A trace element solution comprises at least the following metals: zinc; manganese; selenium; and copper; and which comprises a concentration of the metals of at least 90 mg/ml. The solution may comprise the following concentrations: at least 60 mg/ml zinc; at least 10 mg/ml manganese; at least 5 mg/ml selenium; and at least 15 mg/ml copper. The solution may comprise chromium, iodine and chromium.