Use of sentinel serology in a Bovine viral diarrhea virus eradication program

Forty-seven cattle management groups from 36 herds in a regional Bovine viral diarrhea virus (BVDV) eradication program were selected to evaluate serology as a tool to detect herd infection with BVDV. Serum samples were obtained from 5 non-vaccinated sentinel calves ≥ 6 months old in each management group and virus neutralizing (VN) antibody titers against BVDV genotypes 1 and 2 were determined. A herd was considered positive if 2 or more sentinel calves had VN antibody titers ≥ 128 to either genotype. Results were compared to individual animal testing of all available calves by reverse transcription polymerase chain reaction (RT-PCR) on skin biopsy samples. In 1 management group from 1 herd (n = 24), 3 sentinel calves had VN antibody titers ≥ 128. Three ear notch samples from that herd were positive for BVDV on RT-PCR assay. All other management groups were negative for BVDV. In the present study, the herd sensitivity of sentinel serology was 100% (95% confidence interval [CI]: 0.05-1.0) and herd specificity was 100% (95% CI: 0.90-1.0). The κ value for agreement between sentinel serology and RT-PCR was 1.0 (95% CI: 1.0-1.0). Preliminary results suggest that sentinel animal serology can be utilized in a BVDV eradication program to provide an accurate and efficient evaluation of herd status.