Use of serologic evaluation for antibodies against bovine viral diarrhea virus for detection of persistently infected calves in beef herds.
OBJECTIVE
To determine whether use of serologic evaluation of a sentinel sample of calves or cows for antibodies against bovine viral diarrhea virus (BVDV) would accurately predict whether an animal persistently infected with BVDV could be detected in beef herds.


METHODS
27 cow-calf herds in which the status of persistently infected calves was not known and 11 herds known to have persistently infected calves. Procedure-Detection of persistently infected calves was determined through immunohistochemical testing of tissue obtained at necropsy of all calves that died during calving season and skin (ear notch) specimens obtained from all young stock in the fall of 2002. Serum samples were collected from 30 spring-born calves and 10 mature cows.


RESULTS
Optimum serologic test performance at time of weaning was detected when 10 calves were evaluated. At least 3 of 10 randomly selected calves were likely to have a titer > 1:1000 against BVDV type I or II in 53% of herds in which a persistently infected calf was detected during that year (sensitivity, 53%). However, at least 3 of 10 randomly selected calves were also likely to have a titer > 1:1000 in 20% of herds that did not have a persistently infected calf detected during that year (specificity, 80%).


CONCLUSIONS
Despite the use of a number of various cutoff values and sample sizes, serologic evaluation of a small number of calves or cows could not be used to accurately predict the presence of persistently infected cattle in a herd.
Waldner
Cheryl L
CL
Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
Campbell
John R
JR
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000453:epidemiology*; D002353:Carrier State / Q000662:veterinary; D002417:Cattle; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology*; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies
D000914:Antibodies, Viral