The Sligo regional veterinary laboratory (RVL) recently diagnosed plant poisoning in two three-year-old ewes.
Both sheep had been observed to cough up green material and were treated for pneumonia due to raspy lung sounds.
On post-mortem examination at the laboratory, there was oedema along the ventral neck, splenomegaly, and haemorrhagic intestinal contents.
Pieris leaves were found in the rumen of the ewes. Pieris is of the Ericaceae family which also includes azaleas and rhododendron.
According to the Agri-food and Biosciences Institute (AFBI), the most common plants seen in poison cases are those of the Ericaceae family.
 Pieris species, in particular, accounts for a large proportion of poisoning cases submitted for post mortem examination.
An evergreen shrub, the young leaves start out a bright red colour, before changing to pink/cream and finally to green.
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.
Often more than one animal in the flock is affected and a number may have died before a diagnosis by post mortem is confirmed.
 It is important to check fields for traces of ornamental shrubs before using for grazing. Garden clippings can also cause outbreaks if not disposed of safely.
Farmers who are concerned that their sheep and ewes may have eaten something poisonous, should remove them from the potential source and contact their local veterinary practice for advice.