Association of hematologic variables and castration status at the time of arrival at a research facility with the risk of bovine respiratory disease in beef calves.
OBJECTIVE
To determine the association of CBC variables and castration status at the time of arrival at a research facility with the risk of development of bovine respiratory disease (BRD).


METHODS
Retrospective cohort study.


METHODS
1,179 crossbred beef bull (n = 588) and steer (591) calves included in 4 experiments at 2 University of Arkansas research facilities.


METHODS
Calves underwent processing and treatments in accordance with the experiment in which they were enrolled. Castration status and values of CBC variables were determined at the time of arrival at the facilities. Calves were monitored to detect signs of BRD during a 42-day period.


RESULTS
The areas under the receiving operator characteristic curves for CBC variables with significant contrast test results ranged from 0.51 (neutrophil count) to 0.67 (eosinophil count), indicating they were limited predictors of BRD in calves. The only CBC variables that had significant associations with BRD in calves as determined via multivariable logistic regression analysis were eosinophil and RBC counts. The odds of BRD for bulls were 3.32 times the odds of BRD for steers.


CONCLUSIONS
Results of this study indicated that low eosinophil and high RBC counts in blood samples may be useful for identification of calves with a high risk for development of BRD. Further research may be warranted to validate these variables for prediction of BRD in calves. Calves that were bulls at the time of arrival had a higher risk of BRD, versus calves that were steers at that time.
Department of Agricultural Sciences, College of Agriculture, Science and Engineering, West Texas A&M University, Canyon, TX 79016.
John T
JT
Richeson
Pablo J
PJ
Pinedo
Elizabeth B
EB
Kegley
Jeremy G
JG
Powell
M Shane
MS
Gadberry
Paul A
PA
Beck
Shollie M
SM
Falkenberg
D000818:Animals; D015415:Biomarkers; D048090:Bovine Respiratory Disease Complex / Q000097:blood*; D002417:Cattle; D015331:Cohort Studies; D008297:Male; D015999:Multivariate Analysis; D009919:Orchiectomy / Q000662:veterinary*; D012189:Retrospective Studies; D012307:Risk Factors
D015415:Biomarkers