Production efficiency of Japanese Black calves by transfer of bovine embryos produced in vitro

The objective of this study was to examine the production efficiency of Japanese Black beef calves after transfer of bovine embryos derived from an in vitro procedure In vitro-produced (IVP) embryos were obtained from in vitro maturation and fertilization and in vitro development by co-culture with cumulus cells until 7 or 8 days after insemination. In vivo-developed (IVD) embryos from superovulated Japanese Black heifers and cows 7 days after artificial insemination were used as a control group. Bovine embryos were transferred nonsurgically to recipient cows on Day 7 +/- 1 of the estrous cycle Pregnancy was diagnosed by palpation per rectum at Day 60 to 70 after estrus Pregnancy, abortion, perinatal accident and birth rates were examined according to the origin of embryos (IVP or IVD), the number of transferred embryos (single or twin) and the storage status (fresh or frozen-thawed).