The prevalence of Mycoplasma hyopneumoniae in pig herds in western Finland based on the demonstration of antibodies in colostrum by ELISA.

Swine enzootic pneumonia causes heavy economical losses in fattening herds. The aim of this study was to get an estimate of the prevalence of Mycoplasma hyopneumoniae in the province of Vaasa in Western Finland. There were 112 farrowing herds randomly chosen for a survey. Farmers were asked to milk colostrum samples from every sow. Owners of 22 herds did not send enough samples for a herd diagnosis. Altogether 1773 samples (mean 18.1 samples/herd) were analysed in an indirect ELISA for antibodies to Mycoplasma hyopneumoniae. Thirty-five herds were concluded to be infected with Mycoplasma hyopneumoniae. In these herds the mean prevalence of samples with antibodies was 16.3% (range 2.3%-70.0%, median 8.6%). The infected herds were significantly larger than the rest of the herds (no. of sows 27.0 vs. 18.4 respectively). The true prevalence of Mycoplasma hyopneumoniae infection in the province of Vaasa was estimated to be somewhat lower than the apparent prevalence of 39%. The application of colostrum serology is discussed.