[Modification of the concentration of creatinine and sodium in blood serum and urine and the fractional elimination of sodium by electrolyte therapy in calves].

In 32 calves, creatinine and sodium concentrations were determined in blood and urine samples taken simultaneously four times during two periods of two days each (control period: milk or milk replacer; trial period: oral electrolyte solution). Creatinine urine/serum ratios and fractional elimination of sodium (FENa) were calculated. The influence of the type of liquid feed on these parameters was evaluated statistically. Calves fed milk replacer had higher urine sodium concentrations and FENa than calves fed whole milk. All parameters determined were influenced by intake of oral electrolyte solution: creatinine concentrations in serum and urine decreased, whereas sodium concentrations in serum and urine, as well as FENa, increased. It is concluded that sodium content of liquid feed significantly influences FENa.