Effect of estradiol transdermal system on superovulatory response in Japanese Black cows
2008
Sakagami, N.(Kanagawa-ken. Livestock Industry Technology Center, Ebina (Japan)) | Akiyama, K. | Nakazawa, Y. | Hashimura, S. | Hamano, T. | Kuge, T. | Iwata, H. | Monji, Y.
The aim of this study was to investigate the effect of estradiol transdermal system (ETS) on superovulatory response in Japanese Black cows. Sixteen cows were received an intravaginal progesterone-releasing insert (CIDR) at random stage of the estrus cycle (Day 0). The cows were superovulated with a total of 20 mg of porcine follicle stimulate hormone (pFSH), given twice daily in decrease doses from Day 10 to 12. On Day 12, CIDR was removed and simultaneously 750 microg cloprostenol was injected intramuscularly. The cows were inseminated twice after on set of estrus and embryos were collected 7 days after. The experiment was conducted in two replicates. In the half of cows, ETS were applied to the inside of a tail for 24 hours on Day 7 at the first superovulation, and the other cows were treated on the same day in the 2nd superovulation. Ovarian ultrasonographic examinations were performed on Day 0, 7, 10. In the ETS treated group, the mean number of large follicles of Day 10 was thought to tend to decreased at Day 7. ETS treatment increased significantly the number of corpus lutea (CL) (p0.05). However the mean number of ova/embryos and transferable embryos did not differ between treatments, it increased significantly (p0.05) in the ETS group selected by yielded 3 or less transferable embryos in the control group. These results suggest that superovulation with ETS treatment decreased the number of large follicles, increased the number of CL and improved superovulatory response in the cows that had yielded 3 or less transferable embryos in the control group.
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