INFLUENCE OF EXPERIMENTAL YERSINIA ENTEROCOLITICA INFECTION ON THE COURSE OF PREGNANCY IN SOWS - PRELIMINARY STUDIES. CLINICAL AND LABORATORY EXAMINATIONS

The aim of study was to evaluate the effect of oral Yersinia enterocolitica infection on the course and duration of pregnancy, litter parameters, and endocrine milieu in sows depending on the phase of pregnancy at the moment of infection. The studies were performed on 12 pregnant sows, divided into four groups (n=3) and infected per os on the first (33 d of pregnancy -dp), second (54 dp), and third (89 dp) trimester of pregnancy with the pathogenic Y. enterocolitica strain isolated from palatine tonsil of aborted swine foetus. The control group remained uninfected. The most deviations from physiological and clinical norms exhibited sows infected in the third trimester of pregnancy. In this group deliveries happened the latest (118 dp), the number of stillborn piglets was the highest (14.5%), and mean piglet body weight was the lowest (1.1 kg). In all sows from the group, vaginal purulent effluent occurred and lasted about two weeks after parturition. The least numerous litters were observed in group infected in the first trimester (11.1). Haematological examinations revealed only slight leukocytosis in all infected groups during 2 weeks post infection. No significant abnormalities in the concentration of the examined hormones were found but Y. enterocolitica infection could influence P-4 and E-1-S levels of pregnant animals and that influence was dependent on the pregnancy period when the infection happened.