Análise bayesiana na estimação de correlações genéticas entre escores visuais e características reprodutivas de bovinos Nelore utilizando modelos linear-limiar

Faria, Carina Ubirajara de; Magnabosco, C. de U.; Albuquerque, Lúcia Galvão de; Reyes, Arcadio de los; Bezerra, Luiz Antônio Framartino; Lôbo, Raysildo Barbosa

doi:10.1590/s0102-09352009000400025

Cited by 13 publications

(12 citation statements)

References 24 publications

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“…Considering that successful primiparous rebreeding was associated with a higher Table 2 Posterior means, mode, median and the highest posterior density (HPD) region of variance components and genetic parameters for scores of conformation (C), finishing precocity (P) and muscling (M), subsequent rebreeding (SR), and days to first calving (DC) (2010) reported favourable genetic correlations ranging from )0.23 AE 0.02 to )0.29 AE 0.02 between morphological traits evaluated by conformation, finishing and muscling, and age at first calving of Nellore cattle. Similarly, Faria et al (2009) found favourable genetic correlations between visual scores of muscling, physical structure and conformation, and age at first calving of Nellore animals. These authors concluded that the selection of animals with a better body composition may lead to the choice of sexually more precocious animals and, considering the present results, to an increase in the number of primiparous females that again conceive in the subsequent breeding season.…”

Section: Resultsmentioning

confidence: 88%

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Genetic associations of visual scores with subsequent rebreeding and days to first calving in Nellore cattle

Boligon

Ayres

Pereira

et al. 2012

J Animal Breeding Genetics

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Records of Nellore animals born from 1990 to 2006 were used to estimate genetic correlations of visual scores at yearling (conformation, C; finishing precocity, P; and muscling, M) with primiparous subsequent rebreeding (SR) and days to first calving (DC), because the magnitude of these associations is still unknown. Genetic parameters were estimated by multiple-traits Bayesian analysis, using a nonlinear (threshold) animal models for visual scores and SR and a linear animal models for weaning weight (WW) and DC. WW was included in the analysis to account for the effects of sequential selection. The posterior means of heritabilities estimated for C, P, M, SR and DC were 0.24 ± 0.01, 0.31 ± 0.01, 0.30 ± 0.01, 0.18 ± 0.02 and 0.06 ± 0.02, respectively. The posterior means of genetic correlations estimated between SR and visual scores were low and positive, with values of 0.09 ± 0.02 (C), 0.19 ± 0.03 (P) and 0.18 ± 0.05 (M). On the other hand, negative genetic correlations were found between DC and C (-0.11 ± 0.09), P (-0.19 ± 0.09) and M (-0.16 ± 0.09). The primiparous rebreeding trait has genetic variability in Nellore cattle. The genetic correlations between visual scores, and SR and DC were low and favourable. The genetic changes in C, P and M were 0.02, 0.03 and 0.03/year, respectively. For SR and DC, genetic trends were 0.01/year and -0.01 days/year, respectively, indicating that the increase in genetic merit for reproductive traits was small over time. Direct selection for visual scores together with female reproductive traits is recommended to increase the fertility of beef cows.

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Section: Resultsmentioning

confidence: 88%

“…2010), indicating that selection based on visual scores could promote important genetic changes in beef cattle performance. However, studies correlating visual scores with the reproductive performance of cows are scarce in the literature (Faria et al. 2009; Boligon & Albuquerque 2010).…”

Section: Introductionmentioning

confidence: 99%

Genetic associations of visual scores with subsequent rebreeding and days to first calving in Nellore cattle

Boligon

Ayres

Pereira

et al. 2012

J Animal Breeding Genetics

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“…High genetic variability observed in the herd, indicated by high estimates of the heritability coefficients, reveal that it is possible to make improvements over generations through a selection schedule [ 2 , 47 , 48 ] aiming at genetic progress of traits. Genetic trends ( Fig 3 ) were positive and increasing over the years, which may have contributed to the correct classification and grouping of similar animals within each cluster.…”

Section: Discussionmentioning

confidence: 99%

Selection Indices and Multivariate Analysis Show Similar Results in the Evaluation of Growth and Carcass Traits in Beef Cattle

Lopes

Silva

Magnabosco³

et al. 2016

PLoS ONE

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This research evaluated a multivariate approach as an alternative tool for the purpose of selection regarding expected progeny differences (EPDs). Data were fitted using a multi-trait model and consisted of growth traits (birth weight and weights at 120, 210, 365 and 450 days of age) and carcass traits (longissimus muscle area (LMA), back-fat thickness (BF), and rump fat thickness (RF)), registered over 21 years in extensive breeding systems of Polled Nellore cattle in Brazil. Multivariate analyses were performed using standardized (zero mean and unit variance) EPDs. The k mean method revealed that the best fit of data occurred using three clusters (k = 3) (P < 0.001). Estimates of genetic correlation among growth and carcass traits and the estimates of heritability were moderate to high, suggesting that a correlated response approach is suitable for practical decision making. Estimates of correlation between selection indices and the multivariate index (LD1) were moderate to high, ranging from 0.48 to 0.97. This reveals that both types of indices give similar results and that the multivariate approach is reliable for the purpose of selection. The alternative tool seems very handy when economic weights are not available or in cases where more rapid identification of the best animals is desired. Interestingly, multivariate analysis allowed forecasting information based on the relationships among breeding values (EPDs). Also, it enabled fine discrimination, rapid data summarization after genetic evaluation, and permitted accounting for maternal ability and the genetic direct potential of the animals. In addition, we recommend the use of longissimus muscle area and subcutaneous fat thickness as selection criteria, to allow estimation of breeding values before the first mating season in order to accelerate the response to individual selection.

