SummaryTwo farms applying reproductive technology for the Nellore beef cattle were selected. Both farms had the same technology programme of oestrous synchronization and embryo transfer, but management was different, especially regarding twins pregnancies. In the present study, we followed the farms from the moment of oestrous synchronization, embryo transfer (two per cow), until delivery and first care of the calves. In farm A, cows presenting twin pregnancies (5 from 13) were submitted to delivery induction, as well as calves and cows were monitored after birth. In farm B, such management was not followed with the twin pregnant cows (31 from 49). In both farms, freemartinism was detected, but this was not a problem as none of the animals would be selected for breeding. No dystocia was observed in farm A, while 48% of the twin pregnancies in farm B ended up in dystocia. Furthermore, the mortality rate of new-born calves in farm A was 10%, while in farm B it reached 32%. Although twin pregnancies remain a concern, we showed here that proper management during and after delivery minimizes animal and economic losses.

中文翻译：

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管理由体外生产的 Nellore 胚胎移植引起的双胎妊娠后的胚胎和小牛损失

摘要选择了两个应用 Nellore 肉牛繁殖技术的农场。两个农场都有相同的发情同步和胚胎移植技术方案，但管理不同，特别是在双胞胎怀孕方面。在本研究中，我们从发情同步、胚胎移植（每头奶牛两个）到分娩和小牛的第一次护理，一直跟踪农场。在农场 A，双胎妊娠的奶牛（13 头中的 5 头）接受分娩诱导，并在出生后监测小牛和奶牛。在农场 B，对双胎妊娠奶牛（49 头中的 31 头）没有进行这种管理。在这两个农场中，都检测到了freemartinism，但这不是问题，因为没有一只动物会被选中进行繁殖。农场 A 未观察到难产，而农场 B 中 48% 的双胞胎妊娠以难产告终。此外，农场 A 的新生小牛死亡率为 10%，而农场 B 则达到 32%。尽管双胞胎怀孕仍然是一个问题，但我们在这里表明，分娩期间和分娩后的适当管理可以最大限度地减少动物和经济损失。