Causative agent: Urea fertilizer
Urea poisoning from consumption of urea fertilizer or water containing urea fertilizer killed 15 of 300 bison in Alaska (70).
Clinical signs:
Clinical signs were not reported, since all 15 of the bison were found dead. In cattle, clinical signs of urea poisoning include abdominal pain, frothing at the mouth, muscle tremors, incoordination, weakness, bloat and death (9).
Postmortem findings:
Pathological changes associated with urea poisoning of bison include bloat, hemorrhage and congestion of the lungs, hemorrhage of the spleen, pulpy consistency of the kidney, and serosangenous fluid in the pleural cavity and pericardial sac (70).
Diagnosis:
In cattle, elevated serum ammonia levels can diagnose urea poisoning. Abnormally high levels of urea or ammonia in the rumen would also be diagnostic.
Control:
There is a commonly held belief among bison ranchers that bison have very discriminate eating habits. This may not be the case. To prevent toxicities bison should be denied access to toxic substances.