A Complete Guide to Listeriosis in Goats

Listeriosis is a serious bacterial disease that affects goats and other ruminants. Caused by Listeria monocytogenes, it is a significant concern for goat keepers because it can lead to neurological disease, abortions, and sudden death. The bacteria can also infect humans, making it a zoonotic disease of both animal health and public health importance.

For goat farmers and smallholders in the UK, understanding listeriosis is vital, particularly when feeding silage or managing herds in damp, cold conditions. This guide explores everything you need to know about listeriosis in goats, its causes, symptoms, diagnosis, treatment, prevention, and impact.

What is Listeriosis?

Listeriosis is caused by the bacterium Listeria monocytogenes. This organism:

• Is found widely in soil, water, faeces, and rotting vegetation.
• Thrives in damp, cold, and poorly fermented silage.
• Can survive and multiply at refrigeration temperatures, which makes it a risk in food for humans.

In goats, listeriosis is usually contracted by eating contaminated feed (especially spoiled silage), though wounds or infected bedding can also act as sources of infection.

Causes and Risk Factors

Listeriosis in goats is closely associated with:

• Poor-quality silage: especially silage with a high pH (poorly fermented), mould, or spoilage.
• Rotting vegetation or feed: decaying hay, grass, or bedding.
• Soil contamination: especially in muddy, damp areas.
• Stress: pregnancy, kidding, transport, or sudden weather changes can lower resistance.
• Unhygienic housing: dirty pens or contaminated water troughs.
• Wounds: infections can occasionally occur through oral injuries or eye trauma.

Forms of Listeriosis in Goats

Listeriosis presents in three main forms:

Nervous Form (Encephalitis)

• The most common form in goats.
• Bacteria travel up nerves (often from the mouth or teeth) into the brain.
• Symptoms include:
  • Circling in one direction.
  • Head tilt and facial paralysis.
  • Drooping eyelids or ears.
  • Loss of balance and stumbling.
  • Recumbency and convulsions in advanced cases.

Septicaemic Form

• More common in kids and young goats.
• Bacteria spread through the bloodstream, causing:
  • Fever and depression.
  • Diarrhoea.
  • Weakness and sudden death.

Reproductive Form

• Occurs in pregnant does.
• Causes late-term abortions or stillbirths.
• Placenta and foetal tissues are highly infectious.

Diagnosis

Diagnosis is usually based on clinical signs, history, and sometimes laboratory testing.

• History: feeding silage or spoiled forage, recent abortions, or neurological signs in several goats.
• Clinical signs: circling, head tilt, abortion storms, or sudden deaths.
• Laboratory confirmation:
  • Culture of Listeria monocytogenes from brain tissue, blood, placenta, or foetal material.
  • Post-mortem findings may include lesions in the brain or evidence of septicaemia.

Treatment

Listeriosis requires urgent veterinary attention. Early treatment offers the best chance of survival, but prognosis is often poor once neurological signs are advanced.

• Antibiotics: high doses of penicillin, oxytetracycline, or ampicillin are most commonly used.
• Anti-inflammatories: NSAIDs or corticosteroids may reduce brain inflammation.
• Supportive care: fluids, nursing, and good nutrition.
• Isolation: affected goats should be isolated due to the zoonotic risk and to provide a low-stress environment.

Goats with advanced neurological disease (e.g. unable to rise or eat) have a poor prognosis and may need to be euthanised for welfare reasons.

Prevention

Feed and Forage Management

• Avoid feeding poor-quality silage to goats. They are particularly sensitive compared to cattle.
• Discard any silage that is mouldy, spoiled, or contaminated with soil.
• Feed hay instead of silage where possible, especially for pregnant does.
• Store feed properly and ensure good drainage to prevent spoilage.

Housing and Environment

• Maintain clean, dry housing with adequate ventilation.
• Remove soiled bedding regularly.
• Keep water troughs clean and free of debris.

Reproductive Health

• Isolate aborting does immediately.
• Handle aborted material carefully and dispose of it safely, as it poses a risk to other animals and humans.
• Use gloves and disinfect equipment when handling foetal tissues or placenta.

General Management

• Reduce stress during pregnancy by avoiding unnecessary movement or overcrowding.
• Monitor goats closely during late gestation, especially when feeding silage.
• Implement good biosecurity practices to prevent environmental contamination.

Zoonotic Risk

Listeriosis is a zoonotic disease, meaning it can infect humans.

• It is especially dangerous for pregnant women, newborns, elderly people, and those with weakened immune systems.
• Humans can be infected through handling contaminated material (placenta, aborted foetuses, silage) or consuming unpasteurised dairy products.
• Farmers and handlers should wear gloves, practise good hand hygiene, and avoid eating or drinking while working with goats.

Economic and Welfare Impact

• Welfare: Listeriosis causes severe neurological illness, abortions, and death, making it a major welfare concern.
• Economic losses: Reduced productivity, treatment costs, abortion losses, and sudden deaths in valuable stock.
• Prevention vs cost: Good feed management and hygiene are inexpensive compared to the cost of losing multiple animals to the disease.

When to Seek Veterinary Help

Seek veterinary advice immediately if:

• Goats show circling, head tilt, or neurological symptoms.
• Multiple does abort suddenly.
• You suspect silage-related illness in the herd.
• Sudden deaths occur without clear explanation.

Conclusion

Listeriosis in goats is a devastating bacterial disease caused by Listeria monocytogenes. It can present as neurological disease, septicaemia, or abortion, and it often results in death if not treated early. Because treatment is difficult and prognosis is poor in advanced cases, prevention is essential.

For goat keepers in the UK, avoiding poor-quality silage, maintaining high standards of hygiene, reducing stress, and monitoring pregnant does closely are key steps in preventing listeriosis. By combining good management practices with prompt veterinary care, the impact of this disease can be minimised, protecting both herd health and public health.