Evaluation of the immune response in calves vaccinated with commercial vaccine against pi3 and brsv on a farm in western romania

Respiratory diseases in calves are of significant importance, both globally and locally.This study aimed to compare two calf vaccination protocols on a dairy farm in Western Romania, a protocol already used on the farm and a new one, to determine the optimal time for calf vaccination and the effectiveness of the vacci-nation. To assess the immune response in calves vac-cinated against Bovine Respiratory Syncytial Virus (B RSV) and Bovine Parainfluenza Virus (PI3), we mea-sured the post-vaccination antibody titre using the in-direct ELISA method. The values of serum proteins in the first 24 hours in the calves from the two groups had values above 5 g/100 ml, which demonstrates a good passive transfer of maternal antibodies as a re-sult of colostrum. High levels of maternal antibodies, which persisted during the study period, interfered with post-vaccination antibodies and led to decreased anti-BRSVantibody titres in both protocols.