• Korean Journal of Poultry Science
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• v.20 no.1
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• pp.1-9
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• 1993

This study carried out to build up new synthetic egg production lines which had sex-linked gene for feather color sexing and also superior combining ability for producing the best commercial chicks. The closed flock breeding method was utilized to improve the general performances in the first experiment and combining ability for heterosis was tested for new synthetic line in the second experimental year. In order to test for the egg production ability in cross breeds synthetic lines, the crossing of B$\times$4 B$\times$C, two imported strains and two domestic strains as controls were compared for the general performances. There was on difference in mortality, body weight to 56 weeks of age. Sexual maturity was delayed about 10 days by comparing with other reports, except 153 days of the Manina White, but no difference among mating systems in this experiment. The hen housed egg production in B$\times$A, B$\times$C was 186.3, 191.3 respectively and it was better than the other controls, except ISA imported lines. The hen-day egg production of B$\times$A, B$\times$C was better than other controls, with 75.7%, 76.8% respectively. In the average egg weight, the B$\times$C cross breed was highest with 64.5g. As the sex of hatching chicks was identified by difference of feather color, the genetic composition of synthetic lines must be homogenized. The feather color of female chicks was brown and that of male was silver (99%), In conclusion, the egg production ability of B$\times$A, B$\times$C cross breeds was superior to the imported and domestic lines. Therefore, it suggest that the synthetic lines with sex-linked gene might be utilized for improving egg production performances.

• Journal of Embryo Transfer
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• v.23 no.1
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• pp.43-49
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• 2008

This study was carried out to examine the efficiency of biopsy methods, and the pregnancy rate, calving and abortion rates, gestation length and birth weight of Hanwoo calves following transfer of fresh, frozen and sexed Hanwoo embryos produced in vitro. The survivability of biopsied embryos was 80.0 and 90.0% using aspiration and punching methods at 24 h after culturing, respectively. The ratios of male and female embryos were 42.1 and 52.6%, respectively, and the percentage of sex unidentified was 5.3%. Pregnancy rates was not significantly different between hCG and control group (46.4 vs. 38.5%), fresh and frozen embryos (41.3 vs. 35.0%), and sexed and IVP embryos (27.5 vs. 41.2%) (p>0.05). Calving and abortion rates of IVP and sexed embryos were not significantly different in calving (85.0 vs. 87.0%) and in abortion (15.2 vs. 13.3%) (p<0.05). Gestation length of IVP and sexed calves were 281.3 and 288.2 days in female and 283.0 and 282.3 days in male, and the birth weight of IVP and sexed calves were 23.6 and 25.0 kg in female and 24.6 and 23.8 kg in male, respectively. There were no difference in gestation length and birth weight between IVP embryos and sexed embryos (p>0.05). Administration of hCG to recipients did not improve the pregnancy rate following transfer of Hanwoo embryos produced in vitro and sexed embryos. Although the production of calves derived from sexed Hanweoo embryos cultured in vitro can be obtained, the efficiency of sexed calves production need to be improved in biopsy methods and pregnancy rate. Further study should be focused on the improvement of pregnancy rates for commercial application of embryo transfer.