Abstract
In the present study, weight of calves and gestation periods derived from embryos developed either in vivo or in vitro were investigated. There were significant differences in the birth weight of calves derived from different strains of Japanese Black Cow (Hyogo and Shimane) when in vivo developed embryos were collected and transferred. Moreover, it was found that the average birth weight of Hyogo male calves derived from embryos cultured in in-vitro was significantly heavier than that of calves derived from embryos developed in vivo (in vivo: male; 29.2 kg vs in vitro: male; 37.0 kg ). However, there was no significantly difference between average birth weight of Hyogo female calves developed in vitro and that of calves derived from embryos developed in vivo. Moreover, there was no difference in the gestation periods between calves derived from embryos developed in vivo and those in vitro. In conclusion, it is suggested that (1) the average weight of calves derived from embryos developed in vitro is heavier than that from embryos developed in vivo, (2) heavy calf weight is more frequently observed in male, (3) there is no difference in the body weight of calves derived from embryos developed in TCM-lgg medium or in m-SOF medium, and (4) there is no difference in the average gestation period of embryos developed in vivo or in vitro.
