The aim of this work was to determine whether a cervical dilation protocol (CDP) composed of only oxytocin can be used to perform transcervical (non‐surgical) embryo transfer in sheep (NSET) without affecting the viability of the corpus luteum (CL). Likewise, we evaluated whether a cervical transposing test with a Hegar dilator (CT Hegar test), performed at oestrous time, could be used to screen ewes for NSET (greater or lower chances to transpose the cervix). For that, oestrous and ovulation synchronization was performed in 25 Santa Inês ewes to induce the dioestrous condition. Animals went through the following CDP in a crossover design: E + OX, oestradiol benzoate (100 µg intravenously [IV]) and oxytocin (100 IU IV); OX, oxytocin (100 IU IV); and SAL, saline solution (IV). Using a Hegar dilator, cervical transposing attempts were performed at oestrous (D0) and dioestrous time (D8). The viability of the CL (morphology, luteal blood flow and progesterone values) was evaluated by ultrasonography (colour Doppler and B‐mode) and by serum progesterone measurement from D7 to D13. The cervical transposing rate was lower for the SAL group (64%; 16/25; p < .05) and did not differ between the E + OX (88%; 22/25, p > .05) and OX (84%; 21/25, p > .05) groups. No treatment affected the CL viability. The CT Hegar test showed a high sensitivity (85.7%–93.3%), satisfactory accuracy (72%–84%), low false‐negative rate (6.7%–14.6%), but high false‐positive rate (46%–66.7%). In conclusion, a CDP protocol composed exclusively of oxytocin can lead to good cervical transposing rates and does not affect the viability of the CL. In addition, a screening test (CT Hegar) performed at oestrus can identify ewes for which cervical transposing will likely not occur at NSET.

中文翻译：

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使用催产素实现宫颈扩张以进行绵羊经宫颈胚胎移植。

这项工作的目的是确定仅由催产素组成的宫颈扩张方案 (CDP) 是否可用于在绵羊 (NSET) 中进行经宫颈（非手术）胚胎移植，而不会影响黄体 (CL) 的活力。同样，我们评估了在发情时使用 Hegar 扩张器进行的宫颈转位测试（CT Hegar 测试）是否可用于筛查母羊的 NSET（子宫颈转位的机会更大或更小）。为此，在 25 只 Santa Inês 母羊中进行发情和排卵同步以诱导发情状况。动物在交叉设计中经历了以下 CDP：E + OX、苯甲酸雌二醇（100 µg 静脉注射 [IV]）和催产素（100 IU IV）；OX，催产素（100 IU IV）；和 SAL，盐水溶液 (IV)。使用 Hegar 扩张器，在发情（D0）和发情时间（D8）进行宫颈换位尝试。通过超声检查（彩色多普勒和 B 模式）和从第 7 天到第 13 天的血清孕酮测量来评估 CL 的活力（形态学、黄体血流量和孕酮值）。SAL 组的颈椎转位率较低 (64%; 16/25;p  < .05）并且在 E + OX（88%；22/25，p  > .05）和 OX（84%；21/25，p  > .05）组之间没有差异。没有处理影响 CL 活力。CT Hegar 检测灵敏度高（85.7%–93.3%），准确率令人满意（72%–84%），假阴性率低（6.7%–14.6%），但假阳性率高（46%–66.7 %）。总之，完全由催产素组成的 CDP 协议可以导致良好的宫颈转位率，并且不会影响 CL 的可行性。此外，在发情期进行的筛查测试 (CT Hegar) 可以识别在 NSET 时可能不会发生宫颈转位的母羊。