This study aimed to explore the genetic parameters of milk traits and mastitis susceptibility in Friesian dairy cows. Data from 4,355 test days for somatic cell score (SCS), fat %, and protein % of 511 cows, 147 sires and 277 dams were analyzed. Medium heritability estimates were recorded for 305-day milk yield (0.25± 0.012), protein (0.22% ± 0.039) and fat (0.21% ± 0.035). A low heritability estimate was noted for SCS (0.02±0.008). The estimated Predicted Breeding Value (PBV) for the 305-day milk yield (305dMY) trait varied widely. The range of breeding values was highest for protein and fat (0.264 and 0.131) of cows, and the highest for the 305dMY trait (2633.1 kg) for the sires. The negative environmental connection between 305-day milk yield and SCS suggests that sanitary methods and effective management might help maintain a suitable level of milk yield, while decreasing milk SCS and environmental mastitis incidence. This study recommends the use of more effective management practices aligned with the selection of cows that are more resistant to environmental factors to reduce the levels of SCS in milk by increasing the animals' resistance to mastitis. Furthermore, genetic characteristics for all analyzed features may be useful in developing selection indices to improve udder health and milk production in Friesian dairy cows.