Development of preimplantation goat (Capra hircus) embryos in vivo and in vitro.

Preimplantation goat embryos were cultured with or without goat oviduct epithelial cells in Earle's 199 medium + 10% goat serum (E199 + 10%GS), and in three different simple chemically defined media. In-vivo development was characterized by an extended 8- to 16-cell stage followed by a rapid cleavage rate in the next 3 cell cycles. Culture of 1-8-cell embryos in Medium E199 + 10%GS led to cleavage arrest at the 8-16-cell stage, while in the chemically defined media embryos developed poorly and a high percentage failed to pass the 8-16-cell stage. In co-culture, however, a high percentage (77% and 96%) of 1-2-cell and 4-8-cell embryos, respectively, developed beyond the 16-cell stage. In co-culture, 1-2-cell embryos maintained cleavage rates equivalent to those in vivo until the 8-cell stage, but thereafter cell numbers lagged behind those in vivo, and by 168 h after ovulation, cell numbers (+/- s.e.) in vitro were 47.6 +/- 7.9 compared to 238 +/- 27.2 in vivo (t = 6.93, P less than 0.001). The results demonstrate that co-culture of embryos with oviduct cells allows a high percentage of embryos to develop through the period of cleavage arrest, providing a favourable environment for development through the 1-16-cell stages but a less adequate environment for development to the blastocyst stage.