Effect of estradiol-17beta on superovulatory treatment with CIDR and FSH in Japanese Black heifers.

摘要

Eight heifers were each given a controlled intravaginal drug releasing device (CIDR) containing a progestogen, plus a 5-mg injection of oestradiol-17beta valerate on the day after insertion of the CIDR. Eight control heifers were given CIDRs plus aninjection of sesame oil vehicle. All heifers were superovulated with FSH injections over a 3-day period. Three days after the 1st FSH injection, the CIDRs were removed, and 750 鎔 cloprostenol was injected. The heifers were inseminated at oestrus, and embryos were collected non-surgically. The whole treatment protocol was carried out 4 times. Four heifers were removed from the experiment during the 3rd or 4th treatment repeats. The number of embryos recovered was significantly higher in oestradiol-treated than in control heifers when the number recovered in the oestradiol group did not exceed 10. Ultrasonography of the ovaries indicated that the number of follicles exceeding 8 mm in diameter was lower on the 1st day of superovulation treatment in theoestradiol group than in the controls.