Poisons can come in all shapes and sizes. Cattle are inquisitive by nature and often tend to ingest what they should not, especially younger stock.

The majority of poisons are encountered in the environment, the diet or the water supply.

Poisons can also be in the air, such as slurry gases.

Overdoses of medicines or feed supplements are also common, be it by accident or by an overzealous farmer.

The effect the substance has on the animal depends on the dose, the duration of exposure and how quickly the substance is metabolised by the animal’s body.

A highly toxic substance ingested in a large quantity will cause acute dramatic clinical signs, often ending in death.

Chronic poisoning is more difficult to identify due to slow onset, with less dramatic clinical signs, such as ill thrift or abortions.

Some of the most common environmental poisons we see as veterinary surgeons are lead and botulism.

Less frequently, we see nitrate from fertilisers and mycotoxins from mouldy feed stuffs. Some plants are toxic, such as yew trees, bracken fern and ragwort.

Certain chemicals, such as industrial products and pesticides, are often toxic.

It is possible to get adverse reactions to most drugs licenced for cattle.

This can be as a result of overdosing or misuse of the product.

Poisonings from over supplementation with minerals also occurs, such as copper poisoning.

An integral part of a disease investigation is the differentiation of poisoning from infectious and nutritional diseases.

A poisoning is often suspected by clinical signs and a history of exposure.

If you suspect an incident on your farm you should contact your veterinary surgeon immediately.

One major point to consider is that most poisons have serious implications for food safety and public health if meat or milk from that herd enters the food chain.

In conclusion, poisonings are rare, but should not be ruled out.

Paracelsus (1493-1541) observed that: “All substances are poisons; there is none which is not a poison. The right dose determines a poison from a remedy.”

John Quille works at Castle Veterinary Clinic, Castleisland, Co Kerry. Castle Veterinary Clinic is part of XLVets. XLVets is a group of progressive practices who are working together to achieve a better future for agriculture and veterinary in Ireland. For further information, see www.xlvets.ie.