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Use of genetic variation in short-term feeding behaviour in broiler breeding programmesHowie, Jennifer Ann January 2010 (has links)
Genetic variation between individuals is of great importance for the development of breeding programmes, to select for animals with the most favourable traits. Many production companies routinely measure the feed intake of their animals, in order to calculate efficiency traits such as feed conversion ratio. The development of electronic feeders which automatically record individual intake on a visit-by-visit basis now allows the short-term feeding behaviour of animals to be monitored and analysed as another source of variation between individuals. Due to differences in the resolutions of these feeders as a measurement tool, a standard unit of feeding event needs to be estimated to allow for comparisons between studies. Different models for estimation of the defining value of a meal, the meal criterion, have been used, with the most recent incorporating the change in satiety with time since last feeding as part of the model. In this study I developed a new methodology, based on these models, for use when a within meal population of intervals cannot be easily modelled. I then used this model for application to data from four lines of broiler chickens to estimate meal criteria and compare feeding behaviour within and between the lines. Significant differences were found between fast and slow growing birds, with the faster growing birds having fewer but larger meals than the slower growing birds. However, the lines showed similar structure and bouting of their feeding behaviour, indicating that the fundamental controls of feeding behaviour, such as hunger and satiety, in these lines had been unaltered despite intensive selection for growth. The models were also applied across poultry species, kept in different experimental conditions. A similar structure to the feeding behaviour was found across all these species, with all showing clear separation of feeding events into bouts. In order to estimate the potential use of these behavioural observations in a breeding programme, the heritabilities and genetic correlations with existing performance traits were calculated for the four broiler lines. Heritabilities of all feeding behaviour traits were found to be moderate to high, and very similar across the lines. Correlations with performance traits, however, were low, meaning that there were no clear links of the traits with the current production goals investigated. This indicates that past selection for production has had limited impact on feeding behaviour and also that potential selection for feeding behaviour will have little effect on production gains. To identify the areas of the genome controlling feeding behaviour, traits were associated with a SNP panel. Many regions were found to have highly significant association with feeding behaviour traits, with the most highly correlated traits showing associations with the same regions, suggesting pleiotropic effects of genes in these regions. Future work in this area should include identification of individual genes controlling feeding behaviour to allow prediction of the effects of selection for favourable feeding behaviour on other traits, and comparison of the genotypes of different lines of broilers, to further understand the control of feeding behaviour.
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Pork quality improvement: estimates of genetic parameters and evaluation of novel selection criteriaLeeds, Timothy D. 02 December 2005 (has links)
No description available.
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Phenotypic and genetic relationships between docility and reproduction in Angus heifersOtteman, Kari Lynn January 1900 (has links)
Master of Science / Department of Animal Science and Industry / R. L. Weaber / This thesis includes two studies that assessed the relationships between docility and reproduction in Angus heifers, both from a phenotypic and genetic standpoint. The objective of the first study was to elucidate the phenotypic relationships between docility and first service AI conception rate in heifers. Data (n = 337) included exit velocity (EV), chute score (CS), fecal cortisol (FC), and blood serum cortisol (BC). Statistical analysis was done using logistic regression with 30 day pregnancy rate as the dependent variable. The model included the fixed effect of contemporary group, and the covariates FC, BC, EV, CS, weight, and age. Correlation coefficients were also calculated between all continuous traits. The power of our test could not detect any significant predictors of 30 d pregnancy for the combined data from all ranches. The objective of the second study was to determine the genetic control of docility and reproduction in heifers as measured by pregnancy rate. A subjective chute scoring system was used as the basis of their genetic evaluation for docility. Pedigree information was obtained on approximately 508,015 animals over 30 generations. Data included approximately 26,878 records on heifer pregnancy and 113,412 records on docility, with 7,849 animals having both docility and heifer pregnancy records. Contemporary groups were formed by the concatenation of weaning contemporary group, yearling contemporary group, and breeding contemporary group. Heritabilities were calculated from estimates of genetic and residual variance components computed using ASReml 3.0 (VSN International; Hemel Hempstead, UK). Heifer pregnancy variance components were estimated from a univariate, threshold model, with pregnancy outcome as the dependent variable. Animal and contemporary group were fit as a random effects, while age at first breeding was fit as a covariate. The heritability of heifer pregnancy was estimated to be 0.16 ± 0.02. Docility was fit as a univariate, linear animal model with docility score as the dependent variable. Animal and contemporary group were both modeled as random effects. The heritability for docility score was estimated to be 0.22 ± 0.03.
