Ovarian responses and oocyte recovery in prepubertal swamp buffalo (Bubalus bubalis) calves after FSH or PMSG treatment.

Stimulation of follicular growth was examined using two different gonadotropin treatments in 10 prepubertal swamp buffalo calves (8 to 12 mo old). Each calf received an ear implant consisting of 3 mg norgestromet and 5 mg estradiol valerate during hormonal treatment. Five calves were additionally administered FSH (24 mg, im) and, 2 mo later, PMSG (3,000 IU). The remaining 5 calves were first treated with PMSG followed by FSH. Ovarian responses to treatments were examined by laparotomy, 72 h after ear implant removal, and by the number of follicles (diameter > or = 0.8 cm) and corpora hemorrhagica present. Ovaries had more significant response to FSH than PMSG treatment (13.9+/-8.6 vs 5.9+/-3.3 follicles; P<0.01). Although the recovery rate tended to be lower for FSH treated (64%) than PMSG-treated (82%) animals, more oocytes/animal were harvested in the PMSG treatment (8.3+/-5.0 vs 4.6+/-3.2, respectively). The immature oocytes (n = 38) were cultured for 24 to 25 h in maturation medium (TCM-199 NaHCO3+10% fetal calf serum [FCS] in 5%CO2 in air at 39 degrees C). Oocyte maturation was assessed after fixation and staining with aceto orcein. The in vitro maturation rate was 52.6% (20/38). This study shows the possibility of harvesting oocytes from prepubertal swamp buffalo calves and maturing the oocyte in vitro.