The relative biological availability of Mn in reagent-grade (RG) Mn sources was tested using 41 Rambouillet crossbred wether lambs in a completely randomized design. Lambs were fed a basal corn-soybean meal-cottonseed hull diet (37.6 ppm Mn, DM basis) or this basal diet supplemented with 0, 1,500, 3,000 or 4,500 ppm Mn from RG MnSO4.H20 or 3,000 ppm Mn from RG MnO, MnO2 and MnCO3. Feed intake w...