Plasma micro-element concentrations of copper, zinc, iron, and manganese were studied in 25 buffaloes at varying stages of gestation, between 7 months to term and with varying degrees of vaginal prolapse. A similar number of animals, normally pregnant at identical stages and with no previous history of antepartum vaginal prolapse, was used for control purposes. Plasma iron and manganese concentrations in affected animals were similar to values in normal pregnant animals at all stages. However, plasma copper levels were slightly but not significantly lower in affected animals at all stages, whereas plasma zinc concentrations were significantly low in affected animals from 9 months to term. Possible interactions are discussed between plasma copper and zinc levels, on the one hand, and hormones, like oestrogens and cortisol, on the other.