If you have a suspected ragwort victim it is best to get the vet out, it affects the liver, and symptoms can present in different ways including a stiff neck or death!
Symptoms are those of liver damage: lethargy, loss of appetite, loss of interest in life, weight loss, bloated abdomen, jaundice, blood not clotting properly, blood in the urine, acute photosensitivity, standing in corners pressing the head against the wall, unusual vocalisations, blindness, self harm and harm to others/owner. Not good, any of it, because you only start to see the symptoms when about 70% of the liver has been damaged and ragwort damaged livers cannot regenerate. Liver support = low protein diet, what protein IS fed should be the highest quality affordable, feed little and often, milk thistle, Yea Sac. Never, ever trust the horse NOT to eat ragwort again because, sadly, some develop a taste for it.