Some metabolic aspects of vitamin B 12 deficiency in sheep

Abstract

1. Studies were made with pair-fed vitamin B 12 -deficient and vitamin B 12 -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 B 12 in the tissues. 2. The rate of loss of body-weight of vitamin B 12 -deficient sheep was significantly faster (P<0.01) than that of pair-fed sheep given 50 μg vitamin B 12 /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 B 12 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 B 12 .