The incompletely fulfilled promise of embryo transfer in cattle-why aren't pregnancy rates greater and what can we do about it?
The incompletely fulfilled promise of embryo transfer in cattle-why aren't pregnancy rates greater and what can we do about it?
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DOI：
10.1093/jas/skaa288
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发表时间：
2020-11-01
影响因子：
3.3
通讯作者：
Hansen PJ
中科院分区：
文献类型：
--
作者：
Hansen PJ
通常，牛胚胎在发情或预期排卵后约7天被移植到受体雌性中，此时胚胎已达到发育的胚泡阶段。当将囊胚期胚胎移植到雌性动物体内时，避免了自然或人工授精（AI）后7天雌性动物未能产生囊胚的所有生物学和技术原因。因此，可以合理地预期胚胎移植（ET）受体的妊娠成功率高于授精的雌性。这种期望通常不会得到满足，除非受体暴露于热应激或被归类为重复繁殖雌性。相反，ET和AI的妊娠成功率通常相似。这意味着ET的一个或多个技术方面尚未优化，或者导致胚胎在第7天之前死亡的潜在女性生育能力也会导致其在怀孕后期死亡。ET后妊娠成功率的提高将取决于制造更好的胚胎，改善子宫容受性，以及打造生产和移植胚胎的新工具。加快提高妊娠率的关键是鉴定表型或表型组，从而预测胚胎的存活能力和母体支持胚胎发育的能力。
Typically, bovine embryos are transferred into recipient females about day 7 after estrus or anticipated ovulation, when the embryo has reached the blastocyst stage of development. All the biological and technical causes for failure of a female to produce a blastocyst 7 d after natural or artificial insemination (AI) are avoided when a blastocyst-stage embryo is transferred into the female. It is reasonable to expect, therefore, that pregnancy success would be higher for embryo transfer (ET) recipients than for inseminated females. This expectation is not usually met unless the recipient is exposed to heat stress or is classified as a repeat-breeder female. Rather, pregnancy success is generally similar for ET and AI. The implication is that either one or more of the technical aspects of ET have not yet been optimized or that underlying female fertility that causes an embryo to die before day 7 also causes it to die later in pregnancy. Improvements in pregnancy success after ET will depend upon making a better embryo, improving uterine receptivity, and forging new tools for production and transfer of embryos. Key to accelerating progress in improving pregnancy rates will be the identification of phenotypes or phenomes that allow the prediction of embryo competence for survival and maternal capacity to support embryonic development.
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DOI：
10.1530/jrf.0.0590205
发表时间：
1980-01-01
期刊：
JOURNAL OF REPRODUCTION AND FERTILITY
影响因子：
--
作者：
BETTERIDGE, KJ;EAGLESOME, MD;MITCHELL, D
通讯作者：
MITCHELL, D
影响因子：
3.5
作者：
Burnett, Tracy A.;Polsky, Liam;Cerri, Ronaldo L. A.
通讯作者：
Cerri, Ronaldo L. A.
影响因子：
2.8
作者：
An, Liyou;Marjani, Sadie L.;Du, Fuliang
通讯作者：
Du, Fuliang
影响因子：
2.8
作者：
Barbosa, L. F. S. P.;Oliveira, W. V. C.;Vasconcelos, J. L. M.
通讯作者：
Vasconcelos, J. L. M.
影响因子：
2.8
作者：
Chebel, R. C.;Demetrio, D. G. B.;Metzger, J.
通讯作者：
Metzger, J.