Effect of Syncro-Mate B implants (SMB) on embryo production by repeated superovulation in Japanese black cattle
1998
Dochi, O. (National Livestock Breeding Center, Nishigo, Fukushima (Japan)) | Konishi, K. | Imai, K. | Tomizawa, M. | Okuchi, H. | Okada, M. | Goto, Y. | Takakura, H.
The purpose of this study was to evaluate the effect of repeated superovulation assisted by Syncro-Mate B implants (SMB) on embryo production in Japanese Black cattle. A total of 11 cattle were implanted s.c. with SMB in pinna and injected i.m. with 3 mg of norgestomet and 5 mg of estradiol valerate at the same time without considering stages of the estrous cycle. Six or seven days after SMB implantation, superovulation treatments were initiated with twice-daily injection of FSH with decreasing dosage manner for 4 days (total FSH 28 AU). After 48 h or 55 h of the first FSH injection, all cattle were injected i.m. with 750 mu-g cloprostenol. All cattle showing estrous behavior were inseminated artificially with frozen semen of Japanese Black bull. Six to eight days later, embryos were collected from uterus by flushing out. The embryo collection was repeated five times at an interval of 28 days. The repeated treatment of superovulation affected the proportion of transferable embryos (P=0.0117) and the number of transferable embryos (P=0.0501). The proportion of transferable embryos at second treatment was significantly higher than that of the other treatment cycle (P0.05). The number of transferable embryos after the third treatment were significantly lower than that of the first and second treatments (P0.05). The average of the sum of oocytes/embryos, transferable embryos and good quality embryos were 35.2 +- 25.0, 22.8 +- 18.6 and 10.0 +- 8.7, respectively. The response to superovulation treatment varies largely among individuals. The present study demonstrates that SMB can be effectively applied for embryo collection on repeated treatment of superovulation at an intervals of 28 days in cattle
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