Heterogeneity of (Co)Variance Components for Jersey Type Traits
نویسندگان
چکیده
منابع مشابه
Heterogeneity of (Co)Variance Components for Jersey Type Traits
Heterogeneity of (co)variances for US Jersey linear and final scores was investigated with data from February 2000 USDA genetic evaluations. (Co)variances were estimated from datasets defined by parity, contemporary group size, and mean final score. First-appraisal scores during first or second parity from records that included all traits were studied. Contemporary groups within each parity wer...
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(Co)variance components for final score and 15 linear types traits of Jersey cows were estimated by multitrait REML using multiple diagonalization and a repeatability model with 34,999 records of 22,354 cows. Multiple diagonalization gave relative off-diagonals (ratio of squared off-diagonals to the product of diagonals) of < 0.1%. Heritabilities and repeatabilities, respectively, were estimate...
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Anafi (Associazione Nazionale Allevatori Frisona Italiana) is also in charge of the Italian Jersey cattle genetic evaluations. Since interest about this dairy breed is steadily mounting, (co)variance components for 16 type traits of Italian Jersey cows were estimated, in order to start thinking of how to develop a new and more comprehensive selection index. The canonical transformation, in the ...
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Restricted maximum likelihood estimates of covariance components and the resulting genetic parameters were obtained for birth, weaning, yearling and final weights and postweaning gain of Australian Charolais cattle fitting an animal model including genetic or permanent environmental maternal effects. No 'carry-over' of maternal effects till weaning on postweaning weights w& found. Direct herita...
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The multitrait genetic evaluation system for type traits was modified to estimate adjustments for heterogeneous variance (HV) simultaneously with estimated breeding values (EBV) for final score and 14 linear traits. Each variance within herd, year, and parity was regressed toward a predicted variance, which was determined by fitting a model with fixed effects of the mean final score for herd, s...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 2001
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(01)74613-9