Acorn toxicity

_{Compounds found in acorns and oak leaves can cause renal failure in cattle and sheep.}

Many of you may have noticed that trees are having a bumper year for seeds and nuts, and oak trees are no exception, with many trees currently laden with acorns.

Acorns and oak leaves contain phenols and tannins, such as gallic acid and pyrogallol, which when ingested in excess will bind and precipitate proteins leading to renal failure. Green acorns are known to be more toxic and are a particular risk when large numbers are blown from the trees in stormy weather. Some animals appear to develop a taste for the acorns and ingest larger amounts. Compared to cattle and sheep, pigs are relatively resistant to their effects and can be used to clear acorns.

Clinical signs arise three to seven days after ingestion and may include anorexia, abdominal pain and constipation followed by black tarry faeces. Polyuria/polydipsia may be reported and haematuria and icterus may also be seen on clinical examination. Urea and liver enzymes will become raised. Acutely affected animals can die within 24 to 72 hours, while animals which survive beyond this may lose weight and become chronically ill thriven.

Postmortem findings can include pale, swollen kidneys with surrounding haemorrhage, ascites, ruminal distension and gastrointestinal oedema, ulceration and haemorrhage, as well as oesophageal ulceration secondary to uraemia due to renal tubular necrosis. Depending on the time scale acorns may not be found within the rumen content.

There is no specific treatment and supportive therapy has a poor chance of success. Cattle and sheep should be prevented from accessing high risk areas, especially following a confirmed or suspected diagnosis of acorn toxicity.

We are always happy to help any investigate deaths by carrying out post mortem examinations or supporting you to do so in practice. If you have a suspect case, or any case where you would like our input, send us a WhatsApp, phone us on 01224 711177 and ask to speak to a North vet, or send us an email at vetservices.north@sruc.ac.uk

Posted by SRUC Veterinary Services on 26/10/2023