dEstimating selenium status. Although the importance of selenium in ruminants has been recognised for over 30 years, problems associated with selenium deficiency are still frequently identified in grazing livestock operations. There is a growing diversity of tools available for the management of selenium deficiency giving rise to diagnostic and therapeutic dilemmas for the veterinary practitioner. There is no single test for selenium adequacy which can be considered superior in all diagnostic situations because the method of choice depends on the objective of the testing procedure.