COMPARISON OF ULTRASOUND-GUIDED VS LAPAROSCOPIC TRANSVAGINAL OVUM PICK-UP (OPU) IN SIMMENTAL HEIFERS

Transvaginal ovum pick-up (OPU) offers several advantages over standar d embryo transfer procedures. For a systematic comparison of the ultra sound-guided (U-OPU) and the laparoscopic OPU (L-OPU) method, groups o f Simmental heifers were subjected to 1 of the 2 OPU-methods for 8 wk (15 sessions) followed by a treatment-free interval of 11 wk and then another 8-wk period of OPU using the alternative method. Parameters th at were evaluated included the number of follicles aspirated, number a nd morphology of recovered cumulus-oocyte complexes (COCs), and develo pmental capacity of oocytes after in vitro maturation (IVM) and fertil ization (IVF). Blood samples were also taken from the donors twice a w k for progesterone measurement. To evaluate effects of long-term OPU o n subsequent fertility of donors, all heifers (n=14) were inseminated during the first natural estrus after the OPU experiment. The proporti on of Class I oocytes was significantly (P<0.001) higher after U-OPU t han after L-OPU (38.7% vs 21.0%). Following IVM/IVF, this difference i n oocyte quality was reflected by the cleavage rate (U-OPU: 58.1%; L-O PU: 52.1%; P<0.05) and the rate of development to morulae and blastocy sts (U-OPU: 27.1%; L-OPU: 13.9%; P<0.001). Among other factors, the gr eater changes in vacuum pressure during L-OPU vs U-OPU might be respon sible for the difference in oocyte quality. This problem may be overco me by a more flexible system for regulating the vacuum. Progesterone l evels were higher during the L-OPU than the U-OPU periods. Seven donor s (50%) were diagnosed pregnant by ultrasonography on Day 28 and by pa lpation per rectum on Day 42. (C) 1998 by Elsevier Science Inc.