Effect of cobalt supplementation on serum vitamin B12 levels, weight gain and survival rate in lambs grazing cobalt-deficient pastures.

The effect of cobalt supplementation on serum vitamin B12, growth rate and survival rate was measured in controlled field experiments with Texel twin lambs of the same sex, grazing cobalt-deficient pastures. The non-supplemented lambs had lower serum vitamin B12 concentrations than their supplemented brothers or sisters. During the experiments more lambs died in the non-supplemented than in the supplemented group. At the end of the experiments supplemented lambs weighed (mean live weight) 7.2, 9.5, and 11.0 kg more than non-supplemented lambs in 1991, 1992, and 1993, respectively. Sex-related differences in weight gain and survival rate were observed.