Abstract
This study was performed to investigate the effects of parity and season on the embryo production in superovulated Hanwoo cows. Superovulation was performed from 1 to 8 times by repeated superovulation treatment of Hanwoo cows (n = 22). Irrespective of estrous cycle, donor cows were received a CIDR, progesterone (50 mg) and estradiol benzoate (2.5 mg). After 4.5 days, the donor cows were superovulated with total 28AU FSH (Antorin R-10) administrated twice daily in a decreasing dose for 4 days. On $6^{th}$ and $7^{th}$ of FSH injection, 2.5 mg and 15 mg $PGF_2{\alpha}$ were injected i.m, respectively. CIDR was removed at the $7^{th}$ FSH injection. The donor cows received $200{\mu}g$GnRH at 48 hrs after $1^{st}$ $PGF_2{\alpha}$ injection. The donor cows were artificially inseminated three times after estrous detection at 12 hr intervals and embryos were recovered 7 days after estrous detection. The mean number of total ova, transferrable embryos, degenerated embryos and unfertilized oocytes were $11.6{\pm}7.9$, $5.5{\pm}4.4$, $3.0{\pm}3.3$ and $2.6{\pm}4.1$ per donor cows, respectively. A higher number of total ova were recovered in parity 3~5 ($14.3{\pm}1.3$) than 1~2 ($8.9{\pm}1.9$, P<0.05). The number of recovered normal embryos is significantly higher in parity 3~5 ($7.3{\pm}0.8$) than that of over 6 ($3.7{\pm}1.5$). Significantly higher number of total ova and normal embryos were recovered in summer ($16.4{\pm}2.3$, $8.1{\pm}1.4$) than in autumn ($10.1{\pm}1.8$, $4.5{\pm}1.1$) and winter ($6.3{\pm}1.8$, $3.3{\pm}1.1$), respectively (P<0.05). Transferable embryos were significantly higher in summer ($7.6{\pm}1.3$) than in winter ($3.0{\pm}1.0$, P< 0.05). The results were showed that parity and season affecting on the production of embryos in superovulated Hanwoo.
발정주기와 상관없이 CIDR을 삽입하는 날에 50 mg progesterone, 2.5 mg estradiol benzoate를 근육주사하였다. CIDR 삽입 후 4, 5일에 28 AU FSH (Antorin R10)을 4일 동안 감량법으로 주사하였다. 6, 7회 FSH 주사 후 25 mg, 15 mg $PGF_2{\alpha}$를 각각 주사한 다음, CIDR는 7회 FSH 주사 후 제거하였다. 1회째 $PGF_2{\alpha}$ 주사 후 48시간에 $200{\mu}g$ GnRH를 주사하였다. 공란우는 발정확인 후 12시간 간격으로 3회 인공수정을 실시하였으며, 수정란의 채란은 발정확인 후 7일째 회수하였다. 과배란 처리된 공란우에서 회수된 총 난자수, 이식가능 수정란, 퇴행란 및 미수정란은 각각 $11.6{\pm}7.9$, $5.5{\pm}4.4$, $3.0{\pm}3.3$ 및 $2.6{\pm}4.1$개였다. 1~2산의 공란우($8.9{\pm}1.9$)보다 3~5산의 공란우($14.3{\pm}1.3$)에서 총 난자수가 유의적으로 많았다(P<0.05). 회수된 정상 수정란 수도 3~5산의 공란우($7.3{\pm}0.8$)에서 6산 이상의 공란우($3.7{\pm}1.5$)보다 유의적으로 많았다(P<0.05). 회수된 총 난자수와 정상수정란도 각각 가을($10.1{\pm}1.8$, $4.5{\pm}1.1$)과 겨울($6.3{\pm}1.8$, $3.3{\pm}1.1$)보다 여름($16.4{\pm}2.3$, $8.1{\pm}1.4$)에 유의적으로 많았다(P<0.05). 이식가능 수정란은 겨울($3.0{\pm}1.0$)보다 여름($7.6{\pm}1.3$)에서 유의적으로 많이 회수하였다(P<0.05). 결론적으로 공란우의 산차, 과배란 처리계절은 한우수정란 생산에 영향을 미치는 것으로 나타났다.
