Effect of FSH treatment on cumulus oocyte complex recovery by ovum pick up and in vitro embryo production in beef donor cows

This study was conducted to evaluate oocyte recovery and in-vitro blastocyst production of donor cows superstimulated for ovarian follicular development with FSH administered as twice-daily injections in saline or a single injection diluted in 0.5 % hyaluronan before oocyte aspiration. In Experiment 1, cows were treated with 160 mg of Folltropin-Vdiluted in saline, administered in four twice-daily i.m. injections for 2 days (Multiple FSH group); 160 mg of Folltropin-V diluted in hyaluronan and administered in a single i.m. injection (Single FSH group); or no FSH treatment (Control). In Experiment 2, donor cows were treated with either a single FSH i.m. injection or there was no treatment (Control) before ovum pick up (OPU) was performed. In both experiments, COCs collected using OPU were classified, matured, fertilized and cultured at 38.8 degrees C in a humidified atmosphere for 7 days. In Experiment 1, the number of follicles aspirated and COCs recovered were greater (P < 0.05) in cows treated with multiple and single doses of FSH. Number of blastocysts produced, however, did not differ among groups. In Experiment 2, mean number of follicles aspirated and COCs recovered were also greater (P < 0.05) in FSH-treated cows. Nevertheless, number of blastocysts produced did not differ. In summary, single and multiple FSH administrations induced similar follicular stimulation for OPU. Furthermore, with both FSH treatments there was induction of development of a larger number of follicles to be aspirated and COCs recovered by OPU compared with these values for donor beef cows with no FSH treatment for follicular stimulation.