English yew poisoning in 43 cattle.

Thirty-five privately owned 1- to 2-year-old mixed-breed steers and heifers, weighing 340 to 454 kg, died from accidental ingestion of English yew (Taxus baccata). Estimated dosages ranged from 0.36 to 0.70 g of fresh plant/kg of body weight. Clinical signs of poisoning and death began 2 to 3 hours after first exposure, and cattle continued to have clinical signs, which ended in death 6 to 8 hours later. Most cattle had died by 4 hours after first ingestion. Necropsy of 4 cattle revealed substantial amounts of English yew leaves and small stems in the rumen contents. Grossly, there were areas of hyperemia in the abomasum and small intestine. Histologically, lesions were limited to the lungs and included moderate congestion and interlobular edema. Chemical analysis by thin-layer chromatography of suspected yew plant material from the rumen contents of the 4 necropsied cattle was compared to authentic taxol, and confirmed the presence of taxol in rumen samples.