Estimativas de parâmetros genéticos para características incluídas em critérios de seleção em gado Nelore

Gunski, Ricardo José; Garnero, Analía Del Valle; Borjas, Arcádio de los Reyes; Bezerra, Luiz Antônio Framartino; Lôbo, Raysildo Barbosa

doi:10.1590/s0103-84782001000400007

Cited by 14 publications

(18 citation statements)

References 2 publications

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“…Additive direct heritability for WW was moderate (0.29), in agreement with other authors' studies (Cabrera et al 2001;Gunski et al 2001;De Souza et al 2003) who estimated it averaging 0.25 in Brazil and Paraguay. Nevertheless, our estimate differed from that reported by Silveira et al (2004) who estimated a smaller value (0.17).…”

Section: Genetic Parameterssupporting

confidence: 91%

Genetic parameters for growth traits in Mexican Nellore cattle

Martínez-González

García-Esquivel

Parra‐Bracamonte

et al. 2009

Trop Anim Health Prod

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The aim of this study was to estimate genetic parameters for growth traits in Mexican Nellore cattle. A univariate animal model was used to estimate (co)variance components and genetic parameters. The traits evaluated were birth weight (BW), weaning weight (WW), and yearling weight (YW). Models used included the fixed effects of contemporary groups (herd, sex, year, and season of birth) and age of dam (linear and quadratic) as a covariate. They also included the animal, dam, and residual as random effects. Phenotypic means (SD) for BW, WW, and YW were 31.4 (1.6), 175 (32), and 333 (70) kg, respectively. Direct heritability, maternal heritability, and the genetic correlation between additive direct and maternal effects were 0.59, 0.17, and -0.90 for BW; 0.29, 0.17, and -0.90 for WW; and 0.24, 0.15, and -0.86 for YW, respectively. The results showed moderate direct and maternal heritabilities for the studied traits. The genetic correlations between direct and maternal effects were negative and high for all the traits indicating important tradeoffs between direct and maternal effects. There are significant possibilities for genetic progress for the growth traits studied if they are included in a breeding program considering these associations.

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Section: Genetic Parameterssupporting

confidence: 91%

Genetic parameters for growth traits in Mexican Nellore cattle

Martínez-González

García-Esquivel

Parra‐Bracamonte

et al. 2009

Trop Anim Health Prod

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“…Scrotal circumference (SC) of males and weight at different ages are traits usually used in expected progeny difference indices, and their application has lead to satisfactory gains in growth and reproductive rates Gunski et al, 2001;Pereira et al, 2001). Bourdon and Brinks (1983) and Bergmann et al (1998) reported that the calving interval (CI) is subject to more measurement and estimation bias and errors than days to calving (DC).…”

Section: Introductionmentioning

confidence: 99%

Genetic analyses of days to calving and their relationships with other traits in a Canchim cattle herd

et al. 2007

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Heritabilities and genetic correlations in a Canchim beef cattle herd were estimated using data on the following traits: male scrotal circumference at twelve months (SC12); days to first calving (DFC) for heifers; days to calving (DC) for cows; male and female weight (W) at twelve months (W12); heifer weight at the start of the first breeding season (WFBS) and at first calving (WFC); and cow weight at the start of the breeding season (WBS) and at calving (WC). Analyses of the DFC and DC traits were carried out excluding and including penalized (DFC P and DC P ) non-calving females. The restricted maximum likelihood method was used, applying one-trait models for the DFC and DC analyses and two-trait models for analyses of DFC and DC combined with the other traits studied. Statistical models included fixed and additive direct random effects for all traits, maternal permanent environmental random effect for SC12 and W12, and the animal permanent environmental random effect for DC P , WBS and WC. We found that DFC and DC values can be improved by selecting for an increase in the SC12. Genetic correlations between DFC and W12 and between DC and W12 indicated that selection for increased W12 may increase DFC but does not produce significantly correlated responses in DC. Associations of the other body weight traits with DC and DFC suggest that heavier females experience lower reproductive performance.

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“…Machado et al (1999) encontraram herdabilidade para peso aos 205 dias de idade na ordem de 0,62, enquanto Sarmento et al (2003) verificaram herdabilidade para ganho de peso diário em bovinos Nelore na ordem 0,12. Esses parâmetros são necessários para estimar as respostas diretas e correlacionadas à seleção, para elaborar índices de seleção e predizer o valor genético dos animais (Gunski et al, 2001). Boligon et al (2008), ao realizarem estudos sobre associações genéticas entre pesos e características reprodutivas em rebanhos da raça Nelore, relataram que a estimativa de herdabilidade para peso aos 365 dias de idade (P365) na raça Nelore foi de 0,30.…”

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Avaliação genética para peso corporal em um rebanho Nelore

Gonçalves

Pires

Pereira

et al. 2011

Arq. Bras. Med. Vet. Zootec.

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RESUMOEstimaram-se as herdabilidades para os efeitos genéticos direto e materno e as correlações genéticas entre essas variáveis para os pesos ao desmame (P205), ao ano (P365) e ao sobreano (P550) em um rebanho Nelore do norte de Minas Gerais. O modelo estatístico incluiu os efeitos aditivos direto e materno, os efeitos fixos de grupo de contemporâneos (fazenda, sexo, regime alimentar, estação (seca e água) e ano de nascimento do animal) e o efeito da covariável idade da vaca ao parto (linear e quadrático). P205, P365, and P550 were equal to 0.60, 0.69, and 0.75, respectively. These coefficients showed high magnitude, indicating that the herd in question presents a great additive genetic variability and therefore it is expected a great progress using genetic selection. By the analysis of genetic trend, it was verified a development in animals genetic values over the years studied. Keywords: genetic trend, heritability, beef cattle, REML INTRODUÇÃOEm um programa de melhoramento genético animal, a seleção para maximizar a produção é uma das mais importantes decisões a ser tomada pelo pecuarista moderno. Um pré-requisito para Recebido em 7 de julho de 2009 Aceito em 22 de dezembro de 2010 *Autor para correspondência (corresponding author) E-mail: aldrin@ufvjm.edu.br o sucesso desses programas é a obtenção de estimativas acuradas de parâmetros genéticos. Destaca-se que as estimativas de parâmetros genéticos para características ponderais na raça Nelore têm apresentado grande variabilidade, sendo um bom indicador da resposta à seleção ou ao melhoramento genético a ser alcançado.

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Estimativas de parâmetros genéticos para características incluídas em critérios de seleção em gado Nelore

Cited by 14 publications

References 2 publications

Genetic parameters for growth traits in Mexican Nellore cattle

Genetic parameters for growth traits in Mexican Nellore cattle

Genetic analyses of days to calving and their relationships with other traits in a Canchim cattle herd

Avaliação genética para peso corporal em um rebanho Nelore

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