Caseous Lymphadenitis (CL) in Goats: Symptoms, Diagnosis, and Management

Caseous Lymphadenitis (CL) in goats is a chronic, infectious disease caused by the bacterium Corynebacterium pseudotuberculosis. It primarily leads to abscesses in lymph nodes, both external and internal. Managing CL involves careful diagnosis through aspiration and culture, strict biosecurity, isolation of affected animals, proper abscess management, and strategic vaccination to control its spread and minimize economic losses in your herd.

Finding lumps or swellings on your goats can be worrying. Many goat owners face the challenge of identifying and dealing with Caseous Lymphadenitis, or CL, a common and frustrating bacterial infection. It can spread quickly and impact the health and productivity of your entire herd. But don’t worry, you’re in the right place. This article will walk you through everything you need to know about CL in goats, from spotting the first signs to effective management and prevention strategies, giving you practical solutions to protect your animals.

What is Caseous Lymphadenitis (CL)?

Caseous Lymphadenitis, often simply called CL, is a chronic, infectious bacterial disease that affects goats, sheep, and sometimes other animals like horses. It’s caused by a tough bacterium named Corynebacterium pseudotuberculosis. This bug is known for causing abscesses, which are pockets of pus, primarily in the lymph nodes of infected animals. Think of lymph nodes as small filters in the body’s immune system; when infected with CL, they swell up and fill with a thick, cheesy pus.

CL is a significant concern for goat owners because it can lead to economic losses. While it’s rarely fatal on its own, it can make goats sick, reduce their milk production, cause weight loss, and lower their overall value. The disease is highly contagious and can persist in the environment for long periods, making it tricky to eliminate once it’s in a herd. Understanding what CL is and how it behaves is the first step in protecting your goats.

How CL Spreads: Understanding the Transmission

The bacterium Corynebacterium pseudotuberculosis is incredibly resilient and can survive in the environment for months, especially in cool, moist conditions. This makes controlling its spread a real challenge. CL primarily spreads through direct contact with pus from ruptured abscesses, but there are several other ways it can move through your herd:

• Direct Contact: This is the most common route. When an abscess ruptures, the pus, which is loaded with bacteria, contaminates the environment. Other goats can then pick up the bacteria through cuts, scrapes, or even intact skin.
• Contaminated Equipment: Tools used for shearing, ear tagging, tattooing, or even medical procedures like injecting can spread the bacteria if not properly disinfected between animals. Needles are a particularly high-risk item.
• Environmental Contamination: Pens, bedding, fences, and feed bunks can become contaminated with pus. Goats can pick up the bacteria from these surfaces.
• Entry Points: The bacteria usually enter the goat’s body through breaks in the skin. These can be tiny cuts from thorns, sharp feed, shearing nicks, or even insect bites. Once inside, the bacteria travel to the nearest lymph node and begin to multiply, forming an abscess.
• Nose-to-Nose Contact: While less common than contact with pus, close contact between goats, especially if one has internal abscesses that might be shedding bacteria through respiratory secretions, can also contribute to spread.

Understanding these transmission routes is crucial for implementing effective biosecurity measures to prevent the introduction and spread of CL in your herd.

Recognizing the Signs: Symptoms of CL in Goats

The symptoms of CL in goats can vary depending on whether the abscesses are external (visible on the body surface) or internal (affecting internal organs). External abscesses are much more common and easier to spot, but internal CL can be more serious and harder to diagnose.

External Abscesses

External abscesses are the hallmark symptom of CL. They typically form in the superficial lymph nodes, which are located just under the skin. You’ll usually find these firm, movable lumps in specific areas:

• Prescapular Lymph Nodes: Just in front of the shoulder blade.
• Prefemoral Lymph Nodes: In front of the stifle (knee) joint on the hind leg.
• Parotid Lymph Nodes: Below the ear, near the jaw.
• Submandibular Lymph Nodes: Under the jaw.
• Supramammary Lymph Nodes: Above the udder in females.
• Popliteal Lymph Nodes: Behind the stifle joint.

