Relationship between Estrous Expression, Body Condition Score (BCS) and Transferable Embryos Hanwoo Donors

한우 공란우의 발정발현율, 신체 충실 지수(BCS)와 이식가능 수정란과의 관계

The objective of this study was to investigate the relationship between estrous expression, body condition score (BCS), blood urea nitrogen (BUN) and number of transferable embryos for the purpose of improving reproductive performance in blood of Hanwoo donors. Sixty, at random stages of the estrous cycle, received a CIDR. Four days later, the animals were superovulated with a total of 28AU FSH (Antorin, 2AU=1 ml) administered twice daily in constant doses over 4 days. On the 3th administration of FSH, CIDR was withdrawn and 25 mg PGF2 ${\alpha}$ was administered. Cows were artificially inseminated twice after estrous detection at 12 hr intervals. The cows received 100 ${\mu}g$ GnRH at the time of 1nd insemination. Embryos were recovered 7 or 8 days after the 1st insemination. The estrous inducement rate and estrous expression rate were significantly lower for cows with BCS below 2.25 than for cows with BCS above 2.25. There was 50.0% of rate of mounting in cows with BCS below 2.25 whereas the rate of mounting was markedly increased in cows with BCS above 2.25 (94.1% and 89.5% for BCS 2.25~2.75 and BCS above 2.75 cows, respectively). Cows with BCS <2.25, 2.25~2.75 and ${\geq}$2.75 had number of transferable embryos of $4.5{\pm}0.7$, $5.9{\pm}1.8$ and $5.6{\pm}2.3$ respectively.