Caprine Arthritis and Encephalitis in Goats
- Caprine arthritis and encephalitis, or CAE, is a lifelong viral infection of goats caused by a small ruminant lentivirus.
- Many infected goats never look sick, but clinical disease can show up as swollen painful joints in adults, progressive weakness or paralysis in kids 2 to 6 months old, hard udder, chronic pneumonia, or weight loss.
- There is no vaccine and no cure. Care focuses on supportive management, pain control when appropriate, nursing care, and herd-level prevention.
- The main route of spread is infected colostrum or milk fed to kids. Shared needles, contaminated equipment, and close contact can also help spread infection within a herd.
- Testing usually involves bloodwork such as ELISA or AGID, but one positive test does not prove CAE is the cause of current signs, and one negative test does not always rule out early infection.
- See your vet promptly if a kid has weakness, wobbling, trouble standing, or paralysis, or if an adult goat has chronic joint swelling, severe lameness, breathing trouble, or a firm low-producing udder after kidding.
What Is Caprine Arthritis and Encephalitis in Goats?
Caprine arthritis and encephalitis, usually called CAE, is a contagious viral disease of goats caused by a lentivirus, a type of retrovirus that causes lifelong infection. Once a goat is infected, the virus can stay in the body for life. Many goats remain outwardly normal, while others develop slowly progressive disease months or years later.
CAE can affect several body systems. In adult goats, the best-known form is chronic arthritis, especially in the carpal joints, with swelling, stiffness, and trouble getting around. In kids, CAE is more likely to appear as neurologic disease, with weakness, incoordination, and paralysis. The virus can also contribute to hard udder, chronic pneumonia, and weight loss.
This disease matters both medically and practically. Even when signs are mild, CAE can reduce comfort, milk production, and long-term herd productivity. Because many infected goats never show obvious signs, herd-level testing and prevention plans are often as important as caring for one sick animal.
Symptoms of Caprine Arthritis and Encephalitis in Goats
- Swollen carpal joints or other enlarged joints
- Chronic lameness, stiffness, or reluctance to walk
- Kneeling to eat because standing is painful
- Poor hair coat and gradual weight loss
- Weakness, wobbling, or hind limb incoordination in kids 2 to 6 months old
- Progressive paresis or paralysis
- Head tilt, circling, depression, or abnormal posture in neurologic cases
- Firm swollen udder with poor milk production after kidding
- Chronic cough or progressive breathing difficulty
CAE signs can be subtle at first, especially in adults. A goat may start with mild joint swelling or stiffness and slowly become less active over time. Kids with the neurologic form can worsen much faster.
See your vet immediately if a kid cannot rise, is dragging limbs, seems wobbly, or has other neurologic signs. Also contact your vet promptly for severe lameness, marked joint swelling, breathing trouble, or a hard udder with poor milk production, because other conditions can look similar and may need different care.
What Causes Caprine Arthritis and Encephalitis in Goats?
CAE is caused by caprine arthritis encephalitis virus (CAEV), part of the small ruminant lentivirus group. The most important route of spread is from an infected doe to her kids through colostrum and milk. Pooled colostrum or pooled milk raises herd risk because one infected doe can expose many kids.
The virus can also spread horizontally within a herd. Risk factors include close contact, contaminated feed or water areas, exposure to infected milk in the milking area, and reuse of needles or equipment contaminated with blood. Cross-species transmission with related sheep lentiviruses is possible in some situations, which is one reason mixed small-ruminant management deserves careful planning with your vet.
Not every infected goat becomes sick. Many goats stay subclinical, but they can still test positive and contribute to herd spread. Disease expression depends on age, immune response, management, and time since infection.
How Is Caprine Arthritis and Encephalitis in Goats Diagnosed?
Diagnosis starts with your vet looking at the goat's age, history, and clinical signs. CAE is often suspected when an adult goat has chronic enlarged joints and lameness, or when a young kid develops progressive weakness or paralysis. Your vet will also consider other causes that can look similar, including trauma, Mycoplasma arthritis, listeriosis, polioencephalomalacia, spinal abscesses, and other neurologic disease.