Initially, these abscesses feel like small, firm, painless lumps. Over time, they grow larger, become softer as the pus accumulates, and may eventually rupture, releasing thick, cheesy, odorless pus. This pus can range in color from white to yellow or greenish. Once ruptured, the abscess may drain for a while and then heal, but the goat remains infected and can develop new abscesses.

Internal Abscesses

Internal CL is often called “internal form” or “visceral form” and is much more challenging to diagnose because the abscesses are not visible. They can form in any internal organ, but are most commonly found in the lymph nodes around the lungs, liver, kidneys, or intestines. Symptoms of internal CL are vague and non-specific, often mimicking other chronic diseases. They might include:

• Chronic Weight Loss: Despite a good appetite.
• Reduced Appetite: Leading to poor body condition.
• Chronic Cough: If abscesses are in or near the lungs.
• Difficulty Breathing: In severe respiratory cases.
• Poor Production: Decreased milk yield or poor fiber growth.
• Lameness: If abscesses affect joints or bones (rare).
• Neurological Signs: If abscesses are in the brain or spinal cord (very rare).

Animals with internal CL often act “unthrifty” and fail to thrive. They can be a silent source of infection, shedding bacteria without obvious external signs.

Table: Differentiating External vs. Internal CL Symptoms

Feature	External CL Abscesses	Internal CL Abscesses
Visibility	Visible as lumps under the skin, often in lymph node regions (neck, shoulder, flank, udder).	Not visible externally; located in internal organs or deep lymph nodes (lungs, liver, kidneys, mediastinal, mesenteric).
Palpation	Firm, movable lumps that may soften over time.	Cannot be palpated externally, unless very large and near the body wall.
Rupture	Commonly rupture, releasing thick, cheesy pus.	Rarely rupture externally; may rupture internally, leading to widespread infection or peritonitis.
General Health Impact	Often minimal initial impact on general health, though can be unsightly and spread infection.	Can cause chronic weight loss, poor appetite, decreased production, chronic cough, respiratory distress, and general “unthriftiness.”
Diagnosis	Visual inspection, palpation, needle aspiration for culture.	Difficult; often based on serology, imaging (ultrasound/X-ray), or post-mortem.
Infectivity	Highly contagious when ruptured.	Less direct external spread, but can shed bacteria through respiratory or fecal routes if abscesses are in those systems.

Accurate Diagnosis: Confirming CL

Proper diagnosis is critical for managing CL and preventing its spread. While external abscesses are often highly suggestive of CL, confirmation is important, especially since other conditions can cause similar lumps (e.g., abscesses from other bacteria, tumors, insect bites).

• Visual Inspection and Palpation: This is the first step. Carefully examine your goats, feeling for any lumps, especially in the common lymph node areas mentioned above. Note their size, consistency, and whether they are painful.
• Needle Aspiration and Culture (Gold Standard): This is the most reliable method for diagnosing CL. A veterinarian will carefully insert a sterile needle into the abscess and draw out a sample of the pus. This sample is then sent to a diagnostic laboratory for bacterial culture. If Corynebacterium pseudotuberculosis grows, the diagnosis is confirmed. This method is also crucial for differentiating CL from other types of abscesses.
• Serological Tests (Blood Tests):
  • ELISA (Enzyme-Linked Immunosorbent Assay): This blood test detects antibodies to Corynebacterium pseudotuberculosis in the goat’s blood. A positive result indicates that the goat has been exposed to the bacteria and has mounted an immune response.
  • Limitations of ELISA: It cannot distinguish between active infection, past exposure, or vaccination. A goat might test positive even if it doesn’t have active abscesses or has been vaccinated. Therefore, ELISA is best used for herd-level screening rather than diagnosing individual cases definitively, especially for culling decisions. It’s valuable for identifying infected herds or monitoring the success of control programs.
• PCR (Polymerase Chain Reaction) Test: PCR can be performed on pus samples or tissue to detect the genetic material of the bacteria. This test is highly sensitive and can provide quicker results than culture, though culture remains the gold standard for confirming viable bacteria.
• Post-Mortem Examination: If an animal dies or is culled due to suspected CL, a necropsy (animal autopsy) can confirm the presence of internal abscesses and provide a definitive diagnosis. This is especially useful for understanding the extent of the disease within a herd.

