Accounting for Heterogeneous Variances in Multitrait Evaluation of Jersey Type Traits
نویسندگان
چکیده
منابع مشابه
Accounting for heterogeneous variances in multitrait evaluation of Jersey type traits.
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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A multitrait animal model was used to calculate predicted transmitting ability and reliabilities for final score and 15 linear type traits of 225,632 US Jersey cows. Records were adjusted for age and stage of lactation before analysis. The model contained effects for interactions of herd and date scored; year scored, parity, and age; and herd and sire; effects of permanent environment and addit...
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Covariance components for final score and 13 linear type traits of dairy goats were estimated by multitrait REML using canonical transformation with an animal model. Data were 10,932 type appraisals from 1988 through 1994 from herds with > or = 40 appraisals. Heritabilities were estimated as 0.27 for final score, 0.52 for stature, 0.29 for strength, 0.24 for dairyness, 0.38 for teat diameter, 0...
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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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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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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 2006
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(06)72588-7