Chinese scientists have succeeded in breeding the first cattle from frozen embryos in the rarefied atmosphere of the Qinghai-Tibet Plateau.
Frozen embryos were transplanted into 22 cows living on the Chinese highlands, with an average elevation of 4,000 meters (13,123 feet), resulting in the births of three calves, all in good health.
Transplants had been attempted previously in Tibet, but the pregnancies failed in the low oxygen atmosphere of the highland regions. Frozen semen was also used to make cows pregnant, but the embryos were improperly formed, resulting in poor quality milk and short lifespans of cows born with this technology.
The transplanted frozen embryos were developed in the Beijing Cow Research Center.
Local researchers said that the mother cows all grew up on the plateau and had inured themselves to local environment. So, the embryos were not negatively affected during the pregnancy, guaranteeing pure milk and longer life.
They said inbreeding could be avoided so long as species of embryo were chosen properly.
( April 4, 2002)