Table: Diagnostic Methods for CL

Diagnostic Method	Sample Type	What it Detects	Pros	Cons	Best Use
Visual/Palpation	Physical exam	External lumps/swellings	Quick, non-invasive, inexpensive	Not definitive, can be confused with other conditions	Initial screening, identifying obvious cases
Needle Aspiration & Culture	Pus from abscess	Presence of C. pseudotuberculosis	Gold standard, definitive diagnosis, identifies viable bacteria	Invasive, requires sterile technique, takes a few days for results	Confirming individual cases, guiding treatment decisions
ELISA (Serology)	Blood serum	Antibodies to C. pseudotuberculosis	Less invasive, good for herd screening, can detect internal CL	Cannot differentiate active infection from exposure/vaccination, false positives/negatives possible	Herd-level surveillance, identifying infected herds, monitoring control programs
PCR Test	Pus, tissue, environmental swabs	Bacterial DNA	Sensitive, faster than culture	Does not confirm viable bacteria, more expensive than culture for routine use	Rapid detection, environmental screening, confirming culture results
Post-Mortem Exam	Tissues/organs	Internal and external abscesses	Definitive, reveals extent of disease	Only performed after death/culling	Understanding herd disease status, confirming internal CL

Management Strategies: Living with and Controlling CL

Managing CL in a goat herd requires a multi-faceted approach. There’s no quick fix, and the goal is often to control the disease and minimize its impact rather than complete eradication, especially in established herds. The strategy typically involves a combination of treating individual animals, implementing strict biosecurity, and considering vaccination.

Treatment of Individual Animals

Treating individual goats with CL is primarily focused on managing the abscesses and preventing environmental contamination. It’s important to understand that treatment often doesn’t cure the animal of the infection, meaning they can develop new abscesses later.

• Abscess Lancing and Drainage: This is the most common approach for external abscesses.
  • Isolation: Always isolate the infected goat before lancing an abscess to prevent contamination of the environment and other animals.
  • Preparation: Wear gloves. Clean the area around the abscess thoroughly with an antiseptic solution (e.g., chlorhexidine or iodine scrub).
  • Lancing: Using a sterile scalpel blade, make a large incision at the lowest point of the abscess to allow for complete drainage. Be careful not to cut too deeply or damage underlying structures.
  • Drainage and Collection: Collect all the pus in a disposable container (e.g., a plastic bag or bucket lined with a bag). The pus is highly infectious.
  • Flushing: After draining, flush the abscess cavity thoroughly with an antiseptic solution (e.g., diluted iodine or chlorhexidine).
  • Disposal: Properly dispose of all pus, contaminated materials (gloves, blades, wipes), and bedding by burning or deep burial. Do not spread it on your property.
  • Aftercare: Keep the goat isolated until the wound has completely healed and is no longer draining. Continue to clean and flush the wound daily until it closes.
• Antibiotics: Antibiotics are generally not very effective against CL because the bacteria are protected within the thick wall of the abscess. They cannot easily penetrate the abscess to reach and kill the bacteria. However, antibiotics may be used by a veterinarian to treat secondary bacterial infections that can occur after an abscess ruptures or if internal abscesses cause systemic illness. They are not a primary treatment for CL itself.
• Culling: For animals with recurrent abscesses, internal CL, or those that are chronically ill and unthrifty, culling may be the most humane and economically sound option. This helps reduce the source of infection in the herd.

Herd Management and Biosecurity

Biosecurity is the cornerstone of CL control. Once CL is in a herd, it’s very difficult to eliminate entirely, so preventing its introduction and spread is paramount.

