A Complete Guide to Tetanus in Sheep

Tetanus, often referred to as “lockjaw”, is a life-threatening clostridial disease that affects sheep of all ages. It is caused by the bacterium Clostridium tetani, which produces potent toxins that attack the nervous system. Once symptoms appear, the disease is almost always fatal.

For sheep farmers in the UK, tetanus is a significant concern because of the country’s damp climate and the frequency of management procedures that create opportunities for infection, such as tail docking, castration, and shearing. This guide explains what tetanus is, how it develops, the signs to look for, treatment options, and how to prevent it effectively.

What is Tetanus?

Tetanus is caused by Clostridium tetani, a bacterium that:

• Lives in soil, manure, and the digestive tracts of animals.
• Forms resistant spores that can survive in the environment for years.
• Enters the body through wounds, particularly those that are deep, dirty, or oxygen-poor.

Once inside, the bacteria release tetanospasmin, a neurotoxin that spreads through the nervous system. This toxin blocks normal nerve signalling, leading to severe, painful muscle spasms and paralysis.

Causes and Risk Factors

Sheep are particularly vulnerable to tetanus in the following situations:

• Husbandry procedures: tail docking, castration, ear tagging, or injections with contaminated needles.
• Shearing or foot trimming injuries: open wounds can allow infection.
• Lambing injuries: wounds sustained by ewes or lambs during birth.
• Dirty environments: soiled bedding, muddy conditions, or contaminated housing.
• Unvaccinated animals: flocks not on a clostridial vaccination programme are at greatest risk.

Even very small wounds can provide an entry point for tetanus spores if the conditions are right.

Symptoms of Tetanus

Tetanus usually develops 3–21 days after infection, depending on the wound and toxin levels.

Early signs:

• Stiff gait and reluctance to move.
• Raised tail or ears held rigidly.
• Sensitivity to sound or touch.

Progressive signs:

• Muscle spasms and trembling.
• Protrusion of the third eyelid.
• “Sawhorse stance” – rigid legs and arched back.
• Difficulty chewing or swallowing (hence “lockjaw”).
• Convulsions triggered by noise, light, or handling.

Final stage:

• Paralysis of respiratory muscles.
• Death due to suffocation, usually within a few days of symptoms appearing.

Diagnosis

Diagnosis is generally based on clinical signs and history rather than laboratory tests, as the disease progresses rapidly.

• History: recent wounds, castration, docking, or shearing.
• Signs: characteristic muscle stiffness, spasms, and lockjaw.
• Differential diagnosis: conditions such as hypocalcaemia (milk fever), ryegrass staggers, or pulpy kidney disease may present with neurological signs but differ in progression.

Treatment

Treatment is rarely successful, and survival rates are very low once symptoms are established.

Possible veterinary treatments include:

• Tetanus antitoxin: neutralises circulating toxin if given early.
• High doses of antibiotics (penicillin): to kill remaining bacteria.
• Muscle relaxants and sedatives: to control spasms.
• Wound cleaning and debridement: to remove the source of infection.
• Supportive care: fluids, feeding support, and keeping the animal in a quiet, dark environment.

Even with intensive care, prognosis is poor.

Prevention

Vaccination

• Vaccination is the most effective protection against tetanus.
• Multi-valent clostridial vaccines (e.g. 5-in-1 or 8-in-1) protect against tetanus as well as other clostridial diseases.
• Recommended schedule in the UK:
  • Ewes: booster 4–6 weeks before lambing to protect both the ewe and her lambs via colostrum.
  • Lambs: first dose at 6–12 weeks of age (depending on maternal cover), followed by a second dose 4–6 weeks later.
  • All sheep: annual booster for continued protection.

Antitoxin

• Provides short-term immediate protection.
• Useful for lambs at castration or docking if not yet vaccinated.
• Also used in emergency situations where animals are at risk but not covered by vaccination.

Good Wound Management

• Clean and disinfect wounds promptly.
• Use antiseptics after procedures like docking, castration, or shearing cuts.
• Always use sterile needles and equipment.

Husbandry Practices

• Maintain strict hygiene during lambing, castration, and docking.
• Keep bedding clean and dry.
• Avoid overcrowding, which increases the risk of injury and contamination.

Economic and Welfare Impact

• Welfare: Tetanus causes severe pain and distress before death, making it one of the most concerning conditions in terms of animal welfare.
• Economic loss: Loss of lambs, breeding stock, and the cost of treatment attempts can be considerable.
• Prevention cost vs treatment: Vaccination is inexpensive compared to the high losses associated with outbreaks.

When to Seek Veterinary Help

Call a vet immediately if:

• You see sheep showing stiffness, spasms, or difficulty moving.
• Wounds look contaminated or infected.
• You need guidance on vaccination or antitoxin use.
• Sudden deaths occur in the flock after management procedures.

Conclusion

Tetanus in sheep is a devastating but preventable disease. Caused by Clostridium tetani, it enters through wounds and produces toxins that fatally disrupt the nervous system. Once clinical signs appear, treatment is rarely effective, but prevention through vaccination, good husbandry, and careful wound care provides excellent protection.

For UK sheep farmers, maintaining a robust clostridial vaccination programme is essential for safeguarding flock health, improving welfare, and preventing the heavy economic losses associated with this deadly disease.