Sows Seropositive to Lawsonia intracellularis (LI) Influence Performance and LI Seropositivity of their Offspring

The aim of the study was to test, if seropositivity to L. intracellularis does decline more rapidly in the offspring of Lawsonia intracellularis (LI) positive gilts than in the offspring of LI negative gilts in units infected with endemic Porcine Proliferative Enteropathy (PPE). In a Croatian pigproduction unit late-pregnant gilts were tested by an indirect immunofluorescence antibody (IFA) serum assay for LI. Twenty IFA-positive and 20 IFA-negative gilts were selected. Their 2-weekold piglets (191 from positive gilts, and 192 from negative gilts) were inoculated intragastrically with pure-culture of LI. These animals were tested until 25 weeks of age for seroprevalence of LI. Blood samples were collected at 5, 10, 15, 20 and 25 weeks of age.