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.