REPEATED OVUM PICK-UP IN ITALIAN MEDITERRANEAN BUFFALO COWS

The potential of the ovum pick-up technique, used over a long period, was evaluated in 6 Italian Mediterranean buffalo cows that had more th an 500 d open. The cows were submitted to ovum pick-up twice weekly fo r 2 mo. An additional 2-mo cycle of ovum pick-up was performed in 3 of the buffalo. The ovum pick-up sampling did not affect the resumption of reproductive activity of these animals. In fact, all the buffalo co nceived, on average, 47.5+/-27.5 d after the last ovum pick-up. An ave rage of 5.48 follicles was punctured, and 2.71 oocytes were collected per session. However, only 53.5% of these oocytes were suitable for in vitro embryo production. The number of punctured follicles differed b etween individual cows. There were no differences in the number of col lected oocytes or in the recovery rates. The number of punctured folli cles, the number of collected oocytes and the recovery rate were simil ar in the first and second months; the quality of the oocytes was, how ever, better in the second than in the first month (P<0.05). The incre asing interval between 2 consecutive ovum pick-up sampling (intersessi on interval) caused an increase of the percentage of large follicles. Moreover, the increase of the intersession interval from 4 to 5 d decr eased the duality of the collected oocytes (P<0.05). The efficiency of in vitro production of embryos to expanded blastocysts was 16.7%.