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Estimativas de parametros genéticos para características de crescimento e produtividade em vacas da ra a Canchim, utilizando-se inferência bayesiana  [cached]
Mello Silvio de Paula,Alencar Maurício Mello de,Toral Fábio Luiz Buranelo,Gianloren?o Viviane Karina
Revista Brasileira de Zootecnia , 2006,
Abstract: O objetivo neste trabalho foi estimar as herdabilidades e as correla es genéticas dos pesos à desmama (PD), aos 12 meses de idade (P12) e à idade adulta (PAD), da idade de descarte (TPR - tempo de permanência no rebanho), do número (ND10) e quilogramas (QD10) de bezerros desmamados em até dez anos de idade, do número total (NDT) e quilogramas totais (QDT) de bezerros desmamados durante todo o tempo de permanência no rebanho e dos quilogramas de bezerros desmamados por ano de permanência no rebanho (QTPR) de fêmeas de um rebanho da ra a Canchim. As estimativas dos componentes de (co)variancia foram obtidas pelo método bayesiano, em análises bicaráter de PD, P12 e PAD com as demais características. Os modelos estatísticos incluíram os efeitos aleatórios genético aditivo direto, de ambiente permanente e residual e os efeitos fixos de ano e mês de nascimento ou do parto, da idade da vaca ao parto e da idade do animal, dependendo da característica. As médias das estimativas de herdabilidade foram iguais a 0,38 (PD), 0,40 (P12), 0,54 (PAD), 0,22 (TPR), 0,22 (ND10), 0,24 (QD10), 0,23 (NDT), 0,23 (QDT) e 0,32 (QTPR), indicando que as características possuem varia o genética aditiva suficiente para boa resposta à sele o. As correla es genéticas entre TPR (-0,02; 0,26 e -0,12), ND10 (0,04; 0,10 e -0,29), QD10 (0,37; 0,39 e -0,13), NDT (-0,03; 0,14 e -0,25), QDT (0,20; 0,33 e -0,16) e QTPR (0,21; 0,28 e -0,19) e os pesos (PD, P12 e PAD), ao contrário do aumento do peso adulto, sugerem que a sele o de fêmeas com base nos pesos à desmama e aos 12 meses de idade n o deve prejudicar as características de longevidade e de produtividade estudadas.
Estimativas de parametros genéticos para características de crescimento e produtividade em vacas da ra?a Canchim, utilizando-se inferência bayesiana
Mello, Silvio de Paula;Alencar, Maurício Mello de;Toral, Fábio Luiz Buranelo;Gianloren?o, Viviane Karina;
Revista Brasileira de Zootecnia , 2006, DOI: 10.1590/S1516-35982006000100011
Abstract: the objective of this study was to estimate genetic parameters for body weights at weaning (pd), 12 months old (p12) and adult age (pad), culling age (tpr, days in herd), number (nd10) and kilograms (qd10) of calves weaned up to ten years of age, total number (ndt) and total kilograms (qdt) of calves weaned during herd life, and kilograms of calves weaned per year in herd (qtpr) of canchim (5/8 charolais + 3/8 zebu) females from one herd. data consisted of 3,249, 3,111, 1,138, 1,340, 1,362, 1,362, 1,340, 1,340 and 1,340 records of pd, p12, pad, tpr, nd10, qd10, ndt, qdt and qtpr, respectively. variance and covariance components were estimated by bivariate analyses between pd, p12 and pad and other production traits using bayesian inference. the models included the additive direct, permanent environmental and residual random effects and the fixed effects year and month of birth or calving, calving age and age of the animal, depending on the trait. qd10, qdt and qtpr of each female were obtained by adjusting the weaning weights of calves for year and month of birth, sex and age of cow. average of heritability estimates were 0.38 (pd), 0.40 (p12), 0.54 (pad), 0.22 (tpr), 0.22 (nd10), 0.24 (qd10), 0.23 (ndt), 0.23 (qdt) and 0.32 (qtpr), indicating genetic variability to obtain response by selection. genetic correlations between tpr (-0.02, 0.26 and -0.12), nd10 (0.04, 0.10 and -0.29), qd10 (0.37, 0.39 and -0.13), ndt (-0.03, 0.14 and -0.25), qdt (0.20, 0.33 and -0.16), qtpr (0.21, 0.28 and -0.19) and body weights (pd, p12 and pad) suggest that selection of females based on weaning and 12-month body weights will not affect productivity. however, it may be decreased by increasing female adult body weight.
