Clune Thomas, Lockwood Amy, Hancock Serina, Thompson Andrew N, Beetson Sue, Campbell Angus J D, Glanville Elsa, Brookes Daniel, Trengove Colin, O'Handley Ryan, Kearney Gavin, Jacobson Caroline
Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, WA 6150, Australia.
Nossal Institute for Global Health, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC 3010, Australia.
Animals (Basel). 2021 Dec 21;12(1):10. doi: 10.3390/ani12010010.
The contribution of abortions to the overall mortality of lambs born to maiden (primiparous) ewes in Australia remains unclear. This cohort study aimed to quantify abortion and lamb mortality for ewe lambs and maiden Merino two-tooth ewes. Lamb mortality from pregnancy scanning to marking were determined for 19 ewe lamb and 11 Merino two-tooth ewe flocks across southern Australia. Average lamb mortality from scanning to marking was 35.8% (range 14.3-71.1%) for the ewe lambs and 29.4% (range 19.7-52.7%) for the two-tooth ewes. Mid-pregnancy abortion was detected in 5.7% of ewes (range 0-50%) in the ewe lamb flocks and 0.9% of ewes (range 0-4.4%) in the two-tooth ewe flocks. Mid-pregnancy abortion affecting ≥2% of ewes was observed in 6/19 ewe lamb flocks and 2/11 two-tooth ewe flocks. Lamb mortality from birth to marking represented the greatest contributor to foetal and lamb mortality after scanning, but mid-pregnancy abortion was an important contributor to lamb mortality in some ewe lamb flocks. Variability between the flocks indicates scope to improve the overall reproductive performance for maiden ewes by reducing foetal and lamb losses. Addressing mid-pregnancy abortion may improve the reproductive performance in some flocks.
在澳大利亚，流产对初产（首次产仔）母羊所产羔羊总体死亡率的影响尚不清楚。这项队列研究旨在量化初产母羊和首次产仔的美利奴双齿母羊的流产率和羔羊死亡率。对澳大利亚南部的19个初产母羊和11个美利奴双齿母羊群体，测定了从妊娠扫描到打标记期间的羔羊死亡率。初产母羊从扫描到打标记期间的平均羔羊死亡率为35.8%（范围为14.3%-71.1%），双齿母羊为29.4%（范围为19.7%-52.7%）。在初产母羊群体中，5.7%的母羊（范围为0%-50%）被检测到妊娠中期流产，在双齿母羊群体中为0.9%的母羊（范围为0%-4.4%）。在19个初产母羊群体中有6个、11个双齿母羊群体中有2个观察到妊娠中期流产影响到≥2%的母羊。从出生到打标记期间的羔羊死亡率是扫描后胎儿和羔羊死亡的最大原因，但妊娠中期流产在一些初产母羊群体中是羔羊死亡的重要原因。群体间的差异表明，通过减少胎儿和羔羊损失来提高初产母羊总体繁殖性能的空间很大。解决妊娠中期流产问题可能会提高一些群体的繁殖性能。
