Cause

It is caused by clostridium botulinum toxins that can be picked up from the soil. It is classically associated with cattle grazing on pasture on to which poultry litter had been spread, or grazing land adjacent to where poultry litter was spread. It has also been linked to feeding of round-bale silage contaminated with toxins from bits of bird or animal carcasses that have been picked up by the baler.

Symptoms

In really acute cases, animals may be found dead. In most cases, however, botulism is characterised by a progressive hind limb weakness, with animals having difficulty rising and swaying during walking. Animals have difficulty swallowing and some animals may stand with their tongue hanging out. Following recumbency, death usually occurs due to paralysis of the respiratory muscles and suffocation. In some cases affected animals can be recumbent for several weeks.

Treatment

There is no treatment for botulism apart from removing the animal from the source of toxin, ie the contaminated pasture or feed, in the forlorn hope that only a small amount of toxin has been ingested.

Prevention and control

There is no available vaccine for botulism. Cattle should not be grazed on pasture where chicken litter has been spread and proper disposal of dead animals is imperative.