Toxic Effects of Stable Strontium in Young Pigs

Abstract
The metabolism and toxic effects of strontium in pigs, three to 8 weeks old, were investigated. In experiment 1 Hampshire pigs were fed a synthetic ration containing 0.55% of calcium or 0.16% of calcium and 0.47% of strontium. In experiment 2 a factorial design was used in which 0.89 or 0.16% of calcium and zero or 0.67% of strontium were included in the rations. The pigs fed strontium and 0.16% of calcium were the most severely affected by incoordination and weakness followed by posterior paralysis. Occasionally mild toxic effects were observed in the pigs fed 0.89 or 0.55% of calcium and strontium. One pig fed 0.16% of calcium was mildly affected by the treatment. The bone deformities seen grossly, radiographically, and microscopically were most marked in pigs fed strontium and 0.16% of calcium. There was widening of the epiphyseal plates and cupping of the metaphyses. Radiographically, the margins of the epiphyses were poorly delineated and radiolucidity was marked. The microscopic examination revealed cartilage remaining in the metaphyses and a marked increase in osteoid tissue. When 0.55 or 0.89% of calcium was included in the ration the weight gain, feed efficiency, bone ash, bone total solids, bone calcium and bone strontium were significantly increased as compared with pigs fed 0.16% of calcium. Feeding strontium depressed calcium and fat content of bone. The results were discussed in respect to present knowledge of strontium, calcium, and bone metabolism.