Chlamydiosis in Goats
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A lot of careful planning goes into raising goat kids. You choose the buck and does to make the perfect kid, and you feed the does to ensure appropriate growth. Because of this careful effort, nothing is more disappointing than finding a goat has aborted her kids. All of that effort was a compete loss. In North America, the most common cause of abortion in goats is infection with Chlamydia abortus.
Chlamydia abortus is a bacterium that lives within the cells of its host animal. Animals can become infected with the bacteria by contacting it in the environment and absorption through their respiratory tract. In pregnant does, the bacteria then move into the reproductive tract. The bacteria cause severe inflammation of the placenta but can also infect the kids. This infection of the placenta results in loss of the pregnancy, commonly in the last month. The kids can also be stillborn at term or born very weak due to the infection. The bacteria shed in high numbers in the placenta and birthing fluids. While abortion is the primary sign of infection with chlamydia, it can also cause arthritis, conjunctivitis, and retained placentas within a herd. Animals infected with chlamydia can continue to shed the bacteria within the environment. However, does that experience abortion due to chlamydia in goats can go on to have normal pregnancies after, even without treatment. Infection of a naive herd with Chlamydia abortus can be disastrous. Animals that have never seen this bacterium can experience abortions at a rate of 60% of the herd. In herds with endemic or ongoing infection, the abortion rate is much lower at 1-15%.
Diagnosis of chlamydia infection can be based on clinical signs seen within the herd. Frequent late-term abortions in a herd are highly suspicious for infection with chlamydia. However, testing is necessary to confirm the presence of the bacteria. Ideally, owners send a freshly aborted fetus and the placenta to a laboratory for testing. Because the bacteria proliferate primarily within the placenta, sending in the placenta is imperative to successful testing. Vaginal swabs may also be taken from aborted does, but these can be less likely to find the infection. If you have a goat that experiences an abortion, contact your herd veterinarian. They can help you ensure that you get all the necessary samples for testing and give you the best chance at getting a diagnosis. Abortion due to toxoplasmosis, Q fever, and Campylobacter bacteria can appear similar to chlamydia abortion.
In addition to chlamydia causing abortion in does and ewes, it can transfer to humans. Pregnant women are at high risk of developing an infection if they contact infected animals or their birthing fluids. A severe placental infection can result in loss of the baby. It is recommended that pregnant women do not participate in kidding and practice care if coming in contact with soiled clothing.
In does that abort due to chlamydia, bacterial shedding can be slowed by appropriate treatment with a tetracycline antibiotic. In larger herds experiencing abortions, if treatment with tetracyclines is begun early, near 120 days gestation, it may prevent abortion. However, even with treatment, the animals will continue to shed the bacteria into the environment. Because treatment has limited success, it is far better to prevent chlamydial abortions than treat them.
It is difficult to prevent the introduction of chlamydia into a herd. There are no blood tests available to determine if an animal is a carrier before bringing them into your herd. Conducting a thorough interview regarding a herd’s history before purchasing animals from it can indicate if there is a possible history of chlamydia. There is a commercial vaccine available for Chlamydia abortus in sheep. This vaccine may be used off-label with veterinary prescription in goats with success. When beginning a vaccination program with your herd, vaccinate all goats before breeding. Vaccinate new animals to the herd or young animals entering the breeding program before breeding season. Like treatment with tetracyclines, the vaccine does not prevent bacterial shedding, but it does significantly reduce the incidence of abortion due to the infection.
Infection of a herd with chlamydia can lead to horrible losses. Rapidly and correctly identifying the infection can help reduce the impact and implement treatment and prevention protocols. Should you have a goat experience an abortion, contacting your veterinarian for exams and diagnostics is imperative. As your veterinarian is likely not immediately on hand, save both the aborted fetus and the placenta and place it in a freezer, if possible. Then you can send out these samples to a laboratory for appropriate testing. While you cannot replace the lost kids, proper diagnosis and treatment can help prevent further losses.
Tibary, Ahmed, DVM PhD DACT. Merck Veterinary Manual: Abortion in Goats. Reviewed April 2021. merckvetmanual.com/reproductive-system/abortion-in-large-animals/abortion-in-goats
Maria Lenira Leite-Browning, DVM. Alabama Cooperative Extension System: Causes of Infectious Abortion in Goats. November 2006. ssl.acesag.auburn.edu/pubs/docs/U/UNP-0079/UNP-0079-archive.pdf
Originally published in the January/February 2022 issue of Goat Journal and regularly vetted for accuracy.