• Isolation and Quarantine of New Animals: Any new goat brought onto the farm should be isolated for at least 30-60 days. During this period, observe them closely for any signs of abscesses. Ideally, test them for CL (e.g., ELISA) before introducing them to the main herd. If any abscesses are found, they should be managed and confirmed CL-negative before integration, or the animal should be culled.
• Strict Hygiene and Disinfection:
  • Equipment: Thoroughly clean and disinfect all equipment that comes into contact with goats (shears, clippers, ear taggers, tattoo pliers, hoof trimmers, needles) between each animal. Use effective disinfectants like bleach (1:10 dilution) or commercial veterinary disinfectants.
  • Environment: Regularly clean and disinfect pens, feeders, water troughs, and milking parlors. Remove and properly dispose of contaminated bedding.
  • Needle Protocol: Use a fresh, sterile needle for every injection on every animal. Never reuse needles.
• Proper Wound Care: Any cuts, scrapes, or abrasions on goats should be cleaned and treated promptly to prevent bacterial entry.
• Culling Persistently Infected Animals: Animals that repeatedly develop abscesses or test positive for internal CL despite management efforts should be considered for culling to break the cycle of infection.
• “Test and Cull” or “Test and Segregate” Programs: For herds aiming for eradication, regular testing (especially ELISA) combined with culling or permanent segregation of positive animals can be implemented. This is a long-term, intensive strategy.

Vaccination

Vaccination is a valuable tool in CL management, but it’s important to understand its role. It does not prevent infection entirely or cure existing cases, but it can significantly reduce the incidence, severity, and number of new abscesses in a herd.

• Commercial Vaccines: Several commercial vaccines are available for CL in goats (e.g., Case-Bac®, Glanvac®). These vaccines are typically bacterins, meaning they contain killed bacteria or bacterial components that stimulate an immune response.
• Effectiveness and Limitations:
  • Vaccination helps to reduce the number of new abscesses and may reduce the size and rupture rate of those that do form.
  • It does not eliminate the bacteria from an already infected animal.
  • It does not prevent animals from becoming infected, but rather helps their immune system fight off the disease more effectively, leading to fewer clinical signs.
  • Vaccination protocols typically involve an initial series of two doses, followed by annual boosters. Always follow the manufacturer’s instructions.
• When to Vaccinate: Vaccination is most beneficial in herds where CL is already present or in herds at high risk of exposure (e.g., open herds, those participating in shows). It’s generally not recommended to vaccinate animals with active abscesses. Consult with your veterinarian to develop a vaccination plan tailored to your herd’s specific needs and risk factors.

Prevention is Key: Stopping CL Before It Starts

The best approach to CL is prevention. Keeping the bacteria out of your herd in the first place is far easier and less costly than trying to manage it once it’s established.

• Closed Herd Policy: The most effective way to prevent CL is to maintain a closed herd. This means you do not introduce any new animals once your herd is established. If you must introduce new genetics, consider artificial insemination or embryo transfer from CL-free sources.
• Strict Biosecurity Protocols: As detailed in the management section, rigorous disinfection of all equipment (shears, needles, ear taggers, hoof trimmers) between animals is critical. Use a fresh, sterile needle for every injection.
• Testing New Animals: If you must buy new goats, purchase them from certified CL-free herds. If a CL-free source is not available, quarantine new animals for at least 60 days and test them for CL (e.g., ELISA). Only introduce them to the main herd if they test negative and show no signs of abscesses. Re-test if possible after a few months.
• Minimizing Skin Injuries: Inspect your facilities for sharp edges, protruding wires, or other hazards that could cause cuts and scrapes. Good pasture management to avoid thorny plants also helps.
• Environmental Management: Keep pens clean and dry. Regularly remove and properly dispose of soiled bedding. Avoid overcrowding, which can increase stress and the likelihood of injuries and disease transmission.
• Proper Disposal of Carcasses: If an animal dies from CL or is culled due to it, dispose of the carcass properly (e.g., by burning or deep burial) to prevent environmental contamination.
• Education: Educate all farm workers and visitors about biosecurity measures and the importance of preventing disease spread.

By consistently applying these preventative measures, you can significantly reduce the risk of CL entering your herd and maintain a healthier, more productive goat operation. Remember, a proactive approach saves time, money, and heartache in the long run.

