Lopes A S, Butler S T, Gilbert R O, Butler W R
Danish Institute of Agricultural Sciences, 8830 Tjele, Denmark.
Anim Reprod Sci. 2007 May;99(1-2):34-43. doi: 10.1016/j.anireprosci.2006.04.056. Epub 2006 Jun 13.
This study was carried out to evaluate effects of pre-ovulatory follicle size, plasma concentrations of estradiol and progesterone, and season on pregnancy outcomes in dairy cows. Holstein cows (n = 144) were synchronized and inseminated (Ovsynch/TAI protocol) in two distinct periods (cold versus warm season). Blood samples were collected daily from AI (day 0) to day 8 and on days 15, 22, 29, 36 and 64 to measure progesterone and estradiol. Pregnancy diagnosis was performed at days 29, 43 and 64. The pre-ovulatory follicle size was larger and the plasma estradiol concentrations on the day of AI were greater in animals that became pregnant. Plasma progesterone concentrations diverged and became greater after day 5 post-AI, in cows diagnosed pregnant, as compared to non-pregnant cows. The overall pregnancy rate (33%) or late embryonic/early fetal losses (23%) did not differ between seasons, but plasma estradiol concentrations on the day of AI and plasma concentrations of progesterone in pregnant cows were lower in the warm season. Reduced CL function, measured as plasma progesterone concentrations, from days 22 or 29 post-AI onward for cold and warm season, respectively, was associated with subsequent late embryonic/early fetal mortality. Overall, pregnancy was related to diameter of the pre-ovulatory follicle and plasma E2 on the day of AI, but embryonic/fetal losses were not. Season did not affect these outcomes, even though it influenced luteal function after AI.
本研究旨在评估排卵前卵泡大小、血浆雌二醇和孕酮浓度以及季节对奶牛妊娠结局的影响。选用144头荷斯坦奶牛,在两个不同时期(冷季与暖季)采用同期发情和定时人工授精(Ovsynch/TAI方案)。从人工授精日(第0天)至第8天以及第15、22、29、36和64天每天采集血样,检测孕酮和雌二醇。在第29、43和64天进行妊娠诊断。怀孕动物的排卵前卵泡更大,人工授精当天的血浆雌二醇浓度更高。与未怀孕奶牛相比,怀孕奶牛在人工授精后第5天血浆孕酮浓度出现差异并升高。季节间总体妊娠率(33%)或胚胎后期/胎儿早期损失率(23%)无差异,但暖季人工授精当天的血浆雌二醇浓度和怀孕奶牛的血浆孕酮浓度较低。分别在冷季和暖季人工授精后第22天或第29天起,以血浆孕酮浓度衡量的黄体功能降低与随后的胚胎后期/胎儿早期死亡率相关。总体而言,妊娠与排卵前卵泡直径和人工授精当天的血浆E2有关,但与胚胎/胎儿损失无关。季节虽影响人工授精后的黄体功能,但不影响这些结局。