Ovarian stimulation with a low dose of follicle stimulating hormone improved recovery rates and developmental competence of goat oocytes

The aim of this study was to optimise the ovarian responses using different FSH (follicle stimulating hormone) treatments in goats. Group 1 (control), the ovaries were stimulated with a total dose of 200 mg FSH per doe. The FSH injections were performed at 12-h intervals starting on day 9 after progesterone implantation. The FSH doses were decreased to 160 mg/doe and 130 mg/doe for Groups 2 and 3, respectively. The numbers of small, medium and large follicles were determined by real-time B mode ultrasonography. Ovum pick-up (OPU) was performed by laparoscopy under general anesthesia at 96, 42 and 36 h after the initial dose of FSH for Group 1, 2 and 3, respectively. The numbers of recovered cumulus-oocyte-complexes (COCs) and their quality were examined. The COCs were further matured and fertilised in vitro. It was found that the numbers of small- and medium-sizes follicles in Group 2 and 3 were significantly higher than those in Group 1, whereas the numbers of large follicles in Group 1 were significantly higher than those in the other groups (p < 0.05). There was no significant difference in oocyte recovery rates and the quality of COCs among groups (p > 0.05). However, the low-dose FSH (Group 3) tended to enhance oocyte recovery rates and oocyte quality compared to Group 1 (p = 0.07 and 0.06, respectively). Although the meiotic competence of recovered oocytes from Group 3 was similar to that of Group 1, cleavage rates were significantly greater than those in Group 1 (52.30 vs. 30.15%, respectively). In conclusion, ovarian stimulation with a low dose of FSH, related to the interval time between the first FSH injection and the OPU, improved oocyte recovery rates and the developmental competence of goat oocytes.