Deadly bison virus lacks research: veterinarian

Lambs considered main source | Studies show the virus can be transmitted from sheep feedlots up to 10 kilometres away

A Saskatchewan veterinarian says it’s time industry and government took a closer look at a disease carried by sheep that is fatal in bison.

Laboratory tests have confirmed that malignant catarrhal fever has claimed at least 19 animals in the RJ Game Farm herd near Fairlight, Sask., in the last few years.

Co-owner Robert Johnson suspects MCF in at least 20 more suspicious deaths.

Dr. Clarke Hill, the veterinarian for both the bison herd and a neigh-bouring sheep flock, disputes the cited literature that suggests only three or four cases of MCF are found a year in Saskatchewan.

“I’ve had more than that last month off RJ Game Farms,” he said.

MCF is a herpes virus carried by sheep and shed through respiratory secretions. Sheep carry the virus for life but are unaffected. Six- to eight-month-old lambs are thought to be the main source of MCF because they shed large amounts of the virus.

The problem at the bison farm began several years ago and is compounded by personality conflicts of the people involved.

However, Hill said both the bison and sheep industries have to address it.

A recently released video produced to educate producers says there are only a handful of cases each year, and Hill said that might make producers think they don’t really have to worry.

“I think it’s a bigger problem than what Saskatchewan livestock and some of these producers think there is,” he said, referring to the provincial agriculture ministry’s livestock branch.

Research on MCF is not extensive, and no one really knows how far apart the two species should be to keep the bison safe.

The sheep near RJ Game Farm are two to three kilometres away.

Johnson and his father-in-law, Ryan Clark, have unsuccessfully tried to force the provincial Agricultural Operations Review Board to hear his concerns.

In 2011, then agriculture minister Bob Bjornerud appointed a task force to examine the issue. It recommended the province establish a notifiable disease list, conduct research into how far apart bison and sheep should be and undertake an education and awareness program.

The ministry said last week it continues to consult on the notifiable disease list.

In 2012, it announced $300,000 in research funding over three years and said $50,000 per year goes to the Western College of Veterinary Medicine’s disease investigation unit.

It also provided money for education and awareness as well as the video.

Hill said he finds himself between a rock and a hard place because while at times Johnson and Clark might have exaggerated the problem to get their point across, the deaths really are occurring.

The more post mortems he does, and the more lab samples taken, the more positives show up.

He said he takes precautions and carefully documents when he has been on the sheep farm so that the bison producers are aware.

However, he really doesn’t know whether that matters.

“I don’t have a whole lot of solutions for them because the disease itself is not that well known,” he said.

“Moving the sheep far away would definitely decrease the chance of the problem, but how far nobody knows.”

Research has shown that MCF can be transmitted about 10 km in feedlot situations where the sheep would shed the disease at higher rates.

However, Hill said the sheep farm at Fairlight is a 200-lamb operation.

He said veterinarians and others assumed that two to three km would be far enough when the sheep were first placed in the area, but bison still died.

Hill said it is known that animals under stress can cause and contract MCF.

“Number one, bison is a wild animal, so when are they not stressed?” he said.

Sheep are stressed when lambing, at weaning and if they haven’t been sheared or sheared properly.

RJ Game Farm is a fairly intensive bison operation, which could also be a factor.

Hill said the number of cases has recently gone up, but he doesn’t know if the cause was the heat, the moisture or nothing different at all.

He said some bison and sheep producers have been known to happily co-exist fairly close by, but the sheep may not be carriers or the stocking rates of both species might be the deciding factor.

In any event, he said the industries and government can’t push MCF aside.

The government has said it can’t tell people they can’t farm their land, but Hill said something has to be done if what one farmer does costs a neigbour.

“It’s a multifaceted issue here,” he said. “If I knew the cause (of losses) and that it could be prevented, I’d want something done about it.”

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