Parametros genéticos para características de crescimento e reprodu??o de bovinos da ra?a Canchim
Borba, Luis Henrique Fernandes;Rey, Fernando Sebástian Baldi;Silva, Luiz Otávio Campos da;Boligon, Arione Augusti;Alencar, Maurício Mello de;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011001100020
Abstract: the objective of this work was to estimate genetic parameters for age at first (afc) and at second (asc) calvings, penalized age at first (afcpen) and at second (ascpen) calvings, and occurrence of calving until 38 months of age (pp38) in canchim breed, as well as to estimate the genetic correlations between these traits with weight (pe420) of males and females, and scrotal circumference (ce420) measured at 420 days of age. genetic parameters were estimated by two-trait analyses using the bayesian inference. the analyses were performed between ce420 and pe420, and the reproductive traits measured in the females. the female reproductive traits should show low response to selection, and changes in the management and environmental conditions improve these traits. selection for the higher weight at 420 days of age does not change female reproductive traits, while selection to increase scrotal circumference, at the same age, contributes to improve such traits.
BAYESIAN AND FREQUENTIST APPROACHES IN THREE TRAIT GENETIC ANALYSIS FOR GROWTH AND REPRODUCTION IN NELORE CATTLE ABORDAGEM BAYESIANA E FREQüENTISTA EM ANáLISE GENéTICA TRICARáTER PARA CRESCIMENTO E REPRODU O DE BOVINOS NELORE  [cached]
Carina Ubirajara de Faria,Cláudio de Ulh?a Magnabosco,Lúcia Galv?o Albuquerque,Arcadio de los Reyes
Ciência Animal Brasileira , 2008,
Abstract: The Bayesian inference has been proposed as an alternative for estimating variance components instead of the frequentist approach. The objective of this study was to estimate the (co)variance components and genetic parameters of growth and reproduction traits in Nelore cattle using three-trait animal model by Restricted Maximum Likelihood and Gibbs Sampling. The data set had 15,173 and 6,911 records of weight (W365) and scrotal circumference (SC365) at 365 days of age, respectively, and 10, 388 records of age at first calving (AFC), from the Nelore Breed Genetic Improvement Program farms. The linear model included the contemporary groups and age-of-dam (with exception for AFC) as fixed effects, and residual and additive direct genetic effects as random. Estimates obtained by Restricted Maximum Likelihood were different from those found by Gibbs Sampling. There were no differences in genetic parameter estimates using the three levels of prior information by Gibbs Sampling. The Bayesian inference has advantages in relation to Frequentist approach due to marginal distributions which offer more information about the parameters. KEY WORDS: Beef cattle, genetic parameters, three-trait models. Os objetivos deste estudo foram estimar os componentes de variancia e parametros genéticos de características de crescimento e reprodu o de bovinos da ra a Nelore, em modelo animal tricaráter, utilizando a Máxima Verossimilhan a Restrita e a Inferência Bayesiana. Na implementa o do Amostragem de Gibbs, que aplica a teoria bayesiana, consideraram-se os três diferentes níveis de conhecimento das informa es iniciais dos componentes de variancia e covariancia. O conjunto de dados continha 15.173 registros de peso aos 365 dias de idade (P365), 6.911 registros de perímetro escrotal aos 365 dias de idade (PE365) e 10.388 dados de idade ao primeiro parto (IPP). O modelo linear incluiu o grupo de contemporaneos e a idade da vaca ao parto como efeitos fixos (exceto para IPP), e os efeitos genético aditivo direto e residual como aleatórios. As estimativas obtidas pela Máxima Verossimilhan a Restrita foram diferentes das obtidas pela Amostragem de Gibbs. No entanto, considerando os três diferentes níveis de informa o inicial, n o houve diferen as nas estimativas dos parametros genéticos obtidas pela Amostragem de Gibbs. O método bayesiano apresentou vantagens em rela o ao método freqüentista, gra as às distribui es marginais posteriores, que ofereceram mais informa es sobre os parametros estimados. PALAVRAS-CHAVES: Bovinos de corte, modelo tricaráter, parametros genéticos.
