Real-time characterization of the uterine blood flow in mares before and after artificial insemination.

The research article focuses on understanding the effects of age and endometrial degeneration on the uterine blood flow in mares directly after artificial insemination. The findings suggest that there are immediate changes in uterine vascular perfusion and mesometrial pulsatility index as a response to semen infusion, with reduced uterine blood flow associated with endometrial degenerative changes irrespective of the mare’s age.

Study Design

• The experiment was split into two studies. The first study aimed to characterize the uterine blood flow in mares that exhibited minimal, moderate, or severe endometrial degenerative changes. The second study aimed to evaluate the effect of age on uterine blood flow, using young and old mares for the experiment.
• In both studies, uterine vascular perfusion and mesometrial pulsatility index (PI) were evaluated every hour from the moment immediately before artificial insemination (AI) to 12 hours after.

Major Findings

• In the first study, an evident and temporary increase in uterine vascular perfusion was noticed between one and three hours in all three endometrial groups. Mares with severe endometrial changes showed greater mesometrial PI than those with minimal changes, indicating a reduced uterine blood flow.
• In the second study, a brief increase in uterine vascular perfusion was again seen in both young and old mares in the first hour post-breeding. However, the mesometrial PI of both age groups was found to be similar and constant during the first 12 hours after AI.
• These outcomes demonstrated for the first time, the immediate changes in uterine blood flow due to semen infusion. Furthermore, a strong correlation was found between reduced uterine blood flow during the post-breeding period and endometrial degenerative changes, regardless of the mares’ age.

Implications

• This study provides important insight into the understanding of how age and endometrial health status can influence uterine blood flow during the post-breeding period in mares.
• The presented findings could be significant for equine reproductive health research and could influence future directions of study or treatment protocols for equine artificial insemination.