Random regression models using different functions to model milk flow in dairy cows
نویسندگان
چکیده
منابع مشابه
Random regression models using different functions to model milk flow in dairy cows.
We analyzed 75,555 test-day milk flow records from 2175 primiparous Holstein cows that calved between 1997 and 2005. Milk flow was obtained by dividing the mean milk yield (kg) of the 3 daily milking by the total milking time (min) and was expressed as kg/min. Milk flow was grouped into 43 weekly classes. The analyses were performed using a single-trait Random Regression Models that included di...
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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...
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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...
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Milk flow measurements on 124 cows were analyzed to deternfine how they are affected by vacuum level, pulsation rate, pulsation ratio of the milking maehine, and the breed, age, stage of laetation, and milk yield of the cow. Average rate of flow prior to machine stripping, yield during the first minute, and yield during the first 2 rain of milking were highly correlated with maxinmm rate of mil...
متن کاملanalysis 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...
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ژورنال
عنوان ژورنال: Genetics and Molecular Research
سال: 2014
ISSN: 1676-5680
DOI: 10.4238/2014.september.12.20