Estimativas de componentes de (co)variância e herdabilidade direta e materna de pesos corporais em ovinos da raça Santa Inês

Sousa, Wandrick Hauss de; Pereira, Cláubia; Bergmann, Jose Aurélio García; Silva, Francisco Luiz Ribeiro da

doi:10.1590/s1516-35981999000600012

Cited by 22 publications

(31 citation statements)

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“…Similar results were reported by Lôbo (1997), Ferreira (1999), Scarpati and Lôbo (1999) and Sousa et al (1999). The maternal contribution to the variance of adjusted weights in the single trait analyses was similar to the direct contribution at 120 and 240 days of age, but was much lower for the adjusted weight at 420 days of age, as also reported by Sousa et al (1999).…”

Section: Discussionsupporting

confidence: 89%

“…The low relevance of maternal components in multiple trait analyses was confirmed despite the expressive correlations between the direct and maternal additive effects, thus suggesting that field data limit the quality of maternal effect estimates, as pointed out by Sousa et al (1999). This finding is probably reflects the small number of calves per cow and the fact that cows had all their productions in a single herd.…”

Section: Discussionmentioning

confidence: 91%

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Maternal effects on the genetic evaluation of Tabapuã beef cattle

et al. 2004

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The aim of this investigation was to study the influence of maternal effects on the genetic evaluation of sire production in Tabapuã beef cattle. Single and multiple trait analyses were done with adjusted animal weights at 120, 240 and 420 days of age. Antagonism was observed between additive direct and maternal genetic effects, with the maternal effect being higher until weaning. The inclusion of maternal effects in the models removed part of the additive variance only in single trait analyses and resulted in smaller means and standard deviations for the sire breeding values. The use of maternal effect associated with single or multiple traits may affect sire ranking. The contradictory results of the single and multiple trait analyses for additive direct and maternal effects indicate that caution is needed when considering recommendations about the importance of maternal effects in Tabapuã beef cattle.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 91%

Maternal effects on the genetic evaluation of Tabapuã beef cattle

et al. 2004

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“…These values are higher than those observed in this study. Sousa et al (1999), using an animal model for univariate analysis, estimated values of 0.13 and 0.04 for direct heritability and 0.12 and 0.10 for maternal heritability, respectively, for weights at birth and at 112 days of age (weaning). These values are lower than those observed in this study for the same breed.…”

Section: Resultsmentioning

confidence: 99%

Genetic evaluation of partial growth trajectory of Santa Inês breed using random regression models

2010

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-It was evaluated data set of 19,303 weight records of Santa Inês sheep in order to evaluate distinct polynomial functions with different order for better adjustements of fixed and random regressions of growth trajectory and to estimate (co)variances components and genetic parameters of this trajectory. Fixed effects used in analysis were contemporary group, sex and birth type. Ordinary and Legendre polynomials, ranging from two to four orders, were evaluated for fixed regression of average growth trajectory. Legendre and quadratic b-spline functions, ranging from three to four orders, were evaluated for random regressions. Legendre polynomials of order fourth were suitable to fit random regression, while ordinary polynomials of third order were the best for fixed trajectory. Direct heritabilities on days 1, 50, 150, 250 and 411 were 0.24, 0.12, 0.44, 0.84, and 0.96, respectively, while maternal heritabilities for the same ages were 0.24, 0.19, 0.09, 0.02, and 0.01, respectively. Genetic correlations among weights in subsequent ages were high, tending to unity, and there were negative correlations between weights at early ages and weights at late ages. It is possible to modify the growth trajectory by selection with the observed genetic variability. Genetic control of weights at initial ages is not the same in late ages. So, selection of animals for slaughter in early age must be different from that of replacement animals.Key Words: β-spline functions, genetic correlation, heritability, Legendre polynomials, ordinary polynomials Avaliação genética de parte da trajetória de crescimento em ovinos da raça Santa Inês utilizando modelos de regressão aleatória .303 registros de peso de ovinos da raça Santa Inês com os objetivos de avaliar funções polinomiais com diferentes ordens para melhor ajuste das regressões fixas e aleatórias da trajetória de crescimento e estimar os componentes de covariância e os parâmetros genéticos desta trajetória. Os efeitos fixos utilizados nas análises foram grupo de contemporâneos, sexo e tipo de nascimento. Para ajuste da regressão fixa da trajetória média de crescimento, foram avaliados polinômios ordinários e de Legendre com ordens variando de 2 a 4. Para as regressões aleatórias, foram avaliadas as funções de Legendre e β-spline quadrática, com ordens variando de 3 a 4. As funções com polinômios de Legendre de quarta ordem foram adequadas para ajustar a parte aleatória, enquanto os polinômios ordinários de terceira ordem foram melhores para ajustar a parte fixa. As herdabilidades diretas nos dias 1, 50, 150, 250 e 411 foram de 0,24; 0,12; 0,44; 0,84; e 0,96, respectivamente, enquanto as herdabilidades maternas nessas idades foram de 0,24; 0,19; 0,09; 0,02 e 0,01. As correlações genéticas entre pesos em idades subsequentes foram elevadas, tendendo à unidade, e houve correlações negativas entre pesos tomados em idades mais jovens e aqueles tomados em idades mais avançadas. A variabilidade genética observada permite alterar a trajetória de crescimento por meio de seleção. O co...