Common herd tests are ELISA and AGID blood tests that look for antibodies. These tests are useful for herd screening and control programs, but they have limits. A positive result in an adult goat supports infection, yet it does not prove CAE is the reason for that goat's current symptoms. A negative result does not always rule out infection, especially early on or around late pregnancy when antibody levels may be low.
Testing in very young kids needs extra caution. Kids under about 90 days of age may test positive because of maternal antibodies from colostrum rather than true infection. In some cases, your vet may recommend repeat testing over time, herd-level screening, or additional confirmation with PCR, biopsy, or postmortem examination if the diagnosis remains uncertain.
Treatment Options for Caprine Arthritis and Encephalitis in Goats
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Veterinary exam and practical quality-of-life assessment
- Basic CAE blood testing when appropriate
- Pain-focused supportive care plan directed by your vet
- Deep dry bedding, easier access to feed and water, and regular hoof trimming
- Isolation from kids and milk-management changes to reduce spread
- Monitoring body condition, mobility, and nursing needs at home
Recommended Standard Treatment
- Full veterinary exam with differential diagnosis review
- ELISA or AGID testing and repeat testing plan when needed
- Targeted treatment for secondary problems such as bacterial mastitis or pneumonia if your vet finds them
- Prescription anti-inflammatory plan when appropriate for pain and mobility
- Written herd-control strategy including kid removal at birth, heat-treated colostrum or pasteurized milk, and test-and-segregate planning
- Follow-up visits to reassess mobility, body condition, udder health, and herd risk
Advanced / Critical Care
- Hospitalization or intensive on-farm nursing support for recumbent or severely weak goats
- Expanded diagnostics to rule out competing causes of neurologic disease or severe lameness
- PCR, biopsy, or postmortem confirmation in selected cases
- Aggressive supportive care including fluid support, assisted feeding, pressure-sore prevention, and frequent reassessment
- Comprehensive herd testing, segregation redesign, and culling consultation for larger breeding or dairy programs
- End-of-life planning when quality of life is poor
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Caprine Arthritis and Encephalitis in Goats
Bring these questions to your vet appointment to get the most out of your visit.
- Based on my goat's age and signs, how likely is CAE compared with other causes of lameness or neurologic disease?
- Which test makes the most sense right now, ELISA, AGID, repeat testing later, or another option?
- If this goat tests positive, does that explain the current symptoms or should we keep looking for another problem?
- What supportive care changes at home would most improve comfort, mobility, and body condition?
- Is pain medication appropriate for this goat, and what monitoring should I do while using it?
- How should I manage kids, colostrum, milk, and shared equipment to lower spread in the herd?
- Should I separate or retest herd mates, and how often should the herd be screened?
- What signs would mean this goat needs urgent recheck or that quality of life is becoming poor?
How to Prevent Caprine Arthritis and Encephalitis in Goats
Prevention is centered on kid management and herd biosecurity. The highest-risk exposure is infected colostrum or milk, so many control programs remove kids from positive does at birth and feed heat-treated colostrum and pasteurized milk or another vet-approved alternative. Avoid pooled colostrum and pooled milk unless your herd-status plan makes that safe.
Routine testing and segregation are also important. Your vet may recommend whole-herd screening with ELISA or AGID, then separating seropositive and seronegative groups. If groups are maintained, they should not share needles, feeding equipment, waterers, or milking equipment without proper cleaning and disinfection. Merck notes that some programs also use a minimum separation distance between positive and negative groups.
Good biosecurity lowers risk further. Quarantine and test new arrivals before mixing them into the herd. Do not reuse needles between goats. Clean blood-contaminated tools carefully. If your herd includes sheep, ask your vet how that affects your prevention plan because related small-ruminant lentiviruses can cross species in some settings.
There is no vaccine for CAE, so prevention depends on management rather than immunization. A realistic plan can still work very well. Your vet can help you choose between a conservative control program, a standard test-and-segregate approach, or a more intensive eradication-style strategy based on herd goals and budget.