Toxicity of a vitamin D3 rodenticide to dogs.

As a follow-up to an investigation of 2 dogs that died as a result of apparent toxicosis attributable to a cholecalciferol-containing rodenticide, we tested the toxicity of this product in dogs. Two groups of 2 dogs each were fed amounts of rodenticide that provided 20 and 10 mg of cholecalciferol/kg of body weight (approx one fourth and one eighth of the published LD50, respectively). All dogs developed hypercalcemia and hyperphosphatemia and then died. Major lesions were gastrointestinal hemorrhage, myocardial necrosis, and mineralization of vascular walls. Our data indicate that cholecalciferol-containing rodenticides pose a much greater hazard to dogs than was previously believed.