This study was conducted at Kharabo dairy station belongs to the Faculty of
Agriculture، University of Damascus. 692 productive records for 269 Holstein
Friesian cattle were used to study the effects of calving year, age at first calving،
calving
season and parity on the adjusted 305-day milk yield. Data were
exposed to GLM, analysis of variance was applied to determine the effect of
studied factors and differences between averages were compared according to
Duncan test using SPPS 17. The overall mean for (305-d milk) was 6222.6 ±
62.01 kg. and affected significantly (P < 0.001) by calving year and parity and
(P<0.05) by age at first calving. No significant effect for season was observed.
Results suggested that better management practices and improving the feeding
status might help increasing the 305-d milk and making the status more
economic efficient in the dairy cattle at Kharabo Farm.
