Antibody Changes of Commercial Meat-type Ducks Vaccinated with AI Inactivated Vaccines

To evaluated the growth kinetics of H5 AIV HI antibody level and recommend a feasible vaccinal program,commercial meat-type ducks of different day-old were immunized with 2 kinds of AI inactivated vaccines.The results showed good responses were elicited in 3～10 day-old ducks and persisted until 40 day-old.The presence of maternal antibody could interfere with growth of HI antibody and resulted in a blank stage of immunization in 5～7 days around 20 day-old.Recommended procedure of the AIV vaccine was executed beforehand in earlier Oct,when waterfowl have enough time to produce high HI titer just before migratory birds going through routinely.