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It is poisonous to livestock with Horses and cattle being more susceptible than sheep. When ingested over long periods of time it causes hepatotoxicity which in the severe form is invariably fatal. Exposure to the toxin is usually via ingestion of contaminated hay or silage as the animal will avoid it in the fresh form.  

It is poisonous to livestock with Horses and cattle being more susceptible than sheep. When ingested over long periods of time it causes hepatotoxicity which in the severe form is invariably fatal. Exposure to the toxin is usually via ingestion of contaminated hay or silage as the animal will avoid it in the fresh form.  

The toxin is a pyrrolizidine alkaloid which is converted in the body to the toxic intermediate '''pyrroles''' and their esters which cause intitial and continued damage to hepatocytes. They have an anti-mitotic effect whilst allowing continued synthesis within the cell and its nucleus resulting in a marked increase in the size of the hepatocytes. The attempted repair by fibrosis aids the shunting from the portal triads to the central vein, thereby bypassing the hepatocytes and resulting in the clinical signs associated with liver failure.

The toxin is a '''pyrrolizidine alkaloid''' which is converted in the body to the toxic intermediate '''pyrroles''' and their esters which cause intitial and continued damage to hepatocytes. They have an anti-mitotic effect whilst allowing continued synthesis within the cell and its nucleus resulting in a marked increase in the size of the hepatocytes. The attempted repair by fibrosis aids the shunting from the portal triads to the central vein, thereby bypassing the hepatocytes and resulting in the clinical signs associated with liver failure.

==Signalment==

==Signalment==

===Biopsy===

===Biopsy===

A liver biopsy will reveal hepatomegalocytosis and bilary hyperplasia.

A liver biopsy will reveal '''hepatomegalocytosis''' and '''bilary hyperplasia'''.

===Post Mortem===

===Post Mortem===

==Treatment==

==Treatment==

There is no corrective treatment for the liver damage caused by ragwort poisoning, supportive treatment can improve quality of life and minimise some of the clinical signs by reducing the workload of the liver.

There is no corrective treatment for the liver damage caused by ragwort poisoning, '''supportive''' treatment can improve quality of life and minimise some of the clinical signs by reducing the workload of the liver.

Small, frequent feeds should be given 6 times a day and should consist of a high quality energy and protein source. Stomach tubing may be necessary if the horse is inappetent. Supplementary B vitamins may also be beneficial and can be given orally or parenterally.

Small, frequent feeds should be given 6 times a day and should consist of a high quality energy and protein source. Stomach tubing may be necessary if the horse is inappetent. Supplementary B vitamins may also be beneficial and can be given orally or parenterally.