Is it possible to counterbalance deficiencies or imbalances in cobalt, copper and/or molybdenum in forage based diets by including more and other plants?

To investigate whether species other than perennial grasses may contribute to a more balanced trace element supply for livestock, three studies have been conducted in coastal areas of Norway. From two series of field trial samples of green fodder crops were collected. Fodder vetch, broad beans and lupin may improve the supply of Co but do not solve severe deficiencies. None of the investigated species appeared to have the potential to counterbalance severe deficiencies in Cu and/or Mo. In a third study, samples of common dicotyledonous forbs and leaves from trees were collected from semi-natural pastures. Rumex species and tree leaves were high in Co (0.39-1.1 mg Co kg DM-1) and may be good sources for Co to grazing animals. Ranunculus repens was relatively high in Cu (10-13 mg kg DM-1) whereas the Cu:Mo ratio was not consistently high. Tree leaves on the other hand, would counterbalance a low Cu:Mo ratio.