[The exchange of animals in the form of embryos].

The results are given of transplantation work with cattle embryos from Czechoslovakia. The embryos were taken in the stage of morula or blastocyst, frozen and stored for one to ten months. Following thawing they were transplanted via surgical methods to local, estrus-synchronized recipient heifers at the Ruzhevo Konare village, Plovdiv district. A calf was born to each of six of the recipients, while two heifers that were inseminated seven days prior to transplantation yielded twins. It was considered to be the result of both the embryo-transplantation and the fertilization of own ova. Discussed are the opportunities and advantages of long-term storage and shipping of animals in the form of frozen embryos.