ESTIMATED RUMINAL PRODUCTION OF PSEUDO-VITAMIN B12 FACTOR-A AND FACTOR-B IN SHEEP

Digesta samples from experiments in which ruminal vitamin B12 production was quantitatively estimated were used for electrophoretic separation and estimation of ruminal production of pseudovitamin B12, Factor A and Factor B. Mean estimates based on 61 samples representing a variety of diets were (.mu.g/g digestible dry matter intake .+-. SE): pseudo-B12, .52 .+-. .10; Factor A, 2.15 .+-. .19; Factor B, 1.24 .+-. .14; and B12, 2.84 .+-. .17. Production of B12 and the analogs was differentially responsive to Co level in the diet with B12 being most responsive. Other dietary variables, including the general nature of the diet as well as chemical additives, were shown to influence production of the analogs. Alfalfa meal appeared to be especially effective in stimulating the synthesis of B12, Factor A and Factor B.