the use of fixed and random regression test day models in genetic analysis of daily milk yield of mashhad’s holstein cows
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منابع مشابه
Analysis of Test Day Milk Yield by Random Regression Models and Evaluation of Persistency in Iranian Dairy Cows
Variace / covariance components of 227118 first lactaiom test-day milk yield records belonged to 31258 Iranian Holstein cows were estimated using nine random regression models. Afterwards, different measures of persistency based on estimation breeding value were evaluated. Three functions were used to adjust fixed lactation curve: Ali and Schaeffer (AS), quadratic (LE3) and cubic (LE4) order of...
متن کاملRandom regression models using different functions to model test-day milk yield of Brazilian Holstein cows.
We analyzed 152,145 test-day records from 7317 first lactations of Holstein cows recorded from 1995 to 2003. Our objective was to model variations in test-day milk yield during the first lactation of Holstein cows by random regression model (RRM), using various functions in order to obtain adequate and parsimonious models for the estimation of genetic parameters. Test-day milk yields were...
متن کاملcomparison of fixed regression and random regression test-day models for genetic evaluation of milk yield trait in holstein cows razavi khorasan province
the fixed regression test-day model (frm) and random regression test-day model (rrm) for genetic evaluation of milk yield trait of dairy cattle in khorasan razavi province were studied. breeding values and genetic parameters of milk yield trait from two models were compared. a total of 164391 monthly test day milk records (three times milking per day) obtained from 19217 holstein cows distribut...
متن کاملGenetic Analysis of Milk Yield in Iranian Holstein Cattle by the Test Day Model
Using monthly test day records the genetic parameters of Iranian Holstein cattle in first lactation were studied. Data of 277400 test-day milk records from 65320 cows and 2210 sires were analyzed by an animal random regression model using restricted maximum likelihood methodology. The model included herd-test-date, interaction between year-season of calving, days in milk (linear and quadratic) ...
متن کاملgenetic evaluation of test day milk records of holstein cows in the northern provinces of iran using random regression models
this research used the test day data of the milk production of holstein cows from golestan, mazandaran and guilan provinces collected by animal breeding center of iran between the years of 1988-2011. permanent effects of model, including cattle blend, breeding year and season, also percent of holstein gene and age during recording, were used as a secondary variable. all data obtained in this re...
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عنوان ژورنال:
پژوهش های علوم دامیجلد ۲۲، شماره ۴، صفحات ۵۷-۶۸
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