Abstract：
The reproductive performance of ewe hoggets is poorer than that of mature-age ewes due to production of fewer lambs with poorer survival. Scant data are available on the risk factors for, and causes of, the mortality for lambs born to ewe hoggets, the impact of ewe deaths on lamb loss, and the causes of death for lambs born to ewe hoggets vs. mature-age ewes lambing in the same circumstances. In this study, 297 lambs born to 1142 ewe hoggets were necropsied along with 273 lambs born to 1050 mature-age ewes. Low lamb birthweight, multiple litter size, and increasing ewe hogget average daily gain from breeding to late pregnancy were risk factors for lamb mortality. The most common cause of mortality for lambs born to ewe hoggets was stillbirth and the risk factors for stillbirth were similar to those for lamb mortality generally. Approximately 11% of ewe hoggets\' lamb deaths were due to the death of the dam. Causes of mortality differed between lambs born to ewe hoggets vs. those born to mature-age ewes. Management practices to increase ewe hogget lambs\' birthweights (particularly those from multiple litters) and supervision of ewe hoggets at lambing time are recommended.
摘要：
母羊猪的繁殖性能比成熟母羊差，因为羔羊的产量较少，存活率较差。关于以下风险因素的数据很少，和原因，母猪所生的羔羊的死亡率，母羊死亡对羔羊损失的影响，母羊猪出生的羔羊的死亡原因与成熟时代的母羊在相同的情况下产仔。在这项研究中,对1142只母羊所生的297只羔羊和1050只成熟母羊所生的273只羔羊进行了尸检。低羔羊出生体重，多个产仔数,母羊从繁殖到妊娠晚期的平均日增重增加是羔羊死亡的危险因素。母猪出生的羔羊最常见的死亡原因是死产，死产的危险因素与羔羊死亡率的危险因素相似。大约11%的母羊猪\'羔羊死亡是由于大坝的死亡。母羊猪与母羊出生的羔羊之间的死亡原因不同那些出生在成熟年龄的母羊。建议采取管理措施，以增加母羊猪羔羊的出生重量（尤其是来自多个窝的羔羊），并在产羊时间对母羊猪进行监督。
