It's the latest frontier in cloning, according to Dr. Robert Lanza of Advanced Cell Technologies, who pioneered the technology.
"For the first time, one animal species has been cloned using the eggs of a surrogate mom of a different species," he says.
Bessie is carrying a clone of a gaur, an Asian ox.
Scientists hope cloning may bring it back from the brink of extinction.
First the genetic material is removed from an ordinary cow egg. It's replaced by genetic material from a gaur.
An electrical current is applied which causes the cells to fuse and begin to grow into an embryo. That embryo is then implanted in a surrogate cow.
The technology could be used on many different species.
Lanza says, "So this paves the way towards saving for instance the giant panda, the gorillas of East Africa, and even extinct species such as the bucado mountain goat."
This cloning technology depends on samples of living tissue but it could one day be perfected so that species long extinct could be brought back.
Lanza says: "It's unrealistic to think we will have the technology to clone a dinosaur or wooly mammoth any time soon. The problem with many of these efforts is the DNA is severely damaged."
Micheal Novacek is in charge of the effort at the American Museum of Natural History in New York to collect genetic material from engangered species. But he says cloning can't replace conservation as a way to save species.
Novacek says, "Just cloning one individual doesn't insure that you've got kind of genetic variation in the population that you need to sustain it."
In Iowa, scientists are tracking the unborn gaur's progress by ultrasound, and they've given it a biblical name, Noah.
They hope it will be the first of many endangered animals to inhabit a high-tech ark.