[Vaccination trial against Aujeszky's disease: development of antibody titers in sow serum, colostrum and the serum of suckling piglets and the influence of maternal antibodies on the serologic vaccination reaction of weaned piglets].

In two vaccination trials the influence of different vaccination schedules of gifts on the colostral immunity of their offspring and the influence of maternally derived antibodies on the active formation of antibodies after vaccination in weanlings were tested. It could be shown, that vaccination of gifts 6 and 3 weeks prior to farrowing led to higher blood levels of maternally derived antibodies in their offspring than vaccination earlier during gestation or prior to mating. Correlation between antibody level of sow, colostrum and offspring was good, the halflife of the antibodies was 11.3 days. Low levels of maternally derived antibodies did not influence the active formation of antibodies after vaccination, higher levels reduced antibody-formation, but did not suppress it completely. Sow colostrum and blood of piglets are generally adequate substrates for the serologic control of breeding units regarding Aujeszky's disease. Existing problems are mentioned. The results of this study are discussed concerning their importance for the eradication of Aujeszky's disease with vaccination programs.