Dalin A M, Eliasson L
Acta Vet Scand. 1987;28(3-4):263-9. doi: 10.1186/BF03548592.
Thirty-six gilts which had not shown oestrus at about 8 months of age or more were transported from the pig research station to the clinic, a journey of 12 km. The gilts were examined by laparoscopy and those which had only small follicles in the ovaries were catheterized and placed in pens, with sexually mature boars kept in adjacent pens. Oestrus detection was done twice daily and blood was sampled three times a day. After 7 days the laparoscopy was repeated and gilts which still had only small follicles in their ovaries were given 250 μg GnRH intravenously the following day. Blood samples were taken frequently before and after GnRH treatment. One week. after administration of GnRH the ovaries were inspected by laparoscopy once more. The first laparoscopic examination showed that 42 % of the gilts were sexually mature. One gilt had no uterus or ovaries. Twenty gilts had only small follicles in the ovaries and fourteen of these gilts showed ovulatory oestrus 5.5 days (4-7.5 days) after arrival. In these fourteen gilts a rise in the oestradiol-17B level (>30 pmol/1) was seen at an average time of 1.9 days and a rise in LH (preovulatory peak) was seen at an averaged 4.5 days after the start of blood sampling. Six gilts were given 250 ug GnRH. An immediate rise in LH could be seen in all the gilts (mean peak level was 6.18 μg/l) and the elevated levels had a duration of 4 hours. None of the GnRH-treated gilts responded with oestrus symptoms or increased ovarian activity.
36头约8月龄及以上未出现发情的后备母猪从养猪研究站运至诊所，行程12公里。通过腹腔镜检查这些后备母猪，卵巢中只有小卵泡的母猪进行插管并放入栏中，相邻栏中饲养性成熟公猪。每天进行两次发情检测，每天采集三次血液样本。7天后重复腹腔镜检查，卵巢中仍只有小卵泡的后备母猪在第二天静脉注射250μg促性腺激素释放激素（GnRH）。在GnRH治疗前后频繁采集血样。GnRH给药一周后，再次通过腹腔镜检查卵巢。第一次腹腔镜检查显示42%的后备母猪性成熟。一头后备母猪没有子宫或卵巢。20头后备母猪卵巢中只有小卵泡，其中14头在到达后5.5天（4 - 7.5天）出现排卵发情。在这14头后备母猪中，平均在采血开始后1.9天观察到雌二醇-17β水平升高（>30 pmol/L），平均在4.5天观察到促黄体生成素（LH，排卵前峰值）升高。6头后备母猪给予250μg GnRH。所有后备母猪均可见LH立即升高（平均峰值水平为6.18μg/L），且升高水平持续4小时。经GnRH处理的后备母猪均未出现发情症状或卵巢活动增加。
