A novel method for the diagnosis of bacterial contamination in the anterior vagina of sows based on measurement of biogenic amines by ion mobility spectrometry: A field trial.

To determine if postpartum subclinical infection occurs in sows, a novel device was used to diagnose such bacterial contamination of the vagina. The device was based on the measurement of biogenic amines by ion mobility spectrometry (IMS). The device is portable and results are obtained within 1 min. Vaginal swabs were taken from 449 sows before first-estrus insemination and 133 (29.6%) had elevated biogenic amines and were considered positives. Sixty-one percent of the sows became pregnant following post-weaning first estrus insemination. Positive scores had no apparent effect on fertility rate which was 64%. Of the sows that became pregnant, 197 (69.1%) were diagnosed as "negative" and 88 (30.9%) were "positive", of which 37 received treatment with antibiotics and were termed "positive treated". The average live-born piglets litter size of the "positives" was 10.02 which was significantly lower (P = 0.031) than the "negative" sows (11.06) while "positive treated" sow average litter size was close to the "negative" (10.56). In conclusion, it was demonstrated that subclinical anterior-vaginal bacterial contamination in lactating sows about 2 wks postpartum is a condition that affects sow litter number and could be determined by the measurement of vaginal biogenic amines with IMS.