Caprine Arthritis Encephalitis (CAE) Today

This is a hard blog for me to write for many reasons.

First, the dairy goat community is unforgiving where disease outbreaks are concerned. That may not be obvious to people who are new to the community, but if you've been here for a while, you've heard the gossip and maybe even been encouraged to boycott this farm or that farm because of rumors of disease. The following are two examples that I have experienced directly.

Around 2010, I was looking to purchase a goat from a local farm (Farm A). When I mentioned this to the owner of another local farm (Farm B), she shared the rumor that the farm had an outbreak of caseous lymphadenitis (CL) and threatened to discontinue any business with me should I purchase from that breeder. After sharing the conversation with Farm A, I learned that a buck that had been shipped to her (many years ago) had turned out to be infected with CL, possibly during transit. The breeder had followed appropriate precautions, including digging out the dirt in exposed areas, culling animals, and re-testing survivors. She did everything right and suffered significant losses. Yet still the rumors dogged her, many years later.

In 2017, a prominent farm (Farm C) had an outbreak of caseous lymphadenitis due to circumstances beyond their control. The previous year I had purchased a buck from them. Prior to taking possession I had him tested for CAE and CL. During quarantine at my farm I had him retested. Both times he was negative. Then, a disastrous flood hit Farm C, bringing CL bacterium that had been long buried to the surface in puddles of water. Again, the farm owner did the hard, but right thing. She closed the farm to buyers and worked for years to eradicate the disease through culling and vaccination. Unfortunately, the grapevine in our goat community is enthusiastic where rumors are concerned. Shortly after the news of the outbreak became public, I received a call from a colleague, letting me know that he had received calls from other breeders, sharing the rumor that my farm had been exposed to CL via the buck that I had purchased in 2016. To manage the rumors I posted test results that documented both that the buck was negative for CL as well as documenting that he came to my farm in the year before the disastrous flood. Still the rumors persisted. Fortunately other scandals have emerged since then to distract the gossips.

The second reason why this is a hard blog to write is because my latest experience is still raw. It happened this year and resulted in the euthanization of a sweet buck with exceptional genetics.

Background

Caprine Arthritis Encephalitis Virus (CAE) swept the goat community in the 80s-90s (approximately). The primary mode of transmission is via infected milk consumed by goat kids. 

Prevention measures practiced by farms following the epidemic include: separation of kids from dams immediately following kidding to prevent transmission via colostrum, feeding kids pasteurized milk, and implementation of blood testing programs. Some farms continued to retain CAE-infected goats, isolating them from CAE-negative animals and implementing the prevention measures listed above. 

My Story

Last year I purchased a buckling from a prominent east coast farm (Farm D). His genetics were stellar. I had him collected that September. It was a little premature, but I was eager to put some straws away in my "sperm bank."

In April 2021 I received a distressing message from the breeder. 

In the message (and I paraprase), she explained that some of her animals were housed at a partner farm (Farm E) where they were fed CAE-infected pooled milk. A client who bought a goat from her recently notified her that one of the kids that she had purchased (who had been raised at Farm E) tested positive for CAE. This led the breeder to test the five kids from Farm E that were in her possession. Four out of the five kids tested positive. She then offered to refund my purchase price, the cost of transportation, and any testing fees.

Fortunately I had already scheduled an appointment to draw blood on all of my bucks the very next week. The now-yearling buck was a low positive (51.632). All of my other bucks were negative. They have since been retested and will be retested again in another 6 months. The infected buck had not been used on my does.

The infected buck was euthanized and I consulted with Dr. Evermann at WADDL. Dr. Evermann shared that the buck was  not contagious at that level. I could have isolated the buck and retested him again in 3-6 months. However, given the facts of his case, it was not a risk that I was willing to take. 

The breeder had suggested that I consider collecting him (already done) and preserving his genetics that way. However, after consulting the research, I learned that it is inconclusive where transmission through frozen semen is concerned. The general consensus is that it is possible, albeit unlikely. Again, a risk I am not willing to take. I destroyed his straws.

Lessons Learned:

1. Just because you trust a breeder does not mean that you can trust that breeder's partners. Find out where the kid was born and raised. My mistake was assuming that the buckling was raised at the seller's farm. The breeder's mistakes were in not screening the partner farm more carefully and in omitting the fact that the kids were born at a partner farm. Don't trust. People make mistakes all the time, regardless of how well-intentioned they may be.

2. Ask direct questions about CAE prevention protocols and request blood test records. Ask for whole herd data for the property where the goat was raised. Look for breeders who make test results freely available rather than leaving it to buyers to request them.​

3. Have a quarantine pen with a "sacrificial" wether as a companion. Quarantine for 6 months at a minimum to enable repeated testing for mature animals, one year for kids (test 1 at 6 months, test 2 at 1 year).

4. Be prepared to humanely euthanize animals that test positive for CAE. Enough of kicking the can down the road. One option that had been suggested to me by the breeder was wethering him and selling him to a weed abatement operation. Somehow I don't think that even weed abatement teams want CAE-infected animals in their herds. As long as people shy away from the hard work of culling, we will continue to run the risk of CAE infections.

5. Retest new members of your herd in 6 month intervals for the first 2 years.

6. When buying frozen semen, request the buck's blood test results. CAEV can be transmitted via frozen semen.

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Here are a couple of current articles on the topic of transmission. My gratitude to Clare Staveley for sharing.

Peterhans, E. et al. Routes of transmission and consequences of small ruminant lentiviruses (SRLVs) infection and eradication schemes. 2014 https://www.vetres.org/articles/vetres/pdf/2004/03/V4006.pdf
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de Sousa Rodrigues, A. et al. Evaluation of caprine arthritis-encephalitis virus transmission in newborn goat kids. 2017. https://www.scielo.br/j/aib/a/ddVjKSbHDmKQdxkmxTqxYfc/...