Hope for bison
Four-year study under way to help disease-ridden animals

by Jennifer Pritchett
Northern News Services

NNSL (Apr 07/97) - Diseased bison at Wood Buffalo National Park are getting a second chance.

A detailed study of one of the world's largest herds of bison is under way to determine the best management strategy for the TB-inflicted animals.

The four-year program that started in mid-February has revealed that the herd is in serious danger, said Francois Messier, a University of Saskatchewan professor who's heading the study.

"The key is to compare the reproduction rates of the diseased animals and the ones that aren't diseased," Messier said. "Our hypothesis is that the disease is why the herd has declined."

The herd has dropped to 2,300 in 1997 from 10,000 in 1970. "There has been a considerable decline over the past 25 years," he said.

A population survey in March revealed that more than half the animals are diseased with tuberculosis and brucellosis, both highly infectious. Brucellosis is a disease that induces abortion, and also causes problems such as swelling of the joints for those calves that survive.

Scientists maintain that the diseases were brought into the herd in 1925 when bison from Wainwright, Alta., were shipped in.

"Now those diseases are common," said Messier.

The initial phase of the program was the capture of 136 animals that would be used for testing.

They were captured using two methods, depending on their size.

The smaller animals and mature females were caught using a net that was dropped over them to immobilize them. The larger males were chemically immobilized using a dart gun shot from a helicopter.

Both procedures are safe and easy on the animals, said Messier.

Then the bison undergo testing for the diseases with skin and blood samples. The researchers check the animals' age and general health.

Eighty animals are also tagged with a satellite radio collar that will help track them, and to check if they are still alive, said Messier.

Initial TB test results show that more than 40 per cent of the animals have the disease, the same number that were inflicted in the late 1980s when a smaller study was done.

Brucellosis test results are expected to be completed in about a month. The earlier study revealed that 30 per cent of the animals had the disease.

While the only known way to get rid of the diseases entirely is to slaughter the entire herd, Messier said that he can't even entertain this thought right now.

He said he hopes that by the completion of the study in 2001, they will have devised a management strategy to save the bison ... at least the ones that are left.