Research pinpoints BVD type most important for control programs

Most beef producers are aware that bovine viral diarrhea (BVD) generally falls into two broad categories—Type 1 and Type 2.  A lesser known fact is that BVD viral strains are further classified according to their biotypes as either cytopathic (CP) or noncytopathic (NCP) BVD.  And now research is stacking up that suggests just one of those biotypes appears to be causing all the trouble associated with BVD.

As veterinary scientists have learned more about the differences between the two BVD biotypes—CP and NCP—they’ve discovered the NCP form is responsible for the vast majority of health problems.

According to records from the Animal Disease Research and Diagnostic Laboratory at South Dakota State University, 90 to 95 percent of the BVD biotypes isolated are NCP, while only 5 to 10 percent are CP. In addition, data from the University of Auburn show that 98 to 99 percent of the field samples tested during diagnostic work are NCP BVD.

“The research and diagnostic reports are telling us that NCP is by far the more significant variation of BVD for cattle producers,” said Doug Scholz, DVM, director of veterinary services, Novartis Animal Health.

“We also know the NCP form of BVD is responsible for all persistently infected (PI) calves and that’s the number one reason BVD continues to be such a huge problem, added Scholz. “So in order to make inroads with our BVD control programs, we really need to be focusing on the NCP biotype.”

BVD is particularly devastating because it can affect cattle in every stage of production. Contrary to its name, diarrhea rarely occurs with BVD infections. Diseases caused by BVD vary from subclinical to fatal and are frequently linked to reproductive, respiratory, gastrointestinal, circulatory and immunologic failures.

Because BVD is an immunosuppressive virus, much of the economic impact is the result of a weakened immune system, which often leads to secondary respiratory infections like Pasteurella and, ultimately, bovine respiratory disease.

Keys to BVD Control

U.S. producers have made significant gains by stepping up their herd health programs. By continuing to focus on BVD control and working closely with their veterinarians, producers will make further gains in animal health and performance.

Gaining control of BVD requires good biosecurity measures—including testing and removal of PI animals—along with effective vaccination. For maximum herd protection, veterinarians frequently recommend choosing a vaccine that offers broad-spectrum coverage against field strains of both BVD Type 1 and Type 2 genotypes, including NCP protection.

Currently, the only viral vaccines that offer three-way BVD coverage, including NCP isolates for Type 1 and Type 2 and a CP isolate for Type 1, are Vira Shield® and

BRD Shield™, from Novartis Animal Health.

“Since BVD is the most common and costly cattle disease, we felt it was critical to provide vaccine options that help prevent the strains of BVD that cause the biggest health and performance setbacks in the field,” said Scholz.

Scholz added that proper vaccination is just one part of an effective BVD control program. He offered the following management tips to help reduce the health and performance risks associated with BVD.

Know Your Herd’s Status – diagnostic tests are available to identify PI animals. Test calves at birth and be sure to ear-notch any stillborn calves for testing.

Cull PI Animals – as an industry, we want to reduce the overall numbers of PI calves. Culling PI animals rather than selling them is critical to the health of the industry.

Focus on Biosecurity – be sure to test all incoming animals and keep them separate from the rest of the herd until they are confirmed BVD-free.

Vaccination – cows should be vaccinated for BVD before breeding so they have protection on board during gestation. Be sure to use a vaccine that includes coverage for NCP isolates for BVD Type 1 and BVD Type 2.

Learn & Educate – stay on top of BVD outbreaks in your region so you’re aware of outside threats. Educate your staff about BVD and why vaccination and biosecurity are critical to herd health and operational profitability.

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