RÉSUMÉ
@#There are many infectious animal diseases in Turkey and generally, vaccination is the primarly control strategy to combat them. However, it is difficult to apply all vaccines in a definite period in the field due to limitations of the labor and finance. Rapid vaccination and effective use of labor can be possible with the help of simultaneous vaccine administrations. The study aims to show the effects of simultaneous foot-and-mouth disease (FMD), peste des petits ruminants (PPR), sheep pox and goat pox (SGP), and bluetongue (BT) vaccine administration on the antibody response of sheep. For this aim, 30 sheep were divided into one experiment and 5 control groups. Blood samples were collected in each group at 0, 30 and 60 days post-vaccination (DPV). Immune response was measured with virus neutralization test (VNT) and, liquid phase blocking ELISA (LPBE) for FMDV; VNT for BTV and PPR. A live virus challenge study was performed to determine the immune response of SGP vaccine. As a result, antibody titers for each vaccine agent decreased on 60 DPV with the simultaneous vaccination except FMD. The difference between means of antibody titer decrease with single and simultaneous vaccinations is significant especially for BTV and PPR vaccines at 60DPV (p<0.05). Briefly, this decreasing immune response of three live vaccines can be explained with the development of the interference, administration of these vaccines from the same injection site, the effect of cytokines, especially IL-10 effect of SGP vaccine. It was concluded that four vaccines can not be used simultaneously in sheep.