Field transplantation test of frozen in vitro fertilizaed embryo of Japanese Black cattle: examination of conception result of 7th and 8th day embryos

摘要

Transplantation test of frozen preserved embryos at 7th day and 8th day after in vitro fertilization of ovum of Japanese Black cattle from slaughter house was carried out, and examinations of various factors was made that influenced on the conception result and on the practical use. As for the recipient cow, the individual which had difference of 0 day with the day-age of embryo was selected and transplantation was made. As to the conception result of embryo at 7th day and 8th day, the conception rate was 62.2 percent and 56.1 percent, respectively, and it was 59.3 percent when the both were totaled. When the conception rates of heifer and those of delivered cow were compared, those of heifer was significantly higher. In the promoting treatment of luteal body function by the administration of hCG agent, the conception rate was higher in the treatment group than that of non-treatment group, and it was considered as a useful method. Further, because there was no difference of conception rate by the season, it was considered that there was a practical use.