Acorns are the fruits (achenes) of different species of oak. Common in England and Northern Europe are:

Quercus ilex (holm oak, evergreen oak);
Quercus pedunculata (pedunculate oak);
Quercus robur (common oak, English oak);
Quercus petraea syn sessihflora (sessile oak, durmast oak).

[affected.gif] Animals most affected
Cattle, (sheep, horses).

[etiology.gif] Etiology
Ingestion of extremely large quantities of acorns in autumn, especially during periods of food shortage or drought. Poisoning is extremely frequent and, in certain regions, particularly serious, affecting mainly young animals.

[toxic.gif] Toxicity
Contains pyrogallic acids, up to 8%, although the amounts vary according to the age of the acorn. Unripe, green acorns contain the highest levels of pyrogallic acids, and certain species of oak (e.g. the pedunculate oak) are more toxic than others. In addition, the age of the tree is significant, with youngest trees having the greatest levels of pyrogallic acids and tannins.
Ingestion over a period of 1-4 weeks is necessary before toxic signs become apparent. (Pigs are resistant to pyrogallic and tannic acids.)

[clinical.gif] Clinical features
Gastrointestinal effects
Present first (within 7-10 days), and are severe and persistent:

General effects
Equally intense and persistent, but presenting later:

Urinary effects
(Not persistent, or regular in their presentation)

Neurological effects
(Infrequent and appearing towards the endstage of poisoning):

Haemorrhagic effects
(Delayed onset):

Various effects

A fatal outcome is common (up to 80% of animals with renal signs).

[lesions.gif] Lesions

[treatm~1.gif] Treatment
No antidote. Symptomatic and supportive care only:

To avoid or prevent poisoning: