Jorre de St Jorre T, Hawken P A R, Martin G B
School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
Reprod Fertil Dev. 2012;24(4):523-30. doi: 10.1071/RD11085.
Ewes supposedly need to be separated from rams before male stimuli can increase gonadotrophin secretion and induce ovulation. In the present study, we investigated the LH response of ewes to 'novel' and 'familiar' rams after varying periods of separation. In Experiment 1, ewes (n = 8 per treatment) were separated from familiar rams for 15 min or 1 month and then exposed to either familiar rams, novel rams or novel wethers. After 15 min or 1 month of separation, exposure to novel rams increased pulsatile LH secretion (P < 0.05) and induced an LH surge in all ewes whereas exposure to familiar rams or novel wethers had no effect on LH secretion (P > 0.1). After 1 month of separation, re-exposure to the same familiar rams increased pulsatile LH secretion (P < 0.05) in six of eight ewes, but only induced an LH surge in two of eight ewes. In Experiment 2, familiar rams were removed and returned after 15 min, 1 day or 17 days (n = 5 per treatment). None of these treatments affected LH secretion. We conclude that separation of ewes from rams is a prerequisite for familiar rams to increase LH secretion, but is not necessary if the rams are novel.
一般认为，在雄性刺激增加促性腺激素分泌并诱导排卵之前，母羊需要与公羊分开。在本研究中，我们调查了母羊在不同时间间隔与公羊分开后，对“陌生”和“熟悉”公羊的促黄体生成素（LH）反应。在实验1中，将母羊（每组8只）与熟悉的公羊分开15分钟或1个月，然后让它们接触熟悉的公羊、陌生的公羊或陌生的阉羊。在分开15分钟或1个月后，接触陌生公羊会增加母羊促黄体生成素的脉冲式分泌（P < 0.05），并在所有母羊中诱导促黄体生成素激增，而接触熟悉的公羊或陌生的阉羊对促黄体生成素分泌没有影响（P > 0.1）。在分开1个月后，再次接触相同的熟悉公羊，8只母羊中有6只促黄体生成素的脉冲式分泌增加（P < 0.05），但只有2只母羊诱导出促黄体生成素激增。在实验2中，将熟悉的公羊移除，15分钟、1天或17天后再放回（每组5只）。这些处理均未影响促黄体生成素的分泌。我们得出结论，母羊与公羊分开是熟悉的公羊增加促黄体生成素分泌的前提条件，但如果公羊是陌生的，则没有必要分开。
