This study was carried out in the dairy farm of Almarie company which is located in Bagel city. 748 records were used for 370 Holstein cows covering the period 1992-2004. It included traits of total and daily milk yield. It involved the impact of different characteristics: parity of calving, season of calving, year of calving, calving interval, lactation length, dry period, and age at first calving. It also estimated genetic parameters such as heritability and repeatability for traits. General averages of total and daily milk yield were 4037.3 ± 66.35 kg, 10.47±0.10 kg respectively. Parity of calving has affected significantly total and daily milk yield (p 0.01). Production has gradually increased as cows becoming older reaching highest level at sixth and fifth parity for total and daily milk yield respectively. Season of calving has affected significantly total (P>0.05) and daily milk yield (P>0.01). In spring, calving cows achieved highest total (4077.18 kg) and daily milk yield (11.81 kg). Effect of year of calving on total and daily milk productions was significantly high (p>0.01). In 1992, the highest production was achieved but decreased with year progress, for both total and daily milk productions. Effect of lactation length was significant on total (P>0.05) and daily milk yield (P>0.01). The age at first calving was significant in total milk yield and daily milk yield (P>0.01). Cows of more than 35 months achieved highest total and daily milk yield (11.41, 3969.19 kg) respectively.

Key Words :Holstein Friesian Cows, Milk Yield, Non-genetic Factors.