Prediction of genital health status of cows by exfoliative vaginal cytology

Abstract

Exploration of exfoliative vaginal cytology (EVC) was conducted to detect subclinical uterine infection (SUI) in clinically normal dairy cows and to evaluate the impact of anoestrus and repeat breeding (RB) on reproductive performance. Fifty indigenous and crossbred cows were examined during the first visit (V1). Clinically normal cows (n = 23) were selected based on the absence of disease signs during external examination. Genital discharge was assessed through visual inspection for abnormalities, with or without a history of anoestrus or repeat breeding. All cows were re-examined at the second visit (V2) and subsequently monitored for a minimum of eight months, until they either became pregnant or were culled. EVC was used to establish diagnostic criteria for SUI, based on factors associated with reduced pregnancy rates. At V1, a positive EVC result defined as >45% polymorphonuclear leukocytes (PMN) or an equivalent proportion of exfoliative vaginal cells was significantly associated with lower pregnancy rates and was considered indicative of SUI. At V2, a positive EVC result of >65% PMN or a similar proportion of exfoliative vaginal cells also identified cows with SUI. Cows showing various types of vaginal discharge with exfoliative vaginal cells, particularly those with mean PMN values >45%, were predominantly in anoestrus. In contrast, cows with PMN values >60% were classified as repeat breeders, compared to those without SUI. Given that EVC involves vaginal swab collection and cytological staining, it offers a diagnostic approach with predictive value for pregnancy risk. The findings suggest that SUI, as diagnosed through EVC, is associated with reduced pregnancy rate in dairy cows.

Bang. vet. 2025. Vol. 42, No. 1 – 2, 28 – 37