Bracken Poisoning In Cattle

Many plant poisonings, including bracken poisoning, are common in the autumn. The highest risk period is when grass growth is poor, particularly if this has been combined with bracken control so that rhizomes or new young fronds are available for cattle to eat.

Bracken contains a variety of toxins. For cattle the two most important are a toxin that depresses the bone marrow, and a cancer–causing toxin. These toxins are still active in hay made from pastures with bracken

Clinical Signs

Acute poisoning

This occurs as a result of eating large quantities of bracken. Disease develops because of depression of the bone marrow, which stops the production of the white cells that fight infection and the platelets that help blood to clot. Signs can up to eight weeks after cattle have stopped eating bracken

  • Depression and loss of appetite
  • Bloody diarrhoea accompanied by straining
  • High temperature
  • Weakening, collapse and death (usually within five days of the onset of signs)
  • Secondary infection is very common

Enzootic haematuria This occurs as the result of eating small quantities of bracken over a long period of time. Cancerous changes occur in the bladder leading to:

  • In mild cases – persistently bloody urine (haematuria)
  • In severe cases – severe blood loss and difficulty passing urine with visible blood clots

In some animals, cancer occurs in the gut as well as the bladder. The signs depend on the site of the tumour. Get veterinary advice in animals showing unusual gut signs that have had access to bracken


  • On the clinical signs described above
  • History of access to bracken
  • Blood sample for haematology
  • In many cases a post mortem will be essential to confirm the diagnosis


  • here is no specific antidote for bracken poisoning.
  • Broad-spectrum antibiotics to prevent secondary infection can help in acute cases
  • For animals with haematuria no treatment is effective


  1. Limit access to pastures with bracken, particularly if grazing is poor
  2. Never allow cattle access to recently ploughed land where bracken has been. Exposed rhizomes are the most dangerous part of the plant as they are attractive to cattle. Particularly if they have started to reshoot
  3. Bracken control by burning, ploughing, reseeding, and herbicide is the best method of prevention.


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