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The Minnesota Bison Conservation Herd, composed of 130 animals is spread out between two state parks and the Minnesota Zoo in Apple Valley. Submitted photo.

Yellowstone purebred bison genetics transferred to Minnesota zoo

APPLE VALLEY, Minn.—Jennifer Barfield has salvaged life from the slaughterhouse floor.

That's where the Colorado State University professor has collected ovaries from some of Yellowstone National Park's bison after they met their controversial demise.

"It's definitely not a fun part of the process," said the professor in the Department of Biomedical Sciences. "None of us enjoy that."

But by retrieving some of the bison's ovaries and the eggs they contain, Barfield and CSU have managed to preserve and spread the coveted genetics of the species to conservation herds around the United States.

The Yellowstone Park bison herd is thought to be the last and oldest free-ranging bison herd in the United States that has always existed in the wild

Most recently, Barfield transplanted fertilized embryos from the Yellowstone gene pool into four bison cows at the Minnesota Zoo in Apple Valley, Minn. Now, the waiting begins to see if the bison will give birth this spring.

The four females are part of the Minnesota Bison Conservation Herd, composed of 130 animals spread out between Blue Mounds State Park in far southwest Minnesota near Luverne and Minneopa State Park near Manakot and the zoo.

"We are excited about this partnership with CSU and are very hopeful that this will work and we can finally add valuable Yellowstone bison genetics to our Minnesota Bison Conservation Herd," Tony Fisher, the Minnesota Zoo's director of Animal Collections, said in a press release.

Barfield began her research in 2011, basing the techniques on those used for the cattle industry — which is an odd coincidence considering that bison first contracted the disease brucellosis from cattle, a disease that has since caused numerous problems for cattle ranchers near Yellowstone National Park.

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service, or APHIS, retains a small herd of Yellowstone bison outside of Gardiner, Mont., for scientific study. By extracting live embryos from those bison cows, a technique that does not require surgery, Barfield successfully transplanted an egg into a Bronx Zoo bison in New York City.

That first calf was born in 2012. Barfield has an ultrasound photo of the now 3-year-old male on her desk, as well as a photo of him as an embryo — reminders of how far the research has come.

After that first success, the program has grown to include the successful birth of 10 bison in a conservation herd of 16 bison kept at Fort Collins, Colo. At the Bronx Zoo another six bison cows have received Yellowstone embryos.

"We've continued to work on the procedure and increase our success rate," Barfield said.

The work has been yet another tie between the Bronx Zoo and bison. The zoo's Wildlife Conservation Society was instrumental in preserving bison in the early 1900s.

Key to the success of the CSU program has been the laboratory's ability to clean the brucella abortus bacteria from the embryos and seminal fluid taken from Yellowstone bison. The bacteria can cause the disease brucellosis, which is found in Yellowstone's bison and elk herds where it is believed to be spread by contact with birthing fluids. The disease can cause pregnant cattle to abort, which is why states surrounding Yellowstone have worked hard to keep bison and cattle separated.

Brucellosis is also one of the reasons the National Park Service has agreed to reduce the size of its bison herd through culling and shipment of animals to slaughter. Since 1968 about 8,000 bison have been shipped to slaughter, according to the park's website. The bison herd was recently estimated at 5,500 to 5,800 animals. Meat from the slaughtered bison is donated to American Indian tribes.

In addition to providing zoo conservation herds with new bison genes that are disease free, the CSU program has also stored Yellowstone bison embryos as a safety measure to preserve the animals should there be a catastrophic die-off.

"They serve as insurance for those really valuable genetics," Barfield said.

Once frozen in liquid nitrogen, the embryos could in theory be preserved for thousands of years. The only downside is that frozen embryos are less successful at generating offspring than fresh ones, she noted.

Barfield said preserving and spreading the Yellowstone bison genetics does not dilute the value of the existing Yellowstone herd, nor would the technology ever be used to remove Yellowstone's bison and reintroduce bison free of brucellosis.

"That's absolutely not feasible and not something we would want to do," she said.

Besides, even if bison with brucellosis were removed from the park elk would still carry and be able to transmit the disease.

"It's not a strategy that would work because of the problems involved," Barfield said.

Yet if a vaccine were ever developed to wipe out brucellosis in Yellowstone bison and make Barfield's work obsolete, she said she wouldn't care.

"I'd be happy to work myself out of a job," she said.

Especially the less glamorous part where she has to collect ovaries from bison slaughterhouses. Still, the work justifies the end result.

"We want to preserve them in the gene pool and, hopefully, get them back out onto a prairie somewhere," she said.