Test tube bison could help preserve species

By DAWN WALTON
Tuesday, November 21, 2006
Wood bison have had their habitat destroyed, been hunted to the edge of extinction and been infected with debilitating diseases.

Now Canadian researchers are hoping to use modern-day reproductive technologies to create test-tube bison in an attempt to turn back the clock for the country's largest land mammal.

In a groundbreaking experiment, scientists recently salvaged testes and ovaries from bison in the Northwest Territories, which were sent to slaughter. The animals were sick, but their genetic material is disease-free and a boon to scientists desperate to maintain diversity in dwindling bison bloodlines.

Eggs were extracted in an Alberta laboratory and fertilized with sperm in a culture dish. Now, 27 bison embryos and 780 sperm samples (including some taken from live animals) are frozen in liquid nitrogen, waiting to be implanted in surrogate bison cows.

"Genetic preservation is a huge issue," Jacob Thundathil explained in his lab at the University of Calgary, where he is an assistant professor of veterinary medicine and part of the team hoping to rescue Canada's bison herds.

Next month, the wood bison recovery team will meet to figure out the next steps. Where is there a suitable herd of surrogate mothers? Are they in the wild, on farms or in zoos?

A male wood bison can grow to about 12 1/2 feet in length, stand 6 feet high at the shoulder.. Wood bison, notable for a massive hump at the shoulder, are not to be confused with the smaller and more numerous plains bison, but interbreeding on habitats that overlap has added to the confusion.

Current and historical population estimates for wood bison vary. According to Environment Canada, almost 200,000 wood bison once roamed the West and North, but by the early 1900s, the number fell to fewer than 300. There are now about 8,000, a rebound due to an intensive conservation program launched in the 1980s.

Earlier this year, 30 wood bison from Elk Island National Park in Alberta were flown to northeastern Siberia, where biologists are hoping to reintroduce the animals to a place where they disappeared thousands of years ago.

Ottawa listed the wood bison as "endangered" in 1978, but the national recovery program helped upgrade the animal's status to "threatened" in 1987, where it remains today.

The majority, about 5,000, are in Wood Buffalo National Park, which straddles the Alberta and Northwest Territories boundary. But many of these animals have bovine tuberculosis, an often-fatal chronic respiratory disease, or brucellosis, which causes spontaneous abortions and stillbirths.

Both diseases were brought to Wood Buffalo when Ottawa shipped plains bison there in the 1920s to bolster the new park's population. The plains bison contracted the illnesses from domestic cattle, an inadvertent byproduct of cross-breeding experiments.

For years, Ottawa has been trying to figure out how to eradicate the disease and prevent it from spreading.