Arranjos para efeitos fixos e estruturas de (co)variancias residuais para análises de medidas repetidas do peso de bovinos da ra?a Canchim
Toral, Fábio Luiz Buranelo;Alencar, Maurício Mello de;Freitas, Alfredo Ribeiro de;
Revista Brasileira de Zootecnia , 2006, DOI: 10.1590/S1516-35982006000700010
Abstract: the aim of this work was to evaluate arrays of fixed effects and residual covariance structures that best fit the herd and the animal variability to weights at birth, weaning, twelve and eighteen months of 3,690 canchim animals. different arrays of fixed effects (contemporary groups and, or the main effects of year, month or season of birth and sex) and different residual covariance structures (considering or not change of variance and of correlation between weights at different ages) were studied. the results indicated that the most adequate array of fixed effects to fit herd variability was the contemporary group of year, month and sex. the best residual covariance structures were the first-order factor analytic and the unstructured, which consider increase of residual variance as age increases and different correlation between pair of weights at different ages.
Estruturas de variancia residual para estima??o de fun??es de covariancia para o peso de bovinos da ra?a Canchim
Toral, Fábio Luiz Buranelo;Alencar, Maurício Mello de;Freitas, Alfredo Ribeiro de;
Revista Brasileira de Zootecnia , 2009, DOI: 10.1590/S1516-35982009001100012
Abstract: this study was carried out to evaluate the use of different residual variance structures to estimate covariance functions for weight of canchim beef cattle. the covariance functions were estimated by the restricted maximum likelihood method, in an animal model with fixed effect of contemporary group (year and month of birth and sex), age of dam at calving as covariable (linear and quadratic effects) and mean growth trajectory while the random effects considered were the direct additive genetic and maternal effects, permanent individual environment and maternal and residual effects. different structures were used for residual variance: ordinary polynomials of different orders (linear to fifth) and step functions with 1, 5, 10, 15 and 20 classes. homogeneous residual variance was not adequate. the four-ordered variance function and the step function with 20 classes presented the best fit and the class division was more efficient than residual functions. the estimated heritabilities were between 0.16 and 0.25, and the greatest ones were obtained close to 360 days and at the end of the study period. the estimated heritabilities were similar for models with homogeneous residual variance, four-ordered residual function and step model with 20 classes of heterogeneous variances. the best description of residual variance, for weights at different ages of canchim beef cattle, was by step function with 20 classes of heterogeneous variances. however, as existing classes with the same variances, they can be grouped to reduce the number of parameters to be estimated.
Efeitos de ambiente e estimativas de parametros genéticos para características de carca?a em bovinos da ra?a Canchim criados em pastagem
Meirelles, Sarah Laguna;Alencar, Maurício Mello de;Oliveira, Henrique Nunes de;Regitano, Luciana Correia de Almeida;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010000700006
Abstract: the objective in this work was to study the effects of environmental factors on subcutaneous fat thickness (bft), loin eye area (rea) and body weight (bw) measured at 19 months of age and to estimate genetic parametersfor these traits. it was used information obtained from 987 canchim (5/8 charolais + 3/8 zebu) and ma genetic group (offspring of charolais bulls and 1/2 canchim + 1/2 zebu cows) bulls and heifers, born in 2003, 2004, and 2005. covariance components were estimate by restricted likelihood method using animal model with fixed effects (year of birth, genetic group, herd, and sex) and residual and direct additive genetic random effects. means of loin eye area and weight were higher for males than for females. in the ma genetic group, the means, for all traits, were higher than in the canchim group, and there were still the effects of herd and year of birth. the heritability estimates of rea (0.33 ± 0.09), bft (0.24 ± 0.09) and bw (0.23 ± 0.09) were moderate, while genetic correlation estimate (0.21 ± 0.24) between bft and rea was low, suggesting that traits are controlled by different sets of genes with additive action. genetic correlations of bw with bft (0.57 ± 0.23) and rea (0.62 ± 0.16) are moderate. it is possible to conclude that those traits can respond for selection and they indicate that selection for bw will increase also enhance bft and rea and vice versa.
