The effects of estrous induction on involution of uterus, embryo collection and subsequent reproductive performance in postpartum Japanese black beef cows [Bos taurus]
2006
Taniguchi, M.(Yamaguchi Univ. (Japan). Faculty of Agriculture) | Otoi, T. | Ikeda, A. | Arikawa, E. | Endo, K. | Nakao, T.
The present study was conducted to examine the effects of estrous induction on postpartum uterine involution, embryo collection after superovulation and subsequent conception rate after artificial insemination (AI) with an aim to establish once a year calving including the embryo collection before routine AI. Cows were treated with CIDR 20 days after parturition and PGF2a was injected intramuscularly at Day 8. After induction of estrus, cows were superovulated for embryo collection. The cows were inseminated artificially based on detection of estrus after embryo collection. Control cows were superovulated for embryo collection based on detection of spontaneous estrus 29 days later postpartum. The third ovulation postpartum in the experiment group was observed on day 31 postpartum, which was earlier than that in the control group. The diameter of uterine horns 31 days postpartum in the experiment group was significantly shorter than that in the control group. There were no significant differences between the two groups with respect to the results of embryo collection and intervals between calving and conception. These results indicate that the induction of estrus during early postpartum period is effective for facilitating uterine involution and collecting embryos by superovulation before starting re-breeding to repeat calving at 12-month interval.
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