Immunization program of inactivated bivalent influenza vaccine (H5+H9) in breeder chickens.

To study the protective efficacy and the optimal immunization procedure of the H5+H9 bivalent inactivated vaccine(H5N1 Re-1 and H9N2 Re-2)in the breeder of Yellow Feather chickens,the bivalent vaccine immunized Yellow Feather chickens by different immunization procedure.Results showed that the vaccinated chickens have the similar antibody variation to H5 and H9 but antibody titer of H9 hemagglutinin-inhibition(HI)is little higher than its H5 HI.The HI antibodies against H5 and H9 became detectable and increased at 1 to 2 week post-vaccination(p.v.)and reached a peak about 3 to 4 weeks p.v.After the secondary and third immunization,HI antibody titers quickly ascended and reached 10log2 at 4 weeks after the third immunization.After the secondary immunization,values of the dispersion of HI antibody changed little.The breeding chickens were vaccinated third before egg-laying.The first immunization of these chickens is at the 14 day-old and injected with 0.3 mL per chicken.The secondary immunization is at the 56 day-old and injected 0.5 mL per chicken.The third immunization is at the 119 day-old or before egg-laying.