Valasi Irene, Menegatos I, Papanikolaou Th, Goulas P, Amiridis G S
Department of Reproduction and Obstetrics, Veterinary Faculty, University of Thessaly, Trikalon Str., PO Box 199, 43100 Karditsa, Greece.
Theriogenology. 2006 Dec;66(9):2144-51. doi: 10.1016/j.theriogenology.2006.07.001. Epub 2006 Aug 30.
A study was designed to evaluate whether the time of onset of puberty and fertility of young ewe lambs would be affected by oocyte pick-up conducted in single or repeated sessions during the first months of lambs' live. Five groups of lambs from the Karagouniko breed were used (A-E each n=12). In group A no treatments were applied (control group) while, laparoscopical follicular aspiration (OPU) was performed early in the third, fourth and fifth month of lambs age (groups C-E, respectively). From the second to fifth month of their age, group B lambs were aspirated four times in monthly intervals. All lambs were weighed at birth, weaning, at second month and monthly thereafter until the eighth month of age. Progesterone priming and ovarian stimulation by serial FSH administrations proceeded each OPU session. To determine onset of puberty blood progesterone concentration was assayed in samples collected initially every week and after the seventh month of age twice weekly. From the seventh month a fertile ram was introduced in each group and oestrous behavior/mating was daily monitored and recorded. Pregnancy diagnosis was carried out by transabdominal ultrasound scanning 55 days after rams' removal. At the fourth and fifth month of age group B lambs were lighter (p<0.05) than controls, but this difference was later equalized. The time of onset of puberty did not differ between groups (p=0.069) and ranged between 224 and 270 days. Some animals (n=15) entered puberty with a full-length luteal phase having progesterone concentration greater than 1ng/ml, while others (n=32) exhibited one or two short luteal phases before luteal length restoration. During the first breeding season 41 animals were fertilized and maintained pregnancy to term, without noticeable differences between groups (p=0.555). During the second breeding season, all ewes were naturally served and lambed at the expected time. It is concluded that OPU in young dairy lambs does not affect the time of onset of puberty, the endocrine profile of the lambs and it does not compromise their future fertility even if it is applied at four successive months.
一项研究旨在评估在羔羊出生后的头几个月进行单次或重复采卵，是否会影响年轻母羊羔羊的青春期和生育能力的起始时间。使用了五组卡拉古尼科品种的羔羊（A - E组，每组n = 12）。A组不进行任何处理（对照组），而在羔羊年龄的第三个月、第四个月和第五个月早期分别对C - E组进行腹腔镜卵泡抽吸（OPU）。从第二个月到第五个月，B组羔羊每月进行一次采卵，共四次。所有羔羊在出生、断奶、第二个月以及此后每月称重，直至八个月龄。每次OPU操作前都进行孕酮预处理和通过连续注射促卵泡素进行卵巢刺激。为了确定青春期的起始时间，最初每周采集样本检测血孕酮浓度，在七个月龄后每周检测两次。从七个月龄开始，每组引入一只可育公羊，每天监测并记录发情行为/交配情况。在公羊移出55天后通过经腹超声扫描进行妊娠诊断。在第四个月和第五个月龄时，B组羔羊比对照组轻（p<0.05），但这种差异后来消失了。各实验组之间青春期起始时间没有差异（p = 0.069），范围在224至270天之间。一些动物（n = 15）进入青春期时黄体期完整，孕酮浓度大于1ng/ml，而其他动物（n = 32）在黄体期长度恢复之前表现出一个或两个短黄体期。在第一个繁殖季节中有41只动物受精并维持妊娠至足月，各实验组之间没有显著差异（p = 0.555）。在第二个繁殖季节，所有母羊自然受孕并在预期时间产羔。得出的结论是，即使在连续四个月对年轻母羊羔羊进行OPU，也不会影响其青春期起始时间、内分泌特征，且不会损害其未来的生育能力。
