Pathology of subacute bitterweed (Hymenoxys odorata) poisoning in sheep.

Subacute bitterweed (Hymenoxys odorata) poisoning was produced in sheep by force feeding them ground plant material (1 gm/kg/day) for 15 days. Five sheep died and two became moribund and were killed at the end of the experiment. The forestomach and abomasum were severely congested and occasionally eroded on the mucosal surface. There was an accumulation of edematous fluids along the rumino-reticular folds and ruminal sulci. Gaseous and fluid distension of the forestomachs, abomasum and cecum was a consistent finding. The gall bladder was greatly distended and occasionally the mucosa was sprinkled with petechiae. The most common finding was severe glomerulonephrosis characterized by proteinaceous casts, swollen and degenerated glomerular tufts and degeneration and necrosis in the inner renal cortex and outer medulla. Mild to moderate toxic hepatosis, characterized by vacuolar degeneration of hepatocytes primarily around the central vein, was consistent.