Birth weight and birth rate of heavy calves conceived by transfer of invitro or in vivo produced bovine embryos

摘要

The aim of this study was to evaluate the difference in birth weight and gestation length between Japanese Black calves obtained from transfer of bovine embryos produced in vitro (IVP) and those developed in vivO (IVD). An additional objective was to clarify the sire effect on birth weight and gestation length and to examine the birth rate of heavier calves, Two Japanese Black bulls breed at our experimental station were used as a semen source for production of NP and ND embryos. Thirty-eight Japanese Black heifers and cows of various genetic backgrounds were used as embryo donors for IVD embryos. Ovaries for IVP embryos were collected at random at a local slaughterhouse from Japanese Black cattle of various genetic backgrounds. IVP embryos were produced using co-culturing with cumulus cells in 5% CS + TCM 199. Both the IVD and NP embryos were transferred non-surgically to Holstein recipients on day 7 +/- 1 of estrous cycle. In this study, the birth weights and gestation lengths of half-sib single calves for bull A and B were analyzed.