Fertility is a complex trait that is dependent on many factors; our data suggest that docility is one factor that warrants further investigation.
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Estimation of genetic parameters for udder quality in Hereford cattleBradford, Heather Lynn January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Daniel W. Moser / Udder quality is an important trait for beef producers because udders impact cow longevity and calf performance. The objective of this study was to estimate the genetic parameters for udder quality in Hereford cattle. The Beef Improvement Federation recommends collecting subjective scores on udder suspension and teat size. Prior to these guidelines, the American Hereford Association (AHA) recorded an overall score, which combines all udder characteristics into a single score. In all cases, scores ranged from 1 to 9 with a score of 9 considered ideal. Records on 78,556 animals and a 3-generation pedigree with 196,540 animals were obtained from the AHA, Kansas City, MO. These records contained repeated observations for overall score (n=126,753), suspension (n=61,758), and teat size (n=61,765). Data were modeled using a multiple trait animal mixed model with random effects of additive genetic and permanent environment and with fixed effects of age and contemporary group (herd-year-season). Variances were estimated with ASREML 3.0. Heritability estimates (standard errors) of overall score, suspension, and teat size were 0.32 (0.01), 0.31 (0.01), and 0.28 (0.01), respectively. These results showed udder quality was moderately heritable, agreeing with previous research. The phenotypic correlation (standard error) between teat size and suspension was 0.64 (0.003). Of the records for suspension and teat size, 57% had the same score for both traits. The genetic correlations (standard errors) between teat size and suspension, overall score and teat size, and overall score and suspension were 0.83 (0.01), 0.72 (0.02), and 0.70 (0.02), respectively. The genetic correlations between traits were extremely strong. In addition, producer education is important to ensure the scoring systems are used correctly.
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Potencial das populações Isanão-VF1 e Isanão-VD1 para seleção recorrente recíproca /Garcia, Fabiana Queiroz. January 2009 (has links)
Orientador: João Antonio da Costa Andrade / Banca: Mário Luiz Teixeira de Moraes / Banca: Orivaldo Arf / Banca: José Branco de Miranda Filho / Banca: Pedro Mário de Araújo / Resumo: O milho é uma planta cultivada no mundo todo e de importância econômica mundial. Em função de sua importância, amplos programas de melhoramento são realizados nesta cultura. Das várias técnicas utilizadas, a seleção recorrente recíproca tem sido importante na melhoria do cruzamento entre duas populações e, consequentemente, na obtenção de melhores híbridos entre linhagens extraídas das mesmas. No entanto o sucesso da seleção recorrente recíproca depende da existência de variabilidade genética interpopulacional e heteroze. O objetivo deste trabalho foi verificar a existência de variabilidade genética nas populações de milho de porte baixo Isanão-VF1 e Isanão-VD1, em condições de espaçamento reduzido e alta densidade de plantas, visando o início de um programa de seleção recorrente recíproca. Foram estimados parâmetros genéticos para oito caracteres, avaliando-se 80 progênies de meios irmãos interpopulacionais Isanão-VF1 e 72 Isanão-VD1, semeadas na Fazenda de Ensino, Pesquisa e Extensão da Faculdade de Engenharia, Campus de Ilha Solteira (UNESP), em Selvíria/MS. Foi encontrada variabilidade genética interpopulacional, expressa através dos caracteres florescimento feminino (FF), altura de plantas (AP), altura de espigas (AE) e rendimento de grãos (RG), com herdabilidades (em nível de médias de progênies) de 68,8%, 76,9%, 75,0% e 54,78%, respectivamente. Os índices de variação (coeficiente de variação genético/coeficiente de variação experimental) foram de 0,9; 1,1; 1,0 e 0,6, respectivamente para FF, AP, AE e RG. Espera-se um ganho de 10,76%/ciclo de seleção no RG do híbrido interpopulacional, 19 qualificando as populações Isanão-VF1 e Isanão-VD1 para serem submetidas a um programa de seleção recorrente recíproca. Com uma heterose de 38,2% do híbrido interpopulacional sobre as populações... