Poisonous plants grow in most plant communities found on rangelands an
d pastures. They are one of the principal causes of economic loss to t
he livestock industry. One major costly effect is on reproduction, whi
ch includes birth defects, abortions, lengthened calving intervals, an
d interference with oogenesis, spermatogenesis, libido, and estrus. Th
ose plants that cause wasting, temporary illness, and other such effec
ts can adversely effect reproduction livestock.