Two trials were designed to investigate whether bovine viral diarrhoea virus (BVDV) could be transmitted after the birth of persistently infected calves, even if they were removed immediately after birth. In trial 1, 11 calves were actively exposed to fetal fluids and uterine lochia collected from cows that had delivered calves persistently infected with type 1 BVDV. One calf that was exposed to a sample taken on the day of calving seroconverted. In trial 2, six calves were housed in stables where persistently infected calves were being born and then removed immediately from their dams and from the stable unit within two to three hours. One of four calves in close contact with the cows after delivery seroconverted and one of two calves housed within the same stable unit became infected.