THE USE OF TRANSVAGINAL OOCYTE PICK-UP (O PU) - FIRST OPU CALVES BORNIN BELGIUM

Transvaginal Oocyte Pick-Up (OPU) has proven to be a reliable techniqu e for oocyte retrieval in living donor cows. It can be used in combina tion with IVF, for the treatment of infertile cows. Twelve Belgian Blu e donor cows, which had already been used as donors in an embryo trans fer programme, were submitted to OPU, which was performed without prio r hormonal stimulation, except in 3 cows (6 sessions) in which ovarian activity was found to be low upon echographic examination. These cows were stimulated with a combination of FSH and LH. OPU was performed t he next day using an ultrasonal scanner (PieMed, The Netherlands) equi pped with a 7.5 MHz transducer. Cows were punctured once or twice a we ek, using 18-g disposable 50 mm long single lumen needles. Follicles w ith a diameter between 4 and 10 mm were punctured. Oocytes were collec ted in phosphate buffered saline (PBS) and heparin (125 IU/ml) and wer e processed following standard IVF procedures. Results clearly indicat e a significant difference in the number of cultured embryos among the donor cows, with a percentage of oocytes developing into blastocysts between 2 and 38%, suggesting that the oocytes of some cows are more s uited to IVF procedures than others. Ovarian stimulation increased sig nificantly the number of punctured follicles (4.4 to 20.8), the number of retrieved oocytes (2.1 to 6.3) and the number of blastocysts (0.4 to 1.5) per session. Since most owners didn't have enough well synchro nized recipients, not all embryos were transferred under optimal condi tions. Nevertheless, the first 5 OPU-calves have already been born and 7 more pregnancies are confirmed.