Estimation of genetic parameters for test-day milk yield in Holstein cows using a random regression model
Test-day milk yield records of 11,023 first-parity Holstein cows were used to estimate genetic parameters for milk yield during different lactation periods. (Co)variance components were estimated using two random regression models, RRM1 and RRM2, and the restricted maximum likelihood method, compare...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Sociedade Brasileira de Genética
2005-03-01
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| Series: | Genetics and Molecular Biology |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000100013 |
| _version_ | 1828472579921281024 |
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| author | Jaime Araujo Cobuci Ricardo Frederico Euclydes Paulo Sávio Lopes Claudio Napolis Costa Robledo de Almeida Torres Carmen Silva Pereira |
| author_facet | Jaime Araujo Cobuci Ricardo Frederico Euclydes Paulo Sávio Lopes Claudio Napolis Costa Robledo de Almeida Torres Carmen Silva Pereira |
| author_sort | Jaime Araujo Cobuci |
| collection | DOAJ |
| description | Test-day milk yield records of 11,023 first-parity Holstein cows were used to estimate genetic parameters for milk yield during different lactation periods. (Co)variance components were estimated using two random regression models, RRM1 and RRM2, and the restricted maximum likelihood method, compared by the likelihood ratio test. Additive genetic variances determined by RRM1 and additive genetic and permanent environmental variances estimated by RRM2 were described, using the Wilmink function. Residual variance was constant throughout lactation for the two models. The heritability estimates obtained by RRM1 (0.34 to 0.56) were higher than those obtained by RRM2 (0.15 to 0.31). Due to the high heritability estimates for milk yield throughout lactation and the negative genetic correlation between test-day yields during different lactation periods, the RRM1 model did not fit the data. Overall, genetic correlations between individual test days tended to decrease at the extremes of the lactation trajectory, showing values close to unity for adjacent test days. The inclusion of random regression coefficients to describe permanent environmental effects led to a more precise estimation of genetic and non-genetic effects that influence milk yield. |
| first_indexed | 2024-12-11T05:31:59Z |
| format | Article |
| id | doaj.art-f6ae74cfc29840e19ffaed7e2b3a866a |
| institution | Directory Open Access Journal |
| issn | 1415-4757 1678-4685 |
| language | English |
| last_indexed | 2024-12-11T05:31:59Z |
| publishDate | 2005-03-01 |
| publisher | Sociedade Brasileira de Genética |
| record_format | Article |
| series | Genetics and Molecular Biology |
| spelling | doaj.art-f6ae74cfc29840e19ffaed7e2b3a866a2022-12-22T01:19:24ZengSociedade Brasileira de GenéticaGenetics and Molecular Biology1415-47571678-46852005-03-01281758310.1590/S1415-47572005000100013Estimation of genetic parameters for test-day milk yield in Holstein cows using a random regression modelJaime Araujo CobuciRicardo Frederico EuclydesPaulo Sávio LopesClaudio Napolis CostaRobledo de Almeida TorresCarmen Silva PereiraTest-day milk yield records of 11,023 first-parity Holstein cows were used to estimate genetic parameters for milk yield during different lactation periods. (Co)variance components were estimated using two random regression models, RRM1 and RRM2, and the restricted maximum likelihood method, compared by the likelihood ratio test. Additive genetic variances determined by RRM1 and additive genetic and permanent environmental variances estimated by RRM2 were described, using the Wilmink function. Residual variance was constant throughout lactation for the two models. The heritability estimates obtained by RRM1 (0.34 to 0.56) were higher than those obtained by RRM2 (0.15 to 0.31). Due to the high heritability estimates for milk yield throughout lactation and the negative genetic correlation between test-day yields during different lactation periods, the RRM1 model did not fit the data. Overall, genetic correlations between individual test days tended to decrease at the extremes of the lactation trajectory, showing values close to unity for adjacent test days. The inclusion of random regression coefficients to describe permanent environmental effects led to a more precise estimation of genetic and non-genetic effects that influence milk yield.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000100013random regression modelsREML methodgenetic parameterstest-day milk yieldHolstein cows |
| spellingShingle | Jaime Araujo Cobuci Ricardo Frederico Euclydes Paulo Sávio Lopes Claudio Napolis Costa Robledo de Almeida Torres Carmen Silva Pereira Estimation of genetic parameters for test-day milk yield in Holstein cows using a random regression model Genetics and Molecular Biology random regression models REML method genetic parameters test-day milk yield Holstein cows |
| title | Estimation of genetic parameters for test-day milk yield in Holstein cows using a random regression model |
| title_full | Estimation of genetic parameters for test-day milk yield in Holstein cows using a random regression model |
| title_fullStr | Estimation of genetic parameters for test-day milk yield in Holstein cows using a random regression model |
| title_full_unstemmed | Estimation of genetic parameters for test-day milk yield in Holstein cows using a random regression model |
| title_short | Estimation of genetic parameters for test-day milk yield in Holstein cows using a random regression model |
| title_sort | estimation of genetic parameters for test day milk yield in holstein cows using a random regression model |
| topic | random regression models REML method genetic parameters test-day milk yield Holstein cows |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000100013 |
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