Abstract: Classical swine fever caused by classical swine fever virus is a high fever, bleeding as the main feature of the potent, highly contagious disease and still widely popular in China. Vaccination is the most fundamental methods of the disease prevention and control, in order to identify the immunization effects of classical swine fever in large-scale pig farms of Shanxi, the classical swine fever immune antibody of 465 breast-feeding pigs, 456 nursery pigs, 436 finishing pigs and 419 sows in the 42 scale pig farms of eight cities were detected by ELISA kits. The test identified the antibody positive rate of breast-feeding pigs averaged of 70.11%, the antibody positive rate of nursery pigs averaged 40.57%, the antibody positive rate of finishing pigs averaged 50.22% and the antibody positive rate of sows averaged 69.69%. It was seized that the immune antibody of the swinery detected was not ideal, especially lower antibody levels in nursery pigs. While the immune antibody of 133 breast-feeding pigs, 110 nursery pigs, 105 finishing pigs and 135 sows with four different types of classical swine fever vaccine immunity in the 12 large-scale pig farms was detected. The results showed that porket were hyper immunized firstly six copies of classical swine fever efficient cell-free vaccine at birth, then piglets were immunized secondly four copies at two 21-day-old, at last piglets were immunized thirdly two copies at 60-day-old, besides, it was best that postpartum sows were immunized with fetal immunity after 21 days, so that the antibody positive rate of nursery pigs could reach 89.29%, therefore, the mortality of nursery pigs reduced evidently and the growth and development of pigs walk gradually up to normal after using this immune method in some pig farms, while the use of the worst method that the first immunization of piglets between 28-day-old and 35-day-old with four copies of classical swine fever normal cell-free vaccine after ablactation, the second immunization of 60-day-old piglets with two copies, and the immunization of postpartum sows with fetal immunity after 28 days did not sfpread and exploit. Through the study of immunization effects on classical swine fever in some large-scale pig farms of Shanxi, the immune effect of classical swine fever and the best methods of immunization were identified in some large-scale pig farms. It could give a basis for prevention and control of classical swine fever in pig farms.

Key words: Shanxi; scale pig farms; classical swine fever; immune antibody; study