The Metabolism of Cobalt in Lambs

Abstract

The digestibility of a ration of shelled yellow corn, powdered whole milk, and cobalt-deficient hay was determined with 6 cobalt-deficient and 6 cobalt-fed lambs. The results reveal that the cobalt-fed lambs more efficiently digested the ethersoluble and nitrogen-free extract fractions of the ration. However, the deficient lambs showed a significantly greater coefficient of apparent digestibility for the fibrous fraction of the ration; an effect attributed to the depressed feed intake. Apparently, cobalt deficiency does not markedly affect the cellulose-splitting microorganisms of the rumen. Subcutaneous injection of 10 mg of pteroylglutamic acid per lamb daily or the simultaneous injection of 1 μg of vitamin B₁₂ and 1 mg of cobalt per lamb daily were therapeutically ineffective in cobalt deficiency in lambs. Cobalt feeding gave the usual beneficial response, whereas the negative controls continued to show a depressed appetite, body weight losses, and low hemoglobin levels. Subcutaneous injection of 15 U.S.P. injectable units of a purified liver extract daily per lamb was effective in the treatment of cobalt deficiency, as measured by all criteria; however, oral administration of the same dosage level was of no therapeutic value. The results indicate that the liver preparation contained some factor or group of factors which possess curative activity for cobalt-deficient animals. This apparently is not cobalt. Preliminary efforts to concentrate the active fraction from the liver extract by means of counter-current distribution technics were unsuccessful.