Evaluation of serum metabolic parameters as predictors of bovine respiratory disease events in high-risk beef stocker calves

The primary objective of this study was to evaluate the association between serum metabolic parameters and the risk of bovine respiratory disease (BRD) in high-risk beef stocker calves. Jugular venous blood samples were collected from mixed-breed beef bull, steer, and heifer calves (n=468) at the time of arrival processing at a stocker facility in northeast Georgia. Serum samples were then submitted for determination of serum creatinine, total calcium, phosphorus, magnesium, albumin, serum urea nitrogen, glucose, cholesterol, beta-hydroxybutyrate (BHBA), non-esterified fatty acid (NEFA), sodium, potassium, and chloride concentrations, as well as sodium:potassium ratio and NEFA:cholesterol ratio. Calves were monitored for the development of signs consistent with BRD for 45 days following arrival. A multi-variable logistic regression model was created to evaluate the association between serum variables and subsequent risk of BRD. In this analysis, BRD was associated with higher serum potassium, lower serum urea nitrogen, and lower BHBA concentrations at arrival processing. The area under the receiver operating characteristic curve for the ability of the model to predict morbidity was 0.645. These data suggest that hydration status, nutrient balance, and degree of rumen development may play a role in the development of BRD in high-risk beef stocker calves.