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Maize is a cultivated crop around the globe, and of worldwide economic importance. Due to its importance, wide genetic breeding programs are constantly applied upon it. Among the techniques employed, reciprocal recurrent selection has been important in improving the cross between two populations and in obtaining superior hybrids of inbred lines originated from them. However, the success of reciprocal recurrent selection is dependent of interpopulation genetic variability. The objective of this research was to verify the presence of genetic variability in brachytic populations Isanão-VF1 and Isanão-VD1 maize, cultivated in reduced row spacing and high plant density, aiming at beginning a reciprocal recurrent selection breeding program. Were Genetic parameters estimated for eight traits, evaluated in 80 interpopulation half-sib progenies of Isanão-VF1 and 72 of Isanão-VD1, at the UNESP Research Farm, located in Selvíria, state of Mato Grosso do Sul, Brazil. Interpopulational genetic variability was expressed in the traits silk emergence (FF), plant height (AP), ear height (AE) and grain yield (RG). The coefficients of heritability progeny mean basic were 68.8%, 76.9%, 75.0% and 54.8%, respectively. Estimates of the index of variation (genetic variation coefficient/experimental variation coefficient) were 0.9, 1.1, 1.0 and 0.6, for SE, PH, EH and GY, respectively. A gain of 10.76%/cycle on GY is expected on the interpopulation hybrid, indicating Isanão-VF1 and Isanão-VD1 populations as base for a reciprocal recurrent selection progr am. The heterosis of 38.2% of the interpopulation hybrid over the parental populations qualify the latter as a sources of inbred lines, to be used us hybrid crosses more adapted the condition of high plant density and reduced row spacing. / Doutor
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Modelos de regressão aleatória para a estimação de parâmetros genéticos da produção e constituintes do leite de búfalas /Aspilcueta Borquis, Rusbel Raúl. January 2011 (has links)
Resumo: Foram estimados parâmetros genéticos para a produção de leite, gordura e proteína no dia do controle de primeiras lactações de búfalas leiteiras por meio de análises uni e multicaracterística de regressão aleatória. Para os modelos de regressão aleatória unicaracterística foram analisadas as 1.433 primeiras lactações de búfalas. Para as características em estudo, foram considerados nos modelos utilizados, os efeitos aleatórios genético aditivo, de ambiente permanente e o residual. Como efeitos fixos, foram considerados o grupo contemporâneo e o número de ordenha (1 ou 2 ordenhas). Os efeitos linear e quadrático da covariável idade da vaca ao parto e a curva média de lactação da população, estão modelados por polinômios ortogonais de Legendre de terceira ordem. Os efeitos aleatórios genético aditivo e de ambiente permanente foram estimados por meio de regressão aleatória sobre polinômio ortogonais de Legendre de terceira à sexta ordem. Os resultados indicam que são requeridos polinômios de Legendre de baixa ordem para modelar a estrutura de (co)variância genética e de ambiente permanente. As estimativas de herdabilidade das características em estudo foram moderadas, o que poderia ajudar no processo de seleção dos animais para obtenção de ganhos genéticos. As estimativas das correlações genéticas foram altas entre controles, indicando que seja qual for o critério de seleção adotado, ganhos genéticos indiretos são esperados em toda a curva de lactação. Para o modelo de regressão aleatória multivariada foi analisado o mesmo banco de dados e as mesmas pressuposições do modelo unicaracaterística. No que se refere à modelagem dos efeitos aleatórios, utilizouse, em todas as características, polinômios de Legendre de terceira ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Genetic parameters for milk, fat and protein yields in the test day were estimated for the first lactations of dairy buffaloes by using single- and multiple-trait random regression analyses. To the single-trait analyses were analyzed 1,433 first lactations. The models included as random effects: additive genetic, permanent environment and residual and as fixed effects: contemporary group, number of milkings (one or two), linear and quadratic effects of the covariable age of the buffalo at birth and mean lactation curve of the population, modeled using Legendre orthogonal polynomials of third order. The random regression effects of genetic and permanent environment were estimated by random regression with Legendre orthogonal polynomials from third to sixth orders. The results indicate that low order polynomials are required to model the structure of genetic and permanent environment (co)variances. The heritability estimates of the traits studied were moderated, it permits to do selection of animals to obtain genetic gain. The genetic correlation estimates were high among test-days, indicating that the selection aims may be different, but indirect genetic gain for all the lactation curve was expected. To the model of multiple-trait random regression, the same data was analyzed, with the same presuppositions of the single-trait model. To model the random effects, Legendre polynomials of third and fourth order were used, to genetic effects and permanent environment, respectively. The residual variances were modeled considering four residual classes grouped as: 1, 2-3, 4-8, 9-10 months of lactation. The results indicate that the heritabilities estimates of the traits presented enough genetic variance to be selected. The estimates of the variance components may be used to implement a BLUP evaluation in a Brazilian buffalo population. The genetic correlations among test-days for a trait ... (Complete abstract click electronic access below) / Orientador: Humberto Tonhati / Coorientador: Lucia Galvão de Albuquerque / Coorientador: Milthon Muñoz Berrocal / Banca: Henrique Nunes Oliveira / Banca: Danísio Prado Munari / Banca: Maria Eugênia Zerlotti Mercadate / Banca: Leonardo de Oliveira Seno / Doutor
