Serum antibodies and shedding of infectious porcine circovirus 2 into colostrum and milk of vaccinated and unvaccinated naturally infected sows.

Serum antibodies and shedding of porcine circovirus type 2 (PCV2) into lacteal secretions were examined in naturally infected sows. Total (TA) and neutralising (NA) antibodies against PCV2 were evaluated in serum and colostrum from 20 vaccinated (Vac) and 21 unvaccinated (N-vac) sows. Anti-PCV2 IgA titres and PCV2 infectious titres were determined in colostrum and milk. All sows had high TA and NA levels in serum and colostrum. Infectious PCV2 was detected in 22/41 colostrum samples (7/20 Vac and 15/21N-Vac sows) and 5/20 milk samples (1/5 Vac and 4/15N-Vac sows). Anti-PCV2 IgA was found in high levels in colostrum and varying levels in milk. Infectious PCV2 may be present in milk and colostrum of naturally infected sows, even in the presence of NA.