اعلانات هامة

The objective of this study was to assess the seasonal variations in blood plasma concentrations of urea nitrogen (PUN), triglycerides and total protein in relation to the parity and days in milk. The present study was carried out at the dairy cows station of Deir Ezzor governorate, belonging to the public establishment of dairy cattle, during the period from January till the end of December 2010. A total of (40) Friesian cows at 1 and 3rd parity were used postpartum from the 1 prior to 6 months of lactation. These cows comprised two groups. The first group (20) cows were (10) at 1parity and (10) at 3 parity (bred in winter). The second group (20) cows were (10) at 1st parity and (10) at 3rd parity (bred in summer). The obtained results showed that the overall averages of plasma urea nitrogen concentrations were significantly higher (P<0.05) in the second group (22.44 mg/dl) than in the first group (21.73 mg/dl). Also the cows of the first parity showed a higher significant (P<0.05) averages of plasma urea nitrogen concentrations (22.35 mg/dl) than that in the third parity (21.82 mg/dl). The correlation coefficients indicated a negative significant (P<0.05) relations between plasma concentrations of PUN and triglycerides (r=-0.57), and between plasma concentrations of triglycerides and total protein (r=-0.44). Plasma urea nitrogen concentration was altered during the lactation period due to changes in the energy requirements. So, should be investigated in the means that alleviate the severe energy deficit in early lactation to avoid an increase in the concentration of plasma urea nitrogen and a negative effect on conception rate.

Key words: plasma urea nitrogen, triglycerides, total protein, parity, Friesian cows.

أجريت هذه الدراسة بهدف تقدير التغيرات الفصلية في تركيز نتروجين اليوريا والشحوم الثلاثية والبروتين الكلي في بلازما الدم بالعلاقة مع موسم و مرحلة الحلابة. نفذ هذا البحث في مبقرة ديرالزور التابعة للمؤسسة العامة للمباقر في الفترة من كانون الثاني حتى كانون الأول 2010م. استخدم في هذه التجربة ( 40 ) بقرة حلوب من سلالة فریزیان تنتمي لموسمي حلابة أول وثالث، من بعد الولادة بشهر ولغاية الشهر السادس للحلابة.تم تقسيم حيوانات التجربة إلى مجموعتين حسب فصل الولادة: المجموعة الأولى (الولادة في فصل الشتاء) وضمت (20) بقرة (10موسم أول - 10موسم ثالث). المجموعة الثانية (الولادة في فصل الصيف) وضمت (20) بقرة (10 موسم أول - 10 موسم ثالث).