This study was conducted at fedio dairy station belongs to the General organization
for cattle in Lattakia.. A total of 2534 production records of 1771 Holstein cattle were used
to study factors affecting the Days open (DO) during 1990 to 2013, and
to study the effects
of calving year, calving season, parity and interactions between studied factors on this trait.
Data were analyzed by the Least Square Means, and Duncan test was used to compare
means by SAS 9 program.
The overall mean for Days Open (DO) was 150.23 ± 1.44 days. and affected
significantly (P< .0..1) by calving year, calving season, parity and interaction (calving
year × calving season), (calving year × calving season) and (P<.0.5 ) by interaction
(calving year × calving season × parity) on the Days Open, but there was no significant
effect for interaction (calving year × parity).
Results suggested that better management, and improving the feeding status may
reduce Days Open to typical period (60 - 90 days), reduce interval calving, to get calf
every year, and increase reproductive and economic efficiency of dairy cattle at fedio
station.
