Bioavailability of cobalt sources for ruminants. 2. Estimation of the relative value of reagent grade and feed grade cobalt sources from tissue cobalt accumulation and vitamin B12 concentrations

摘要: Abstract Three experiments were conducted to estimate the bioavailability of cobalt (Co) in reagent grade and feed Co sources for sheep. In Experiments 1 2, 27 mature sheep assigned randomly nine treatment groups. Treatments basal diet supplemented with 0, 20, 40, or 60 ppm (RG) sulfate (standard) 40 as either RG oxide carbonate (FG) oxide, carbonate, a by-product (BP). Sheep fed experimental diets 20 days. Experiment 1, liver, kidney, heart, muscle, spleen collected. serum 3, lambs control FG glucoheptonate 16 days Vitamin B 12 was determined liver 3. Cobalt concentration on all other samples. There no effect intake any experiments. Tissue concentrations increased supplementation three trials. vitamin increasing up added Co. variable but generally decreased did total corrinoid concentrations. Based kidney sulfate, both carbonates more available than that forms.