Canada’s first cases of “X disease” were described in Saskatchewan in the summer of 1946. It was eventually renamed bovine viral diarrhea (BVD). But that isn’t the best name either, because diarrhea isn’t the big problem. The bigger concerns are abortion, infertility, immune system suppression and calf death.
Persistently infected (PI) calves occur when BVD virus crosses the placenta during the first four months of gestation. Because the BVD virus is already present before the PI calf’s immune system starts to develop, the virus isn’t recognized as foreign, and the calf never mounts a protective immune response to eliminate it. Before they die, PI calves can shed large amounts of BVD virus, infect susceptible cattle and cause illness ranging from a mild fever to abortion, premature births, deformities, stunted growth and death.
Cheryl Waldner and collaborators at the Universities of Saskatchewan, Calgary and Montreal recently assessed the prevalence of BVD virus in weaned beef calves and whether antibodies against BVD varied among vaccination programs (Bovine viral diarrhea virus and virus-neutralizing antibody titers in beef calves at or near fall weaning; PMC12044622).
What They Did
At weaning in 2021, blood samples were collected from about 20 spring-born calves in each of the 107 commercial beef herds participating in the Canadian Cow-Calf Surveillance Network. A total of 1,934 calves were sampled out of the 21,069 calves weaned from these herds. The research team looked for BVD virus and anti-BVD antibodies in the serum. Cooperating herds also shared their vaccination records, and the relationship between BVD vaccination practices and BVD virus and anti-BVD antibody levels were determined.
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