Two studies including a total of 59 heifers were conducted to determine the extent and duration of either the protection against a fetal BVDV infection or the presence of BVDV neutralising antibodies after vaccination with PregSure((R)) BVD, an inactivated BVDV type I vaccine. Following the primary vaccination schedule consisting of two injections at a 3 week interval the fetal protection rate was 100% using a challenge model that caused fetal infection in 100% in the control heifers. The duration of the protection was demonstrated at 6 months. Furthermore, vaccination also clearly reduced signs associated with BVDV infections, such as BVDV viraemia and nasal excretion. A single booster injection given 12 months after the primary vaccination course stimulated a strong memory response in BVDV neutralising antibodies even exceeding the response seen after the initial vaccination regime.