It’s a boy: Bison delivers healthy bull calf

It’s a boy! In a pasture on Colorado State University’s Foothills Campus, at 11:35 a.m. Friday, bison cow No. 50 delivered a 45-pound male calf after a hard two-hour labor.

And it’s no ordinary bison baby, if that were possible in 2015.

This sturdy, tawny-colored calf is destined for a home on the range: He is the first calf born this spring and bound for the Laramie Foothills Bison Conservation Herd, which soon will roam open space owned by the city of Fort Collins and Larimer County.

The creatures set to live on historic grazing grounds in northern Colorado are purebred Yellowstone bison – without lingering cattle genes that are typical in most bison herds as a result of interbreeding between the two species.

Yet unlike bison living in and near Yellowstone National Park, the Laramie Foothills herd is entirely free from an infectious disease called brucellosis that spreads easily among cattle, bison and elk and can cause devastating “abortion storms” in herds. The presence of brucellosis, and the fear of its spread, has largely prevented the propagation of purebred Yellowstone bison.

ART rids herd of disease

Colorado State University Biomedical Sciences graduate student Will Falbo demonstrates to a group of City of Fort Collins and Larimer County dignitaries and media representatives, March 6, 2015, embryo handling techniques used to establish a genetically pure, Brucella abortus-free bison herd to release in the City of Fort Collins Soapstone Prairie Natural Area in northern Larimer County, Colorado.
From blastocyst to baby: CSU’s assisted reproductive technologies are helping to make purebred bison reintroduction a reality. (Click to enlarge.)

Assisted reproductive technologies developed at CSU’s Animal Reproduction and Biotechnology Laboratory are helping solve the conundrum. This scientific expertise, including a fascinating method of sperm washing, has rid brucellosis from the bison at CSU, allowing northern Colorado conservationists to realize their dream of bison restoration.

“We really want to be able to contribute to bison conservation, and being able to preserve the Yellowstone genetic lineage is a valuable contribution to that effort,” said Jennifer Barfield, a CSU reproduction expert and the project’s scientific leader. “The Yellowstone bison are not known to have ever bred with cattle, which makes them a valuable line to continue on. With our techniques, those genetics are no longer isolated to the park. They can be spread out to other herds that can benefit from increased genetic diversity.”

On Nov. 1, about a dozen bison will be released on fenced property at Soapstone Prairie Natural Area and Red Mountain Open Space, about 20 miles north of Fort Collins. The Laramie Foothills Bison Conservation Herd is expected to expand from there.

It’s no wonder, then, that veterinarians and researchers from CSU and the U.S. Department of Agriculture monitored bison cow No. 50, a first-time mother, when her labor began Friday morning. She lay down in the grass, straining with each contraction, then ambled around the pasture as other bison cows took turns sniffing at her. She rebuffed them with grunts and head butts.

Breech calf born naturally

A genetically pure bison calf is born at the National Wildlife Research Center June 5, 2015
These bison will be reintroduced to the Soapstone Prairie Natural Area and Red Mountain Open Space in fall 2015. (Click to enlarge.)

By the second hour, the watchful team had begun to consider an intervention. But Mother Nature took over. As thunder rumbled and the skies opened up, the laboring mama gave a final, mighty push and the baby emerged back-feet first.

“The birth took a little longer than we expected. She is a first-time mother and the real surprise at the end was that the baby came out backwards,” said Barfield, who watched the delivery through binoculars. “Mother and baby seem to be OK. It was a natural birth. We were prepared to intervene if she had difficulty much longer, but we gave her enough time and she sorted it out on her own.”

Bison are pregnant for nine months, and their labor usually lasts about 45 minutes. They often give birth at night, so researchers rejoiced at the chance to witness the process.

“Oh, this was neat. I was surprised it happened so well in front of a crowd. That rarely happens, so that was pretty special,” said Dr. Jack Rhyan, a veterinarian with the U.S. Department of Agriculture who has worked with bison since 1982 and has seen just three other births in his career. “Usually you come out in the morning, and there’s a calf.”

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Destined for the prairie

Since 2004, descendants of Yellowstone National Park bison have lived on CSU’s Foothills Campus, quarantined as researchers have worked to ensure the animals and their offspring are free from brucellosis.

Barfield is using a variety of assisted reproductive technologies, including embryo transfer, to produce the newest generation of disease-free, genetically valuable animals at CSU.

The bull calf born Friday was conceived with artificial insemination using a Yellowstone bull’s sperm, which went through a high-tech cleansing process in Barfield’s lab. The mother is a grand-daughter of Yellowstone bison.

“If we were to take some animals out of Yellowstone, there would be a chance that some would be brucellosis-positive, and if we allowed them to breed naturally outside of the park, they could carry the disease and potentially infect other animals. So we’re trying to solve that problem by using assisted reproduction,” Barfield explained.

Partners realize restoration dream

In partnership with the USDA, the city of Fort Collins and Larimer County, Colorado State is helping to write a new chapter in the bison conservation story, with the goal of returning the iconic animals to the northern Colorado prairie.

“It’s nice that we can pick up that story of restoration with some of the Yellowstone genetics and begin to establish some public herds and some tribal herds again,” Rhyan said.

Two more cows are pregnant and will deliver later this summer.

“I hope we’re seeing a happy, healthy herd of a dozen or so bison running along that shortgrass prairie,” Barfield said, referring to Soapstone Prairie Natural Area and Red Mountain Open Space. “Hopefully you will see this calf, a little bigger and still hanging out with his mom, up there on the prairie.”

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Media Assets


Bison Calf – Full package, nat sound

Bison Calf – B-roll and interviews with Jennifer Barfield and Dr. Jack Rhyan


Click on photos to enlarge

Photos by John Eisele, Colroado State University photographer