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Variabilidade genética de progênies de polinização aberta de Eucalyptus Grandis Hill ex Maiden e correlações entre caracteres juvenil-adulto /Brizolla, Thiago Fernandes, 1981- January 2009 (has links)
Resumo: A espécie Eucalyptus grandis Hill ex Maiden é a mais cultivada em estandes comerciais no Brasil e no mundo. A espécie é plantada como cultivar e também na forma de plantios clonais de seus híbridos interespecíficos. O trabalho é um estudo da variabilidade genética em progênies de polinização livre de Eucalyptus grandis de árvores selecionadas fenotipicamente em pomar de sementes por muda, cuja procedência é originária de Coff's Harbour - Austrália. Este pomar, de propriedade da empresa Duratex S.A. encontra-se na Fazenda Morro D'Ouro, no Município de Botucatu. Tem também como objetivo analisar as correlações entre os diferentes caracteres nas diferentes idades e estudar as correlações entre as idades juvenis e de final de rotação da cultura, visando subsidiar a seleção precoce em programas de melhoramento com espécie. Os ensaios foram instalados em três experimentos em cada um dos dois locais, Angatuba-SP e Lençóis Paulista-SP, em fevereiro de 1988. O delineamento experimental utilizado foi o blocos casualizados, com 10 repetições, 6 plantas por parcela, ao espaçamento de 3 x 2 metros e totalizando 75 progênies. Os caracteres avaliados foram o diâmetro a altura do peito (DAP); altura de planta e volume de madeira. As avaliações foram feitas em quatro anos consecutivos (02, 03, 04 e 05 anos) em Lençóis Paulista (local 2), sendo que em Angatuba (local 1) foram realizadas avaliações anuais do segundo ao sexto ano. Os resultados mostraram haver variabilidade genética suficiente para avançar as gerações de melhoramento com a espécie... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The species Eucalyptus grandis Hill ex Maiden is the most commonly cultivated in commercial stands in Brazil and throughout the world. The species is planted as a cultivar, by seed, e also by clonal plantings of its interspecific hybrids. The research is a study of genetic variability in open pollinated progenies of Eucalyptus grandis of phenotipically selected trees in Seedling Seed Orchard of Coff's Harbour - Australia provenance. The orchard is of Duratex S.A. company located in Morro D'Ouro Experimental Station, in Botucatu city, S.P., Brazil. The study also have as objective to analyze the correlations between different traits in different ages and to study the correlations between juvenile and final of culture rotation, aiming to get support for procedures of early selection in forest tree breeding programs of Eucalyptus grandis. The experiments were set up by three trails in each one of two localities, Angatuba and Lençois Paulista, both in São Paulo State, Brazil, in February of 1988. The experimental design was the randomized blocks, with 10 replications, 06 plants per plot, 3 x 2 spacing, and totalizing 75 progenies. The diameter of breast height (dbh), plant height, and wood volume were the studied traits. The evaluations were made through the consecutive years (02, 03, 04, and 05 years old) in Lençois Paulista (Locality 2), and in Angatuba (Locality 1) were made annual evaluations from de second to the sixth years old. The results have shown sufficient genetic variability to advance breeding generations of species... (Complete abstract click electronic access below) / Orientador: Edson Seizo Mori / Coorientador: Léo Zimback / Banca: Maurício Dutra Zanotto / Banca: Edwin Camacho Palomino / Mestre
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Variabilidade genética de progênies de polinização aberta de Eucalyptus Grandis Hill ex Maiden e correlações entre caracteres juvenil-adultoBrizolla, Thiago Fernandes [UNESP] 04 September 2009 (has links) (PDF)