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“…A seleção para precocidade de acabamento está em evidência, em estudos com bovinos de corte, pois o encurtamento do ciclo de produção, principalmente em sistemas a pasto, é um grande passo para aperfeiçoar os índices produtivos da bovinocultura de corte brasileira. Neste contexto, escores visuais poderiam ser utilizados para a seleção de tipos morfológicos que atendam às exigências do mercado (Faria et al, 2009), ao se considerar a variabilidade genética em rebanhos puros (Boligon et al, 2009) e mestiços (Araújo et al, 2010).…”

Section: Introductionunclassified

“…Entre as características indicadoras de fertilidade e precocidade sexual, a única amplamente empregada nos programas de melhoramento, em razão da facilidade de mensuração e da variância genética aditiva (Cyrillo et al, 2001), é a circunferência escrotal (Boligon et al, 2009). Entretanto, estudos que relacionam escores visuais com o desempenho reprodutivo de zebuínos, ou compostos de zebuínos como a raça Brangus, são escassos na literatura (Faria et al, 2009).…”

Section: Introductionunclassified

Abordagem bayesiana multivariada para características de crescimento, fertilidade e escores visuais de rebanhos da raça Brangus

Araújo

Marcondes²,

Everling

et al. 2012

Pesq. agropec. bras.

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Resumo -O objetivo deste trabalho foi estimar parâmetros genéticos e tendências genéticas e fenotípicas de uma população da raça Brangus. As características peso, circunferência escrotal e escores visuais de conformação, precocidade, musculatura e umbigo, padronizadas para 550 dias de idade, foram avaliadas a partir de 6.789 registros de animais nascidos de 288 touros e 5.949 vacas, entre 1991 e 2001, em 49 fazendas localizadas nas regiões Centro-Oeste, Sudeste e Sul do Brasil. Para a estimação dos parâmetros, das correlações e das tendências genéticas, foi adotado o modelo animal linear-limiar hexacaracterística. As estimativas de herdabilidade direta foram de 0,39 e 0,27, para peso e circunferência escrotal, respectivamente, e de 0,22, 0,20, 0,23 e 0,33 para conformação, precocidade, musculatura e umbigo, o que indica considerável variação genética aditiva e que é possível obter ganho genético por meio da seleção. As correlações genéticas entre peso e circunferência escrotal com os escores de conformação, precocidade e musculatura mostram a possibilidade de resposta correlacionada. As tendências genéticas estimadas indicam grande contribuição de fontes de variação não genéticas para todas as características no período estudado, e apontam a necessidade de melhoria das condições ambientais, para que os animais expressem todo seu potencial genético.Termos para indexação: amostragem de Gibbs, características morfológicas, modelo de limiar, precocidade de acabamento. Bayesian multivariate approach for growth, fertility and visual score traits of Brangus cattle herdsAbstract -The objective of this work was to estimate genetic parameters, and genetic and phenotypic trends of a Brangus breed population. Weight, scrotal circumference, and visual scores of conformation, precocity, musculature, and navel, adjusted to 550 days of age, were evaluated from records of 6,789 animals sired by 288 bulls and 5,949 dams, born between 1991 and 2001 in 49 farms located in the Center-West, Southeast, and South regions of Brazil. To estimate parameters, correlations, and genetic trends, a six-trait, linear-threshold animal model was adopted. Direct heritability estimates were 0.39 and 0.27 for weight and scrotal circumference, respectively, and 0.22, 0.20, 0.23, and 0.33 for conformation, precocity, musculature, and navel, indicating considerable additive genetic variation, and that it is possible to obtain genetic gain by selection. Genetic correlations between weight and scrotal circumference with the scores of conformation, precocity, and musculature show the possibility of correlated responses. Genetic trends indicate great contribution of non-genetic sources of variation in the evaluated traits, which leads to the necessity of improving environmental conditions, in order for the animals to fully express their genetic potential.

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Análise bayesiana na estimação de correlações genéticas entre escores visuais e características reprodutivas de bovinos Nelore utilizando modelos linear-limiar

Cited by 13 publications

References 24 publications

Genetic associations of visual scores with subsequent rebreeding and days to first calving in Nellore cattle

Genetic associations of visual scores with subsequent rebreeding and days to first calving in Nellore cattle

Selection Indices and Multivariate Analysis Show Similar Results in the Evaluation of Growth and Carcass Traits in Beef Cattle

Abordagem bayesiana multivariada para características de crescimento, fertilidade e escores visuais de rebanhos da raça Brangus

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