Mastitis is an endemic disease that is considered to be one of the most frequent and costly
dairy diseases, so that the aim of this study was to investigate different factors affecting
mastitis incidence, and their effect on productivity and profitability of dairy farms. Data used
in this study were estimated from 1353 lactation records of Friesian dairy cows within private
and governmental farms. The productive, reproductive and economic data for a whole
lactation season were recorded for healthy and mastitic cows. Four risk factors for mastitis
were included (production sector, calving season, parity and milk-production level). Data
were classified according to risk factors into two production sectors private and
governmental, two calving seasons, summer and winter and Six lactation orders from 1stto 6th,
two milk production levels (high and low milk producing cows). Winter calving, older and
high producing cows and private sector had the highest mastitis incidence, mastitis reduced
the 305-milk yield of Mastitic cows by 33.7 & 20.3Kg during disease period, and 62.7 &
37.7Kg milk was discarded during the treatment period for private and governmental sector
respectively. Finally, economic loss of mastitis per animal estimated 695.7 EGP yearly.