الفهرس 
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Abstract
In this study data were collected from1366 records for pure Holstein cows from a private dairy farm. The cows were in different seasons of lactation and have different production level and different season of calving. The data recorded in software dairy comp 305 VAS (Vally Agriculture Software).The classification of the cows in the study were divided according to the following (Overall as healthy and diseased cows, production level the cows were divided into high producing and low producing ,lactation order the cows were divided into primiparous and pluriparous and according to season of calving the cows were divided into winter and summer season of calving).Productive traits as Peak milk yield (MPEAK), daily milk yield (DMY) & 305 Milk Yield (M305) were determined. Also the reproductive traits as Days in milk for first heat (DIMFH), Days in milk for first bred (DIMFB), Days open (DOPN) &Total numbers of bred (TBRD) also were determined.
The results in the study revealed that: The incidence of occurrence of clinical mastitis increased with the increase in the lactation numbers. The highest level of occurrence of positive cases of clinical mastitis was at (0-30 DIM) with percentage of 23.28%). In general the mastitic cows were showed significant losses in (MPEAK), (DMY) & (M305) by 5.2%, 11.79% & 5.95% respectively compared to the healthy ones. Negative effects of clinical mastitis on productive parameters as (MPEAK), (DMY) & (M305) of high–producing cows were significant & observed, and in low producing cows the effects were found significant on (DMY)&(M305).The impact of clinical mastitis on (DIM) was non-significant in all groups of cows. Mastitic cows required on the average, (3.37) more days from calving to the first heat, (2.96) more days from calving to the first insemination, (25.67) more days and (0.02) more inseminations to conceive compared to their unaffected matched controls.
Genital diseases have not significant effect on productive parameters in all group of cows in the study except in high yielding cows it was noted that the diseased cows produce significantly less milk in (MPEAK) and in (M305) . Cows infected with genital diseases required on the average (6.41) more days from calving to the first heat, (9.65) more days from calving to the first insemination, (22.42) more days open and (0.76) more inseminations to conceive compared to their unaffected matched controls.