Diagnostic confirmation of M. hyopneumoniae population exposure determines Day 0 and the start of closure, which is the first of two key time points in a herd closure and medication program.

To “confirm” gilt or previously naïve breeding herd exposure, timing of diagnostics should be based on the replacement gilt exposure method. PCR should be used for detection of M. hyopneumoniae genetic material in deep tracheal secretions.

All samples should be tested individually at this time point to determine if at least 85% of samples are positive. It is highly recommended to obtain a sequence of the genetic material from these samples. Sample pooling is not advised in this high-prevalence scenario. In certain circumstances, pathogen-specific serological evidence could inform exposure in the existing endemic breeding herd, however, results should be interpreted with vaccination status in mind. 

The “herd” is defined on Day 0, which includes the sow farm AND all females confirmed M. hyopneumoniae exposed in on-site/off-site GDUs. There must be NO additions to gilt pool populations, including saving back internal replacement gilts or bringing in teaser boars.