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brizolla_tf_me_botfca.pdf: 254524 bytes, checksum: 7729f6929f3138aa2ec6cbf4147cd6b8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A espécie Eucalyptus grandis Hill ex Maiden é a mais cultivada em estandes comerciais no Brasil e no mundo. A espécie é plantada como cultivar e também na forma de plantios clonais de seus híbridos interespecíficos. O trabalho é um estudo da variabilidade genética em progênies de polinização livre de Eucalyptus grandis de árvores selecionadas fenotipicamente em pomar de sementes por muda, cuja procedência é originária de Coff’s Harbour – Austrália. Este pomar, de propriedade da empresa Duratex S.A. encontra-se na Fazenda Morro D’Ouro, no Município de Botucatu. Tem também como objetivo analisar as correlações entre os diferentes caracteres nas diferentes idades e estudar as correlações entre as idades juvenis e de final de rotação da cultura, visando subsidiar a seleção precoce em programas de melhoramento com espécie. Os ensaios foram instalados em três experimentos em cada um dos dois locais, Angatuba-SP e Lençóis Paulista-SP, em fevereiro de 1988. O delineamento experimental utilizado foi o blocos casualizados, com 10 repetições, 6 plantas por parcela, ao espaçamento de 3 x 2 metros e totalizando 75 progênies. Os caracteres avaliados foram o diâmetro a altura do peito (DAP); altura de planta e volume de madeira. As avaliações foram feitas em quatro anos consecutivos (02, 03, 04 e 05 anos) em Lençóis Paulista (local 2), sendo que em Angatuba (local 1) foram realizadas avaliações anuais do segundo ao sexto ano. Os resultados mostraram haver variabilidade genética suficiente para avançar as gerações de melhoramento com a espécie... / The species Eucalyptus grandis Hill ex Maiden is the most commonly cultivated in commercial stands in Brazil and throughout the world. The species is planted as a cultivar, by seed, e also by clonal plantings of its interspecific hybrids. The research is a study of genetic variability in open pollinated progenies of Eucalyptus grandis of phenotipically selected trees in Seedling Seed Orchard of Coff’s Harbour – Australia provenance. The orchard is of Duratex S.A. company located in Morro D’Ouro Experimental Station, in Botucatu city, S.P., Brazil. The study also have as objective to analyze the correlations between different traits in different ages and to study the correlations between juvenile and final of culture rotation, aiming to get support for procedures of early selection in forest tree breeding programs of Eucalyptus grandis. The experiments were set up by three trails in each one of two localities, Angatuba and Lençois Paulista, both in São Paulo State, Brazil, in February of 1988. The experimental design was the randomized blocks, with 10 replications, 06 plants per plot, 3 x 2 spacing, and totalizing 75 progenies. The diameter of breast height (dbh), plant height, and wood volume were the studied traits. The evaluations were made through the consecutive years (02, 03, 04, and 05 years old) in Lençois Paulista (Locality 2), and in Angatuba (Locality 1) were made annual evaluations from de second to the sixth years old. The results have shown sufficient genetic variability to advance breeding generations of species... (Complete abstract click electronic access below)
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Diversidade e estrutura genética de populações naturais de Erythrina velutina Willd / GENETIC DIVERSITY AND STRUCTURE OF NATURAL POPULATIONS OF ERYTHRINA VELUTINA WILLD.Melo, Marília Freitas de Vasconcelos 09 July 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A study based in DNA and isozyme markers was carried out to evaluate the diversity and genetic structures of natural populations of Erythrina velutina Willd., aiming monitored
prospection of the genetic variability for two populations from the Atlantic Forest (Santana do São Francisco-SE) and Caatinga (Pinhão-SE) Biomes. Young leaves of twenty individuals per population were sampled from each population. Primers of ten arbitrary bases sequence and fifteen enzymatic systems were used. In RAPD analysis, the population from Atlantic Forest Biome originated 100 polymorphic loci and population from Caatinga Biome, 112 loci. It was observed that the genetic structure for population from Caatinga present higher number of observed and effectives alleles, which implicate in a higher heterozigozity. The observed average heterozygozity was higher than the expected heterozigozity by Hardy- Weinberg, which indicate a excess of heterozygotes, and this value might be confirmed by
negative value of the Wright´s fixation index (-0.5098). In relation to genetic diversity between populations (Fst and Gst) the values were similar for both markers. The results suggest the use of M1, M7, M11 and M14 individuals from Atlantic Forest Biome; and the M5, M6, M18 and M19 individuals from Caatinga Biome as most divergent for future chemical, biochemical and pharmacological studies. / Um estudo baseado em marcadores de DNA e isoenzimáticos foi realizado para avaliar a diversidade e estrutura genética de populações naturais de Erythrina velutina Willd., visando à prospecção monitorada da variabilidade genética, para fins de seleção das matrizes mais divergentes, em duas populações naturais do estado de Sergipe. Foram amostradas folhas
