Determining the dynamics of maternally derived antibodies in piglets prior to vaccination against porcine circovirus type 2.

Porcine circovirus type 2 (PCV2) is the major causative agent of porcine circovirus-associated disease. We investigated the dynamics of maternally derived anti-PCV2 antibodies (MDA) in 40 piglets born to five healthy, unvaccinated sows on a Japanese swine farm. Anti-PCV2 antibody levels were measured by ELISA from birth to 19 days of age and analyzed together with serum total protein and IgG concentrations. Data were stratified by sow, and uncertainty was estimated using sow-cluster bootstrap analysis. The S/P ratio increased after colostrum intake, peaked at 1-3 days of age, and then declined exponentially until day 19. These findings characterize pre-vaccination anti-PCV2 MDA kinetics and indicate that serum total protein at birth may reflect passive immune status.