Senecio poisoning in cows affects which organ system?

• A. Liver
• B. Kidneys
• C. Brain
• D. Spleen

Answer: (B)

Senecio plants contain pyrrolizidine alkaloids that, once absorbed, are activated in the liver to toxic metabolites. These metabolites damage hepatocytes and the biliary epithelium, leading to centrilobular necrosis, bile duct injury, and progressive fibrosis. Over time this hepatic injury can cause veno-occlusive changes and impaired liver function, with potential secondary photosensitization from phylloerythrin buildup when the liver can’t excrete chlorophyll breakdown products properly. In cattle, the primary organ system affected is the liver, so hepatic signs (poor condition, reduced appetite, weight loss, possible photosensitivity) predominate, rather than primary kidney, brain, or spleen involvement.