The effect of two ovum pick-up protocols on amount/quality of oocytes retrived and on in vitro embryo production of Gyr cows was evaluated in non-lactating cycling cows with good body and reproductive conditions. Estrous cycles were synchronized with cloprostenol. During the experiment, animals received norgestomet ear implants, replaced every 14 days. Animals were submitted to protocol I (without hormonal estimulation) and protocol II (pre-stimulation with 250 IU of FSH three days before aspiration). Recovered oocytes were transported in Talp-Hepes to the laboratory, classified and maturated. Twenty two hours after fertilization, presumptive zygotes were co-culture with granulosa cells in CR2aa supplemented with 10% of fetal calf serum. Cleavage rate was assessed at 72 hours post-fertilization, and blastocyst production 192 hours post-fertilization. The total number of follicles, the number of large and medium follicles and the diameter of the largest follicle were higher (P<0.05) in protocol II, and the number of small follicles (P<0.05) was lower than in protocol I. No difference between protocols I and II was observed for oocytes recovered per aspiration section (P>0.05). The number of grade I oocytes and cleavage rate were higher (P<0.05) in protocol II and the number of degenerated oocytes was lower (P<0.05). The pre-stimulation with FSH can improve the quality and cleavage rate of oocytes recovered by ovum pick-up in zebu animals.
bovine; Gyr; in vitro embryo; ovum pick-up; FSH