Economic Impact of CL

While CL is rarely fatal, its economic impact on a goat operation can be substantial and often underestimated. The costs associated with CL extend beyond just veterinary bills and include both direct and indirect losses:

• Reduced Production:
  • Milk Production: Does with CL, especially those with internal abscesses or severe external ones, often show a significant drop in milk yield.
  • Meat Production: Affected goats may experience chronic weight loss, poor feed conversion, and reduced growth rates, leading to lower carcass weights and poorer meat quality.
  • Fiber Production: For fiber goats, CL can lead to poor coat quality and reduced fiber yield.
• Culling and Replacement Costs: Chronically ill or severely affected animals may need to be culled, representing a direct loss of investment and the cost of replacing them with new, healthy animals.
• Treatment Costs: While antibiotics are not highly effective, the costs associated with lancing abscesses, wound care supplies, disinfectants, and veterinary consultations add up.
• Reduced Market Value: Goats with visible abscesses are often discounted or unsellable for breeding or show purposes. Carcasses with internal abscesses may be condemned at slaughter, leading to total loss.
• Labor and Time: Managing CL-affected animals requires significant time and labor for isolation, treatment, and ongoing monitoring.
• Biosecurity Implementation Costs: While a long-term saving, the initial investment in improved fencing, dedicated quarantine facilities, and disinfection protocols can be a short-term cost.
• Loss of Reputation: A herd known to be infected with CL may suffer from a damaged reputation, making it harder to sell animals or products.

Understanding these cumulative costs underscores why a robust prevention and management strategy for CL is not just about animal welfare, but also about the financial health of your goat enterprise.

Frequently Asked Questions (FAQ)

Q1: Can humans get CL from goats?

A1: Yes, though rare, humans can contract Corynebacterium pseudotuberculosis, typically through direct contact with pus from infected animals through cuts or abrasions on the skin. It usually causes localized skin infections, but more serious internal infections are possible in immunocompromised individuals. Always wear gloves when handling infected animals or their abscesses.

Q2: If my goat has a lump, is it definitely CL?

A2: Not necessarily. While CL is a common cause of lumps in goats, other conditions can cause similar swellings, such as other bacterial abscesses (e.g., from staph or strep), insect bites, reactions to injections, or even tumors. It’s crucial to get a definitive diagnosis from a veterinarian, ideally through needle aspiration and culture of the pus.

Q3: Can a goat with CL be cured?

A3: Once a goat is infected with CL, it is generally considered to be a carrier for life, even if external abscesses are drained and heal. The bacteria can remain dormant or cause internal abscesses. Treatment focuses on managing the symptoms and preventing spread, not on complete eradication from the animal’s body.

Q4: Is there a vaccine for CL in goats?

A4: Yes, there are commercial vaccines available for CL in goats. While they don’t prevent infection entirely, they can significantly reduce the incidence, severity, and number of new abscesses. Vaccination is a key tool in a comprehensive CL management program, especially in herds where the disease is already present or highly likely to be introduced.

Q5: How long does the CL bacterium survive in the environment?

A5: Corynebacterium pseudotuberculosis is very hardy and can survive for months in the environment, especially in cool, moist conditions and organic matter like soil, bedding, and manure. This persistence makes thorough cleaning and disinfection vital for controlling the disease.

Q6: Should I cull all goats that test positive for CL?

A6: The decision to cull depends on your herd goals, the prevalence of the disease, and the individual animal’s value. For commercial herds aiming for eradication, culling all positive animals might be considered. For smaller herds or those with valuable breeding stock, segregation and careful management of positive animals might be a more practical approach. Discuss the best strategy for your specific situation with your veterinarian.

Q7: Can I eat meat from a goat that had CL?

A7: If the goat had only external abscesses that were properly managed and the animal was otherwise healthy, the meat is generally considered safe for consumption, provided there are no internal abscesses and the carcass is inspected by a qualified professional. However, if there are internal abscesses, especially widespread ones, the carcass is typically condemned. Always consult with a veterinarian or meat inspector if you have concerns.