Between July and September 2015, two cases of botulism were diagnosed on separate farms in the Republic of Ireland resulting in the loss of six cattle.

According to the Department of Agriculture’s Quarterly Surveillance report, one farm lost five two-year-old bullocks.

The second farm lost a 13-month-old heifer, the report found.

Botulism is caused by the ingestion of preformed toxin which has been produced by the growth of Clostridium botulinum bacteria in decaying vegetation or in animal or bird carcases, the Department has said.

Carrion and broiler litter are the most frequently associated sources of botulism in cattle.

Direct access to broiler litter or grazing on fields near to where broiler litter has been spread are associated risk factors.

Outbreaks of botulism have occurred in cattle and waterfowl in Ireland in recent years often involving significant numbers of animals, according to the Department.

Outbreaks tend to occur typically between March and November and are often associated with warm weather.

However, the Department said that winter outbreaks have occurred in association with contaminated silage.

Here are the clinical signs of botulism:
  • Progressive weakness.
  • Posterior Ataxia.
  • Progressive Flaccid Paralysis.
  • Drooling.
  • Animals are generally alert.
  • Difficulty swallowing.
  • Death.

Prevention of botulism

According to the Department, preventing botulism requires minimising animal contact with carrion and decaying matter.

Prevention also requires preventing animals ingesting feedstuffs contaminated with decaying materials where possible such as decaying grasses or spoiled silage, hay, or grains.

The Department advises to be aware of the potential for small quantities of contaminated feed (e.g. one loader scoop) to reach larger numbers of animals when using feeder/mixer wagons.

To prevent animals contracting the disease, it also advises to prevent the ingestion of decaying animal/ bird carcasses in feedstuffs e.g. silage pits/bales, grain stores, or on grassland.

Wildlife and poultry carcasses can produce particularly high levels of toxins and inappropriate storage or disposal of poultry litter or poultry carcasses can pose a risk of botulism for animals, it said.