Proper Methods Found for Anesthetizing Bison

By University of Saskatchewan

Reprinted from Smoke Signals, May 1999

Summary

Two new anesthetic combinations are being used to safely immobilize bison. This article briefly describes the combinations and their antidotes as they are used by Nigel Caulkett from the Western College of Veterinary Medicine at the University of Saskatchewan.

Proper Methods Found for Anesthetizing Bison

Until recently there have been few drugs that can safely anesthetize bison. Nigel Caulkett, associate professor of anesthesiology at the Western College of Veterinary Medicine at University of Saskatchewan in Saskatoon, said the only reliable anesthetics for bison were potent narcotics that could kill a human with one drop.

Many veterinarians and wildlife officers refused to handle them but the need to anesthetize bison grew as bison became more common on prairie farms.

Last February, Caulkett and his colleague, Marc Cattet, began a project to develop anesthetic protocols for bison that would be safe for users and bison. The project was supported by Sk. Agri Development Fund.

Working with seven wood bison from Elk Island National Park near Edmonton, they administered two different combinations of drugs and monitored the effects.

No plains bison were available for tests at the time so the larger wood bison were used. "We found that the bison could be knocked down with a relatively inexpensive combination of xylazine-telazol, and awakened with tolazoline. The more potent combination of medetomidine-telazol was also effective at knockdown, with a successful reversal with atipamezole," said Caulkett.

Both combinations anesthetized the animals quickly for one hour and provided a quick wake-up.

The only major side effect of both, said Caulkett, was a decreased level of oxygen in the blood, so he recommends giving the animals oxygen when using the drugs, which is easily done by flowing it into one nostril.

Caulkett also warned of an extremely rapid recovery rate when the wake-up drug is given intravenously. Caulkett and Cattet recommend administering the wake-up drug intramuscularly unless the handler can reach a safe location in less than one minute.

Although only veterinarians and wildlife officers will be allowed to use these drugs, bison producers will be relieved to know their ill or escaped animals can be safely treated. The new protocol has been proven successful in clinical trials at the vet college and at Prince Albert National Park.

For more information, contact: Dr. Nigel Caulkett, Associate Professor of Anesthesiology Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK.S7N 5B4 or phone 306- 966-7082; Fax 306-966-7174.

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