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Watch out for acorn poisoning this autumn

This year acorns appear to be particularly abundant, and this poses an increased risk of acorn poisoning in heifers and sheep. Acorns are extremely toxic to most livestock and when eaten in large enough quantities can be fatal. 


Some suggest that 2020 could be a mast year; mast years normally occur every 5-10 years and during these years’ trees will produce a bumper crop of fruits.

Combined with the changeable and stormy weather normally seen in autumn means we are seeing lots of acorns on the ground this year.

It is believed that acorn’s toxicity comes from their tannin content, which when metabolised can lead to ulcerations in the digestive tract and kidney damage.

Once kidney damage has occurred prognosis is poor, with mortality rates as high as 70%.

Symptoms of acorn poisoning

Animals with acorn poisoning can start displaying symptoms within hours or up to several days after eating acorns. Symptoms of acorn poisoning include:

  • Vomiting and diarrhoea
  • Abdominal tenderness
  • Depression
  • Rapid weight loss
  • Loss of appetite
  • Tiredness
  • Dehydration


“There is no specific treatment for acorn poisoning and so prevention is key. If possible, try to limit access to fields with lots of oak trees during autumn, but if this is not possible then fence off oak trees to limit access and frequently clear acorns (particularly after windy weather),” says James Hague, Technical & Marketing Director at ForFarmers.

“Livestock which have access to sufficient, palatable feed are less likely to eat acorns so ensure that animals in fields with lots of oak trees have access to sufficient feed. Including a pelleted ration supplement (1 kg/head/day) containing 10-15% calcium hydroxide can also be a useful preventative measure,” he concludes.

For more information

For more information on animal health, nutrition or winter feeding please speak to your local ForFarmers account manager or send us an online enquiry here.