Sixty animals (six groups) of the native cattle bred at different physiolo gical status were investigated in summer time. Blood analysis of such cases revealed the following findings. 1- Serum cortisol levels in these physiologically normal cattle were between 3200 nmol/L. and 4700 n mol/L. Exception was the non preg nant-nonlactating aged cows 1500 nmol/L. to 3010 n mol/L. p. Raised levels attributed to adrenocortical activity. 2- No distinct difference in the total serum proteins level. 3- No obvious changes were detected in the serum chloride level between the examined groups and most of these values lie within the acceopted physiological limits. 4- Distinct decrease in the totalipid contents in the highly lactating cows, while rise was obvious in heifers (8-12 months of age).