ABSTRACT
Pinus ponderosa or western yellow pine (Pinaceae) is widely distributed in the US, but is most abundant in the western US and western Canada. It was suggested by L. R. James et al. that in addition to the possible toxins in Pinus ponderosa needles, several other factors may be associated with and/or predispose animals to abort following their consumption. These include: stage of gestation when agent(s) are ingested, environmental stresses, condition of the animal, and the general physiology of the animal. The feeding of Pinus ponderosa needles to late pregnant cattle results in an abortion in from 3 days to 3 weeks, with most occurring 5-15 days after the initiation of daily feeding. Although Pinus ponderosa needle abortion is a common name for the syndrome afflicting cattle, it is in some ways misleading, since abortion is normally taken to mean expulsion of a nonviable fetus.
