A nutritional prognostic model for hospitalized Belgian blue calves: The Calf-CONUT ratio for predicting survival

Malnutrition is a major factor in disease management failure. In humans, the CONUT (COntrolling NUTritional status) score assesses nutritional status based on albumin, cholesterol, and lymphocyte levels (sensitivity 92,30 %; specificity of 85 %). In bovine medicine, few studies focus on calf nutrition status. This study compares serum urea, cholesterol, and albumin levels in Belgian Blue calves between hospital admission and discharge (or death) and between survivors (S) and non-survivors (NS). At admission, cholesterol levels did not significantly differ between groups (p > 0.1). Albumin levels were higher in S (p = 0.02), while urea levels were lower (p = 0.04). At discharge, S showed a significant increase in cholesterol (p < 0.05) and a decrease in urea (p < 0.01) and albumin (p < 0.05). A urea/albumin ratio, named the Calf-CONUT ratio, above 2.64 was associated with increased mortality risk (Relative Risk: 2.29, Odds Ratio: 5.75) but demonstrated low sensitivity (46 %) and high specificity (87 %), suggesting limited standalone predictive power. If the analysis focuses solely on calves suffering from enteritis, the threshold value is 2.85, with improved sensitivity and specificity (Se 83 %; Sp 78 %; relative risk: 10; odd ratio: 15). This study provides initial insights into the nutritional assessment of hospitalized calves and paves the way for innovative approaches to their nutritional and medical management. Further research on specific diseases and breeds is needed to refine these thresholds.