Taxus baccata
Tree up to 20m tall; bark reddish, flaky and deeply fissured in old trees. Branches spreading, branchlets rather pendulous. Leaves linear, usually strongly curved, shortly pointed dark green above, 2 3cm long, midrib prominent. Flowers: male and female cones on separate trees, solitary and axillary. Seed broadly ellipsoid, brown, borne in an almost globose, fleshy, scarlet aril. Irish yew branches are more upright or erect. The common or English yew branches spread more or less horizontally.
Irish yews (var. fastigiata) seem commoner in NZ. They have a very distinctive shape. Young totara trees could be mistaken for English yews (south American podocarps are often also called yews despite being unrelated).
Grown throughout NZ as single trees in gardens, on farms, cemetaries and parks. Sometimes planted as hedges; occasionally escapes. Originally grown in graveyards (for their timber), as the only places to which cattle did not have access.
Taxine is considered the main toxin: it is a complex mixture of alkaloids, the major part of which is composed of ester alkaloids. The oil of yew is also volatile and irritant, there are also traces of ephedrine and the cyanogenetic glycoside taxiphyllin. Chief action is due to the non irritant alkaloids. The leaves, bark and seeds are poisonous, but the red ‘fruit’ is not. Poisoning is usually caused by clippings being thrown over the hedge.
Cattle, calves and sheep. Also poisonous for humans - children sometimes eat the fruit.
Bradycardia. Sudden death cardiac glycoside toxin. Some cases pronounced excitement, nausea and regurgitation, trembling and staggering precede death
Abomasum is distended and inflamed and the liver, spleen, and lungs are usually found engorged with blood. Empty right heart and dark tarry blood in left heart and limited non specific post mortem lesions.
Often drop dead "as if they had been shot". Leaves and twigs may be seen in the contents of the stomach.
Other toxicities such as lightning strike and plants that result in sudden death. (Anthrax)
Symptomatic at best, usually futile once clinical signs appear. Atropine might be helpful.
Very poor.
Prevent access to yew trees, dispose of clippings properly.
Conner H.E. The Poisonous Plants In New Zealand. 1992. GP Publications Ltd, Wellington
Cooper M R, Johnson A W. Poisonous Plants and Fungi in Britan: Animals and Human Poisoning. Her Majesty’s Stationary Office. London. 1998
Hare, W.R. 1998. Bovine Yew (Taxus species.) Poisoning. Large Animal Practice. 24 28. Jan Feb.
Hill, F. (1998). Plant poisonings in cattle. Vetscript. XI. 9:14 15.
Hutton, J.B. (1996). Plant poisoning in New Zealand. Surveillance. 23(1):18 21.
Parton K, Bruere A.N. and Chambers J.P. Veterinary Clinical Toxicology, 2nd ed. 2001. Veterinary Continuing Education Publication No. 208
Surveillance (1974) 1(1): 19 Yew poisoning calves.
Surveillance (1974) 1(3): 14 Yew poisoning of cattle
Surveillance (1977) 4(4): 22 Yew poisoning (house cow)
Trewheellar MR (2006) Yew (Taxus baccata) toxicosis in red Devon beef heifers. Sheep and Beef Cattle Newsletter, (29) 20 - 22
