Embryo loss in cattle between Days 7 and 16 of pregnancy
Embryo loss in cattle between Days 7 and 16 of pregnancy
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DOI：
10.1016/j.theriogenology.2009.09.005
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发表时间：
2010-01-15
期刊：
影响因子：
2.8
通讯作者：
Pfeffer, P. L.
中科院分区：
文献类型：
--
作者：
Berg, D. K.;van Leeuwen, J.;Pfeffer, P. L.
使用2449个（3 - 30个组）体外生产（IVP）囊胚的移植，分析了非泌乳牛（Bos taurus）胚胎第7 - 16天（第0天= IVF当天）的胚胎丢失。在152次转移中，仅因受体失败而导致的妊娠损失在6%（肉牛）和16%（经产奶牛）之间，其中3%由子宫感染引起。无论是季节、年份，还是取出胚胎的年龄都不会影响怀孕率。后一项观察表明，受体未能保留胚胎的原因在移植时就已经存在。值得注意的是，随着移植更多的胚胎，特别是在后期（第14天，P < 0.01），回收的胚胎比例降低（P = 0.03）。每多移植一个胚胎，胚胎的平均长度减少约5%（P < 0.0001）。这些影响可能与胚胎迁移有关。妊娠第二周胚胎固有的死亡率为24%。此外，9%的第14天胚胎质量较差，因为它们不含外胚层。结合胚胎和受体原因，但不包括感染影响，妊娠第二周IVP胚胎的胚胎丢失率为26%（小母牛）或34%（经产奶牛）。在第9天至第16天之间，胚胎的长度每天增加一倍，大小范围为4.4倍，占长度变化的三分之二。从小母牛中取出的胚胎大小是经产母牛中孵育的胚胎大小的两倍（P < 0.0001），表明小母牛中胚胎发育/滋养层增殖更快。而季节不影响胚胎回收率，冬季胚胎长度较低（50%）（冬-秋，P < 0.05;冬-春，P < 0.001）。最后，当移植多个胚胎时，牛的经子宫迁移开始于第14天（4%），并在第16天发生在所有受体中（38%的胚胎在对侧发现）。(C)2010年爱思唯尔公司All rights reserved.
Embryo loss between embryonic Days 7 and 16 (Day 0 = day of IVF) in nonlactating cattle, Bos taurus, was analyzed using transfer of 2449 (in groups of 3 to 30) in vitro produced (IVP) blastocysts. In 152 transfers, pregnancy losses attributable solely to recipient failings amounted to between 6% (beef heifers) and 16% (parous dairy cows), of which 3% were caused by uterine infections. Neither season, year, nor the age of the embryos on retrieval affected pregnancy rates. The latter observation indicated that the reason that a recipient failed to retain embryos was already present at the time of transfer. Notably, the proportion of embryos recovered decreased (P = 0.03) as more embryos were transferred, particularly at later stages (Day 14, P < 0.01). The average length of embryos decreased by approximately 5% for every additional embryo transferred (P < 0.0001). These effects may be linked to embryonic migration. Embryo mortality inherent to the embryo during the second week of pregnancy was 24%. Additionally, 9% of Day 14 embryos were of inferior quality, as they did not contain an epiblast. Combining embryo and recipient causes but excluding infection effects, embryonic loss of IVP embryos during the second week of pregnancy amounted to 26% (heifers) or 34% (parous dairy cows). The length of embryos doubled every day between Days 9 and 16, with a 4.4-fold range in sizes representing two thirds of the variation in length. Embryos retrieved from heifers were twice the size of those incubated in parous cows (P < 0.0001), indicating faster embryonic development/trophoblast proliferation in heifers. Whereas season did not affect embryo recoveries, length was lower (50%) in winter (winter autumn, P < 0.05; winter spring, P < 0.001). Lastly, transuterine migration in cattle, when transferring multiple embryos, commenced at Day 14 (4%) and had occurred in all recipients by Day 16 (38% of embryos found contralaterally). (C) 2010 Elsevier Inc. All rights reserved.