7427

6933

كارشناسي ارشد

ژنتيك و اصلاح نژاد دام

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1391

يازده،55ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

سعيد انصاري مهياري، محمدعلي ادريس

حميد غلامي

16/10/91

علي صادقي سفيدمزگي، محمد مهدي مجيدي

مهندسي كشاورزي

ID6933

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Estimation of Genetic Trends for Milk Production Traits in Dairy Cow Herds Using Random Regression Model Sepideh Hatamian Hatamiansp@yahoo com Date of submission September 19 2012 Department of Animal Science Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor S Ansari Mahyari S Ansari@cc iut ac ir Supervisor M A Edriss Edriss@cc iut ac ir Abstract Test day records of Holstein cows from 1996 to 2011 was used in this study Data consisted of 1114734 test day records of 138407 cows in 42 herds of first lactation in Iran Data was edited by Foxpro9 0 software and deleted records less than 6 kg and more than 51 kg Variance components and breeding values and genetic trend were estimated using random regression model and DMU software The heterogeneity of the residual variance in days 5 to 305 of lactation was modeled using 12 stage of 25 days interval Additive genetic and permanent environmental random effects for the first lactation curve were taken in to account by applying orthogonal legendre polynomials of order four in the model The results showed that the lowest and highest additive genetic variances were at the beginning 30 55 and end of the lactation period 280 305 respectively and generally were 4 59 0 16 and 10 56 0 30 Permanent environmental variance was high at the beginning 5 30 and end of lactation period 280 305 so was 19 81 0 21 and 18 29 0 24 respectively Heritability of milk was between 0 17 0 006 and 0 26 0 007 protein was between 0 089 0 006 and 0 23 0 008 and fat was between 0 094 0 005 and 0 134 0 005 respectively Genetic permanent and phenotypic correlation among test days decreased as the interval between consecutive test day increased Genetic correlations were positive and higher than phenotypic correlations at all days in lactation Genetic trend for all 3 traits milk yield protein and fat were 28 67 1 51 0 93 0 04 and 0 9 0 02 kg in year respectively The result of this research showed that the genetic trend for milk yield was satisfied It be concluded that animal breeding programs were on milk yield trait in these years Keywords Holstein cow milk yield traits random regression model test day record

سعيد انصاري مهياري، محمدعلي ادريس

حميد غلامي

علي صادقي سفيدمزگي، محمد مهدي مجيدي