If you have looked at purchasing goats, you’ve probably seen some breeders advertise they test for CL, CAE, and Johne’s. Maybe you’ve wondered why that matters and if it’s something you should consider when buying or for your herd in general.
All three of these diseases are contagious and there is no cure for any of them, only ways to mitigate transfer. Please keep that in mind as you read through this information.
The information below is my opinion derived from the research I’ve done on diseases. If you ask 20 people, you will get 10 different opinions. All I ask is that you read the information provided below, do some independent research, and make an informed decision on testing your herd.
The first thing is to understand what each disease is and how it can affect your herd.
First, we’ll look at CASEOUS LYMPHADENITIS or CL:
Basically, CL is an abscess, usually located in the lymph node areas of the goat. The abscess fills and will eventually burst open and drain. Unsightly, highly contagious (and will remain on your property for years) but CL itself is not going to kill your goat. Technically it can be managed with proper bio-security measures but to stop the spread of CL you have to have strict procedures in place and follow them every time there is an abscess.
So what is the big deal? I personally think the biggest issue is resale. Many people are not going to buy a CL positive goat. It’s a lot of work to properly treat and manage an abscess to avoid contaminating other, healthy stock and most people just don’t want to deal with it or take the risk of the disease spreading.
Now, there are some breeders out there that will say all herds have or will have CL so learn to minimize the risk and deal with it in your herd. Personally, I will cull any animal that tests positive for CL. There are too many nice goats out there to deal with the biosecurity issues that arise with a positive goat, and honestly, the purchase price of any animal is the cheapest part of owning them so if you are going to spend money on an animal, why would you spend money on one that already has a disease and that you know is going to not only accrue additional costs but could ultimately spread disease to your other, healthy animals?
A couple other things to note about CL:
There is a vaccine. A warning about it though - by giving the vaccine you have introduced CL to your goat and your goat will always test positive for CL.
There are many people that will not buy a CL positive goat. So if you decide to vaccinate your herd for CL I highly recommend you test first and keep the negative test results as part of your herd history. That way you can prove that you are not masking a CL issue with the vaccine. I would advise this practice every time you bring a new goat into your herd also.
The second thing is that although there is a CL ELISA (blood) test it’s not 100% accurate. The best, and truly only way to know if a goat is positive or negative is the presence (or not) of abscesses, and even then I will add not all abscesses are CL so if you see an abscess in a CL area, have it tested. I won’t go into it here but there are procedures you should follow for this, so you don’t contaminate the area, yourself, or other goats. Research this before just jumping in!
Let’s talk about Caprine Arthritis Encephalitis or CAE
CAE is a viral disease that is typically spread from mom to kids through nursing. It can be spread from adult to adult through blood, feces, and urine but that is not as common.
While there are five forms of CAE the most common forms are arthritis in adults and the encephalitic (inflammation of the brain) form in kids. Infected kids will generally show clinical symptoms around 2-6 months old and can include depression, head tilt, circling, blindness, lameness and issues with limb placement such as hyperreflexia (overactive or overresponsive reflexes) and hypertonia (too much muscle tone making it difficult to move). Neurological signs are rarely seen in adults, they are most likely to show signs of painful gaits (lameness), walking on their knees, mastitis (or low milk production), and in some cases chronic pneumonia.
Last, we’ll look at Johne’s
I’m going to go through what I learned through research and speaking with multiple veterinarians regarding Johne’s; I’m also going to speak about my personal opinions and why I believe the way I do. Everyone has their own opinions, I only ask that you consider what is below, do your own research and make an informed decision based on what you learn.
What we know –
Johne’s is a wasting disease caused by the bacterium Mycobacterium avium subspecies paratuberculosis (MAP). In short, the digestive tract is not able to absorb nutrients and the infected goat will starve to death.
The most common way for disease to spread is when kids are very young and either nurse from an infected doe or get it by “mouthing” something with MAP on it, like teats, or even fecal matter (much like human kids, babies’ “mouth” almost everything).
Feed and water sources are another way MAP is transferred.
There are mixed reports on whether it can be spread through semen. When I first started to research Johne’s most of the information I read said the “experts” didn’t think it could be spread through semen and advised A.I. or hand breeding when breeding to a Johne’s positive buck. More recent studies done on cattle have proven that Johne’s can be spread through semen.
