A novel risk assessment tool for bovine respiratory disease in preweaned dairy calves

摘要

Due to the increased morbidity and mortality ofbovine respiratory disease (BRD) in dairy calves, aswell as an increasing urgency for the judicious use ofantimicrobials in farm animals, a comprehensive riskassessment tool for BRD in preweaned dairy calveshas been designed based on a longitudinal and a crosssectionalstudy. As a multifactorial disease complex inwhich immune function stressors increase susceptibilityto respiratory pathology, risk management programsfor environmental and husbandry practices may be aneffective approach for BRD control. Practices of knownor suspected effect on BRD in preweaned calves havebeen explored in 2 large studies correlating managementfactors to BRD prevalence (BRD 100 study) andincidence (BRD 10K study) and forming the scorespresented here. Priority was given to results from multivariableover univariable model estimates. However,when used, univariable model estimates were adjustedfor confounders or stratified by effect modifiers if necessary.Regression coefficients were translated into scores,which are presented in a field-ready tool consisting of(1) a risk assessment questionnaire, which identifies theherd-specific risk factors and the risk scores associatedwith each; (2) the California BRD scoring system toestimate the BRD prevalence at the time of risk assessmentfor future comparison with the prevalence afterinterventions; and (3) the BRD control and preventionherd management plan, which can be used to plan andtrack the interventions identified. Scores for 100 dairiesacross California were used to benchmark a dairy’s riskon a spectrum. With the help of the risk assessmenttool, dairy producers, calf managers, and veterinariansmay be able to adjust management factors that affectBRD risk on a farm and objectively monitor BRDprevalence before and after management interventions.As a result, the BRD risk assessment tool describedhere is the first comprehensive effort for herd-specificBRD control and prevention.