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

• Published in: Theriogenology 2018-09, Vol.117, p.7-15
• Main Authors: Thompson, Renee L., Gunn, Allan J., Stephen, Cyril P., Ip, Heather, Brookes, Victoria J.
• Format: Article
• Language: English
• Subjects: Endometrial biopsy; Equine; Lavage; Uterine pH; Vinegar
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2018.05.014

Uterine luminal pH has been demonstrated to be a valid indicator of uterine health in species such as cattle and sheep. However, research regarding uterine luminal pH in equines is lacking. The objectives of this study were to assess uterine luminal pH in mares during the estrous cycle, and evaluate the effect of dilute vinegar lavage on both uterine luminal pH and endometrial health. The study was conducted using a randomized block design in which eight mares (four Thoroughbred and four Standardbred) were aged matched then randomly assigned to two groups. Endometrial biopsies were taken from each mare prior to trial commencement. The treatment group (n = 4; 1 Thoroughbred, 3 Standardbreds) received a uterine lavage of one liter dilute vinegar (20 mL of vinegar in 1 L saline) every second day during each estrus period throughout the trial. Control group mares did not receive a uterine lavage. Uterine luminal pH measurements were recorded in all mares in both groups for a period of up to 10 min immediately prior to lavage (0 h), one hour and 24 h post lavage (same time points in control group mares as if they had been treated). Diestrus uterine luminal pH measurements were recorded once between days 6–10 post-ovulation. Endometrial biopsies were repeated from all mares at trial completion. Mean uterine luminal pH ranged from pH 5.3 to 7.6 and was significantly lower during diestrus compared to estrus (P