Frequency and diagnostic reliability of laboratory variables in cows with traumatic reticuloperitonitis and type 1, 2, 3, 4 and 5 abomasal ulcer

Abstract Background: A number of laboratory abnormalities occur in cows with traumatic reticuloperitonitis (TRP) as well as in those with abomasal ulcers (AU). This prompted us to compare the frequencies of laboratory abnormalities of healthy cows and cows with TRP and cows with abomasal ulcers and to calculate diagnostic sensitivities and specificities, predictive values and positive likelihood ratios for laboratory findings. The 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. Haematocrit, total leukocyte count, concentrations of total protein, fibrinogen, urea, potassium and chloride, base excess and rumen chloride concentration were analysed.Results: Values outside the reference interval occurred in 2 to 24% of control cows (rumen chloride 2%, urea 6%, serum chloride 11%, haematocrit 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 ill 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 ulcers. Urea also had a high diagnostic specificity and like rumen chloride 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, azotaemia was significantly more frequent in ill cows than in controls. Cows with U2 (70%) had urea concentrations >8.5 significantly more often than cows of the other groups, which may have been prerenal azotaemia attributable to hypovolaemia. Even though the groups of ill cows differed significantly with respect to several variables, no variables were identified to reliably differentiate the various groups.Conclusions: Isolated results are not suitable to distinguish among groups of ill cows and instead the history, the clinical findings and results of additional diagnostic techniques such as ultrasonography are required.