Cryptosporidium parvum (C. parvum)-caused calf diarrhoea (scours) is widespread and leads to calf mortality in cattle industries worldwide. A recent discovery of a glycopeptide epitope on the Cryptosporidium parasite recognized by a monoclonal antibody has led to the development of a new vaccine. It was designed for cows to pass on passive immunity to their neonatal calves. This vaccine has been demonstrated to be safe and efficacious in pre-clinical studies. In the process of marketing registration, two clinical studies were conducted with this vaccine on 16 commercial dairy and beef farms collecting data, assessed by the European Medicine Agency. In these studies, its effectiveness in the field was evaluated. The natural challenge and clinical disease caused by Cryptosporidium parvum in the calves in these studies was, however, not high enough to show a significant reduction of most of the clinical signs, although all trends were in favour of the vaccination groups. Nonetheless, the duration of the diarrhoea episodes of the dairy calves was significantly shorter in the vaccination group. Additionally, the levels of Gp40 antibodies in the blood of the calves was notably higher in the vaccination groups, demonstrating the principle of passive immunization. Overall, this vaccine, which can be used concurrently, non-mixed with Bovilis^® Rotavec^® Corona, introduces an additional approach to mitigate the impact of C. parvum infections in neonatal calves.