The ailment, closely related to tuberculosis, can be found in all ruminants but has particularly high incidence in dairy cattle.

That is believed to be connected to herd management techniques of beef versus dairy herds and the primary transmission vector through fecal matter. Johne’s is linked to decreased milk production and can lead to culling.

Razieh Eshraghi Samani, researcher at the University of Calgary’s Faculty of Veterinary Medicine, said Johne’s symptoms usually appear two to five years after infection, causing what’s called an iceberg effect.

“The animals having symptoms are in low numbers but the whole problem is bigger and there are probably more animals infected in the herd that you don’t see,” she said.

Samani said the vaccine she and her team have developed could greatly reduce the impact of the disease.

“There are vaccines across the world but none of them are approved for use in Canada because they have some shortcomings,” said Samani. “They don’t eliminate the bacteria; they just postpone the symptoms.”

The U of C’s vaccine prevents infection and spread of the disease, she said, while also tackling the most common version of the bacteria that causes Johne’s in Canada.

The beef cattle industry could benefit if the vaccine slows rates of infection. It can also combat different strains of the bacteria, Samani said. However, dairy producers would feel the most immediate economic benefits.

“If this vaccine prevents infection, it will prevent the economic burden on the dairy industry. It can prevent the reduction in milk production, prevent lack of fertility, increase the carcass quality at slaughter.”

The vaccine is still in development. The next step is to see if it can be combined with a Johne’s vaccine being developed at the University of Saskatchewan, said Samani.

“If our vaccine can be mixed with the other vaccine, they can have complementary benefits and maybe fully protect animals.”

Commercial access to the vaccine is still at least two years away.

“This is not something that’s coming tomorrow or next week or next year but we can see that there is some promising results,” said Samani.

The post Prairie researchers at work on Johne’s vaccines appeared first on Grainews.

“Johne’s disease is particularly challenging to manage because we have so few options,” says Dr. Cheryl Waldner, professor at the University of Saskatchewan’s Western College of Veterinary Medicine.

To help beef producers make better management decisions about a disease with such uncertainty, the Beef Cattle Research Council (BCRC) created an interactive tool to analyze testing and management options for Johne’s disease. Waldner helped develop the tool.

The chronic disease causes weight loss, persistent diarrhea and death in cattle, resulting in numerous negative effects on beef herds. In addition to premature culling, these effects can include reduced slaughter value, replacement costs, lost gain in calves, loss of genetics and considerable veterinary testing costs.

ALSO READ: Prairie researchers at work on Johne’s vaccines

Because calves younger than six months are more susceptible to Johne’s, efforts to reduce the spread of infection on calving grounds — like those used to reduce calf scours — can help manage the disease.

However, as the beef industry consolidates, the risk of Johne’s entering a herd through new animals bears watching.

“The only way to find and get rid of those infected animals so that they don’t transmit to our calf crop is by testing and culling, and that sounds pretty straightforward, but it’s not. This particular disease is very frustrating because it has a long silent phase,” says Waldner. It can take two to 10 years between the time an animal is infected to when it shows clinical signs, she adds.

Even when animals are shedding the virus, this can be inconsistent and may not show up in tests. As well, the accuracy of available testing is limited.

“There’s a lot of uncertainty in this, and because of that, it makes it really hard for producers and veterinarians to try to evaluate the cost-benefit possibilities of actually doing a testing and culling program in their herd. There’s a lot of information to pull together, and it’s easier if we can basically get the computer to do it for us.”

The Johne’s disease risk-reward calculator “pulls together what we do know about the disease, how it might progress in individual animals, how it might spread in the herd and how well the diagnostic tests work in Canadian beef herds,” Waldner says.

“The tool can be customized to fit individual herd sizes, replacement strategies, plans for expansion and a wide range of possible testing possibilities.”

Two versions of the calculator, basic and advanced, are available on the BCRC website. Instead of running the model once and showing one scenario, the tool runs it multiple times and factors in the uncertainties presented by this disease to provide producers with a range of management scenarios.

“It’s a little bit more complicated than a lot of the Excel tools that we typically use for these types of calculations, but given the level of uncertainty, we needed something that allowed us to actually factor that uncertainty into the calculations.”

A key part of developing this tool was incorporating data from Canadian herds into the risk model. “The important thing for us was having this tool reflect data from western Canadian cow-calf herds,” Waldner says, noting much of the existing research on how this disease spreads was conducted in U.S. dairy herds and not useful to this context.

The Canadian Cow-Calf Surveillance Network provided some of the data used to create the model.

Although it’s difficult to determine how fast the disease spreads through a herd, data collected by the Saskatchewan Stock Growers Association on this topic helped to inform the model for the calculator. The association has worked with producers who have dealt with Johne’s disease to help track the progress of the disease in their herds, and many of the producers anonymously shared their data with the project developers.

Waldner notes the tool can’t predict exactly what will happen in a herd, but it does provide producers with scenarios to analyze that may help inform their management decisions.

“What I am hoping is that individuals will be able to make better decisions about whether it makes sense to test in their herds and to come up with a testing protocol that makes the most sense for them.”

The Saskatchewan government, Saskatchewan Cattlemen’s Association and Alberta Beef Producers also funded this calculator’s development.

The post Calculator can analyze Johne’s options appeared first on Grainews.