Uterine involution in mares treated with progesterone and estradiol-17 beta.

This research explores the influence of progesterone and estradiol-17 beta injections on uterine involution, or the return to pre-pregnancy state, in mares post-parturition. The findings suggest that the treatment prompts greater gland proliferation and ciliated cell proportion, essentially giving more time for uterine involution in the early postpartum period.

Research Objective

• The primary aim of this study was to evaluate the impact of daily injections of progesterone and estradiol-17 beta on uterine involution in mares following childbirth. The analysis centered on tracking and comparing gland proliferation, gland density, and the proportion of ciliated to secretory cells.

Methods Employed

• Uterine involution in 27 mares was observed and analyzed with the help of bacteriology, histology, and scanning electron microscopy. The mares received daily injections of 150 mg of progesterone and 10 mg estradiol-17 beta within 18 hours of giving birth.
• The results from these treated mares were compared to data from a control group of 24 untreated mares, at about postpartum days 10 or 11.

Results and Conclusions

• The treatment showed a significantly greater uterine gland proliferation (P less than 0.05).
• Gland density was notably higher in mares treated for a period of 6 to 10 days than in mares treated for 2 to 5 days (P less than 0.05).
• The ratio of ciliated cells to secretory cells in the endometrial lining was significantly higher in mares during delayed foal estrus than in mares at postpartum days 10 to 11 (P less than 0.05).
• The proportion of ciliated to secretory cells increased correspondingly with the length of the treatment.
• In conclusion, the treatment with progesterone and estradiol-17 beta provided additional time for uterine involution in the early postpartum period.

This study provides crucial insight into a potential method to manage and optimize uterine involution in mares, leading to better reproductive health.