Some metabolic aspects of vitamin B12 deficiency in sheep

Abstract

1. Studies were made with pair-fed vitamin B12-deficient and vitamin B12-treated or cobalt-treated ewes fed a Co-deficient diet in cages. Measurements were made of body-weight changes and some observations were made of energy and nitrogen metabolism. The effects of oral Co on energy and nitrogen metabolism were examined in sheep fed the Co-deficient diet, but not yet deficient of vitamin B12 in the tissues. 2. The rate of loss of body-weight of vitamin B12-deficient sheep was significantly faster (P<0.01) than that of pair-fed sheep given 50 μg vitamin B12/d by injection. 3. In a limited number of observations of pair-fed sheep no significant differences were found in retention of combustible energy from the diet, but excretion of faecal nitrogen was higher in deficient animals than in animals receiving vitamin B12 or Co. 4. There was no significant effect of supplementary Co on energy metabolism, nitrogen metabolism, production of methane or digestibility of fodder in sheep that were not deficient of vitamin B12.