Gustafsson H
Department of Obstetrics and Gynaecology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden.
Theriogenology. 1985 Mar;23(3):487-98. doi: 10.1016/0093-691x(85)90021-4.
The characteristics of 7-day-old embryos non-surgically collected from 35 repeat breeder heifers (RBH) and 24 virgin heifers (VH) were compared by repeated observations within each animal. A higher incidence of the embryos collected from the VH was classified as normal and had reached a more advanced developmental stage than embryos from the RBH. Nearly all VH yielded normal (N) embryos, but morphologically deviated (MD) or degenerated embryos (D) appeared occasionally in many VH. The RBH group contained three subgroups of animals. One group of RBH yielded a high percent of N embryos. A second group yielded mostly MD or D embryos with an occasional N embryo, and the third group only D embryos or no embryos. Heifers from which no embryos were recovered on day 7 yielded uncleaved ova, apparently retarded embryos or no embryos when slaughtered three days after insemination. It is concluded that retarded embryonic development may be a common factor for most RBH. The embryo morphology and the degree of retardation differ among animals and between oestrous periods in the same animal.
通过对每头动物进行重复观察，比较了从35头重复配种母牛（RBH）和24头未孕母牛（VH）非手术采集的7日龄胚胎的特征。从VH采集的胚胎中，正常胚胎的发生率较高，且发育阶段比RBH的胚胎更高级。几乎所有VH都产生正常（N）胚胎，但许多VH偶尔会出现形态异常（MD）或退化（D）的胚胎。RBH组包含三个亚组动物。一组RBH产生的N胚胎比例很高。第二组主要产生MD或D胚胎，偶尔有N胚胎，第三组只产生D胚胎或无胚胎。在第7天未采集到胚胎的母牛，在输精后三天屠宰时，产出未受精卵、明显发育迟缓的胚胎或无胚胎。得出的结论是，胚胎发育迟缓可能是大多数RBH的常见因素。胚胎形态和发育迟缓程度在不同动物之间以及同一动物的不同发情期之间存在差异。
