Abstract: An experiment was performed using 317 piglets to investigate the changes of antibody level before(day 20) and after(day 35 and 38) vaccination with classical swine fever(CSF) vaccine on day 21 after birth.The results showed that the antibody levels of piglets of different ages and different dams were significantly different(P 0.01).There was strong interaction between ages and sows.The change pattern between ages differed in piglets of different sows and was dependent on the antibody level on day 20(range from 0.039-0.897 in different dam families).Piglets with antibody level on day 20(0.102 had their antibody level steady increased on day 35 and 38.Piglets with antibody level on day 20 between 0.102 and 0.411 had their antibody level decreased on day 35 and then increased on day 38.Piglets with antibody level on day 20(0.412 had their antibody level steady decreased on day 35 and 38.These results suggest that for piglets with antibody level lower than 0.4 vaccination can enhance their initiative immune ability,while for those with antibody level higher than 0.4 vaccination would reduce their initiative immune ability because the vaccine would be balanced out by the existing antibody and therefore it is suitable to delay their first immunization.

Key words: Classical swine fever(CSF), Maternal antibody, Competitive, ELISA

CLC Number: 

• S858.5