Effect of FSH stimulation prior to ovum pick-up on follicular dynamics, oocyte competence, and in vitro embryo production in Ongole cows (Bos indicus)

Abstract

. The current study evaluated the influence of follicle-stimulating hormone (FSH) administration on the stimulation of ovarian follicles, oocyte quality, and embryo production rate in Ongole cows with synchronized follicular wave emergence. Follicular waves were synchronized using 10 μg of gonadotropin-releasing hormone (GnRH), followed by FSH administration (250 μg) in three divided doses of 125, 75, and 50 μg at 48, 60, and 72 h post-GnRH administration, respectively. Although the total number of follicles was similar in both groups, the hormonal stimulation regimen increased ( P < 0.01) the number of large follicles without affecting small and medium follicles. FSH stimulation had no effect on the mean count of aspirated follicles; however, the cows administered FSH showed a higher ( P < 0.001) aspiration rate. An analysis of the proportion of cumulus oocyte complexes revealed that FSH stimulation did not affect their mean number. Nevertheless, FSH-stimulated cows had a lower recovery rate ( P < 0.001) of cumulus oocyte complexes (COCs) compared to the control group. In addition, the proportion of good-quality COCs was higher ( P < 0.01), with a simultaneous lower ( P < 0.01) percentage of poor-quality COCs in the FSH group. In vitro fertilization of both good and poor quality COCs revealed a higher ( P < 0.01) blastocyst formation rate within 7 to 8 days of fertilization. The study concluded that the FSH super-stimulation protocol improved follicular number, aspiration rate, oocyte competence and blastocyst percentage in cows synchronized for follicular wave emergence.