Abstract

This study was conducted to investigate the effects the interference of ND, AI, IBD vaccines on efficacy of the IBV vaccination program (H120 and Ma5). Three hundred broiler chicks (Ross308) from Al-Haddi hatchery / Babel province were divided randomly into three equal groups, each group contain 100 chicks and treated as follows: the 1^st group; IB vaccine (H120) was given at one day old by intranasal and ocular drop methods, IB vaccine Ma5 strain vaccine was given at age 14 days by spray method. The 2^nd group at one day old IB H120 + ND LaSota alive vaccines strain was given by intranasal and ocular drop method, also given mixed killed vaccine contain ND with AI by S/C injection. At 10 days old alive ND vaccine LaSota strain gives by drinking water. At 12 in day old attenuated IBD vaccine gives by drinking water. At day old IB Ma5 strain vaccine was given using spray method. The 3^ed group: control group without vaccine. Blood samples were collected from jugular vein at 1, 7, 14, 21, 28, 35 and 40 day old to determine the antibody titer against IBV by ELISA test and samples were taken from trachea and kidney for Real- time quantitative -PCR (viral load) at 21 and 35 days old. All groups were challenged with local virulent IBV isolate (IBV CH Babylon F2 2013) 100×10^6.5 ELD₅₀/ml at 28 days old by ocular and intranasal drop method. Morbidity and mortality were recorded in all the challenged birds. The result show that the significant differences between all groups in different parameters at P<0.05.