Venous blood samples of 300 healthy female Holstein calves were used to study the effect of the age on the acid-base balance in the neonatal period. The calves were divided in 15 age groups: from birth to 8 h; 8 to 16 h; 16 to 24 h; 2 d; 3 d; 4 d; 5 d; 6 and 7 d; 8 and 9 d; 10 and 11 d; 12 and 13 d; 14 and 15 d; 16 to 20 d; 21 to 25 d; and 26 to 30 d. Blood pH, pCO2, pO2, HCO3-, TCO2, BE, StB and SatO2 values were measured and the results were analysed through ANOVA. The correlation between the variables and age in the first day of life was studied. The influence of the type of parturition (normal versus assisted or dystocic) on the acid-base status was compared. Blood pH and pCO2 values were respectivelly lower and higher in the first age group; BE and StB were reduced in the first 16 h of life, showing a trend to increase up to the 5th day of life. The older the calf, in the first day of life, the higher the blood pH, BE, and StB; the lower the blood pCO2. Few changes occurred in the acid-base status of calves born from different types of parturition. These results reforced the evidence that mixed acidosis presented at birth tend to be reverted during the first days of life. The acid-base vriables remained stable along the rest of the neonatal period.
Calf; Infant; Newborn; Acid-base equilibrium
