Cattle producers in southern Manitoba say confusion reigned this summer while they tried to contend with an anthrax outbreak.
Mark Lebeau, a cattle producer who farms close to where the first anthrax infection was confirmed this year, said producers weren’t certain how close a herd needed to be to an infected farm before vaccinations were warranted. There were also mixed messages about the need for a follow-up vaccination.
“It was nerve wracking because of the fact that even if you did inject your animals, it would take several days before it would kick in.”
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Cattle producers aired their concerns during a district meeting of the Manitoba Cattle Producers Association. Besides the lack of clear direction from veterinarians, producers said there were also shortages of the anthrax vaccine.
“They were always running out,” Lebeau said in an interview, describing what he encountered at a local veterinary clinic.
“They were saying they’d get 1,000 doses in and it would be gone in a day or so because everybody was vaccinating.”
The anthrax outbreak killed at least 37 cattle and 10 horses this summer in Manitoba. The most severe case was in a herd southwest of Mariapolis, where 10 cattle died.
In an e-mail, Shelagh Copeland, manager of farm production extension for Manitoba Agriculture’s livestock knowledge centre in Brandon, said annual vaccinations are needed in areas where anthrax occurred this year or in previous years.
“How large is an area? Unfortunately, there are no hard and fast rules,” she wrote.
Confirmation of anthrax in an area likely indicates that other animals died from anthrax at the site, possibly more than a century earlier.
Copeland said anthrax spores probably were brought to the surface by flooding in Manitoba earlier this year and then concentrated by evaporation during the summer.
Although the degree of risk is not yet known, she said it is possible that anthrax can be spread from an infected site by scavengers, infected wildlife such as deer and perhaps by large biting insects such as horseflies. She cited an anthrax expert in the United States who believes those kinds of insects can fly more than eight kilometres, depending on weather conditions.
“Given that and possible movement of wildlife, it would seem the recommendation by Minnesota of vaccinating in a 10-mile (16 km) radius should cover scavengers and tabanids (such as horseflies),” she said.
Considering those risks, as well as the possibility of unknown anthrax sites in Manitoba, Copeland said producers should consider vaccinating against the disease if they are in an area with a high risk of flooding in late winter or early spring.
Regardless of where they are in Manitoba, she advised producers to report sudden livestock deaths when the cause is unknown, which could prevent cases of anthrax from being overlooked. It could also reveal whether another important disease is at play.
“Although we usually think of anthrax as a late summer disease, it can occur any time animals are on pasture and also, although rarely, in animals from contaminated feed such as hay (usually poor hay with dirt and roots) taken off flooded areas.”
Producers should not put dead animals in a compost pile unless they are reasonably sure they know the cause of death, Copeland said. Diseases such as anthrax and blackleg can survive composting so spreading the compost could spread the disease.
Some northern U.S. states were also hit by anthrax this year. South Dakota lost 538 animals to the disease, North Dakota lost nearly 500 animals and Minnesota reported losing 20 head of cattle, according to Copeland.
