Prolonging the interval from ovarian hyperstimulation to laparoscopic ovum pick-up improves oocyte yield, quality, and developmental competence in goats

The objective was to evaluate the effect of the interval between ovarian hyperstimulation and laparoscopic ovum pick-up (LOPU) on quality and developmental competence of goat oocytes before and after in vitro maturation (IVM) and intracytoplasmic sperm injection (ICSI). Estrus was synchronized with an intravaginal insert containing 0.3 g progesterone (CIDR) for 10 d, combined with a luteolytic treatment of 125 μg cloprostenol 36 h prior to CIDR removal. Ovaries were hyperstimulated with 70 mg FSH and 500 IU hCG given im 36, 60, or 72 h prior to LOPU (n = 15, 16, and 7 does, respectively). For these groups, oocyte retrieval rates (mean ± S.E.M.) were 24.7 ± 2.9, 54.5 ± 4.7, and 82.8 ± 4.6% (P < 0.001), and the proportions of cumulus-oocyte complexes (COC) with more than five layers of cumulus cells were 29.7 ± 8.3, 37.6 ± 6.9, and 37.3 ± 7.0% (P < 0.001). The proportion of IVM oocytes was highest at 72 h (82.1 ± 2.8%; P < 0.05), with no significant difference between 36 and 60 h (57.3 ± 8.9% and 69.0 ± 8.4%). Cleavage rates of ICSI embryos were 4.2 ± 4.2, 70.9 ± 8.4, and 78.9 ± 8.2% with LOPU 36, 60, and 72 h post FSH/hCG (P < 0.01), with a lower proportion of Grade-A embryos (P < 0.05) following LOPU at 36 h compared to 60 and 72 h (29.7 ± 8.3%, 37.6 ± 6.9%, and 37.3 ± 7.0%). In summary, a prolonged interval from FSH/hCG to LOPU improved oocyte retrieval rate and oocyte quality. Therefore, under the present conditions, LOPU 60 or 72 h after FSH/hCG optimized yields of good-quality oocytes for IVM and embryo production in goats.