’re very, very close. And they’re very strict now that you can’t introduce goats into Switzerland without coming from a tested-free herd. And they will actually trace and destroy any goats that are illegally imported.

Deborah Niemann 23:11
You mentioned sheep just a minute ago. So what would you do if somebody has sheep on their farm also? Would you be testing the sheep for OPP?

Dr. Sandra Baxendell 23:22
Yes. A lot of researchers now regard OPP and CAE as the same virus, and they call it the “small ruminant lentivirus.” It not only affects both sheep and goats, but also some of the wild ruminants. Even though they’re different species, they can all be affected by this small ruminant lentivirus. So that’s what scientists now call it. And they regard it as a disease that affects both sheep and goats. And certainly, there was a case in New Zealand, where someone who ran both dairy goats and sheep for milk, they fed their lambs on some bulk milk from their dairy goats. And those lambs came down with arthritis. And that was shown to be CAE. So it can certainly spread between species. So, if you are going to manage your CAE, then you’ve got to be very careful about their exposure to sheep, because sheep can introduce either OPP or CAE to your goats. And they can also introduce Johne’s disease to your goats as well. So, it’s a good idea, when you’re thinking about your biosecurity, don’t just think about goats, but also think about other livestock species that may introduce animals into your herd. So we also have an accreditation scheme for Johne’s disease, and that looks at things like guardian alpacas or guardian llamas, and whether they could introduce Johne’s disease into the herd. As well as cattle.

Deborah Niemann 25:13
Oh, wow, that’s interesting. This has been so informative and so educational. Is there anything else that people need to know about CAE, and either keeping it out of their herd to begin with, or getting rid of it after they discover they have a positive animal?

Dr. Sandra Baxendell 25:32
There’s a lot of people have eradicated CAE. It can be done. It’s a lot of work for a couple of years. But you will never ever regret it. Because the animals are just so much healthier. They’re so much happier. They’re… You don’t have to worry about other diseases, because CAE makes them more prone to things like worms, more prone to mastitis. And the difference between the two herds, the CAE-positive and the CAE negative herds, is a real eye opener. And once people have seen that, then there’s no going back. They are converts to eradication for CAE. CAE is still around in Australia, unfortunately, it’s mainly just in some larger commercial herds. That is very distressing, because they quite often sell the kids to pet goat owners. And then I’ve got to go and tell them, “Sorry, your goat’s got CAE, there is no treatment, there is no vaccine. All I can offer is pain relief.” And so some of these goats have been on pain relief every 36 hours for a year or more. They don’t want to destroy them, they’re family pets, but they’re never going to get better. And eventually, I’m gonna have to destroy ’em.

Deborah Niemann 26:57
Wow, that is so sad. I think most people. it’s not something that most people think about if they’re just completely new to goats, or they’ve just moved to the country and think, “Oh, I want to get a couple goats to put in the pasture, or a couple sheep.” They don’t realize that sheep and goats can have a disease that has no symptoms in the early stages. And that can be so terribly tragic.

Dr. Sandra Baxendell 27:22
We call CAE and Johne’s “iceberg diseases.” So you’ll see a few cases in your herd, but there will be a large number of carriers, and a large number of goats incubating clinical signs. So that when you start to see the symptoms in one or two goats, you’re in for a hell of a lot of difficulty, because you know more cases are coming.

Deborah Niemann 27:50
Mm hmm. Well, thank you so much for joining us today. This has been really, really wonderful. And I’d love to have you back sometime to talk about some of these other diseases that we just barely touched on today.

Dr. Sandra Baxendell 28:03
Yeah, my pleasure.

 

 

 

 

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