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| Ferreira,Priscila Becker; Rorato,Paulo Roberto Nogara; Breda,Fernanda Cristina; Michelotti,Vanessa Tomazetti; Rosa,Alexandre Pires; Macedo,André. |
| ABSTRACT: This study aimed to test different genotypic and residual covariance matrix structures in random regression models to model the egg production of Barred Plymouth Rock and White Plymouth Rock hens aged between 5 and 12 months. In addition, we estimated broad-sense heritability, and environmental and genotypic correlations. Six random regression models were evaluated, and for each model, 12 genotypic and residual matrix structures were tested. The random regression model with linear intercept and unstructured covariance (UN) for a matrix of random effects and unstructured correlation (UNR) for residual matrix adequately model the egg production curve of hens of the two study breeds. Genotypic correlations ranged from 0.15 (between age of 5 and 12... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Barred Plymouth Rock; Heritability; Laying rate; White Plymouth Rock. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782017000500652 |
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| Feltes,Giovani Luis; Michelotti,Vanessa Tomazetti; Prestes,Alan Miranda; Bravo,André Padilha; Bondan,Carlos; Dornelles,Mariana de Almeida; Breda,Fernanda Cristina; Rorato,Paulo Roberto Nogara. |
| ABSTRACT: The objective of this study was to identify a nonlinear regression model that better describes the milk production and the percentages of fat and protein curves, and to identify the season and age of calving that result in higher productions. For the analysis, 8,047 records of milk production and percentages of fat and protein obtained from 1,330 Holstein breed cows raised in Rio Grande do Sul, born from 1989 to 2011, were used. After determining the most appropriate nonlinear regression model, the identity of models and the equality of parameter tests for the different classes of season and age of calving were performed. Residual mean square, mean absolute deviation, mean squared prediction error and percentage of estimated curves per animal,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calving season; Hyperbolic linear function; Age at calving; Identity model test. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016000400700 |
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| Dornelles,Mariana de Almeida; Rorato,Paulo Roberto Nogara; Breda,Fernanda Cristina; Bondan,Carlos; Gama,Luis Telo Lavadinho da; Cobuci,Jaime Araujo; Feltes,Giovani Luis; Michelotti,Vanessa Tomazetti; Prestes,Alan Miranda. |
| Objetivou-se comparar um modelo multi-característica padrão com modelos de análise de fatores (AF) e de componentes principais (CP) para estimar parâmetros genéticos para a produção de leite no dia do controle (PLDC) de vacas da raça Holandesa. O arquivo de trabalho constituiu-se de 4.616 registros mensais de PLDC de primeiras lactações de vacas da raça Holandesa. As PLDC foram agrupadas em dez classes mensais, entre o 5o e 305o dia da lactação (PLDC1 a PLDC10). Foram realizadas análises considerando 11 modelos diferentes, como segue: multi-característica padrão (MC); cinco modelos de posto reduzido, para a matriz de covariância genética, ajustando um a cinco (CP1 ... CP5) componentes principais; e dois modelos utilizando análise de fatores (F1, F2, F3, F4... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Componentes de variância; Correlações genéticas; Herdabilidade; Posto reduzido. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015000601087 |
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| Dornelles,Mariana de Almeida; Rorato,Paulo Roberto Nogara; Gama,Luis Telo Lavadinho da; Breda,Fernanda Cristina; Bondan,Carlos; Everling,Dionéia Magda; Michelotti,Vanessa Tomazetti; Feltes,Giovani Luis. |
| ABSTRACT: The objective of this study was to compare the functions of Wilmink and Ali and Schaeffer with Legendre polynomials in random regression models using heterogeneous residual variances for modeling genetic parameters during the first lactation in the Holstein Friesian breed. Five thousand eight hundred and eighty biweekly records of test-day milk production were used. The models included the fixed effects of group of contemporaries and cow age at calving as covariable. Statistical criteria indicated that the WF.33_HE2, LEG.33_HE2, and LEG.55_HE4 functions best described the changes in the variances that occur throughout lactation. Heritability estimates using WF.33_HE2 and LEG.33_HE2 models were similar, ranging from 0.31 to 0.50. The LEG.55_HE4... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ali and Schaeffer function; Classes of residual variance; Lactation curve; Legendre polynomials; Wilmink function. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016000901649 |
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