On a number of farms on which the young stock showed symptoms of copper deficiency, copper was injected in the form of the following compounds: Biodalbene, Robasfer and Coprin. The effects of the agents administered on the copper status of the animals were compared. This showed that there only is an effect when the concentration of copper in the blood is low (less than or equal to 50 mg/l. of blood serum). The most satisfactory results were obtained by administration of Coprin (100 mg as copper-calcium edetate) followed by Robasfer (40 mg. of copper at the recommended dosage of 25 ml), administration of Biodalbene failing to produce any improvement in copper status, which hardly could be expected by such low copper content (0.135 mg/ml). When there are practical objections to administering copper in the form of concentrates or top dressing to young stock, it is entirely practicable to use the compounds Coprin and Robasfer for this purpose.