Ultrasonographic monitoring of 103 recipient mares of different reproductive status during the first 30 days after embryo transfers.

The research investigated the effectiveness and outcome of embryo transfers in 103 recipient mares. It assessed the outcomes in relations to the reproductive status of the mares and found no significant differences in the rate of embryo growth among the different groups.

Research Goals

• The objective of this study was to monitor the success rate and outcome of embryo transfers in recipient mares, as well as any potential impact of the reproductive status of the mares on the process and outcomes.

Methodology

• 103 mares, divided into three categories, served as recipients for the embryo transfers. The categories included 31 nulliparous mares (first-time mothers), 34 pluriparous and lactating mares, and 38 pluriparous and non-lactating mares.
• Embryos were obtained from ten pluriparous donor mares and transferred to the recipient mares.
• Embryo recovery was conducted eight days after ovulation.
• Confirmation of pregnancy occurred six days post-transfer via ultrasound, with the embryos measured ultrasonographically on days 12, 14, 16, 18, 20, 25, and 30 after the embryo transfer.

Findings

• Of 200 flushes, 115 embryos were collected, of which 103 were viable and 12 degenerate.
• From the 103 total embryo transfers, 51 pregnancies were confirmed within 30 days of the procedure.
• In terms of success rate per category, 16 out of the 31 nulliparous recipients, 16 out of the 34 pluriparous lactating, and 19 out of 38 pluriparous non-lactating recipients got pregnant.
• The rate of growth of embryos observed between day 12 and day 30 of gestation did not vary significantly among the different mares’ groups.

Implication

• This research suggests that reproductive status (nulliparous vs. pluriparous, lactating vs. non-lactating) does not significantly impact the success of embryo transfer in mares or the subsequent rate of embryo growth.