Effects of insemination-ovulation interval on fertilization rates and embryo characteristics in dairy cattle
2006
Roelofs, J.B. | Graat, E.A.M. | Mullaart, E. | Soede, N.M. | Voskamp-Harkema, W. | Kemp, B.
The objective of this study was to examine effects of the interval between insemination and ovulation on fertilization and embryo characteristics (quality scored as good, fair, poor and degenerate; morphology; number of cell cycles and accessory sperm number) in dairy cattle. Time of ovulation was assessed by ultrasonography (every 4 h). Cows were artificially inseminated once between 36 h before ovulation and 12 h after ovulation. In total 122 oocytes/embryos were recovered 7 d after ovulation. Insemination-ovulation interval (12 h-intervals) affected fertilization and the percentages of good embryos. Fertilization rates were higher when AI was performed between 36-24 and 24-12 h before ovulation (85% and 82%) compared to AI after ovulation (56%). AI between 24 and 12 h before ovulation resulted in higher percentages of good embryos (68%) compared to AI after ovulation (6%). Insemination-ovulation interval had no effect on number of accessory sperm cells and number of cell cycles when corrected for embryo quality. This study showed that the insemination-ovulation interval with a high probability of fertilization is quite long (from 36 to 12 h before ovulation). However, the insemination-ovulation interval in which this fertilized oocyte has a high probability of developing into a good embryo is shorter (24-12 h before ovulation).
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