Topic of the Month: Diseases

There are several diseases that goats can get in this area. The ones I will discuss here are CAE, CL, and Johnes. These can be subclinical for part of their infection cycle which makes them hard to detect just by looking at the goat. Another reason they might not be easily recognized is that some of them share similar symptoms to other goat ailments. Due to this, a blood test utilizing an ELISA assay is one of the most effective ways to diagnose goats with these diseases. There are a few labs that will run an ELISA blood test on goats. BioTracking, Inc. will accept samples directly from goat owners (no veterinarian needed) and will run tests for CAE. This company is very well respected for having accurate results. You can check them out at www.biotracking.com. Another company that will run ELISA assays for CAE, CL, and Johnes is Pan American Vet Labs, located in Texas. They will test blood samples that are mailed to them. They do not require a veterinarian to draw the blood or send the samples. They can be found at www.pavlab.com.

Below is a description of each disease as I understand it:

1.       CAE – CAE (Caprine Arthritis Encephalitis) is a viral disease of the goat. It does not hurt humans in any way and is not spread to other animals, except very rarely in sheep. This disease is very widespread in North America and can be found in any type of goat. The symptoms are usually subclinical and don’t cause a problem unless the goat is weakened by other diseases. Symptoms can include paralytic encephalitis in kids under 6 months old, severe arthritis and lameness in goats 1-2 years old, very hard udders in newly freshened goats, and wasting/condition loss in older goats. The virus is spread through white blood cells to other goats. The most common way to spread the virus is from an infected dam to a newborn kid through the colostrum. Kids who are pulled from their dams at birth and fed heat treated colostrum and then pasteurized milk do not get the virus. Less commonly, adult goats can spread it to each other through blood to blood contact, ingestion/contact of infected milk during milking, through nasal secretions and mucous, or through sharing equipment between infected and non-infected goats. Many farms have been successful at eliminating the virus from their herds by bottle-raising kids on clean or pasteurized milk and by eliminating older, infected animals from the herd when they show symptoms of the disease. Taking care not to share unsanitized equipment between uninfected and infected animals is very important to the prevention of disease spread. Testing of all the goats in a herd on a semi-annual basis is the ONLY way to track infection.  Testing for CAE is a simple blood test. BioTracking, Inc. is one of the leading companies that perform CAE testing. You can order the blood tubes, needles, and needle holders from them. You take 2mL of blood from each goat that is over 6 months old and mail the blood back to BioTracking. If you send the blood on Monday, they will email you the results by Friday afternoon. The results will consist of a percent inhibition (0-100%) and a “positive” or “negative” rating. Goats that have 0-30% inhibition are considered negative and uninfected. Goats that have 30-40% inhibition are considered “suspect” of being infected and need to be retested in 6 months or less. Goats that score over 40% are positive and infected. Once you begin testing with BioTracking, it is recommended that you retest every 6 months in order to assess the true health of your herd.

Testing for CAE and following prevention is a personal choice. Since most goats do not exhibit symptoms of CAE during their lives, many people chose to ignore the disease. In the Adirondacks, it is uncommon for people to worry about CAE. Most goats in the area are not raised on CAE prevention and most of them are infected due to this. If you want your goats to be CAE free you must breed them, take their kids away at birth, feed them pasteurized milk, and then cull the adult goats that are positive. By starting over with a clean herd, you can eliminate CAE as long as you are careful. Although even with a “clean” herd you must test semi-annually to make sure that none of the goats develop CAE. Since it is largely subclinical, testing is the only way to know if goats have it.

2.       CL – Caseous lymphandenitis is a bacterial disease. Its symptoms include large abscesses located where the lymph nodes are. There can be external abscesses as well as internal ones. The bacteria spread from goat to goat through the pus from the abscesses. The pus looks like cream cheese. The internal abscesses can burst and the bacteria can spread through the infected mucous to other goats. A veterinarian can culture the pus and determine whether it is CL or an abscess for a different reason. Any time a goat has an unexplained abscess, a veterinarian should test the abscess for CL. CL is very contagious and very hard to get rid of once a herd has been exposed. Any goats that have CL abscesses should be euthanized immediately. There is no treatment or cure for CL. CL can spread to humans and cause localized abscesses. Whenever working with an abscess on a goat, be sure to wear gloves and be sure to burn or sterilize any materials that came in contact with pus from the abscess. The pus contains the bacteria so care should be taken to sanitize anything that has come in contact with it. You can have a blood test for CL done. The blood test looks for antibodies in the goat’s blood to the CL bacteria. Sometimes a goat can have CL but not have antibodies to it. The blood test is not entirely fool-proof but it can help you assess the health of your herd.

3.       Johnes – Johnes (pronounced “yo-nays”) disease or paratuberculosis is commonly found in cows. It is a bacterial disease that can be found in all ruminants and is very contagious. It causes rapid weight loss in spite of the animal having a hardy appetite. It can also cause long-term diarrhea. The bacteria do this by creating inflammation in the intestines that limits nutrient absorption. Johnes can be tested for through a blood test or fecal sample. The disease is uncommon in goat herds but many people chose to test for it when they take blood for routine CAE and CL tests. Johnes can lay dormant in a herd and not show itself for many years. Once you have it in your herd it is impossible to get rid of because it spreads easily and can live in the soil. Culling infected animals and starting over with a clean herd in a new location is ideal.

Due to the wasting nature of Johnes and CAE, it is easy to confuse the symptoms of these diseases with other goat ailments. Parasite overload can also cause wasting and death in a relatively short amount of time. Tetanus and meningeal worm have neurological symptoms that are similar to what can be seen in these other diseases. Testing your goats routinely for CAE, CL, and Johnes can help to diagnose what is going on when a goat is sick. It is hard to determine exactly how many goats in the Adirondacks have these diseases since most people do not test for them. Also due to the lack of adequate veterinary care in the area most people do not have a necropsy or diagnostic tests run after a goat dies from an undetermined reason. It is unknown how many goats die from these diseases or die due to other ailments that have similar symptoms. Testing is the only way to get an idea of what diseases are in your herd.