Abstract: In order to prevent duck short beak and dwarfism syndrome effectively, a purified egg yolk antibody against novel duck parvovirus （strain SD03） was prepared. Agar diffusion test and neutralization test were used to determine the titer of egg yolk antibody. The growth and decline law of egg yolk antibody was analyzed to determine the optimal immune program, highly immunized egg collection time and clinical application titer standard. The clinical application effect of three batches of the test samples was evaluated. The results showed that a purified egg yolk antibody against duck short beak and dwarfism syndrome was successfully prepared. Both of the agar diffusion titer and neutralizing titer of the antibody reached the peak on the 15^th day of the third immunization, which were 1 ∶ 64 and 1∶640, respectively. Therefore, the collection time of highly immunized eggs was determined to be 15 days after the third immunization. After the completion of the basic immunization, the best enhanced immunization time was once every 30 days. The results showed that the titer of the antibody could be maintained at a high level after one time booster immunization. The agar diffusion titer of the antibody ≥ 1 ∶ 32 or neutralizing titer ≥ 1 ∶ 320 were determined as the clinical application titer standard. The results of clinical application tests of three batches of samples showed that the purified egg yolk antibody against duck short beak and dwarfism syndrome was safe, and had good prevention and emergency prevention effect on duck short beak and dwarfism syndrome.

Key words: duck short beak and dwarfism syndrome, egg yolk antibody, titer determination, clinical application