An Antibody Survey for Field Application of Hog Cholera Live Vaccin

An antibody survey was conducted on three groups of swine inoculated with one and two doses of hog cholera livve vaccine and with inactivated and live vaccine, simultaneously, respectively. It revealed that the neutralizing natibody (NA) production after inoculation was affected considerably by the maternal antibody (MA) titer determined at the time of inoculation.In the one-dose inoculation group, NA was produced to the utomst to persist when MA titer was lower than 1: 4 at the time of inoculation, but did not increase in titer when MA titer was higher than 1: 64.In the two-dose inoculation group, NA titer increased to persist after inoculation with the second dose even when MA titer was 1: 64 or higher. In the simultaneous inoculation group, composed of adult sows on breeding, the decrease in NA titer was very slow, remaining in the order of 1 to 3 tubes even 18months after inoculation.In piglets, MA titer was reduced to half in 8 to 11 days. It was presumed that the difference in MA titer among the piglets of the same litter might be in the orderof 2 or 3 tubes.These results indicate that it is desirable to perform the initial inoculation of live vaccine at the age of 60 to 65days. It is necessary to carry out booster inoculation in piglets which are assumed to have a high MA titer.