Genetic parameters for first lactation test-day milk flow in Holstein cows
Genetic parameters for test-day milk flow (TDMF) of 2175 first lactations of Holstein cows were estimated using multiple-trait and repeatability models. The models included the direct additive genetic effect as a random effect and contemporary group (defined as the year and month of test) and age of...
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| Format: | Article |
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Elsevier
2012-01-01
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| Series: | Animal |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1751731111001376 |
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| author | M.M.M. Laureano A.B. Bignardi L. El Faro V.L. Cardoso L.G. Albuquerque |
| author_facet | M.M.M. Laureano A.B. Bignardi L. El Faro V.L. Cardoso L.G. Albuquerque |
| author_sort | M.M.M. Laureano |
| collection | DOAJ |
| description | Genetic parameters for test-day milk flow (TDMF) of 2175 first lactations of Holstein cows were estimated using multiple-trait and repeatability models. The models included the direct additive genetic effect as a random effect and contemporary group (defined as the year and month of test) and age of cow at calving (linear and quadratic effect) as fixed effects. For the repeatability model, in addition to the effects cited, the permanent environmental effect of the animal was also included as a random effect. Variance components were estimated using the restricted maximum likelihood method in single- and multiple-trait and repeatability analyses. The heritability estimates for TDMF ranged from 0.23 (TDMF 6) to 0.32 (TDMF 2 and TDMF 4) in single-trait analysis and from 0.28 (TDMF 7 and TDMF 10) to 0.37 (TDMF 4) in multiple-trait analysis. In general, higher heritabilities were observed at the beginning of lactation until the fourth month. Heritability estimated with the repeatability model was 0.27 and the coefficient of repeatability for first lactation TDMF was 0.66. The genetic correlations were positive and ranged from 0.72 (TDMF 1 and 10) to 0.97 (TDMF 4 and 5). The results indicate that milk flow should respond satisfactorily to selection, promoting rapid genetic gains because the estimated heritabilities were moderate to high. Higher genetic gains might be obtained if selection was performed in the TDMF 4. Both the repeatability model and the multiple-trait model are adequate for the genetic evaluation of animals in terms of milk flow, but the latter provides more accurate estimates of breeding values. |
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| institution | Directory Open Access Journal |
| issn | 1751-7311 |
| language | English |
| last_indexed | 2024-12-22T01:04:57Z |
| publishDate | 2012-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Animal |
| spelling | doaj.art-e9a1bcd9ec1746658e55a83b8c1467202022-12-21T18:44:07ZengElsevierAnimal1751-73112012-01-01613135Genetic parameters for first lactation test-day milk flow in Holstein cowsM.M.M. Laureano0A.B. Bignardi1L. El Faro2V.L. Cardoso3L.G. Albuquerque4Department of Animal Science, Universidade Federal do Amazonas, Parintins, 69.152-450, Amazonas, BrazilDepartment of Animal Science, São Paulo State University (UNESP), Jaboticabal, 14.884-900 São Paulo, BrazilAgência Paulista de Tecnologia dos Agronegócios – APTA, Pólo Regional Centro Leste, Ribeirão Preto, 14.001-970 São Paulo, BrazilAgência Paulista de Tecnologia dos Agronegócios – APTA, Pólo Regional Centro Leste, Ribeirão Preto, 14.001-970 São Paulo, BrazilDepartment of Animal Science, São Paulo State University (UNESP), Jaboticabal, 14.884-900 São Paulo, Brazil; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Instituto Nacional de Ciência e Tecnologia—Ciência Animal, BrazilGenetic parameters for test-day milk flow (TDMF) of 2175 first lactations of Holstein cows were estimated using multiple-trait and repeatability models. The models included the direct additive genetic effect as a random effect and contemporary group (defined as the year and month of test) and age of cow at calving (linear and quadratic effect) as fixed effects. For the repeatability model, in addition to the effects cited, the permanent environmental effect of the animal was also included as a random effect. Variance components were estimated using the restricted maximum likelihood method in single- and multiple-trait and repeatability analyses. The heritability estimates for TDMF ranged from 0.23 (TDMF 6) to 0.32 (TDMF 2 and TDMF 4) in single-trait analysis and from 0.28 (TDMF 7 and TDMF 10) to 0.37 (TDMF 4) in multiple-trait analysis. In general, higher heritabilities were observed at the beginning of lactation until the fourth month. Heritability estimated with the repeatability model was 0.27 and the coefficient of repeatability for first lactation TDMF was 0.66. The genetic correlations were positive and ranged from 0.72 (TDMF 1 and 10) to 0.97 (TDMF 4 and 5). The results indicate that milk flow should respond satisfactorily to selection, promoting rapid genetic gains because the estimated heritabilities were moderate to high. Higher genetic gains might be obtained if selection was performed in the TDMF 4. Both the repeatability model and the multiple-trait model are adequate for the genetic evaluation of animals in terms of milk flow, but the latter provides more accurate estimates of breeding values.http://www.sciencedirect.com/science/article/pii/S1751731111001376functional traitgenetic correlationheritabilitymilkability |
| spellingShingle | M.M.M. Laureano A.B. Bignardi L. El Faro V.L. Cardoso L.G. Albuquerque Genetic parameters for first lactation test-day milk flow in Holstein cows Animal functional trait genetic correlation heritability milkability |
| title | Genetic parameters for first lactation test-day milk flow in Holstein cows |
| title_full | Genetic parameters for first lactation test-day milk flow in Holstein cows |
| title_fullStr | Genetic parameters for first lactation test-day milk flow in Holstein cows |
| title_full_unstemmed | Genetic parameters for first lactation test-day milk flow in Holstein cows |
| title_short | Genetic parameters for first lactation test-day milk flow in Holstein cows |
| title_sort | genetic parameters for first lactation test day milk flow in holstein cows |
| topic | functional trait genetic correlation heritability milkability |
| url | http://www.sciencedirect.com/science/article/pii/S1751731111001376 |
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