黒毛和種受胚牛における凍結胚移植前日および当日の血中プロジェステロンおよびエストロジェン濃度と受胎成績

概要

論文の詳細を見る
The relationship of blood progesterone (P) and estradiol- 17β (E2) concentrations to the pregnancy rates in Japanese Black beef cattle recipients was investigated by determining blood P and E2 concentrations on the day before (day 6; day 0=onset of estrus) and the day of embryo transfer (day 7). Embryos were thawed by the stepwise method and transferred on day 7. The pregnancy rate showed a tendency toward increase with increasing P concentrations on both days 6 and 7 of embryo transfer. There was no significant correlation between the blood E2 concentration on day 6 and the pregnancy rate, wthereas pregnancy rate tended to rise when the blood E2 concentration on day 7 was low. The relationships of the blood E2/P ratio (× 103) on days 6 and 7 to the pregnancy rate were investigated. When the E2/P ratio was ≥1.0, the pregnancy rate tended to decrease. The bovine recipients, which showed poorly development CL, high blood E2/P ratio and coexistence of follicle ≥1.0 in diameter with CL, showed a tendency toward decrease in the pregnancy rate. From these observations, it is supposed to be important to select bovine recipient with the high bood P concentration and with the low blood E2 concentration on days 6 and 7 as bovine recipients for improvement of the pregnancy rate in bovine frozen-thawed embryo transfer.
日本繁殖生物学会の論文