Effect of follicular wave synchronization using a progesterone-releasing intravaginal device-based protocol on in vitro embryo production in Bos taurus cows subjected to 14-day intervals ovum pick-up

by Selleckchem | Feb 11 2024

Follicular wave synchronization (FWS) before ovum pick-up (OPU) is one of the strategies used to improve the efficiency of in vitro embryo production (IVP). This study aimed to evaluate the effect of FWS on the total follicular number, cumulus-oocyte complex (COC) recovery, and in vitro embryo development in Angus cows (n = 33) subjected to OPU with 14-day intersession intervals. Additionally, it was also evaluated the presence of carryover effects given the short intersession interval used. The experiment was run as a 2-treatment (FWS vs. Control) x 2-period (1 vs. 2) crossover design. Animals in the FWS group received an intravaginal progesterone implant (1gr), estradiol benzoate (2 mg), and D-cloprostenol (150 μg) on day 0 and the OPU was performed on day 5. Control group animals did not receive any hormone treatment. The FWS increased the number of 6-10 mm follicles (P = 0.05), but it decreased the COC recovery rate (P < 0.01). The FWS did not affect the total or frozen embryo numbers (P = 0.49 and P = 0.17; respectively), but it increased the total blastocyst cell number (P < 0.01). A carryover effect was found on the total and < 6 mm follicles number (P = 0.10 and P < 0.01; respectively), and on the regular, atretic, viable, and total number of COC (P = 0.01, P = 0.08, P = 0.02 and P < 0.01; respectively). We concluded that the FWS increased the quality of embryos after OPU with 14-day intersession intervals in Angus cows and that this kind of OPU/IVP scheme enabled the existence of a carryover effect, especially on the follicle number and COC morphology.

Comments:

This study on follicular wave synchronization (FWS) before ovum pick-up (OPU) in Angus cows sounds intricate and comprehensive. FWS protocols are crucial in enhancing in vitro embryo production (IVP) efficiency, and your research appears to have interesting findings.

The administration of progesterone, estradiol benzoate, and D-cloprostenol resulted in increased 6-10 mm follicle numbers, indicating FWS's effectiveness in stimulating follicular growth during the protocol. However, it's noteworthy that the FWS decreased the cumulus-oocyte complex (COC) recovery rate, which might suggest a trade-off between quantity and quality.

The observed increase in total blastocyst cell numbers post FWS indicates a potential positive impact on embryo quality, despite no significant changes in total or frozen embryo numbers. This is a crucial finding as it underscores the importance of assessing embryo quality beyond mere quantity.

The identification of carryover effects from the FWS protocol on various follicle numbers and COC morphology suggests a lingering impact of the synchronization process, especially on the reproductive structures involved in oocyte development. This insight into carryover effects is valuable for understanding the sustained influence of hormonal interventions on subsequent follicular development and COC quality.

Your study's conclusion emphasizes the positive influence of FWS on embryo quality in Angus cows following OPU at 14-day intervals. Additionally, it sheds light on the existence of carryover effects, particularly regarding follicle numbers and COC morphology. These insights contribute significantly to optimizing protocols for IVP in bovine reproductive technologies.