Assessment of uterine luminal pH in mares and the effect of dilute vinegar lavage on uterine luminal pH and endometrial health.

The paper reports a study exploring the acidity levels in the womb of female horses (mares) during different stages of their sexual cycle, and how washing the uterus with diluted vinegar impacts these acid levels and overall uterine health.

Research Context

• In past studies involving other species like cattle and sheep, the pH (a measure of acidity) of the uterine fluid has been shown as an accurate measure of the health of the uterus.
• A gap in research was identified for a similar study in mares.
• The current research attempts to measure the uterine pH in mares during their ovulation cycle (estrus cycle), and to further understand if washing the uterus with dilute vinegar affects the pH and overall uterine health.

Research Methodology

• The study was carried out as a randomized block design, featuring eight mares – four Thoroughbred and four Standardbred.
• The eight mares, after being paired by age, were divided into two random groups – a control group, and a group treated with uterine lavage (womb wash) using dilute vinegar every alternate day during their estrus period.
• Initial endometrial biopsies (endometrial tissue sampling) were carried out before starting the study and another set was taken at the end of the study.
• pH measurements from both groups were taken at specific intervals – before the wash, after one hour, and after 24 hours on every second day of their estrus period.
• pH measurements were also taken once during their non-reproductive stage (diestrus) between 6-10 days after ovulation.

Research Findings

• The pH of the uterine fluid varied between 5.3 and 7.6 and was found to be consistent with the stages of the estrus cycle—it was higher during the estrus period and lower during the diestrus period (P < 0.001).
• The variation was linked closely with the estrous cycle, with a pH increase of 0.03 units each day from 6-10 days post-ovulation through to ovulation (P < 0.001).
• The washing of the uterus with diluted vinegar, however, showed no significant effect on the uterine pH (P > 0.05).
• On investigating the abundance of different cell types in the endometrial biopsies, it was discovered that the treatment group experienced a significant decrease in certain types of immune cells (P = 0.03).
• The mares in the treatment group also showed a decrease in white blood cells (P = 0.05).

Conclusion

• While the dilute vinegar washing didn’t significantly alter the uterine pH, there was a notable improvement in endometrial biopsy scores, suggesting an enhanced health status.
• The research indicates that the change could be due to the dilute vinegar or the effect of the washing itself, warranting further research to distinguish their individual impacts.