Investigation on the safety and immune response after vaccination of pregnant cows with a temperature-sensitive bovine diarrhoea virus (BVD) vaccine strain (Rispoval R BVD/MD)

摘要

Nine cows were vaccinated in early pregnancy with a temperature-sensitive vaccine strain of bovine diarrhoea virus (BDV) designated 'RIT 4350'. The vaccine was applied parenterally in 2 doses of a commercial vaccine administered 4 weeks apart. BDV vaccine virus was not reisolated from blood samples taken shortly after the 2 doses of vaccine. Transplacental infections caused by vaccine virus did not occur in any of the vaccinated cows. Nine calves were born clinically healthy and were virologicallyand serologically negative. In 8 of 9 cows the vaccination resulted in seroconversion but only to low titres of homologous antibodies. A cross-neutralizing effect to heterologous BDV virus (reference strain NADL) was detected for a short period in only 1out of 8 vaccinated cows. At time of birth only 3 out of the 8 serologically positive cows still revealed homologous antibodies with low titres. The results are reviewed with respect to a possible insufficient protection in breeding cattle after use ofthis vaccine. The possible reasons for the unsatisfactory immune response and the consequences for BDV control measures according to the official guidelines are discussed.