I never advocate live cover for Johne’s positive bucks. My issue with hand breeding is that if you’ve ever seen a buck in rut you know they spit, slobber, and rub against the doe. All these are ways MAP can be transferred from buck to doe. Granted, in very small amounts but it IS transfer. You have to decide if breeding to a Johne’s positive buck, either by live cover or A.I. would be worth the risk.
Many sources also promote that adult to adult transfer is rare. Please don’t rule this out! I personally know several does that were infected by a buck during live cover. Adult to adult transfer is completely possible!
Johne’s infected goats can stay healthy for years, but experts say that generally around one year of age they start to “shed” the MAP bacterium in their manure and are then able to spread the disease to other goats. When shedding begins it is intermittent and in small doses but as the goat ages more of the MAP bacterium is produced and thus more leaves the infected goat and enters the environment.
This shedding can continue to happen for years and the goat may not show outward signs of infection. Positive goats can be fat, sleek, and shiny. It’s not until the advanced stages of the disease that they begin to show weight loss. Generally speaking, goats don’t show weight loss until they are several years old. In many cases 5+ years old. Think about that - if a goat is infected as a baby, begins shedding around a year old and doesn’t show outward signs until they are 5 they have been spreading the disease for years and you wouldn’t know.
Goats can be infected but usually it’s age (3-5 years+) or a stressor that makes them go from negative to positive in tests. Kidding, moving from one herd to another are just a couple things that can change a goat’s status.
Once an animal is showing signs, they are considered clinical. Those signs include changes to their coat, weight loss, and in some cases (not all, or even many) diarrhea. So many times, people that don’t test miss the goat being positive all together or for a while at least because these are also signs we deal with as goat owners – usually worm or mineral deficiency related. I have also seen an infected goat that had a sleek, shiny coat but was literally skin and bones (she was in an advance stage of the disease). This is why testing is so important. There are just too many variables, and too much we don’t know about Johne’s.
Experts say Johne’s can stay on your property for over a year as the organism is quite resistant to drying, heat and cold; it can survive in the soil and water sources, but it can’t reproduce outside its host (the goat). This means that given enough time, even a pasture, lot, or barn can become disease free again. Time is the key.
Testing can be done by fecal (Direct PCR), milk (ELISA) or blood (ELISA). Most breeders choose blood testing due to cost, which are reported as antibody titer levels. There are good and bad to testing. In short, tests are not always accurate, but this is the reason I advocate for whole herd annual testing. If you have a problem with your herd testing all animals will give you a greater chance of an animal showing as positive. If you own 25 goats and test one you are only giving yourself a 4% chance of finding an issue. Along the same line, by testing every year you are more likely to catch a goat that has previously tested negative go positive.
A note about test results:
When testing by ELISA (blood) you can get false negative and false positive results. ELISA is testing antibody titer levels so if, for example, you recently gave your goat their CT&T shot they could test positive for Johne’s (I’ve been told) because of how the titer panel reads. On the other side, some goats that have been infected never develop antibodies so they will never test positive. Usually titer panels are accurate, but the test is not 100% accurate. This is also why you should always test a second time if you get a positive result through ELISA.
Now there are no false positives when testing through PCR. Why? Because MAP is either present or it isn’t. You can get a false negative result though because in the early stages of the disease the goat sheds intermittently so it’s possible the fecal tested didn’t include any MAP. That doesn’t mean they aren’t shedding though. This is also why I advocate annual testing. As the goat ages they will shed MAP in higher amounts and will more likely be picked up during the PCR test.
A couple things about testing in general:
Use an accredited lab. There is a list of labs online – look under aphis.usda.gov for the list. No, they will not be the cheapest but retesting because of a false positive result isn’t cheap either.
Testing costs can add up, but there are ways to cut down on your costs without compromising your results:
Cost saving tips:
How to avoid disease in the first place:
I also keep a sprayer of bleach water in my barn and use it every day on water buckets, feed buckets and in general around the barn. Keep a bucket of bleach water (in a safe place, away from animals which is why I use a sprayer) within easy reach. If you don’t, you are less likely to actually get around to using it. I found that if I keep it handy, I use it daily.
I made the choice to test every year, regardless of the expense. I think it’s one of the most important things you can do for your herd’s health.
As you make choices about your goats’ health, I encourage you to do your research, talk with reputable breeders that test and those that don’t, then make your own, informed decision!