Monitoring antibodies to Mycoplasma hyopneumoniae in sow colostrum - a tool to document freedom of infection

In a survey in Finland in 1995, 14919 colostral whey samples from 530 Farro wing herds were analysed by a monoclonal blocking-ELISA to detect antibodie s to Mycoplasma hyopneumoniae (M. hyopneumoniae). Antibodies were detected in 274 (1.8%) samples and in 42 herds (7.9%). The median prevalence of sows with antibodies in seropositive herds was 28.2% (range, 2.7-100%). Accordi ng to clinical and pathological follow-up in finishing herds in 1996, all o f the farrowing herds which were seronegative in 1995, were truly non-infec ted with M. hyopneumoniae. In acutely infected herds, samples collected ear lier than 2 h after farrowing were 3 times more likely to contain antibodie s than samples collected 2-12 h after farrowing (odds ratio, 3.0; 95% CI, 1 .4-6.6). Repeated freezing or spoilage of the colostrum samples did not cau se biologically relevant problems for the ELISA. Antibodies to M. hyopneumo niae were shown to persist up to 3 years in some sows. As a conclusion, col ostrum samples were very sensitive samples for the screening of herds for M . hyopneumoniae infection and possibly also for a regular surveillance.