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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.
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==
==Diagnosis==
==Diagnosis==
===Clinical signs===
===Clinical signs===
*Weight loss
*Weight loss
===Biopsy===
===Biopsy===
A liver biopsy will reveal hepatomegalocytosis and bilary hyperplasia.
A liver biopsy will reveal hepatomegalocytosis and bilary hyperplasia.
===Post Mortem===
On gross post mortem examination the liver is small, dense and fibrotic with prominent biliary tracts.
==Treatment==
==Treatment==
* Knottenbelt, D.C. '''A Handbook of Equine Medicine for Final Year Students''' ''University of Liverpool''
* Knottenbelt, D.C. '''A Handbook of Equine Medicine for Final Year Students''' ''University of Liverpool''
*Rose, R. J. and Hodgson, D. R. (2000) '''Manual of Equine Practice''' (Second Edition) Sauders.
*Rose, R. J. and Hodgson, D. R. (2000) '''Manual of Equine Practice''' (Second Edition) Sauders.
[[Category:Hepatotoxicity, Chronic]][[Category:Horse]][[Category:Sheep]]
[[Category:Hepatotoxicity, Chronic]][[Category:Horse]][[Category:Sheep]]
[[Category:To_Do_- lizzyk]]
[[Category:To_Do_- lizzyk]]