Cause:
Feeding pine needles (Pinus ponderosa) to pregnant bison causes abortion. Abortion caused by consumption of pine needles occurs frequently in pregnant cattle on pasture (71). Naturally occurring abortion from the consumption of pine needles has not been observed in bison (71). Pine needle abortion has only been produced in bison by experimentally feeding pine needles to pregnant bison (71).
Clinical signs:
Pregnant bison in late stages of pregnancy fed up to 2.25 kg of pine needles did not develop any clinical signs other than abortion. The calves that were not aborted were all born alive and all survived (71).
Postmortem:
There were no bison cow or calf mortalities associated with feeding pine needles to bison (71).
Diagnosis:
Establishing the diagnosis of pine needle abortion would be difficult. There were no clinical signs observed in bison cows fed pine needles and the bison calves that were aborted were born as normal healthy calves.
Treatment:
There is no known treatment for pine needle abortion in cattle or bison.
Control:
It is thought that bison, as opposed to cattle, do not consume pine needles when they are on pasture, even if ponderosa pines are present. Control programs to prevent the consumption of pine needles by bison have not been required.