Evaluation of concurrent shedding of bovine coronavirus via the respiratory tract and enteric route in feedlot cattle.
OBJECTIVE
To assess the relationship between shedding of bovine coronavirus (BCV) via the respiratory tract and enteric routes and the association with weight gain in feedlot cattle.


METHODS
56 crossbred steers.


METHODS
Paired fecal samples and nasal swab specimens were obtained and were tested for BCV, using antigen-capture ELISA. Paired serum samples obtained were tested for antibodies to BCV, using antibody-detection ELISA. Information was collected on weight gain, clinical signs, and treatments for enteric and respiratory tract disease during the study period.


RESULTS
Number of samples positive for bovine respiratory coronavirus (BRCV) or bovine enteric coro navirus (BECV) was 37/224 (17%) and 48/223 (22%), respectively. Some cattle (25/46, 45%) shed BECV and BRCV. There were 25/29 (86%) cattle positive for BECV that shed BRCV, but only 1/27 (4%) cattle negative to BECV shed BRCV. Twenty-seven of 48 (56%) paired nasal swab specimens and fecal samples positive for BECV were positive for BRCV. In contrast, only 10/175 (6%) paired nasal swab specimens and fecal samples negative for BECV were positive for BRCV. Only shedding of BECV was associated with significantly reduced weight gain. Seroconversion to BCV during the 21 days after arrival was detected in 95% of the cattle tested.


CONCLUSIONS
Feedlot cattle infected with BCV after transport shed BCV from the respiratory tract and in the feces. Fecal shedding of BCV was associated with significantly reduced weight gain. Developing appropriate control measures for BCV infections could help reduce the decreased weight gain observed among infected feedlot cattle.
Cho
K O
KO
Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster 44691, USA.
Hoet
A E
AE
Loerch
S C
SC
Wittum
T E
TE
Saif
L J
LJ
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000032:analysis; D001835:Body Weight; D002417:Cattle; D002418:Cattle Diseases / Q000821:virology*; D018352:Coronavirus Infections / Q000097:blood / Q000473:pathology / Q000662:veterinary*; D017938:Coronavirus, Bovine / Q000254:growth & development*; D004751:Enteritis / Q000662:veterinary* / Q000821:virology; D005243:Feces / Q000821:virology; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D009296:Nasal Cavity / Q000821:virology; D012140:Respiratory Tract Diseases / Q000662:veterinary* / Q000821:virology; D017201:Virus Shedding
D000914:Antibodies, Viral; D000956:Antigens, Viral