Relationship between Superovulation Treatment and Blood Urea Nitrogen(BUN) Concentration in Hanwoo Donors

한우 공란우 과배란 처리와 혈액 내 요소태 질소 수준과의 관계

The objective of this study was investigate the superovulation treatment and to relate concentrations of blood urea nitrogen(BUN) in Hanwoo donors. Thirty six, 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 On the 3th administration of FSH, CIDR was withdrawn and 25 mg $PGF_2a$ was administered.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 1st insemination. Embryos were recovered 7 or 8 days after the 1st insemination. Cows with BUN <10, 11~18 and ${\geq}$19 mg/dl had return of estrus of 34.6, 30.5 and 30.4 days respectively. Return of estrus after superovulation treatment was not significantly lower for cows with blood urea nitrogen (BUN) above 10 mg/dl than for cows with BUN below 10 mg/dl. Cows with BUN <10, 11~18 and ${\geq}$19 mg/dl had number of transferable embryos of $3.2{\pm}1.2$, $5.4{\pm}1.9$ and $4.1{\pm}2.1$ respectively.