Page 908 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

Poisonous Plants of the United States Chapter | 61 863

VetBooks.ir TABLE 61.6 (Continued) Common Name Location ICA Concentration (%DW)

Species
Pinus radiata Radiata pine New Zealand n.d. 0.26
Pinus strobus White pine n.d.
Pinus taeda Loblolly pine Arizona n.d.
Arkansas n.d.
Pseudotsuga menziesii Douglas fir Utah 0.04
Colorado 0.05
California n.d.
Idaho n.d.
Arizona n.d.
Oregon n.d.
Thuja plicata Western red cedar Arizona 0.42
New Mexico 0.33
Utah 0.84
Germany n.d.
Tsuga mertensiana Mountain hemlock Oregon n.d.
n.d., not detected (,0.01%).

Pinus ponderosa var. ponderosa (western variety) The toxin in ponderosa pine that induces abortion in
extends from the mountains of southern California north- cattle is the labdane resin acid isocuppressic acid (9)
ward on the western and eastern sides of the Sierra (ICA; Gardner et al., 1994). Two related derivatives (suc-
Nevada Cascade crest to Canada. The eastern variety cinyl ICA and acetyl ICA) also contribute to the induction
P. ponderosa var. scopulorum meets the western variety of abortion after hydrolytic conversion to ICA in the
near the Continental Divide in west-central Montana and rumen (Gardner et al., 1996). Other related labdane acids
extends southward throughout mountains, plains, and (agathic acid, imbricatoloic acid, and dihydroagathic acid)
basins to scattered stands in the Sierra Madre Occidental that are found in ponderosa pine needles at low levels
and Sierra Madre Oriental of northern Mexico. Pinus ari- may also contain abortifacient properties based on their
zonica (once considered a third variety) has scattered similar chemical structure to ICA. Other genera and spe-
populations in southern Arizona and New Mexico. cies have also been implicated in abortions, such as
Monterey cypress (Parton et al., 1996), Korean pine (Kim
et al., 2003), and California juniper and lodgepole pine
Toxicology (Panter, personal communications). Table 61.6 sum-
marizes current information on plant species analyzed for
ICA and/or ICA derivatives believed to contribute to
abortions. Current research indicates that the concentra-
tion of ICA in ponderosa pine needles is not uniform
throughout the same tree, the concentration of ICA in
CH OH ponderosa pine needles can vary from location to loca-
2
tion, and there is evidence for seasonal fluctuations as
well (Cook et al., 2010).
The primary toxicological effects of ponderosa pine
needles in cattle are abortion and complications associ-
CO H ated with abortion, such as retained fetal membranes,
2
metritis, and occasional overt toxicosis and death
(9)
Isocupressic acid (Gardner et al., 1999). The abortions generally occur in
the last trimester of pregnancy in the late fall, winter, or