Listeriosis is a brain infection in cattle caused by the bacteria listeria. These bacteria can accumulate in mouldy silage and in silages contaminated with soil at harvest.

Given the weather conditions in which some silage cuts were taken in the latter half of last summer, the risk of soil contamination will undoubtedly be heightened.

Although more common in younger cattle, listeriosis can affect pregnant cows, causing abortions.

The bacteria can also cause nasty eye problems in cows and sheep, beginning as faint white spots in the centre of the eye, but quickly causing clouding of the whole eye and blindness if not picked up.

Indeed, I have seen increased instances of pinkeye-like symptoms in sheds this winter.

Cattle with listeriosis will walk in circles and sometimes tilt their heads sideways.

They can also exhibit stroke-like conditions – a drooping of the ear, eye and mouth on one side of the face.

Often where cattle show these kinds of extreme symptoms, the prospects for recovery are weak.

Their swallowing ability will have been affected and they can fail very quickly.

Prevention

Reduce the risks of listeriosis by continually removing mouldy silage from the feed face, particularly from younger animals.

Dry cows will usually draw the short straw on beef farms during the winter, getting the very worst silage that’s on offer.

I have experienced listeria-induced abortions brought about by bad bales. It was grim, and worse, entirely avoidable.

While loader implements that can strip plastic and netting from bales are fantastic labour-saving tools on a livestock farm, it is important that farmers pay close attention to the bales that they’re feeding.

If feeding bales that are known to be mouldy with such a loader or if you see mould on a bale that you’ve just pushed in, swallow your pride, hop down from the cab, grab a fork and pick out the mould.

You might work up a sweat, but it’ll be nothing like the potential sweat you would work up seeing four or five aborted calves on the slats on a morning in late January.

Key points:

  • Brain infection.
  • Caused by bacteria in mouldy/soil contaminated silage.
  • Responsible for abortions in cows.
  • Also causes ‘pinkeye’ symptoms.