de Blockey M A, Parr R A, Restall B J
Aust Vet J. 1975 Jun;51(6):298-302. doi: 10.1111/j.1751-0813.1975.tb06957.x.
Eight sub-flocks each of 48 to 51 Merino ewes were mated for 18 days with 1 ram to each subflock. Four of the sub-flocks were of non-parous 1.5-year-old ewes and the other 4 were of parous 2.5-year-old ewes. Fertilisation rates for the subflocks of 1.5-year-old ewes varied from 83 to 94%, and the sub-flocks of 2.5-year-old ewes ranged from 81 to 94%. By day 29 post coitum 42% and 56% of 1.5-year-old ewes in sub-flocks 1 and 2 respectively were no longer pregnant. Embryonic mortality was low in other sub-flocks of 1.5- and 2.5-year-old ewes. Virtually all embryonic death occurred after day 12 post coitum. The sporadic occurrence of high ova wastage in maiden 1.5-year-old ewes in this experiment and in others is discussed in relation to the short duration of oestrus in young ewes and the great variation in service activity of rams.
将8个亚群，每个亚群有48至51只美利奴母羊，与1只公羊配种18天，每个亚群配备1只公羊。其中4个亚群是1.5岁未产的母羊，另外4个亚群是2.5岁经产的母羊。1.5岁母羊亚群的受胎率在83%至94%之间，2.5岁母羊亚群的受胎率在81%至94%之间。在配种后第29天，亚群1和亚群2中分别有42%和56%的1.5岁母羊不再怀孕。在1.5岁和2.5岁母羊的其他亚群中，胚胎死亡率较低。几乎所有胚胎死亡都发生在配种后第12天之后。结合年轻母羊发情期持续时间短以及公羊配种活动差异大的情况，讨论了本实验及其他实验中1.5岁初产母羊偶尔出现高卵子浪费现象的原因。
