Clarke L, Yakubu D P, Symonds M E
School of Animal and Microbial Sciences, The University of Reading, Whiteknights, UK.
Reprod Fertil Dev. 1997;9(5):509-14. doi: 10.1071/r97016.
Although body condition score was not significantly different between light (<55 kg, n = 6) and heavy (> or =60 kg, n = 7) ewes at mating, it declined between Day 30 and Day 90 of gestation in light but not heavy ewes, and remained lower up to term. All ewes bore twins, delivered near term (Days 144-146) by Caesarean section. One lamb was immediately placed into a warm (30 degrees C; WD) and its twin into a cool (15 degrees C; CD) ambient temperature, and tissues were sampled at 0.5 h or 6 h. All CD lambs born to light ewes exhibited hypothermia and/or respiratory failure and did not survive longer than 30 min; these symptoms were not observed in their WD twins or any lamb born to heavy ewes. Total lamb birth weight, placental weight and fetal cotyledonary weight were lower with light than with heavy ewes. Lambs born to light ewes had less perirenal adipose tissue and smaller liver, heart, kidneys, brain, adrenals and thyroid, although their heart, brain and pancreas represented a larger proportion of total bodyweight; pancreas weight was similar to that in lambs born to heavy ewes. Hence, maternal bodyweight critically influences placental weight and lamb size and survival after birth.
尽管在配种时，体重较轻（<55千克，n = 6）和体重较重（≥60千克，n = 7）的母羊体况评分没有显著差异，但在妊娠第30天至第90天期间，体重较轻的母羊体况评分下降，而体重较重的母羊则没有，并且直到足月时体重较轻母羊的体况评分仍较低。所有母羊都怀有双胞胎，在接近足月时（第144 - 146天）通过剖腹产分娩。一只羔羊立即被置于温暖（30摄氏度；WD）环境中，其双胞胎被置于凉爽（15摄氏度；CD）环境中，并在0.5小时或6小时时采集组织样本。所有体重较轻母羊所生的CD羔羊均出现体温过低和/或呼吸衰竭，存活时间不超过30分钟；在其WD环境中的双胞胎或体重较重母羊所生的任何羔羊中均未观察到这些症状。体重较轻母羊所生羔羊的出生总重、胎盘重量和胎儿绒毛叶重量均低于体重较重的母羊。体重较轻母羊所生的羔羊肾周脂肪组织较少，肝脏、心脏、肾脏、大脑、肾上腺和甲状腺较小，尽管它们的心脏、大脑和胰腺占总体重的比例较大；胰腺重量与体重较重母羊所生羔羊的胰腺重量相似。因此，母体体重对胎盘重量、羔羊大小及出生后的存活情况有着至关重要的影响。
