Here is our next installment in a series of online Dairy Producer Short Courses from our sponsor, Fort Dodge Animal Health.
Our topic this week is BVD Vaccination: Staying One Jump Ahead.
The BVD virus taught dairy producers not to take it for granted when it killed thousands of cows in 1993. Its ability to mutate presents a challenge when designing a vaccine to protect against all the forms of the disease, says Fort Dodge Animal Health Technical Services Consultant Mark van der List, DVM.
THE BVD VIRUS’ molecular structure creates genetic instability, which allows it to evolve quickly. Today, we know of as many as 11 Type 1s and possibly four type 2s, which have resulted from that evolution.1 2 Although Type 1B is the most common in U.S. cattle, followed by Type 2A and then Type 1A, all the implications of that diversity aren’t clear.
- Both Type 1 and Type 2 can cause either acute disease or persistent infection.
- There has been little or no proven correlation between the type of BVD infecting a group of cattle and the clinical effect the disease has on them, from acute to chronic to fatal.
- Researchers now believe preventing persistent infection is critical to controlling BVD’s spread; however, you can’t ignore the role of circulating virus transmitted by acute cases and possibly wildlife. Some herds have been shown to maintain the disease without the presence of a PI animal for years.
Those unique aspects of the virus help explain why even biosecure, well-managed dairies may have difficulty ridding themselves of BVD. Effectively vaccinating can be difficult as well, due both to some vaccines’ insufficient cross-protection and the tendency for producers to not complete the full course of vaccinations.
We know the quest to broaden the potential ability of vaccines to protect can’t stop at just including a Type 2. Even within the same subtype, it’s important to constantly refine vaccine strains, testing their capability to cross-protect as cattle face evolving BVD strains. For example, when we developed our PYRAMID line of vaccines,we weeded through the hundreds of strains now commonly identified to choose the two we believe offer the most potential to cross-react with the broadest range of wild BVD. That breadth helps keep us one jump ahead of the virus’ next change.
Fort Dodge offers Pyramid to combat the BVD virus. You can read more about this disease in their full short course publication (pdf).