This work was carried at the exp < /strong>erimental station of Animal Production, Dep < /strong>t. of Animal Production, Faculty of Agriculture, Assiut University on 60 selected Friesian and Jersey animals of different ages. The aim of the present investigation is to study the effect of age, season, breed difference on skin thickness and some hair characters and their relation with milk yield. The results could be summarized as follows: - Jersey animals had thicker skin compared with Friesian ones. Significance differences differences were detected between the two breeds at the shoulder region.
• There was a significant effect of age on skin thickness in both breeds. The skin thickness
increased as age advanced. Seasonal variations were noticed in skin thickness which reached maximum influence at winter and minimum at autumn. Skin thickness at the shoulder region was relatively higher than the last rib region in both breeds. Insignificant negative correlation was also noticed between skin thick
ness and milk yield, while insignificant positive correlation was detected between skin thickness and fat percentage of milk from both breeds. Hair weight per standard unit area from Jersey breed is heavier compared with Friesian,
although the latter is characterized by thin hair diameter. - There are significant positive correlations between hair diameter, hair weight per unit
area and fat percent of milk from Jersey cows, while insignificant correlations were
found in Friesian cows. . A significant negative correlation was detected between milk yield and hair diameter
of Jersey cows and milk yield and hair weight of Friesian cows.