MINNEAPOLIS (AP) -

Researchers have transplanted embryos originating from the bison herd at Yellowstone National Park into female bison in Minnesota in hopes of increasing the genetic diversity of herds in the state and helping to restore America's official mammal to the landscape.

Yellowstone bison are prized because they're free of domestic cattle genes. But experts say using them in breeding programs is difficult because they carry a contagious disease that causes spontaneous abortions in pregnant cattle.

Colorado State University animal reproduction professor Jennifer Barfield last month implanted embryos in four female bison at the Minnesota Zoo.

Researchers will check in the coming months to see if the animals become pregnant. If all goes well, they'll give birth to baby bison in the spring.