Piglets acquire passive immunity directly after birth by absorbing maternal antibodies in the colostrum. This protection is almost immediately active. As the maternal antibodies decrease with time, this protection is only effective for the first few weeks after birth. Vaccination or a natural infection are necessary for the young pigs to develop active immunity as the immune system will respond by actively producing antibodies. This protection takes longer to build but lasts correspondingly longer. The duration depends on the individual pathogen. |