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“…Não houve diferença significativa (P<0,05) entre os modelos 2 e 3, evidenciando que a covariância entre os efeitos direto e materno, a princípio, pode ser negligenciada. Os resultados obtidos neste estudo estão de acordo com os relatados por Sousa et al (1999), Mandal et al (2006) e Bosso et al (2007, que também verificaram forte influência do efeito materno sobre o peso ao nascimento das crias.…”

Section: Resultsunclassified

Estimativas de componentes de covariância e parâmetros genéticos de pesos corporais em caprinos Anglo-Nubiano

Sousa¹,

Sarmento²,

Sousa³

et al. 2009

Agraria

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Estimativas de componentes de covariância e parâmetros genéticos de pesos corporais em caprinos AngloNubiano RES UMOParâmetros genéticos e componentes de covariância foram estimados para pesos corporais do nascimento ao 112 o dia de idade de caprinos da raça Anglo-Nubiana pertencentes à Empresa Estadual de Pesquisa Agropecuária da Paraíba (EMEPA-PB). Os componentes de covariância e os parâmetros genéticos foram estimados pelo método da máxima verossimilhança restrita (REML) utilizando o programa DFREML. Modelos animais foram ajustados por meio da exclusão ou inclusão do efeito gené-tico materno, considerando ou não a covariância genética entre os efeitos direto e materno. Três modelos foram testados e, de acordo com o teste de razão de verossimilhança, o modelo que incluiu os efeitos aditivo direto e materno, assumindo covariância genética igual a zero, foi indicado para todas as características estudadas. Quando o efeito materno é excluído do modelo, as estimativas de herdabilidade direta são substancialmente inflacionadas, logo, os efeitos maternos devem ser incluí-dos nas análises dos pesos de caprinos Anglo-Nubiano em programas de seleção. Palavras-chave: caprino, correlação genética, efeito materno, herdabilidadeEstimates of covariance components and genetics parameters for growth traits of in Anglo-Nubian goats AB S TR ACTGenetic parameters and (co)variance components were estimated for body weight form birth to 112 th day of age of Anglo-Nubian goats from experimental herds of Empresa Estadual de Pesquisa Agropecuária da Paraíba (EMEPA-PB). Covariance components and genetic parameters were estimated by REML using DFREML software, including or not the maternal genetic effect and covariance between direct and maternal genetic effect in the models. Three different animal models were fitted for all traits. Likelihood ratio test indicated that the model including additive direct and maternal effects was the most suitable model for all traits. The exclusion of maternal genetic effect in the model resulted in a substantially inflation of direct heritability estimates. The maternal effects must be included in the analysis for body weight trait in Anglo-Nubian goats in selection program.

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Estimativas de componentes de (co)variância e herdabilidade direta e materna de pesos corporais em ovinos da raça Santa Inês

Cited by 22 publications

References 20 publications

Maternal effects on the genetic evaluation of Tabapuã beef cattle

Maternal effects on the genetic evaluation of Tabapuã beef cattle

Genetic evaluation of partial growth trajectory of Santa Inês breed using random regression models

Estimativas de componentes de covariância e parâmetros genéticos de pesos corporais em caprinos Anglo-Nubiano

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