Litter size in modern so called hyperprolific pig (Sus scrofa Linnaeus) breeds such as of crossbred Danish Landrace x Danish Yorkshire (LY/YL) sows increased remarkably over recent years, however, commonly associated with reduced piglet birth weight and higher within litter birth weight variability likely due to a limited uterine capacity. Since investigation into this issue is patchy, the aim of this study was to investigate uterine capacity based on litter and placental characteristics in two sow lines with different prolificacy, that is crossbred Danish genetic (Danish Landrace x Danish Yorkshire; DG; n = 14) and purebred German Saddleback (GS) sows (n = 12). Parameters recorded were litter size, piglet birth weight and vitality, placental weight and surface area as well as placental vascularization. Litters of DG were on average larger than of GS (p < .001). Piglets of DG weighed on average less than GS (p < .001) and were less vital (p < .001–.142). Increasing litter size was associated with reduced piglet birth weight and increased within litter birth weight variability in GS, but not in DG. DG had on average a lower placental weight (p < .001) and smaller placentae (p < .001) than GS, but the placenta was on average more efficient than of GS (based on the quotient of piglet and corresponding placental weight; p < .001). Vascularization of placentae was on average not or only slightly different between breeds (p < .05 – .982). Remarkably, however, vascularization of the lateral and apical chorionic epithelium of the chorionic ridges as the immediate foetal/maternal interface was on average slightly higher in DG than GS (p < .05–.111). Results thus demonstrate that uterine capacity based on litter and placental characteristics is higher in DG than GS sows.

中文翻译：

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根据多胎和多胎两种母猪的产仔和胎盘特性对子宫容量进行调查（丹麦长白×丹麦约克郡与德国马鞍形）

近年来，所谓的高产猪（Sus scrofa Linnaeus）的杂种大小（如杂交丹麦地方品种x丹麦约克郡（LY / YL）母猪）近年来显着增加，但通常与仔猪出生体重降低和窝产仔体重增加有关子宫容量有限可能导致变异性。由于对该问题的调查是零星的，因此本研究的目的是根据具有不同繁殖力的两头母猪系的繁殖力和胎盘特性来研究子宫容量，这两种母猪是丹麦的杂交种（Danish Landrace x Danish Yorkshire； DG；n  = 14）。和纯种德国马鞍（GS）母猪（n = 12）。记录的参数是产仔数，仔猪出生体重和生命力，胎盘重量和表面积以及胎盘血管形成。DG的凋落物平均大于GS（p  <.001）。DG的仔猪平均体重小于GS（p  <.001），而活力较弱（p  <.001–.142）。GS中的产仔数增加与仔猪出生体重的降低相关，而GS中的产仔体重变异性增加，而DG中的则不增加。DG平均 比GS具有更低的胎盘重量（p  <.001）和较小的胎盘（p <.001），但是平均而言，胎盘比GS更有效（基于仔猪和相应胎盘重量的比值；p <.001）。平均而言，不同品种之间胎盘的血管化没有或只有一点点不同（p  <.05 – .982）。然而，值得注意的是，DG的直接胎儿/母体界面的绒毛膜的绒毛膜的外侧和顶端绒毛膜上皮的血管形成平均比GS略高（p  <.05–.111）。因此结果表明，DG的母猪的产仔量和胎盘特性要高于GS母猪。