Timing of superovulation treatment in postpartum Japanese Black cows.

概要

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Twenty-nine postpartum Japanese Black cows were divided into 5 groups based on expected dates of estrus, at 4249 d (Group 1), 6370 d (Group 2), 8491 d (Group 3), 105112 d (Group 4), and 126133 d (Group 5), to determine the optimum time to initiate superovulation treatment. They were superovulated with FSH-P on Day 10 of the estrous cycle. The concentrations of plasma estradiol-17β and progesterone in groups 1, 3, and 5 were determined on the following periods: before superovulation treatment, at standing estrus, and at embryo recovery. The mean numbers of recovered and transferable embryos were 12.8±11.6 and 3.0±2.5; 6.5±2.5 and 4.0±2.0; 25.4±12.3 and 12.0±6.5; 6.5±0.5 and 3.5±0.5; and 12.0±6.5 and 3.0±3.4, for groups 1, 2, 3, 4, and 5, respectively. Group 3 had a significantly higher number of recovered and transferable embryos as compared to the other groups (P<0.05). The concentrations of estradiol-17β at standing estrus in groups 3 and 5 were similar. On the other hand, the progesterone concentration at embryo recovery was higher in group 5, but more embryos were recovered from group 3. It is concluded that the optimum time to initiate superovulation treatment using FSH-P, regardless of the number of estrus after parturition, is 94101 d postpartum (10 d following estrus at 8491 d postpartum).
日本繁殖生物学会の論文