Tansy ragwort, a yellow flowered weed so feared by farmers that it is known as the yellow peril, threatens the health of countless animals unless it is kept in check, warned the UK's leading animal welfare agency Monday. Tansy ragwort is a member of the largest genus of the sunflower family. The plant contains pyrrolizidine alkaloids which are toxic to cattle, deer, horses, and goats.
Sheep are less affected.
It causes a group of diseases called seneciosis. The toxins impede the function of the animal's liver which will eventually degenerate, resulting in the animal's death. Many weeks or months may pass before symptoms arise because the animal may only be consuming small amounts, but damage is being done. In one recent UK case, a young bay foal died suffering severe internal damage after eating ragwort. Despite emergency veterinary treatment the horse, which was found abandoned in the Newark area of Nottinghamshire, died from liver poisoning.