In bulls and heifers of the Gasconne breed, the selected indicators of the internal environment were determined. The effects of sex on changes in the concentration of total proteins, urea and total cholesterol were found. Enhanced growth intensity had apositive effect on the plasma concentration of total cholesterol but a negative correlation was detected between the growth intensity and activity of alanine aminotransferase, aspartate aminotransferase and Mg. The age of the animals affected the concentration of plasma triiodothyronine, alkaline phosphatase, urea and Fe. The indicators of internal environment determined in this study were within the physiological range and therefore helped to specify the health and nutritional status of animals rearedin extensive suckling cows systems.