This study was done on the records of 564 milk cows
during the period 2004-2007 .Those cows were dismissed
for many reasons and in different ages. The range of
dismissing age is between 3-6 years. The ratio of
dismissing of those cows was between
20-25% . The rate
of dismissing was high in the first lactation season . It
reached 27,43% for the years 2004-2005, and 24,45% for
the years 2006-2007. The highest percentage of dismissing
was in the first month of milk seasons .It reached 34,49%
in the years 2006-2007.
تتبوأ الأبقار المرتبة الاولى في إنتاج الحليب بين الحيوانات الزراعية كونها تنتج ما يعادل 58.4% من مجمل إنتاج الحليب
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.
