Prevalence of calves persistently infected with bovine viral diarrhea virus in beef cow-calf herds enrolled in a voluntary screening project.
OBJECTIVE
To report the prevalence of bovine viral diarrhea virus (BVDV) in calves and calf groups (ie, calves from the same farm) in beef breeding herds and evaluate the ability of biosecurity risk assessment questionnaires to identify calf groups with positive results for BVDV.


METHODS
Nonrandom survey.


METHODS
12,030 calves born in spring from 102 operations.


METHODS
Cow-calf producers that voluntarily enrolled in a screening project submitted ear notch specimens from calves and answered a 29-question survey instrument. Ear notch specimens were tested for BVDV with an antigen-capture ELISA (ACE), and ear notch specimens with positive ACE results for BVDV were immediately retested by performing immunohistochemistry (IHC). Follow-up testing, 3 to 4 weeks after initial positive ACE results, was done by use of a second IHC test and virus isolation on a subsequently submitted ear notch specimen from the same calves to identify those that were persistently infected (PI).


RESULTS
102 producers submitted ear notch specimens for BVDV screening. Initially, 24 of 12,030 calves had positive ACE results for BVDV. A second ear notch specimen was submitted for 20 of these 24 calves. Of 20 retested calves, 12 had positive ICH results for BVDV, confirming PI status. The 12 PI calves came from 4 calf groups (3 singletons and 1 calf group with 9 PI calves).


CONCLUSIONS
Prevalence of BVDV in calf groups was low, and questions designed to identify high-risk biosecurity behaviors had little value in identifying calf groups with positive results for BVDV.
O'Connor
Annette M
AM
Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
Reed
Matthew C
MC
Denagamage
Thomas N
TN
Yoon
Kyoung-Jin
KJ
Sorden
Steven D
SD
Cooper
Vickie L
VL
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000276:immunology; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000175:diagnosis / Q000453:epidemiology*; D002417:Cattle; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology* / Q000302:isolation & purification; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D006306:Health Surveys; D007150:Immunohistochemistry / Q000662:veterinary; D008297:Male; D008403:Mass Screening / Q000662:veterinary; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies
D000914:Antibodies, Viral; D000956:Antigens, Viral