This study was carried out during the period from February 2016 to February 2017 on 100 Friesian dairy cows aged (3-7 years old) of different parities belonged to private dairy farm which locate at Hehia city at Sharkiya governorate. The aim of the present study was to investigate the effect of age of dairy cows on their ingestive behaviour, suckling disorders, productive performance, milk constituents and serum cortisol level of Friesian dairy cows. The results were revealed that, on ingestive behaviour, the age of 4th years old was the highest significant (P