337 OVUM PICK UP IN NON-PREGNANT AND POSTPARTUM SWAMP BUFFALOES (BUBALUS BUBALIS) AFTER FSH PRETREATMENT

The feasibility of OPU has already been reported in prepubertal swamp buffaloes and heifers (Promdireg et al. 2000 Thai J. Vet. Med. 30(1), 41–50; Techakumphu et al. 2003 Theriogenology 61, 1705–1711) and it has to be emphasized that the reproductive potential of females can be maximized, if OPU and IVEP are applied in the course of non productive periods such as anestrus and postpartum. The objective of this study was to evaluate the efficiency of Ovum Pick Up (OPU) in non lactating, pluriparous non-pregnant (n = 5) and lactating, postpartum swamp buffaloes, started 3 mts after calving (n = 6) with gonadotropin stimulation. OPU was performed every two weeks in the two groups of animals for a total of 6 sessions. To buffaloes receiving hormonal stimulation, a total of 400 mg of FSH was administered for three days in decreasing dose together with 100 µg of GnRH 24 h after the last FSH injection. The number of aspirated follicles between non-pregnant and postpartum buffaloes was not significantly different, 7.2 ± 3.7 (217) and 9.0 ± 3.2 (285), respectively (P > 0.05). Recovered oocytes between the two groups of hormonally stimulated animals was also not statistically different: 3.7 ± 2.7 (112) in the non pregnant and 5.9 ± 3.5 (198) in the postpartum group, respectively (P > 0.05). Among stimulated buffaloes, most aspirated follicles were of the small size (<5 mm). Overall oocyte recovery rate in both the groups was 61.8% (41–77.4%). Collectively the majority of recovered oocytes were single- and multi-layered, at a higher rate in non-pregnant than postpartum buffaloes. In conclusion, as already reported in cattle, this study confirms the possibility of retrieving oocytes by OPU from non-pregnant and postpartum buffaloes. The number and quality of recovered oocytes was similar in both groups of buffaloes. This study was supported by National Research Council, Thailand (year 2002). AP is PhD candidate under Royal Golden Jubilee program, Thailand Research Fund.