jovens de vinte indivíduos em cada população. Um total de vinte oligonucleotídeos decâmeros de sequência arbitrária e 15 sistemas enzimáticos foram testados. Na análise de RAPD, a população do Baixo São Francisco Sergipano originou 134 locos, sendo 100 polimórficos e a população do município de Pinhão, 143 locos, sendo 112 polimórficos. Observou-se para a estrutura genética da população do município de Pinhão maior número de alelos observados e efetivos, o que implica numa maior heterozigosidade. A heterozigosidade média observada foi maior que a esperada pelo equilíbrio de Hardy-
Weinberg, o que indica um excesso de heterozigotos e pode ser confirmado pelo valor negativo do índice de fixação de Wright (-0,2304). Em relação à diversidade genética entre
populações (Fst e Gst) os valores foram similares para os dois marcadores. Sugere-se o uso dos indivíduos M1, M7, M11 e M14 do Baixo São Francisco Sergipano; e dos indivíduos M5,
M6, M12 e M19 do município de Pinhão como os mais divergentes para futuros estudos químicos, bioquímicos e farmacológicos.
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Avaliação de características de desempenho e qualidade de carne em linhagens e touros representativos da raça Nelore, utilizando ultrassonografia, análise de imagens e NIRS / Evaluation of growth and beef quality traits in lineages and representative Nellore sires, using ultrasound, video image analysis and NIRS measurementsBonin, Marina de Nadai 05 October 2012 (has links)
Esta pesquisa teve como objetivo avaliar as diferenças nos padrões de desenvolvimento ponderal, composição de carcaça e qualidade de carne entre linhagens e touros representativos da raça Nelore, com aplicação de tecnologias modernas para coleta de dados e estimação de parâmetros genéticos e fenotípicos das características em estudo. Foram utilizados dados de desenvolvimento ponderal, características de carcaça e qualidade de carne de machos da raça Nelore, terminados a pasto e confinamento e pertencentes a programas de avaliação genética. Desses animais, foram coletadas informações individuais de características de carcaça avaliadas por ultrassonografia e medidas corporais para estimação do frame de cada animal. Ao abate, foram avaliadas características de carcaça e carne, diretamente na carcaça e também através de imagens digitais do músculo Longissimus para determinação de atributos relacionados à qualidade, como maciez, perdas por cozimento, gordura intramuscular e pH. Avaliações por infravermelho com comprimentos de onda na faixa do visível próximo (VIS-NIRS) foram tomadas para associação com valores de pH, força de cisalhamento e lipídios no músculo Longissimus. Foram estimados parâmetros genéticos para todas as características avaliadas neste trabalho. As características de ganho ponderal, frame, medidas de ultrassonografia e qualidade de carne foram utilizadas para comparação entre genearcas e novos genearcas da raça Nelore. Estas informações em conjunto com a validação ferramentas auxiliares para coleta de fenótipos poderão ajudar na condução de programas de melhoramento genético de características de desempenho e qualidade de nos rebanhos dessa raça, bem como a obtenção de importantes informações sobre a variabilidade e valor genético de genearcas e touros representativos da raça Nelore. / The objective of this study was to evaluate the differences of growth, carcass composition and beef quality traits among lineages and representative Nellore sires, using new technologies to collect data and estimate genetic and phenotypic parameters. Data on growth, carcass and meat quality traits of Nellore bulls, raised in pastures and included in genetic evaluation programs were analyzed. Individual information on live ultrasound carcass measurements and frame were, also, collected. After slaughter, carcass, beef quality traits and video image analysis (VIA) of muscle Longissimus were obtained for estimation of beef quality attributes like tenderness, cooking losses, intramuscular fat and pH. Evaluations with Near Infrared Spectroscopy (VIS-NIRS) were made to quantify tenderness and lipid in Longissimus muscle. Genetic parameters were estimated for all traits analyzed in this study. Traits like performance, frame, ultrasound carcass evaluation and meat quality were used to compare lineages and representative Nellore sires. This research provide precious information to development of auxiliary tools for genetic improvement of growth, carcass and meat quality traits in Nellore herds, and provide important information about variability and genetic value of founders and representative sires of this breed.
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