Jang Y D, Ma Y L, Lindemann M D
Department of Animal and Food Sciences, University of Kentucky, Lexington 40546.
Department of Animal and Food Sciences, University of Kentucky, Lexington 40546
J Anim Sci. 2014 Oct;92(10):4400-6. doi: 10.2527/jas.2014-7762. Epub 2014 Aug 22.
To investigate the effect of intrauterine positions on fetal growth throughout gestation, data from a total of 65 gilts (n = 784 fetuses) that were slaughtered at assigned days of gestation (d 43, 58, 73, 91, 101, and 108) on a project to evaluate fetal mineral deposition were used. Placenta units were removed from the uterus, and position, sex, weight, and crown-rump length (CRL) of each fetus were recorded. Fetuses were classified into 5 categories within a uterine horn for the absolute intrauterine position: the ovarian end (OE) of the uterine horn, next to the ovarian end (NOE), the middle (MD), next to the cervical end (NCE), and the cervical end (CE), and also classified for the relative fetal position with respect to the sex of adjacent fetuses. Fetuses at the OE and NOE of the uterine horn tended to be heavier (P = 0.06) and longer (P < 0.05) than those at the MD of the uterine horn at d 58 of gestation. Fetuses at the OE of the uterine horn were also heavier and longer than those at the MD and NCE of the uterine horn at d 101 and 108 of gestation (P < 0.05). Fetuses at the CE of the uterine horn were intermediate in weight and length. There were no major effects of adjacent fetal sex (fetuses surrounded by the opposite sexes) in weight or length. Male fetuses were heavier than female fetuses at d 43, 58, 73, and 108 of gestation (P < 0.05) and longer than female fetuses at d 58 (P = 0.06), 73 (P < 0.05), 101 (P = 0.07), and 108 (P < 0.05) of gestation. Fetal weight was highly correlated with CRL at all gestational ages (P < 0.01). These results indicate that 1) the absolute intrauterine position affects fetal growth more than the sex of the adjacent fetus in the uterine horn, 2) each end of the uterine horn (OE and CE) has heavier fetuses than the MD, and 3) male pigs grow faster than female pigs even before birth.
为研究整个妊娠期子宫内位置对胎儿生长的影响，我们使用了一个评估胎儿矿物质沉积项目中，在指定妊娠日（第43、58、73、91、101和108天）屠宰的65头后备母猪（共784头胎儿）的数据。从子宫中取出胎盘单位，记录每个胎儿的位置、性别、体重和顶臀长（CRL）。在子宫角内，根据绝对子宫内位置将胎儿分为5类：子宫角的卵巢端（OE）、紧邻卵巢端（NOE）、中间（MD）、紧邻子宫颈端（NCE）和子宫颈端（CE），并根据相邻胎儿的性别对相对胎儿位置进行分类。在妊娠第58天时，子宫角OE和NOE处的胎儿往往比子宫角MD处的胎儿更重（P = 0.06）、更长（P < 0.05）。在妊娠第101天和108天时，子宫角OE处的胎儿也比子宫角MD和NCE处的胎儿更重、更长（P < 0.05）。子宫角CE处的胎儿体重和长度处于中间水平。相邻胎儿性别（被异性胎儿包围的胎儿）对体重或长度没有主要影响。在妊娠第43、58、73和108天时，雄性胎儿比雌性胎儿更重（P < 0.05），在妊娠第58天（P = 0.06）、73天（P < 0.05）、101天（P = 0.07）和108天（P < 0.05）时，雄性胎儿比雌性胎儿更长。在所有妊娠阶段，胎儿体重与CRL高度相关（P < 0.01）。这些结果表明：1）子宫内绝对位置对胎儿生长的影响大于子宫角内相邻胎儿的性别；2）子宫角的两端（OE和CE）的胎儿比MD处的胎儿更重；3）雄性猪在出生前比雌性猪生长得更快。
