This research was conducted I during 2009-2010 at Dier Alhajar station,
General Commission for Scientific Agricultural Research to determine the
length of calving interval (CI) and the effect of sire, calving year, calving
season, parity and age o
f cow and their interactions in Shami Cattle.
It was concluded that CI can be reduced by better
management and providing good and suitable feeding conditions.
This study was conducted at Kharabo Dairy Station belongs to the Faculty
of agriculture, University of Damascus. 553 records for 206 Holstein Friesian
cattle were used to study factors affecting the calving interval during 1982 to
2007. Data were
exposed eccording to GLM, and analysis of variance was used
to determine the calving interval (CI) and the effect of calving year, calving
season, parity and interactions on the calving interval, and Duncan test was
used to compare means by SPSS program. The overall mean for (CI) was
459.12±4.90 days. and affected significantly (0.001>P) by calving year, but
there was no significant effect for calving season, parity and interactions
between studied factors on the calving interval. These results suggested that
better management, and applaying more efficient administration practices as
well as to improving the feeding status may reduce calving interval to typical
period of 365 days and increase reproductive and economic efficiency of dairy
cattle at Kharabo station.
Records of ٤٤٥ Friesian cows were analysed for calving interval and its
components; days open, lactation length and length of dry period. The model
included parity, calving year and calving season. The overall means were
٤٢٥,٧٧ ± ١,٨٩, ١٤١,٣ ± ١,٣
٧, ٣٥٣,٩ ± ٠,٨٨ and ٧٣,٠٢ ± ٠,٧٧ days for calving
interval, days open, lactation length and length of the dry period respectively.
These estimates are high by tropical and subtopical standards, but they remain
lower than the reproductive performance of Friesian cattle in temperate
countries.
