[Selenium deficiency as a cause of secondary retention of the placenta in a herd of dairy cattle].

A farm is described, on which the placenta was retained in approximately forty per cent of the cows and on which selenium deficiency (0.03 +/- 0.010 micrograms/ml) and unduly reduced activity of glutathione peroxidase (GSH-Px) in the erythrocytes (65.2 +/- 26.4 u/g Hb) were observed. When 0.5 mg of Se per kg of dry matter of a mixture of concentrated feeds were added, the concentrations of Se and GSH-Px were restored to normal and the symptom consisting in retained placentae disappeared. This incident shows that selenium deficiency occurs in the Netherlands.