• Journal of Embryo Transfer
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• v.26 no.1
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• pp.27-32
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• 2011

This study evaluated the effect of recipient's breed on the gestation length and birth weight of Hanwoo calves produced by Hanwoo ovum pick up (OPU) derived embryos. Embryos of OPU derived Hanwoo cows were transferred into the Hanwoo and Holstein recipients at 6~7 days of estrus cycle. Gestation length was expressed in days from the day of embryo transfer to the birth day of offspring, and birth weight of offspring was recorded within 24 h of birth. Breed of recipient cows (Hanwoo and Holstein) has no effect on overall gestation length ($280.9{\pm}6.2$ vs. $284.4{\pm}9.8$ days) and birth weight of calves ($23.56{\pm}3.75$ vs. $27.70{\pm}7.92\;kg$). The gestation length was higher (p<0.05) for male calves than female calves in both Hanwoo ($283.8{\pm}6.7$ vs. $277.3{\pm}3.3$ days) and Holstein ($287.3{\pm}8.9$ vs. $280.1{\pm}9.1$ days) recipient cows. Birth weight of Hanwoo calves did not differ when Hanwoo recipients ($26.5{\pm}1.3$ vs. $23.3{\pm}1.2\;kg$) were used for embryo transfer. However, male calves were heavier (p<0.05) at birth than that of female calves when embryos were transferred into the Holstein cow ($33.5{\pm}4.9$ vs. $27.8{\pm}4.9\;kg$). In conclusion, the present results demonstrated that breed of recipient cows have no effect on gestation length and birth weight of OPU derived Hanwoo calves. However, gestation length and birth weight of male calves were higher in both Hanwoo and Holstein recipient cows.