پديد آورنده :
رئيسي واناني، رضا
عنوان :
ارتباط بين صفات توليدمثلي و طول عمر توليدي در گله هاي گاو شيري استان اصفهان با استفاده از مدل خطر نسبي تكه اي وايبول
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي
صفحه شمار :
يازده، ۴۹ص.: مصور، جدول، نمودار
استاد راهنما :
سعيد انصاري مهياري
استاد مشاور :
عباس پاكدل، محمد علي ادريس
توصيفگر ها :
آناليز بقا , طول عمر توليدي , صفات توليد مثلي , عملكرد زايش , اثرات غير ژنتيكي , گاو هلشتاين
استاد داور :
احمد رياسي، قدرت اله سعيدي
تاريخ ورود اطلاعات :
1397/06/17
چكيده انگليسي :
Relationship between reproductive traits and functional longevity indairy cows in Isfahan province using a piecewise Weibull proportional hazard model Reza Reisi Vanani reza reisi@ag iut ac ir Jun 10 2017 Department of Animal Science Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Saeid Ansari Mahyari s ansari@cc iut ac irAbstractThe objective of this study was to assess the relationship between reproductive traitsand functional longevity of Isfahan dairy herds using survival analysis Data consistedof 82 505 daughter s life records of 1952 sires calving between 2001 and 2016 Functional longevity was defined as the number of days from first calving to last knowntest day record The piecewise Wiebull baseline hazard function with 25 differenthazard functions were defined for each combination of lactation 1 to 5 and stage oflactation 1 to 5 The model included the time dependent fixed effects of withinherd year lactation class of milk production 305 class of annual variation in herd size year season of calving calving traits calving ease and calf survival female fertilitytraits the number of services interval from calving to first service interval from firstservice to conception and days open and the time independent fixed effect of age atfirst calving Random effects of herd year and sire and maternal grandsire were addedto the model to estimate nongenetic and genetic parameters All effects were used in themodel had a significant P 0 001 associations on longevity The risk of being culledincreased with age at first calving The relative risk for within herd year lactation classof milk production 305 varied from 1 72 for the worst class and 0 67 for the best class A Decreased in risk of being culled in shrinking herds and expanding herds compared tostable size Increased relative risk was observed for cows had hard pull and surgeoryand cows with dead calves Moreover cows which demand more services perconception a longer interval between calving to first service and first service toconception and also increased in days open had a higher risk of culling compared withthe reference classes The estimate of the sire genetic variance was 0 068 0 0012 andthe theoretical heritability was 0 17 in the complete absence of censoring information In conclusion cows with poor fertility had a more risk of being culled compared toreference classes Key WordsSurvival analysis Functional longevity Reproductive traits Nongenetic effects Holstein cows
استاد راهنما :
سعيد انصاري مهياري
استاد مشاور :
عباس پاكدل، محمد علي ادريس
استاد داور :
احمد رياسي، قدرت اله سعيدي