Estimativas de parametros genéticos para características de crescimento em bovinos da ra?a Canchim utilizando modelos de dimens?o finita
Baldi, Fernando;Alencar, Mauricio Mello de;Albuquerque, Lucia Galv?o de;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010001100013
Abstract: the objectives of this work were to evaluate different models, regarded to considered maternal effects, for growth traits and to estimate genetic parameters for these traits in canchim breed bovine, by one, two and multitrait analyses. the weight traits at birth, at weaning, standardized weight for 12, 18, 24 and 30 months of age in males and females, and mature female weight were analyzed using four models with random effects added in sequence. maternal effects influenced birth weight at 2 years of age and weaning weight was the most affected by maternal effects. direct heritability estimates obtained by two- and multitrait analyses were higher than those obtained through one-trait analyses. estimates of direct genetic effect heritability obtained using multi-trait analyses were 0.39 for weight at birth; 0.31 for weight at weaning; 0.29 for weight at 12 months of age; 0.28 for weight at 18 months of age; 0.26 for weight at 24 months of age; 0.30 for weight at 30 months of age and 0.38 for weight at mature age. genetic correlations estimated among weights at early ages and mature weight were high, above 0.79. selection based on growth traits at any age can promote intermediate genetic gains on the body weight of canchim breed animals at all standard ages, including weight at birth and at mature age of females. it is important to consider in the analyses the weights previous to selection to estimate genetic parameters for weights after selection. multitrait analyses is the best indicated.
Desempenho em confinamento de machos bovinos inteiros Canchim, Aberdeen angus e cruzamentos recíprocos  [cached]
Perotto Daniel,Moletta José Luiz,Lesskiu Carlos
Ciência Rural , 2002,
Abstract: Foram analisados o consumo diário de matéria seca (MS) por 100kg de peso vivo (CMS), a convers o alimentar (CA) e o ganho de peso médio diário (GMD) de 118 machos bovinos inteiros Canchim (Cn), Aberdeen Angus (Ab) e cruzamentos recíprocos (CnAb (F1, 3/4Cn+1/4Ab, 5/8Cn+3/8Ab e 11/16Cn+5/16Ab) e AbCn (F1, 5/8Ab+3/8Cn e 11/16Ab+5/16Cn)). Esses animais foram alimentados em baias individuais por 84 a 95 dias com silagem de milho à vontade mais concentrado (17,8% de PB e 79% de NDT) fornecido à base de 1% do peso vivo do animal por dia. As características foram analisadas por um modelo que incluiu os efeitos fixos de ano do confinamento, grupo genético, período e ano x período e o efeito aleatório de animal dentro de grupo genético dentro de ano. A rela o MS do concentrado:MS da silagem foi incluída como co-variável no modelo. Posteriormente, as características foram analisadas por um modelo de regress o que incluiu coeficientes representando as fra es esperadas de Ab nos genótipos dos animais e das m es e as heterozigoses individual e materna. As médias para CMS, CA e GMD foram 2,44kg de MS/100kg de PV/dia, 6,97kg de MS/kg de GMD e 1,435kg/dia, respectivamente. O grupo genético influenciou o CMS (P<0,01) e o GMD (P<0,06). O Ab igualou-se ao AbCn apresentando maior CMS e menor GMD que o Cn e o CnAb. N o houve heterose para qualquer das características indicando que o cruzamento alternado Cn x Ab seria igual à média das ra as paternas.
Pontes de miocárdio em bovinos da ra?a Canchim
SANTOS, José Wilson dos;BOMBONATO, Pedro Primo;BELETTI, Marcelo Emílio;SEVERINO, Renato Souto;CARNEIRO E SILVA, Frederico Ozanan;
Brazilian Journal of Veterinary Research and Animal Science , 2000, DOI: 10.1590/S1413-95962000000200006
Abstract: it was studied 30 hearts of adult bos taurus, females of the race canchim, with the objective of observing the frequency, width, location and angulation of the myocardial bridges. for the macroscopic study the hearts had injected the coronary arteries with solution of neoprene red-faced latex 450, with posterior fixation in aqueous solution of formol to 10% and after dissection. the results indicate that the myocardial bridges happen in 100% of the hearts, with medium width of 1.24 cm and they locate more commonly in the portions average (38.87%), ventral (26.11%). multiple bridges are observed in 93.33% of the hearts varying from two to six. the muscular fibers of the segment form angles with the longitudinal axis of the arterial vases with medium of 46o.
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