Egg transfer in the Mongolian gerbil (Meriones unguiculatus) during lactational delay of implantation.

Lactating pregnant gerbils in which one oviduct was ligated during early pregnancy were used on Day 6-14 p.c. as recipients for eggs (morulae and blastocysts) recovered on Day 6-12 p.c. from lactating donors. Eggs were transferred to the ligated (experimental) horn and the litter was removed. About half of the recipients had implantations in the non-ligated (control) horn 15 days after litter removal. Of these 40 females, 37 had implantations in the experimental horn and 32 had some normal fetuses present. Of 179 eggs transferred into the ligated uteri, 61% implanted and 41% developed into normal fetuses. The time after copulation of recipient and donor did not appear to influence the number of implantations or post-implantation development of the transferred eggs.