Frequency and diagnostic reliability of laboratory variables in cows with traumatic reticuloperitonitis and abomasal ulcers

Abstract

A number of laboratory abnormalities occurs in cows with traumatic reticuloperitonitis (TRP) as well as in those with abomasal ulcers (U; classified as type 1 to 5). The goal of our study was to compare the frequency of individual laboratory variables of cows with traumatic reticuloperitonitis and cows with abomasal ulcers and determine the diagnostic significance of individual laboratory variables. The present study included 182 healthy control cows, 503 cows with TRP, 94 cows with U1, 145 cows with U2, 60 cows with U3, 87 cows with U4 and 14 cows with U5. Hematocrit, total leukocyte count, concentrations of total protein, fibrinogen, urea, potassium and chloride, base excess and rumen chloride concentration were analyzed. The frequency distributions of all variables for all groups of cows were compared and the diagnostic reliabilities (diagnostic sensitivities and specificities, predictive values, positive likelihood ratios [LR+]) were calculated. Values outside the reference interval occurred in 2 to 24 % of control cows (rumen chloride 2 %, urea 6 %, serum chloride 11 %, hematocrit 13 %, base excess 18 %, fibrinogen 20 %, total protein 21 %, total leukocyte count 22 % and potassium 24 %), which made differentiation of healthy and ill cows difficult. Therefore, the variables best suited for distinguishing healthy and affected cows were rumen chloride and blood urea concentration. This was also supported by an LR+ of 14 to 27 for rumen chloride > 30 mmol/l and 6 to 15 for blood urea > 6.5 mmol/l in cows with abomasal ulcers. Urea also displayed a high diagnostic specificity and was suited for differentiation of healthy and diseased cows. The urea concentration was > 8.5 mmol/l in only 0.5 % of controls, and the LR+ for a urea concentration > 8.5 mmol/l ranged from 11 in cows with TRP to 128 in cows with U2. Except for cows with TRP, azotemia was significantly more frequent in affected cows than in controls. Cows with U2 (70 %) had urea concentrations > 8.5 mmol/l significantly more frequently than cows of the other groups. Even though the groups of diseased cows differed significantly with respect to several variables, no variables were identified to reliably differentiate the various groups. Different disorders in cows cannot be differentiated based on single laboratory variables. For a definitive diagnosis the history, clinical findings and results of additional diagnostic techniques such as radiography of the reticulum, ultrasonography and abdominocentesis are required. In many cases, a definitive diagnosis can only be made via exploratory laparotomy and/or postmortem examination.