effect of the commercial mixed live newcastle disease and infectious bronchitis vaccines and the use of two separate vaccines given simultaneously on systemic antibody responses

background and aims: the objective of this study was to investigate the effects of newcastle disease and infectious bronchitis vaccination programs in chickens. materials and methods and results: in the present study, 225 day-old broiler chicks divided into 5 groups. the groups were submitted to vaccinations, except for the non-vaccinated control group. the chickens in the groups 1 were kept as a control group and did not receive vaccine. the chickens in the group 2 were vaccinated with commercial mixed vaccine. the chickens in the groups 3 were vaccinated with two separate vaccines simultaneously. the chickens in the group 4 were vaccinated with single nd vaccine. the chickens in the groups 5 were vaccinated with single ib vaccine. sera were collected at 18 and 45 days of age and submitted to serologic tests to assess antibody levels. conclusion: results demonstrate that there is not any significant statistical difference between the vaccinated groups.