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| Raidan,Fernanda Santos Silva; Tineo,Juan Salvador Andrade; Moraes,Mariana Mamedes de; Escarce,Thiago Campos; Araújo,Andresa Eva Melo de; Gomes,Muller Marques de Carvalho; Ventura,Henrique Torres; Toral,Fabio Luiz Buranelo. |
| ABSTRACT This study aimed to evaluate associations among final weight (FW), average daily gain (ADG), scrotal circumference (SC), and visual score (VS) of beef cattle in performance tests on pasture or in feedlots. Genetic parameters for FW, ADG, SC, and VS of young Nellore bulls performance-tested on pasture or in feedlots were evaluated by mixed model. The performance test and final age were considered as fixed effects and additive genetic and residual effects were considered as random effects. Additive genetic and residual variances for final weight and average daily gain were smaller on pasture than in feedlots. There was no difference between genetic and residual variances and heritability for scrotal circumference on pasture or in feedlots. Genetic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bos indicus; Genetic correlation; Heritability; Phenotypic selection. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000400309 |
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| Ribeiro,Virgínia Mara Pereira; Merlo,Fernanda Albuquerque; Gouveia,Gabriela Canabrava; Winkelstroter,Larissa Kretli; Abreu,Luíza Rodrigues Alves; Silva,Marcos Vinícius Gualberto Barbosa da; Panetto,João Cláudio do Carmo; Paiva,Leandro de Carvalho; Cembranelli,Marcello de Aguiar Rodrigues; Toral,Fabio Luiz Buranelo. |
| Abstract: The objective of this work was to determine whether the random regression model using linear splines (RRMLS) is suitable to estimate the genetic parameters for productive and reproductive traits of a multiple-breed dairy cattle population, as well as to investigate the effect of the genetic group of the progeny on the genetic merit of the sire. The multiple-trait model (MTM) and the RRMLS with one knot fitted for every genetic group were used to obtain the genetic parameters. Records of 1/2 Holstein + 1/2 Gyr (1/2HG), 5/8 Holstein + 3/8 Gyr (5/8HG), and 3/4 Holstein + 1/4 Gyr (3/4HG) crossbreed dams were considered. The RRMLS showed better fitting. The additive and residual variances estimated by the MTM and the RRMLS were similar. Heritability... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gyr; Heritability; Heterosis; Holstein; Selection. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2017001101109 |
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| Reis Filho,João Cruz; Verneque,Rui da Silva; Torres,Robledo de Almeida; Lopes,Paulo Sávio; Raidan,Fernanda Santos Silva; Toral,Fabio Luiz Buranelo. |
| The objective of this study was to estimate genetic parameters and to evaluate the effects of inbreeding on productive and reproductive traits of dairy Gyr cattle. Single-trait animal models were used to estimate genetic parameters and solutions for inbreeding coefficients for milk (milk 305-d), fat (fat 305-d), protein (protein 305-d), lactose (lactose 305-d), and total solids (TS 305-d) yield up to 305 days of lactation, days in milk (DIM), age at first calving (AFC) and calving intervals (CI). The mean inbreeding coefficient was 2.82%. The models with linear and quadratic effects of inbreeding coefficients fitted the data better than the models without or with only linear effect of inbreeding coefficient for all traits. The increase in inbreeding... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dairy cattle; Genetic parameter; Heritability; Inbreeding depression. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982015000500174 |
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| Filho,João Cruz Reis; Verneque,Rui da Silva; Torres,Robledo de Almeida; Ribeiro,Virgínia Mara Pereira; Toral,Fabio Luiz Buranelo. |
| O objetivo deste trabalho foi avaliar componentes de covariância e valores genéticos para produção de leite acumulada em até 305 dias, a partir dos dados das três primeiras lactações de vacas Gir. Foram analisados dados de 14.659 lactações, de 9.079 vacas, por meio dos modelos de repetibilidade, multicaracterístico (Mult) e de regressão aleatória com variância residual homogênea (MRAHo) ou heterogênea (MRAHe). A produção de leite foi considerada como característica distinta em cada lactação, no modelo Mult. Polinômios lineares foram utilizados nos modelos de regressão aleatória para ajuste das trajetórias médias e dos efeitos genético aditivo e de ambiente permanente individuais, de acordo com a ordem de parto. As médias a posteriori da herdabilidade foram... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bos indicus; Gir leiteiro; Modelo multicaracterístico; Regressão aleatória; Repetibilidade; Seleção precoce.. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2015000400298 |
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| Scalez,Daiane Cristina Becker; Fragomeni,Breno de Oliveira; Santos,Dalinne Chrystian Carvalho dos; Passafaro,Tiago Luciano; Alencar,Maurício Mello de; Toral,Fabio Luiz Buranelo. |
| ABSTRACT The objective of this study was to estimate genetic parameters for body weight of beef cattle in performance tests. Different random regression models with quadratic B-splines and heterogeneous residual variance were fitted to estimate covariance functions for body weights of Nellore and crossbred Charolais × Nellore bulls. The criteria −2 residual log-likelihood (−2RLL), Akaike Information Criterion (AIC), and consistent AIC (CAIC) were used to choose the most appropriate model. For Nellore bulls, residual variance was modeled with six classes of age, and direct additive genetic and permanent environment effects were modeled with quadratic B-splines with two and one intervals, respectively. For crossbred bulls, quadratic B-splines with one... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Animal breeding; Bos indicus; Genetic correlation; Heritability. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982018000100407 |
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