Fatal Wedelia glauca intoxication in calves following natural exposure.

A group of 342 beef calves, corralled in the Patagonia region of Argentina, were fed alfalfa hay that had been inadvertently contaminated with Wedelia glauca. A total of 147 (43%) calves died within 4 days. Pathologic findings in 2 calves were diffuse centrilobular hepatic necrosis and hemorrhage with edema in the gallbladder, common bile duct, and choledochoduodenal junction. Epidermal fragments of W. glauca were identified in rumen contents by microscopy. Intact W. glauca plants and leaf fragments were found in the hay. Patches of defoliated W. glauca were also identified in the alfalfa pasture from which the hay had been baled.