ABSTRACT
The objective of the experiment was to improve the multifollicle stimulation technique and the ovarian response examination in prepubertal swamp buffalo calves. Six animals were stimulated by gonadotropin hormone 7 days after a progesterone ear-implant. The first stimulation was done by giving 24 mg FSH + 100 microg GnRH (FSH+GnRH) and the second, one month after by giving 2,000 IU PMSG + 100 microg GnRH (PMSG+GnRH). Twenty-four hours after GnRH, the ovarian responses were checked using rectal palpation and real-time B mode ultrasonography. Five out of six animals (83.3%) responded to both treatments and were selected for oocyte collection. The oocytes were aspirated directly following a caudal midline laparotomy. The results of ovarian responses to FSH+GnRH and PMSG+GnRH averaged 17.6+/-12.1 (L-9.8+/-8.7, R=7.8+/-6.2) and 17.4+/-5.6 (L-9.4+/-2.9, R=8.0+/-3.7), respectively. The average number of recovered oocytes per animal was 9.0+/-6.4 and 8.4+/-1.1, respectively which represented a recovery rate of 56.3 (+/- 9.2)% and 51.9 (+/- 10.3)%. More than eighty percent of the recovered oocytes were in an immature stage with more than 2-3 layers of compact cumulus mass. The present study showed that the oocytes were collected successfully in prepubertal buffalo calves after the FSH+GnRH or PMSG+GnRH stimulation and most of the recovered oocytes were immature, which made them suitable for in vitro maturation and fertilization.