Acorn Toxicity
Poisoning by tannins and volatile phenols in plants of the Oak is relatively common. Ingestion of acorns is the most common cause, but ingestion of leaves and young shoots can also cause toxicity. Clinical signs of toxicity develop soon after ingestion (within days), and young animals seem to be more severely affected than older animals. It is often seasonal, occurring in autumn when the acorn ‘crop’ is at it’s highest and more are present on the ground around the trees.
Symptoms
Oak tannins are nephrotoxic, and result in renal (kidney) dysfunction. Affected animals will often present with some of the following clinical signs:
Diarrhoea (black and watery, sometimes bloody)
Increased urination
Lethargy
Reduced appetite
Dehydration
Oedema (swelling under the jaw or abdomen)
Sometimes sudden death may occur
Diagnosis
Diagnosis can be difficult, so generally a diagnosis is made based on a history of the animal recently grazing in an area where there are oak trees/acorns present on the ground (Autumn).
Blood tests may be run to identify the level of injury that the internal organs have undergone (kidneys) and could be helpful in determining the prognosis of an individual animal.
Treatment
There is no specific treatment for acorn toxicity, but animals should be removed from the area where the oak/acorns are present. Fluid therapy with IV fluids is generally cost-prohibitive, but providing ad-lib access to oral fluids, energy supplementation for lethargic animals and ad-lib feed (hay and grass) as a form of nursing care, may be beneficial. If the animal is spending more time lying down, then a soft and sheltered area should be provided. In severe cases, prognosis is poor to grave.
References
Parkinson TJ, Vermunt JJ, Malmo J & Laven R (2019) Diseases of Cattle in Australasia (second edition). Pg 418.