Aleutian disease challenges mink ranchers

Aleutian disease (AD) showed up in Digby County in the mid-to late-1960s in mink with the Aleutian fur color gene. All color phases of mink are susceptible to the virus and is considered the most infectious disease affecting ranch-raised mink.

Aleutian disease costs the province’s mink industry over a million dollars annually in testing and loss of herds.

Nova Scotia mink are universally recognized for their excellence but AD affects quality, production and sale of breeding stock as there is no cure and previous attempts to produce a vaccine have not been successful.

AD is controlled through a test and slaughter program. Blood testing at the Weymouth Aleutian Disease (WAD) laboratory identifies infected mink, which allows for prompt removal from the rest of the herd.

Head laboratory technologist Heather Harris said the lab is a service set up by the ranchers for ranchers. “Our busiest times are November and February before pelting and breeding begins,” said Harris. “Last month, we processed 136,000 samples, with the processing and reporting completed within 48 hours. “This efficiency of time allows ranchers to act quickly if tests are positive for AD,” she said. “Ranchers dispose of the positive mink as soon as they receive the testing fax.”

The Weymouth facility has become the world’s second largest AD testing lab, handling the testing for six Canadian provinces.

Local rancher Hazen Prime, who is vice-president of the Nova Scotia Mink Breeders Association, said that the incidence of AD has gone up in the area and changes need to be implemented.

The association is urging the provincial government to make AD testing and ranch fencing mandatory, and Prime also wants ranchers to have access to clean mink if they are forced to slaughter their animals.

Prime said the association is working on building a ‘clean farm’ for ranchers to repopulate breeding stock after ‘pelting out’—slaughtering the mink.

Two other local ranchers Charlie Brooks from Hassetts and John Sullivan from Hilltown agreed that unless there is a source of clean mink, many farmers, including themselves could be in trouble.

Brooks, who has been ranching for nearly 35 years and operates an average-size farm with 7,500 breeders, said his animals were AD-free until three or four years ago. “I pelted out the diseased mink and brought the clean stock from my Plympton ranch to the main ranch here in Hassetts,” said Brooks. “The Plympton ranch will be cleaned and left empty all summer. “AD spreads so quickly that if 25 percent of your herd tests positive you might as well pelt out.”

Sullivan who had killed his mink the last two years because of AD is looking to restock his breeders in April but is becoming discouraged with how AD had affected his farm. “I pelted out my 2,000 breeders in December and have spent the winter cleaning up the pens,” said Sullivan. “I plan to restock from a local breeder but it is discouraging to clean, disinfect and burn for a fresh start only to run the risk of having AD resurface on my ranch.”

Sullivan said that with the rise in production costs for each pelt and the uncertainty in the fur markets ranching is getting harder and harder. “With the profit margin shrinking one can only hope AD goes down and pelt prices go up,” he said.

In January 2007, the Nova Scotia Agricultural College received $1.8 million for a five-year research and development project on developing genetic tools to control Aleutian disease in mink.

It is hoped that NSAC and the mink industry partners will develop the tools, technologies and biological materials to design alternate strategies to control AD with the possibility of creating a breed of mink resistant to the AD virus.

Until this research finds an answer, local ranchers continue to deal with impact of AD in their herds.

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