The Level of Cobalt Tolerance in Yearling Sheep

Abstract

Data have been secured to determine the level of dietary cobalt tolerated by fattening yearling sheep. Yearling wethers fed a ration of shelled yellow corn, soybean oil meal, and mixed legume hay have been drenched daily with cobalt chloride at levels varying from 10 to 500 mg. of elemental cobalt per centiweight daily for periods up to eight weeks. Results obtained show that levels up to 160 mg. of cobalt per centiweight daily can be tolerated for at least eight weeks without harmful effects. Dosages of 200 or 500 mg. of cobalt per centiweight daily caused a severely depressed appetite and body weight losses; an anemia was noted at the higher level. Polycythemia was absent, and blood sugar determinations revealed no significant departure from normal. Endeavors to produce polycythemia in six sheep by daily intravenous injections of cobalt at the rate of 75 mg. of cobalt daily resulted in death of two of the animals; there was no elevation of the hemoglobin level. Pathological studies of the sheep which died of cobalt toxicosis showed fatty infiltration of the liver, and slight pulmonary edema and congestion in all cases. In addition, three animals which received the highest cobalt intake also showed petechial to ecchymotic hemorrhages in the small intestine. Copyright © . .