摘要
Cervical anatomy limits the use of transcervical intrauterine artificial insemination (TC AI) in sheep. We have developed an instrument to cope atraumatically with the cervix; although this instrument has not affected fertilization rate or pregnancy rate through Day 3, the effects on sperm transport and pregnancy after Day 3 are not known. The objective of the present study was to determine whether our TC AI instrument affected sperm transport, pregnancy rates, or lambing rate. In Experiment 1, ewes were assigned to two treatments: TC AI using the new TC AI instrument (n=10) or AI via laparotomy using a laparoscopic AI instrument (n=10). Twenty hours after artificial insemination, the uterine horns and oviducts were recovered and flushed to collect spermatozoa. Sperm transport did not differ (P>0.05) between the two treatments. In Experiment 2, ewes were assigned to three treatments: TC AI using the new TC AI instrument+sham intrauterine AI via laparotomy (n=29); sham TC AI+intrauterine AI via laparotomy using a laparoscopic AI instrument (n=29); and sham TC AI+intrauterine AI via laparotomy using the new TC AI instrument (n=30). On Day 14 after AI, uteri were collected and flushed to recover blastocysts. Transcervical deposition of semen reduced (P<0.05) Day 14 pregnancy rate (17.2% versus 61%), but intrauterine deposition of semen using the TC AI instrument via midventral laparotomy increased (P<0.05) Day 14 pregnancy rate (76.6% versus 44.8%). In Experiment 3, ewes were assigned to two treatments: sham cervical manipulation (n=40) or cervical manipulation to mimic TC AI (n=40). Immediately after treatment, each ewe was mated with a ram and watched until the ram mounted and ejaculated into the ewe. Treatment did not affect Day 30 or 50 pregnancy rate (67.5 and 66.2%, respectively), determined ultrasonically, or lambing rate (62.5%). The differences between Days 30 and 50 pregnancy rates and lambing rate were not significant. In Experiment 4, ewes were assigned to two treatments: TC AI (n=99) or laparoscopic AI (n=99). Transcervical AI reduced (P<0.01) Day 30 (TC AI versus laparoscopic AI; 5.0% versus 46.0%) and Day 50 pregnancy rates (4.0% versus 41.0%), determined ultrasonically, and lambing rate (4.0% versus 41.0%). Although the TC AI procedure significantly reduced pregnancy and lambing rates, large numbers of spermatozoa deposited at natural insemination seemed to compensate. Because our TC AI procedure has all but eliminated any visual evidence of trauma, and because the procedure does not seem to affect sperm transport or embryonal survival until Day 3, we speculate that cervical manipulation associated with TC AI may activate pathways that interrupt pregnancy between Days 3 and 14.
摘要译文
宫颈解剖限制使用经宫颈子宫内人工授精（TC AI）的羊。我们开发了一种仪器来防止宫颈受损。尽管该仪器在第3天没有影响受精率或妊娠率，但第3天后对精子运输和妊娠的影响尚不清楚。本研究的目的是确定我们的TC AI仪器是否影响精子运输，妊娠率或产羔率。在实验1中，母羊被分配到两个处理：TC AI使用新的TC AI仪器（n \x3d 10）或AI通过剖腹手术使用腹腔镜AI仪器（n \x3d 10）。人工授精20小时后，子宫角和输卵管被回收和冲洗收集精子。两种处理之间的精子运输没有差异（P 0.05）。在实验2中，母羊被分配到三个处理：TC AI使用新的TC AI仪器+假宫内AI通过剖腹手术（29例）;使用腹腔镜AI仪器（n \x3d 29），通过剖腹手术假发TC AI +宫内AI。并使用新的TC AI仪器（n \x3d 30）通过剖腹手术假发TC AI +子宫内AI。在AI之后的第14天，收集子宫并冲洗以回收囊胚。精液经宫颈沉积减少（P 0.05）第14天妊娠率（17.2％对61％），但使用TC AI仪经宫腔剖腹探查发现子宫内精液沉积增加（P 0.05），第14天妊娠率（76.6％比44.8％）。在实验3中，母羊被分配到两个处理：假颈椎操纵（40例）或宫颈操纵模仿TC AI（40例）。治疗后立即，每只母羊都与一只公羊交配，直到公羊被安放并射入母羊为止。治疗不影响第30或50天的妊娠率（分别为67.5和66.2％），超声确定，或产羔率（62.5％）。第30和50天怀孕率和产羔率之间的差异不显着。在实验4中，母羊被分配到两个处理：TC AI（n \x3d 99）或腹腔镜AI（n \x3d 99）。经阴道宫颈AI降低（P 0.01）第30天（TC AI与腹腔镜AI：5.0％对46.0％）和第50天的妊娠率（4。0％比41.0％），超声测定和产羔率（4.0％对41.0％）。尽管TC AI程序显着降低了怀孕和产羔率，在自然授精过程中沉积的大量精子似乎可以补偿。由于我们的TC AI程序几乎消除了任何外伤的视觉证据，并且因为该程序在第3天似乎不影响精子运输或胚胎存活，我们推测与TC AI相关的子宫颈操纵可能会激活在第3天和第14天之间中断妊娠的途径。
Meghan CWulster-Radcliffe[1];ShiquanWang;Gregory SLewis;. Transcervical artificial insemination in sheep: effects of a new transcervical artificial insemination instrument and traversing the cervix on pregnancy and lambing rates☆[J]. Theriogenology, 2004,62(6): 990-1002