Accidental superphosphate fertilizer poisoning in pregnant ewes

Consumption of superphosphate fertilizer by 200 pregnant ewes resulted in signs of toxicosis in 41 ewes, 14 of which died. Predominant clinical signs were marked teeth grinding, voluminous diarrhea, CNS depression, apparent blindness, and a stiff-legged atactic gait. Biochemical abnormalities were hypocalcemia, hypoglycemia, and a high anion gap. The primary toxic principal in superphosphate fertilizers is the fluorine contaminant; however, calcium pyrophosphate and calcium orthophosphate also contribute to toxicosis, which results in acute proximal renal tubular necrosis. Voluntary consumption of superphosphate fertilizer in well-fed livestock is not expected, and was believed to be related to the lack of availability of salt.