Aussagekraft von Blut- und Harn-pH-Werten bezüglich des Grades einer Azidose bei Durchfallkälbern

eng: The present study was performed to investigate if the urine pH, which is rather simple to determine, correlates with the blood pH and if veterinarians in the field, who usually lack a blood gas analyzer, could use the urine pH as a help in predicting the severity of metabolic acidosis in diarrheic calves. 60 healthy and 45 diarrheic neonatal calves were given a physical examination. In addition to that blood gas analysis was performed, hematocrit, serum total protein, serum sodium, potassium and chloride concentrations were measured, plasma glucose and lactate and serum urea and creatinine concentrations were determined.
Furthermore the enzyme activities of aspartate-amino-transferase and creatinine kinase as well as urine pH and specific gravity were measured. 67% of the diarrheic calves suffered from a metabolic acidosis. It is true there was a correlation between blood pH and urine pH (r=0,43, p=0,003), but it was not possible to predict the severity of acidosis precisely. Base excess had a better correlation with urine pH (r=0,55, p;0,001), nevertheless this relationship failed in estimating the degree of acidosis, too. Of course there was a certain tendency of the urine pH to drop with aggravating blood acidosis. As a diagnostic device the urine pH proved to be of small value due to its vague and unsure results leading to serious errors in the prediction of base deficit. Clinical signs were used to assign the calves to one of the three categories mildly, moderately or severely diarrheic. These clinical findings were significantly correlated with the severity of acidosis (r=0,65, p;0,001). The calf's demeanour or the level of dehydration alone turned out to be of less predictive value (both r=0,55, p;0,001).