The present invention provides a pharmaceutical and/or veterinary composition comprising a retard release formulation of a Solarium glaucophyllum preparation. The composition further preferably comprises a calcium source. The composition of the invention is suitable to prevent and/or treat hypocalcaemia. Furthermore, the composition is suitable to prevent milk fever in cows. Advantageously, the composition is administered only once before calving so as to prevent the occurrence of mil fever in cows.