Color Doppler provides a reliable and rapid means of monitoring luteolysis in female donkeys.

The research paper studies how Color Doppler can effectively monitor the process of luteolysis in female donkeys. The researchers measured plasma progesterone concentration, luteal blood flow, and luteal cross-sectional area before and after administering a drug that induces luteolysis, and found strong correlation between these variables and the stage of luteolysis.

Objective of the study

• The overall objective of the study was to examine the utility of Color Doppler as a tool for monitoring luteolysis in female donkeys (Catalonian jennies) for successful artificial reproductive technology applications.

Methodology

• The study was designed in two experiments. In the first experiment, data was collected daily for 4 days after a drug inducing luteolysis (dinoprost thromethamine) was administered. Observations were made on changes to plasma progesterone concentrations, luteal blood flow and Corpus luteum cross-sectional area (CL-CSA).
• The second experiment focused on the first 24 hours after the drug administration since most luteolytic activity seemed to occur during this time in the first experiment.
• The monitored variables were not only measured but also correlated with each other and the time of sampling.
• The drug was administered on Day 10 following ovulation.

Main Findings

• For all measured variable, values decreased over time after the administration of dinoprost thromethamine.
• Within the first 24 hours after the drug administration, an increase in luteal blood flow was observed between 0 and 3 hours, followed by a progressive reduction.
• Plasma progesterone and CL-CSA values also gradually decreased from the time of drug administration.
• Negative correlations were found between all variables and the time of sampling – indicating that the parameters decreased over time.
• Conversely, positive correlations were observed between plasma progesterone, CL-CSA, uterine tone, and luteal blood flow – suggesting these metrics were interconnected during luteolysis.
• A strong correlation was recorded between plasma progesterone and luteal blood flow, indicating the luteal blood flow was closely related to the progesterone concentration.

Conclusion

• The study concluded that both plasma progesterone and CL-CSA reduced after induced luteolysis in Catalonian jennies.
• Contrary to what happens in mares, an increase in luteal blood flow soon after induced luteolysis, similar to that seen in cows, occurs in Catalonian jennies.
• Because the luteal blood flow, as evaluated by color Doppler, was closely related to the plasma progesterone concentration, color Doppler provides a quick and easy method to examine the state of luteolysis.