能量对妊娠后期母羊健康及其羔羊的影响

妊娠后期是胎儿生长发育的关键时期，胎儿体重增长的80%在此阶段完成，因此该阶段母羊的能量需要量大于其他生理阶段。高产多胎是肉用种母羊的重要培育目标，当母羊处于营养水平较低的草场或舍饲条件下，怀双羔或多羔母羊的日粮能量水平不能满足其营养需要时，母羊会动用体内的糖原、体蛋白和体脂以弥补能量不足，致使母羊的代谢紊乱，肝机能受损，产生羊妊娠毒血症，影响母羊的健康和胚胎的健康生长，产出弱羔、病羔，并可能影响产后羔羊的健康生长。因此，研究妊娠后期能量水平对母羊健康、胚胎发育、羔羊生长及肉羊养殖业的发展都有重要的指导意义。作者对不同能量水平对妊娠母羊的健康、繁殖性能、泌乳性能、胚胎与羔羊生长的影响展开讨论，阐明妊娠后期能量的作用。当母羊妊娠后期能量受到限制时，母羊的体重降低，乳腺发育受阻，泌乳能力下降，受胎率下降；同时胚胎的生长速度降低，影响胚胎与产后羔羊组织器官发育和正常生长。

Effect of Energy Levels During Late Gestation on the Ewe Health and Growth Performance of Lambs

The late pregnancy is a critical period of fetal growth and development. As approximately 80% of fetal body weight is obtained during late gestation, so that the amount of energy needed for the ewes at this period is much greater than the other periods. Now ewes with multiple fetuses are mutton sheep breeding cultivation objectives, however,under the grazing or confined feeding conditions where nutrient requirement can't satisfy the nutrient requirement of sheep, especially for pregnant ewes with twins or more lambs.The body glycogen and protein as well as body fat will be mobilized for energy needed for the fetal growth and reproduction, which would lead to bad influence on ewes (metabolic disorders, liver function damage, pregnancy toxemia, embryonic development and health) and also on lamb (weak lamb, dead lamb and health). Therefore, investigating the effects of dietary energy levels during late gestation on the ewe's health and growth performance of lambs are essential for the sustainability of livestock production systems. This review summarized the effect of different energy levels on the ewes' health, reproductive performance of the ewes, lactation performance, embryo development and the growth of lambs, then expounded the roles of energy in later gestation. When the dietary energy of ewes in late gestation are restricted, the weight, breast development, lactation capacity, pregnancy rate will all be decreased, and the growth rate and organ development of embryos and lamb will also be restricted.