Ireland’s rising rural population has brought with it an enhanced risk of sheep being poisoned by ornamental plants.

Agri-food and Biosciences Institute (AFBI) research veterinarian Dr. Siobhan Corry explains:

“As the winter months continue, AFBI wants to make farmers aware of the risk of plant poisoning in sheep, particularly due to ornamental garden plants. Whilst plant poisoning is diagnosed throughout the year, the majority of outbreaks of poisoning by plants in sheep occur over the winter months when grass is scarce.

A common history is of animals that have recently been moved to new or rented pasture, that have broken out, or animals that have been brought in to fields closer to the farm, for dosing or lambing for example.

By far the most common plants seen in poison cases are those of the Ericaceae family which include azaleas, rhododendron and Pieris species such as 'Forest Flame'.

The AFBI veterinarian confirmed that Pieris species, in particular, accounts for a large proportion of poisoning cases submitted for post mortem examination.

These plants contain the toxin acetylandromedol which is very poisonous to sheep. Poisoning due to Ivy can also occur in sheep; while it is used in livestock as a traditional folk tonic, ingestion of large quantities can cause death in sheep.

Clinical signs of plant poisoning in sheep occur a few hours after ingestion. The animal will become dull, salivate and may vomit. The animal may develop obvious abdominal pain and may develop nervous signs if it lives long enough. Frequently, the animal will become recumbent and die.

Dr. Corry continued:

“There are no specific antidotes but supportive therapy may be beneficial. In particularly valuable animals, surgery to remove the toxic leaves from the rumen may be indicated.

Often more than one animal in the flock is affected and a number may have died before a diagnosis by post mortem is confirmed.

According to Corry, it is important to check fields for ornamental shrubs before using for grazing. Garden clippings can also cause outbreaks if not disposed of safely.

Farmers who are concerned that their sheep may have eaten something poisonous, should remove them from the potential source and contact their local veterinary practice for advice.