CSU team partners with USDA, Bronx Zoo to create purebred bison calves

One down, herds to go.

Part two of the process that created the first genetically pure Yellowstone bison calf for the Bronx Zoo’s herd is underway because of researchers at CSU’s Animal Reproduction and Biotechnology Laboratory (ARBL).


The project began October 2011 and was the first time attempting a bison embryo transfer, according to Jennifer Barfield, a reproductive physiologist who worked on the project. The team  transferred an embryo on-site from a purebred diseased Yellowstone bison into a genetically impure and healthy recipient. The recipients were moved to the Bronx Zoo where the calf was born June 20.

“Our lab is know for these kind of technologies in cattle and horses. We’ve been doing it for years and decades,” said George Seidel, a professor of biomedical sciences who worked on the project. “From an out-and-out scientific standpoint, we’re really taking procedures that have worked in other species and adapting them and it’s not trivial.”

This year the team is adding a new element to the process. They will collect embryos Sept. 24 and immediately fly them to New York for transfer. Collection a month after the bison breeding season last time may have affected the pregnancy success rate, according to Barfield.

“We really didn’t know what to expect,” Barfield said. “We were assuming that [bison] are very similar to cattle and so we used technology that is known to be successful in cattle and used them on the bison hoping they would work.”

Producing a purebred bison calf through embryo transfer is like an episode of “Dirty Jobs,” according to Barfield.

“It doesn’t feel very prestigious when it’s six in the morning and you’re covered in poop,” Barfield said. The team starts work early so the bison do not overheat and it takes 30 to 45 minutes to extract the embryo from each bison.

After collection, Barfield cleans the embryos with a series of chemical drops that successively purges them of disease. The process takes approximately 30 seconds.

The project began by a chance connection. A contact in South Dakota put Barfield in touch with The federal Animal and Plant Health Inspection Service (APHIS), which owned land and a bison herd next to ARBL.

“The idea kind of developed by word of mouth that there was this herd of Yellowstone bison here at APHIS and they wanted to look into doing some sort of genetic rescue because Yellowstone bison are genetically very valuable,” Barfield said. “We had no idea there were bison over here…
we learned about each other and the two groups across the street started to collaborate.”

Restoration projects aim to preserve genetically pure bison, but the Yellowstone variety have brucellosis which could infect other herds. Quarantine and now embryo transfer are methods of getting rid of the disease, according to Jack Rhyan, who worked on the APHIS side of the project.


Barfiled said the project’s success has led ARBL to consider creating a longer, more sustained bison program.

“I think students will be interested in learning more about bison,” Barfield said. “It’s probably not a species that a lot of undergrads who come through biology or animal sciences have ever thought about working with.”

Pioneering reproductive techniques is not new to ARBL and it puts the laboratory ahead in its field.

“With embryo transfers bovine and equine this department has done in past years there’s been new breakthroughs routinely for embryo transfer. We’ve just had a lot of firsts and with this bison its one of the firsts in the United States that was born,” said Zella Brink, the technician who performed the embryo collection and transfers. “It’s another first for CSU.”

Politics Beat Reporter Kate Winkle can be reached at news@collegian.com.