Parameters of Test Day Milk Yield and Milk Components for Dairy Ewes
نویسندگان
چکیده
منابع مشابه
Estimation of genetic parameters of weekly test-day milk yields and first lactation 305-day milk yield in Murrah buffaloes
Aim: The aim was to estimate genetic parameters of weekly test-day (TD) milk yields and first lactation 305-day milk yield (FL305DY) in Murrah buffaloes. Materials and Methods: The data on 39059 weekly test-day milk yield (WTDY) records during first lactation of 961 Murrah buffaloes calved from 1977 to 2012 and sired by 101 bulls maintained in an organized farm at National Dairy Research Instit...
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...
متن کاملGenetic parameters affecting 180-days standardised milk yield, test-day milk yield and lactation length in Spanish Assaf (Assaf.E) dairy sheep
A total of 42,197 records of test-day milk yield (TDY) and 7654 lactations from 3854 individuals belonging to the Spanish Assaf Assaf.E) breed were analysed using univariate and multivariate models to estimate genetic parameters affecting TDY, total milk ield standardised to 180 days (MY180) and lactation length (LL) in order to asses their possibilities of use in the selection scheme f the Ass...
متن کاملUse of Test-day Milk Yield for Genetic Evaluation in Dairy Cattle: a Review
The use of appropriate method for genetic evaluation of dairy animals is an important aspect of dairy cattle production. Traditional 305-day lactation model does not account for the changes in environmental factors within 305-day lactation and may involve unjustified projection of incomplete lactations. The use of test-day model in the recent past has made it possible to economize the genetic e...
متن کاملTest-day milk yield as a selection criterion for dairy buffaloes (Bubalus bubalis Artiodactyla, Bovidae)
Due to the great demand for buffalo milk by-products the interest in technical-scientific information about this species is increasing. Our objective was to propose selection criteria for milk yield in buffaloes based on total milk yield, 305-day milk yield (M305), and test-day milk yield. A total of 3,888 lactations from 1,630 Murrah (Bubalus bubalis) cows recorded between 1987 and 2001, from ...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1998
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(98)75692-9