RESUMO
The objective of this study was to estimate the genetic parameters for feed efficiency-related traits and their genetic correlations with growth, male fertility, and carcass traits using multi-trait analysis in Guzerat cattle. Further, it aimed to predict the direct and correlated responses for feed efficiency traits when selection was applied for growth, male fertility, and carcass traits. The evaluated traits were adjusted weight at 120 (W120), 210 (W210), 365 (W365), and 450 days of age (W450), adjusted scrotal circumference at 365 days of age (SC365) and at 450 days of age (SC450), scrotal circumference, ribeye area (REA), backfat thickness (BFT), rump fat thickness (RFT), residual feed intake (RFI), and dry matter intake (DMI). The genetic parameters were obtained by the restricted maximum likelihood method (REML), using an animal model in multi-trait analyses. The heritability estimates for W120, W210, W365, W450, SC365, and SC450 varied from low to high (0.17 to 0.39). The carcass traits, REA, BFT, and RFT, displayed low to moderate heritability estimates, 0.27, 0.10, and 0.31, respectively. The heritability estimates for RFI (0.15) and DMI (0.23) were low and moderate, respectively. The RFI showed low genetic correlations with growth traits, ranging from - 0.07 to 0.22, from 0.03 to 0.05 for scrotal circumference, and from - 0.35 to 0.16 for carcass, except for DMI, which ranged from 0.42 to 0.46. The RFI and DMI presented enough additive genetic variability to be used as selection criteria in Guzerat breed genetic improvement program. Additionally, the response to selection for RFI would be higher when selection is performed directly for this trait. The selection for residual feed intake would not promote unfavorable correlated responses for scrotal circumference, carcass (yield and finish), and growth traits. Therefore, the selection for more efficient animals would not compromise the productive, reproductive, and carcass performance, contributing to reduce the production costs, increasing the profitability and sustainability of beef cattle production in tropical areas.
Assuntos
Bovinos , Fenômenos Fisiológicos da Nutrição , Escroto , Aumento de Peso , Bovinos/fisiologia , Tecido Adiposo/anatomia & histologia , Composição Corporal/genética , Ingestão de Alimentos/fisiologia , Fertilidade/genética , Fenômenos Fisiológicos da Nutrição/genética , Escroto/anatomia & histologia , Seleção Artificial , Aumento de Peso/genética , AnimaisRESUMO
This paper aims to estimate the (co) variances components on the genetic parameters for growth traits in Nelore Mocho cattle, raised in Cerrado biome, using Bayesian statistics. The data has been obtained from 48,063 cattle, provenient of Nelore Mocho herd, born from 1987 to 2009, participant of Breeder and Research Nacional Associations (ANCP) Nelore Brazil Program. It has been evaluated the standard weight in 120 (P120), 210 (P210), 365 (P365), 450 (P450) years old, the weight gain from the birth to the weaning (GPND), and the weight gain from weaning to yearling (GPDS). The estimates on (co) variances components and genetic parameters have employed univariate analyses considering the Bayesian statistics animal model by the MTGSAM (Multiple Trait using Gibbs Sampler under Animal Model). The estimated values for direct heritability ranged from medium to high magnitude in standard weights (with range of 0.23 to 0.33) and the weight gain (0.18 for GPND and 0.24 for GPDS), for the creates and recreates phase, respectively. These results indicate that there is genetic variability in Nelore Mocho herd for growth traits, showing effective genetic growth when using the direct selection of these features in genetic improvement programs(AU)
O objetivo deste estudo foi estimar os componentes de (co) variância e parâmetros genéticos para as características de crescimento de bovinos da raça Nelore Mocho criados em bioma Cerrado, utilizando a inferência bayesiana. As informações foram obtidas de 48.063 animais Nelore Mocho, nascidos entre 1987 a 2009, provenientes de rebanhos participantes do Programa Nelore Brasil da Associação Nacional de Criadores e Pesquisadores (ANCP). Foram avaliadas as características de pesos padronizados aos 120 (P120), 210 (P210), 365 (P365) e 450 (P450) dias de idade, além do ganho de peso do nascimento a desmama (GPND) e o ganho de peso da desmama ao sobreano (GPDS). Os componentes de (co)variância e parâmetros genéticos foram estimados por meio de análises uni-características considerando a estatística bayesiana sob modelo animal e utilizando o programa MTGSAM (Multiple Trait using Gibbs Sampler under Animal Model). Os valores estimados para as herdabilidades foram de média a alta magnitude para todas as características de pesos padronizados (variando de 0,23 a 0,33) e de média magnitude para as características de ganho em peso (0,18 para GPND e 0,24 para GPDS). As herdabilidades estimadas indicaram a existência de variabilidade genética para as características de crescimento na raça Nelore Mocho, portanto, a seleção direta para tais características trará progresso genético apreciável.(AU)
Assuntos
Animais , Bovinos , Crescimento e Desenvolvimento , Aumento de Peso , Hereditariedade , Seleção Genética , Teorema de BayesRESUMO
This paper aims to estimate the (co) variances components on the genetic parameters for growth traits in Nelore Mocho cattle, raised in Cerrado biome, using Bayesian statistics. The data has been obtained from 48,063 cattle, provenient of Nelore Mocho herd, born from 1987 to 2009, participant of Breeder and Research Nacional Associations (ANCP) Nelore Brazil Program. It has been evaluated the standard weight in 120 (P120), 210 (P210), 365 (P365), 450 (P450) years old, the weight gain from the birth to the weaning (GPND), and the weight gain from weaning to yearling (GPDS). The estimates on (co) variances components and genetic parameters have employed univariate analyses considering the Bayesian statistics animal model by the MTGSAM (Multiple Trait using Gibbs Sampler under Animal Model). The estimated values for direct heritability ranged from medium to high magnitude in standard weights (with range of 0.23 to 0.33) and the weight gain (0.18 for GPND and 0.24 for GPDS), for the creates and recreates phase, respectively. These results indicate that there is genetic variability in Nelore Mocho herd for growth traits, showing effective genetic growth when using the direct selection of these features in genetic improvement programs
O objetivo deste estudo foi estimar os componentes de (co) variância e parâmetros genéticos para as características de crescimento de bovinos da raça Nelore Mocho criados em bioma Cerrado, utilizando a inferência bayesiana. As informações foram obtidas de 48.063 animais Nelore Mocho, nascidos entre 1987 a 2009, provenientes de rebanhos participantes do Programa Nelore Brasil da Associação Nacional de Criadores e Pesquisadores (ANCP). Foram avaliadas as características de pesos padronizados aos 120 (P120), 210 (P210), 365 (P365) e 450 (P450) dias de idade, além do ganho de peso do nascimento a desmama (GPND) e o ganho de peso da desmama ao sobreano (GPDS). Os componentes de (co)variância e parâmetros genéticos foram estimados por meio de análises uni-características considerando a estatística bayesiana sob modelo animal e utilizando o programa MTGSAM (Multiple Trait using Gibbs Sampler under Animal Model). Os valores estimados para as herdabilidades foram de média a alta magnitude para todas as características de pesos padronizados (variando de 0,23 a 0,33) e de média magnitude para as características de ganho em peso (0,18 para GPND e 0,24 para GPDS). As herdabilidades estimadas indicaram a existência de variabilidade genética para as características de crescimento na raça Nelore Mocho, portanto, a seleção direta para tais características trará progresso genético apreciável.