NADIS disease bulletins are written specifically for farmers, to increase awareness of prevalent conditions and promote disease prevention and control, in order to benefit animal health and welfare. Farmers are advised to discuss their individual farm circumstances with their veterinary surgeon.

Water dropwort POISONING

The current dry and hot weather will mean that in many areas there will be poor grass growth. This is likely to mean that cattle are likely to spend a lot of time around ditches and streams and be attracted to the plants growing there. Many of the plants they encounter will be potentially toxic; one of the most important of such plants is water dropwort, a plant of the parsley family which is very common in the western and southern regions of Great Britain and common throughout Northern Ireland. Water dropwort (Oenanthe crocata) is also known as water hemlock and hemlock water dropwort

Cattle are particularly at risk after ditches have been cleared out exposing the most poisonous part, the roots (often referred to as "dead man's fingers").

water dropwort

Water Dropwort

(Inset: “dead man’s fingers”)

Clinical Signs

The toxin found in water dropwort is a neurotoxin, the main effect of which is to cause convulsions

The first signs are often salivation and dilated pupils, followed rapidly by difficulty breathing, collapse and convulsions. The convulsions are spasmodic, that is the whole body shakes violently, then relaxes and then, after a short period, starts convulsing again. In the majority of cases affected cattle die; in the small percentage that don’t die, diarrhoea is a common clinical sign in the recovery phase

Diagnosis

Convulsions and sudden death are clinical signs associated with many toxins, so diagnosis is best based on a proper post mortem to rule out other cause and to confirm that the the cattle have eaten the plant

Treatment

There is no specific treatment. In valuable animals a vet can administer an anaesthetic to help control the convulsions. If poisoning is suspected remove all cows from areas with access to the plant

Prevention

Poisoning is most commonly associated with the digging up of the roots during ditching. So prevention is based on identifying the plant and removing all parts of it before stock are allowed access.

Identification of the plant above ground is not easy without a guide book as the plant resembles many non-poisonous parsleys, but the roots are distinctive. They are pale-yellow in colour consisting of five or more fleshy tubers which ooze a yellowish liquid from their cut surface. (These roots are poisonous for humans too, so it is essential to take care when handling the plant)

Richard Laven PhD BVetMed MRCVS