engleski

The efficiency of ovum pick up and in vitro embryo development in charolais and holstein-friesian cows

The aim of the present study was to investigate the efficiency of ovum pick-up (OPU) and subsequent embryo development of oocytes collected from two cattle breeds. OPU was performed in 17 nonlactating donor cows (9 Charolais and 8 Holstein-Friesian). Cows were synchronized with PGF2 and stimulated with pFSH, twice a day during two days (Folltropin®, Bioniche, a total dose: 200 mg NIH-FSH-P1). OPU was performed 24 hours after the last FSH injection and procedure was repeated every second week for eight consecutive weeks. The number of aspirated follicles, the number of retrieved oocytes and oocyte recovery rate were recorded. The recovered oocytes were morphologically classified into four (1-4) quality categories. Grade 1 and 2 oocytes were matured, fertilized and subsequently cultured in vitro for 9 days. In order to study the kinetics of early cleavage, the number of cleaved embryos was recorded at 24, 27, 30, 33, 36 and 48 hpi. Embryo yield was recorded on day 5, 6, 7, 8 and 9 of IVC. Data were analyzed by Chi-square test. Charolais donor cows showed significantly better results in number of follicles punctured, total number of oocytes and number of grade 1 and 2 oocytes recovered by OPU. The percentage of cleaved embryos at 24 hpi was significantly higher in Charolais donor cows (41, 1% vs. 29, 4%), but overall cleavage rate assesed 48 hpi showed no differences between two breeds. In terms of blastocyst rate at day 5, 6, 7, 8 and 9 of IVC, no statistical differences was observed between breeds. These results show that a higher number of oocytes can be retrieved by OPU from Charolais donor cows compared to Holstein-Friesian. However, there was no differences in developmental competence of retreived oocytes between breeds.

cow; breed; oocyte; ovum pick up

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