استخدم في هذه الدراسة خلط تجاري بين عرق الهيرفورد وابقار من عرق الهولشتاين فريزيان بهدف الحصول على حيوانات هجينة تتمتع بقدرات وراثية إضافية لانتاج اللحم وكان الهدف من ذلك تعويض التدهور الحاصل في منتج اللحم بسبب توجه القواعد الزراثية للابقار في سورية لتحسين انتاجها من الحليب.
No English abstract
References used
عيسى بسام (2004) كتاب التحسين الوراثي منشورات جامعة دمشق
أدى استخدام عرق الهولشتاين فريزيان بشكل واسع في أعمال الخلط التربوي و الإنتاجي مع تحسين
العوامل البيئية إلى تحسين إنتاجية الأبقار من الحليب، إلا إنه قد سجل مع هذا التطور في إنتاج الحليـب
ازدياد في حالات أمراض التهاب الضرع Mastitis ، و قد أشارت المر
اجع العلمية في هذا السياق إلـى أن
الإصابة بأمراض التهاب الضرع يزداد احتماله مع ارتفاع إنتاجية الأبقـار مـن الحليـب، كمـا سـجلت اختلافات بين سلالات أو عروق الحليب بالنسبة لهذا المرض.
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.
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.
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.