Development of a diagnostic diagram for rapid field assessment of acidosis severity in diarrheic calves

Objective—To develop a diagnostic diagram for rapid field assessment of acidosis severity in diarrheic calves. Design—Prospective cross-sectional study. Animals—148 Piedmontese calves (38 calves in preliminary experiments; 83 diarrheic calves and 27 healthy control calves in the primary experiment). Procedures—Physical examination was performed and a standard data collection form was completed for each calf. Blood samples were obtained and submitted for evaluation of acid-base balance, performance of a CBC, and measurement of electrolyte and total protein concentrations. Results—Severe metabolic acidosis (extracellular base excess more negative than –10 mmol/L) was associated with abnormal mental status, delayed or absent suckle reflex, abnormal posture or gait, enophthalmos, and cold oral mucosal membranes. Clinical signs associated with severe metabolic acidosis were arranged into a grid to create a diagnostic diagram. Sensitivity and specificity of the diagnostic diagram for the prediction of severe metabolic acidosis were 88% and 79%, respectively. Conclusions and Clinical Relevance—Use of the diagnostic diagram may aid differentiation between severe and nonsevere acidosis patterns as determined on the basis of clinical signs.