Effect of sire, age at first calving, season and year of calving and parity on reproductive performance of Friesian cows under semiarid conditions in Egypt.

摘要: The objective of this paper was to study some factors affecting reproductive performance a locally-born Friesian herd in Egypt. Data 2096 records representing 482 cows daughters 38 sires raised at the Dairy Unit Milk and Meat Project Faculty Agriculture, Alexandria University, Egypt (located northern western part Nile Delta) between 1985-2002 were utilized effects sire cow, age first calving (AFC), season year calving/birth parity on period from parturition service (FSP), days open (DO), interval (CI), number services per conception (NSC), AFC breeding efficiency (BE). least squares mixed model analysis by SAS (1999) indicated that overall means (± standard error) FSP, DO, CI, NSC, BE 88.4 ± 1.1, 130.7 1.9, 403.1 1.9 days, 2.1 0.1 services, 30.7 months 90.1 0.6 %, respectively. Sire had highly significant (P<0.01) effect NSC AFC, but insignificant FSP BE. influence not DO Cows more than 36 longest (92.6±4.5) less 29 87.8±2.7 FSP. Season (P<0.01), CI (P<0.05), NSC. birth no both autumn shortest (394.3±4.7 days) comparing with those calved other seasons (ranged 404.8±6.5 409.4±5.2 days). also (122.6±4.8 Year (P<0.05 or P<0.01) all traits studied. A decreasing observed over time. 1988 1990 (64.3±5.3 98.1±8.9 respectively) 2000 2002 (107.5±5.2 188.1±8.8 respectively). Calving increased 371 1988-1990 450