peer reviewed ; Previous surveys demonstrated the association between the bovine enterotoxaemia syndrome and proliferation of Clostridium perfringens toxintype A. The purpose of this study was to establish rules for vaccination of calves against the a toxin. Bovines were Belgian Blue (BBB) or BBB x Charolais originating from 6 farms with no history of clostridial vaccination. One hundred and thirty-three calves were injected with Tasvax (R) and 70 with Miloxan (R) at one and two months of age, while 94 calves received no vaccine. To study sero-conversion in calves born from vaccinated dams, 67 cows were vaccinated with Tasvax at 7 and 8 months pregnancy. Twenty-nine calves born from these cows were vaccinated at one and two months of age with the same vaccine while 38 calves were not vaccinated. The results of these 67 calves were also compared to the results obtained from the calves born from non-vaccinated cows and vaccinated with Tasvax. Anti-alpha toxin antibodies were measured using an indirect ELISA assay. Anti-alpha toxin antibodies are naturally present in the serums of non vaccinated animals and are transferred to the newborn calf by the colostrum. The two vaccinal injections cause sero-conversions in proportion of the total amount of immunogen received. The best protocol for calf vaccination is a first injection at one month of age, followed by a booster injection four weeks later. Boosters every six months are necessary to maintain a high level of antibody. In case of early problems (< 2 months of age) of enterotoxaemia in a farm, high antibody titres are obtained only following the vaccination of the pregnant cow and colostral transfer. Unfortunately this protocol is not compatible with vaccination of the calf itself. ; Des études précédentes ont démontré l’association de l’entérotoxémie bovine avec une prolifération de Clostridium perfringens toxino-type A. Cette étude a pour but de formaliser les règles essentielles d’utilisation des vaccins dirigés contre la toxine a de C. perfringens afin ...