Livestock producers along the Mouse (Souris) and Missouri rivers should consult with their veterinarians about vaccinating their animals for anthrax this summer.

“River floodwaters may contain anthrax spores and can expose spores already present in the soil, increasing the risk of anthrax on pasture and grazing land,” says North Dakota Agriculture Commissioner Doug Goehring. “If your veterinarian says your livestock – cattle, sheep horses and all grazing animals – are at risk and recommends vaccination, please follow that recommendation.”

The state veterinarian, Susan Keller, says vaccination has proved very effective in reducing anthrax deaths in North Dakota.

“Vaccination takes about a week to establish some level of immunity and must be followed up with annual boosters,” Keller says. “If fly control application is needed, it may be just the time to run the cattle through an alleyway and vaccinate them as well.”

Keller also urged producers to monitor their herds for unexpected deaths and report them immediately to their veterinarians.

“The carcasses of animals that die from anthrax decompose quickly, often with little or no signs of rigor mortis,” Keller says.

Animal health officials are concerned that the history of anthrax in North Dakota, together with reports of the disease in nearby states and provinces, ideal weather conditions and the overland flooding could result in widespread cases of the disease among unvaccinated animals.

Most frequently reported in northeast, southeast, and south central North Dakota, anthrax has been confirmed almost everywhere in the state. The state usually records a few cases every year, but in 2005, anthrax killed an estimated 1,000 head of cattle, bison, horses, sheep, llamas and farmed deer and elk. Vaccinated animals rarely die from the disease.

The bacteria Bacillus anthracis causes anthrax. The bacteria’s spores can lie dormant in the ground for decades, becoming active under ideal conditions, such as heavy rainfall, flooding and drought. When animals graze or consume forage or water contaminated with the spores, they may develop anthrax.