What to look for

  • Animals are found dead or paralysed
  • Paralysis usually affects the muscles of the legs, tongue, jaw and throat
  • Affected animals stumble, lie down and are unable to eat, but usually remain upright
  • Characteristic weakness and paralysis of the legs and head
  • Mildly affected cattle may recover over several weeks


A toxin produced by bacteria (Clostridium botulinum). This bacteria grows only in environments low in oxygen such as inside rotting carcases. Clostridium botulinum produces spores that can last many years in the soil. Cattle are very sensitive to fatal poisoning by the botulism toxin. Exposure most often occurs via rotting carcases of cattle in water courses, carcases of rodents, snakes or possums trapped during hay or silage production, or in rotted food by-products such as brewer’s grains, citrus pulp and cannery waste. Outbreaks have occurred in cattle with access to poultry manure that contained poultry carcases.

Animals likely to be affected

Animals of any age.

Other diseases with similar signs

Other causes of sudden death. May be confused with calving paralysis.

Confirming the diagnosis

Identify the toxin in the gut contents of affected animals and/or in material that is suspected of causing the disease.

Spread of the disease

Does not spread from animal to animal but multiple cases may occur if a group of animals access toxic material.

Risks to people

People do not contract botulism from cattle and the toxin does not pass into their milk.


Nursing of mild cases can be effective.

Risk factors

  • Cattle have access to toxic material e.g. dead animals in watercourses
  • Feeding poorly made hay or silage that may contain animal carcases
  • Failure to vaccinate in high risk regions


In regions where botulism occurs, vaccinate animals that may be exposed to toxic material.

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