There has been an increase in submissions of carcases to the Agri-Food and Biosciences Institute (AFBI) veterinary lab, where the animal was exposed to ragwort.
The plant, also commonly known as benweed, is usually not eaten by cattle, but when ensiled or made into hay, it becomes more palatable due to the release of sugar.
Animals that are very tightly grazed may have no option, but to eat the plant.
The cases submitted to AFBI for analysis involved multiple deaths in bovines around 12 to 18 months old, which is unusual given clinical signs are normally seen in older animals after weeks to months of ingestion. The acute form of ragwort poisoning occurs when cattle eat a large volume of the plant, leading to liver damage and rapid death.
Chronic disease is more common and is due to repeated eating of low volumes.
Clinical signs include diarrhoea with jaundice and weight loss.
Ragwort is included in the Noxious Weeds order of 1977. Options for control include pulling, cutting before flowering or spraying.
When sprayed, animals must be removed from the field until ragwort is fully rotted, which can take up to six weeks.