Genetic parameters for test day milk yield of first lactation Holstein cows estimated by randon regression using Legendre polynomials.
Data comprising 263,390 test-day (TD) records of 32,448 first parity cows calving in 467 herds between 1991 and 2001 from the Brazilian Holstein Association were used to estimate genetic and permanent environmental variance components in a random regression animal model using Legendre polynomials (LP) of order three to five by REML. Residual variance was assumed to be constant in all or in some classes of lactation periods for each LP. Estimates of genetic and permanent environmental variances did not show any trend due to the increase in the LP order. Residual variance decreased as the order of LP increased when it was assumed constant, and it was highest at the beginning of lactation and relatively constant in mid lactation when assumed to vary between classes. The range for the estimates of heritability (0.27 - 0.42) was similar for all models and was higher in mid lactation. There were only slight differences between the models in both genetic and permanent environmental correlations. Genetic correlations decreased for near unity between adjacent days to values as low as 0.24 between early and late lactation. A five parameter LP to model both genetic and permanent environmental effects and assuming a homogeneous residual variance would be a parsimonious option to fit TD yields of Holstein cows in Brazil.
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Format: | Artigo de periódico biblioteca |
Language: | Ingles English |
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Revista Brasileira de Zootecnia, Viçosa, MG, v. 37, n. 4, p. 602-608, 2008.
2009-03-20
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Subjects: | Avaliação genética, Bovinos de leite, Componentes de co-variância, Herdabilidade, Seleção, |
Online Access: | http://www.alice.cnptia.embrapa.br/alice/handle/doc/596325 |
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dig-alice-doc-5963252023-01-23T20:02:03Z Genetic parameters for test day milk yield of first lactation Holstein cows estimated by randon regression using Legendre polynomials. COSTA, C. N. MELO, C. M. R. PACKER, I. U. FREITAS, A. F. TEIXEIRA, N. M. COBUCCI, J. A. Cláudio Nápolis Costa, Embrapa Gado de Leite; Cláudio Manoel Rodrigues de Melo, UFSC; Irineu Umberto Packer, ESALQ/USP; Ary Ferreira de Freitas, Embrapa Gado de Leite; Nilson Milagres Teixeira, Embrapa Gado de Leite; Jaime Araujo Cobuci, UFRGS. Avaliação genética Bovinos de leite Componentes de co-variância Herdabilidade Seleção Data comprising 263,390 test-day (TD) records of 32,448 first parity cows calving in 467 herds between 1991 and 2001 from the Brazilian Holstein Association were used to estimate genetic and permanent environmental variance components in a random regression animal model using Legendre polynomials (LP) of order three to five by REML. Residual variance was assumed to be constant in all or in some classes of lactation periods for each LP. Estimates of genetic and permanent environmental variances did not show any trend due to the increase in the LP order. Residual variance decreased as the order of LP increased when it was assumed constant, and it was highest at the beginning of lactation and relatively constant in mid lactation when assumed to vary between classes. The range for the estimates of heritability (0.27 - 0.42) was similar for all models and was higher in mid lactation. There were only slight differences between the models in both genetic and permanent environmental correlations. Genetic correlations decreased for near unity between adjacent days to values as low as 0.24 between early and late lactation. A five parameter LP to model both genetic and permanent environmental effects and assuming a homogeneous residual variance would be a parsimonious option to fit TD yields of Holstein cows in Brazil. 2023-01-23T20:02:03Z 2023-01-23T20:02:03Z 2009-03-20 2008 Artigo de periódico http://www.alice.cnptia.embrapa.br/alice/handle/doc/596325 Ingles en openAccess Revista Brasileira de Zootecnia, Viçosa, MG, v. 37, n. 4, p. 602-608, 2008. |
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Avaliação genética Bovinos de leite Componentes de co-variância Herdabilidade Seleção Avaliação genética Bovinos de leite Componentes de co-variância Herdabilidade Seleção |
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Avaliação genética Bovinos de leite Componentes de co-variância Herdabilidade Seleção Avaliação genética Bovinos de leite Componentes de co-variância Herdabilidade Seleção COSTA, C. N. MELO, C. M. R. PACKER, I. U. FREITAS, A. F. TEIXEIRA, N. M. COBUCCI, J. A. Genetic parameters for test day milk yield of first lactation Holstein cows estimated by randon regression using Legendre polynomials. |
description |
Data comprising 263,390 test-day (TD) records of 32,448 first parity cows calving in 467 herds between 1991 and 2001 from the Brazilian Holstein Association were used to estimate genetic and permanent environmental variance components in a random regression animal model using Legendre polynomials (LP) of order three to five by REML. Residual variance was assumed to be constant in all or in some classes of lactation periods for each LP. Estimates of genetic and permanent environmental variances did not show any trend due to the increase in the LP order. Residual variance decreased as the order of LP increased when it was assumed constant, and it was highest at the beginning of lactation and relatively constant in mid lactation when assumed to vary between classes. The range for the estimates of heritability (0.27 - 0.42) was similar for all models and was higher in mid lactation. There were only slight differences between the models in both genetic and permanent environmental correlations. Genetic correlations decreased for near unity between adjacent days to values as low as 0.24 between early and late lactation. A five parameter LP to model both genetic and permanent environmental effects and assuming a homogeneous residual variance would be a parsimonious option to fit TD yields of Holstein cows in Brazil. |
author2 |
Cláudio Nápolis Costa, Embrapa Gado de Leite; Cláudio Manoel Rodrigues de Melo, UFSC; Irineu Umberto Packer, ESALQ/USP; Ary Ferreira de Freitas, Embrapa Gado de Leite; Nilson Milagres Teixeira, Embrapa Gado de Leite; Jaime Araujo Cobuci, UFRGS. |
author_facet |
Cláudio Nápolis Costa, Embrapa Gado de Leite; Cláudio Manoel Rodrigues de Melo, UFSC; Irineu Umberto Packer, ESALQ/USP; Ary Ferreira de Freitas, Embrapa Gado de Leite; Nilson Milagres Teixeira, Embrapa Gado de Leite; Jaime Araujo Cobuci, UFRGS. COSTA, C. N. MELO, C. M. R. PACKER, I. U. FREITAS, A. F. TEIXEIRA, N. M. COBUCCI, J. A. |
format |
Artigo de periódico |
topic_facet |
Avaliação genética Bovinos de leite Componentes de co-variância Herdabilidade Seleção |
author |
COSTA, C. N. MELO, C. M. R. PACKER, I. U. FREITAS, A. F. TEIXEIRA, N. M. COBUCCI, J. A. |
author_sort |
COSTA, C. N. |
title |
Genetic parameters for test day milk yield of first lactation Holstein cows estimated by randon regression using Legendre polynomials. |
title_short |
Genetic parameters for test day milk yield of first lactation Holstein cows estimated by randon regression using Legendre polynomials. |
title_full |
Genetic parameters for test day milk yield of first lactation Holstein cows estimated by randon regression using Legendre polynomials. |
title_fullStr |
Genetic parameters for test day milk yield of first lactation Holstein cows estimated by randon regression using Legendre polynomials. |
title_full_unstemmed |
Genetic parameters for test day milk yield of first lactation Holstein cows estimated by randon regression using Legendre polynomials. |
title_sort |
genetic parameters for test day milk yield of first lactation holstein cows estimated by randon regression using legendre polynomials. |
publisher |
Revista Brasileira de Zootecnia, Viçosa, MG, v. 37, n. 4, p. 602-608, 2008. |
publishDate |
2009-03-20 |
url |
http://www.alice.cnptia.embrapa.br/alice/handle/doc/596325 |
work_keys_str_mv |
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