Covariance components by a repeatability model in Slovenian dairy sheep using test-day records
نویسندگان
چکیده
منابع مشابه
Genetic evaluation of dairy cattle with test-day models with autoregressive covariance structures and with a 305-d model.
This study compared genetic evaluations from 3 test-day (TD) models with different assumptions about the environmental covariance structure for TD records and genetic evaluations from 305-d lactation records for dairy cows. Estimates of genetic values of 12,071 first-lactation Holstein cows were obtained with the 3 TD models using 106,472 TD records. The compound symmetry (CS) model was a simpl...
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The objective of this study was to compare test-day (TD) models with autoregressive covariance structures for the estimation of genetic and environmental components of variance for milk, fat and protein yields, and somatic cell score (SCS) in Holstein cows. Four models were compared: model I (CS model) was a simple TD repeatability animal model with compound symmetry covariance structure for en...
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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) ...
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Mixed model methodology and recursive estimation techniques (Kalman filter) were combined to detect significant changes in the performance level of both individual cows and an entire herd. Yields were predicted for the next time of recording using all data available up to that time. Predicted yields were compared with actual measurements. If the error of prediction, or innovation, exceeded +/- ...
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ژورنال
عنوان ژورنال: Czech Journal of Animal Science
سال: 2009
ISSN: 1212-1819,1805-9309
DOI: 10.17221/1680-cjas