Escherichia cxh stains with pill and enterotoxins p<dwiUe ability were used for vaccine production. The newly cleveloai vaccine was used to irnmunire 56 exjrerimental sows, 2 sows oberved at the laboraxy and 54 sows on two farms. Solid immunity but no side reaction was ohserval. The anti - K88, K99 and 98W antibxly titersarosefrom<1 or1owlevelsto32-2,G48xinsewnorcoktalwheyof immunized tows determined by slide agglutination test, while anti - heat labile enterotoxin antibody titers were 4 x in sewn and? 32x in colc6tral whey by immuncdiffusion test. For piglet that sucked the oalostal of immunized tows, the anti
K88, K9 and 98W antibody titers in sewn were almcct same as thcce of their mother tows. The average anti-heat labile enterotoxin antibody titers of piglet borne from the sow No.1 and2 kept at the laboratory were 3,6x and6x and’7.lx infarmA and B, respectively. Solid goeztion from challenge exposure with 10 rid of 58tY’10 CFUhnl of enterotoxins and pill mixed cell susrension by stomach uike drninistation in piglets were demonsiratl. On the other hand, potency test in mice immunized by intraperitoneal inctulation was also conducted. The survival rate for vaccinated group was 1CO%(20,20)while confrol group was 0% fll 0) aft the P challenge with 0.1 ml cell susgension of enterotoxins and pib, 8-9K)4 8 CFUhril.