This study was carried out to confirm the effects of luteotrophin, human chorionic gonadotrophin (hCG), and an anti-luteolytic agent, flunixin meglumin (FM), on pregnancy rates in Hanwoo with in vitro produced (IVP) embryo transfers (ET), and to research the effects on the estrus cycle. Treatments included hCG and FM administration 3~10 minutes prior to ET. Also, pregnancy rates were compared with lidocane treatment and FM treatment prior to ET. The results are shown below. 30-day pregnancy rate was 76.7% in the hCG-treated group and 75.7% in the FM-treated group. Both rates were higher than the 70% rate for the control group. 42-day pregnancy rate was 76.7% in the FM-treated group. This was higher than 66.7% recorded for both the hCG-treated and control groups. The pregnancy rate of the hCG-treated group was high at Day 30 (76.7%) but low at Day 40 (66.7%), and there were no differences from the FM-treated and control groups. The recurrent estrus rate of infertile individuals at 2 weeks after ET was 36.4% in the hCG-treated group, under 71.4% in the FM-treated group and 80.0% in the control group. The non-pregnancy rate of individuals without recurrent estrus was 18.2% in the hCG-treated group, which was higher than the 0% rate in both the FM-treated and control groups. The pregnancy rates were higher in the FM-treated group than the Lidocane-treated group with 72.3% versus 67.5% in the heifers and 48.9% versus 43.6% in the cows. From the above results, the FM treatment proved more effective than the hCG treatment and no treatment whatsoever in increasing pregnancy rates after ET. In addition, hCG treatment was shown to be undesirable due to the deviations it caused in the reproductive physiology of the hCG-treated recipients. Therefore, in our study, the FM treatment resulted in a higher pregnancy rate than either lidocaine treatment or no-treatment in the trials of ET.

As a simple and economical method for in vitro produced embryos, we have used BSA instead of serum for the production and embryo transfer of Hanwoo in vitro fertilized (IVF) embryos and obtained the following results: 1) When using serum (FBS; fetal bovine serum) or BSA-containing culture media as the initial culture media for immature oocytes, it is regarded as inappropriate to add only BSA to the culture solutions from maturation of the immature oocytes to development stage culture, but serum still needs be added though there is no significant difference in the concentration, with a change from 5% to 10%. 2) The results of culturing IVF embryos after development (4 cell stage) in the Medium199 solutions containing BSA instead of serum (FBS) showed that 0.3% BSA concentration is not optimal and 0.5% or higher BSA concentration has no significant difference among 0.5%, 0.7%, 1% and 2% (p > 0.05). 3) The post-freezing survival ratio after development in 5% FBS-Medium199 showed that 1% BSA concentration of the culture solution is the most suitable in the BSA concentrations of 0.3% (51%), 0.5% (67%), 0.7% (69%), 1% (77%) and 2% (75%). 4) The pregnancy rates of the transplanted fresh(not frozen) blastocyst had no significant concentration dependency (p > 0.5), and the average pregnancy rate was 63.8%. 14% of overweight calves were found among the calves given birth to by the transfer of IVF blastocysts cultured in the serum-added culture solution, but none was found in the experimental groups in which BSA was added instead of serum.

As an preliminary experiment for making transgenic animals producing human follicle stimulating hormone (hFSH), we tried to express recombinant hFSH gene in vitro. hFSH is a heterodimeric glycoprotein hormone produced in the anterior pituitary gland. The hormone is essential in the regulation of reproductive processes, such as follicular development and ovulation. Genes encoding the common gonadotrophin alpha subunit and FSH-specific beta subunit were inserted into retroviral vectors under the control of the rat beta actin promoter. Gene transfer to the Chinese hamster ovary (CHO) cells was done by infection of the retroviruses harvested from PT67 packaging cells transfected with recombinant retrovirus vector DNA. After selection with G4l8, PCR and RT-PCR analyses of the G4l8-resistant CHO cells showed successful transfer and expression of both and fragments of the FSH gene.