Estudo genético da produção de ovos em uma linha de frango de corte por meio de análises multicaracterísticas e regressão aleatória

• Ano de defesa: 2010
• Autor(a) principal: Pacheco, Rodrigo de Oliveira
• Orientador(a): Euclydes, Ricardo Frederico
• Banca de defesa: Barreto, Sérgio Luiz de Toledo , Carneiro, Antônio Policarpo Souza
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Crescimento; Caipira; Ovos
• Palavras-chave em Inglês: Growth; Hick; Eggs
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::GENETICA E MELHORAMENTO DOS ANIMAIS DOMESTICOS
• Link de acesso: http://locus.ufv.br/handle/123456789/5675

This work aimed to estimate genetic parameters for the partial periods and for the total period of egg production, through the bi-characteristics analyses, to verify the possibility of using the performance in partial periods, replacing total period, in genetic evaluation (Chapter 1) and compare random regression models with different orders of Legendre polynomials to evaluate which of the models evaluated promotes the best fit for eggs production, and from model topromote the best fit, obtain the heritability, variances and correlations of production eggs (Chapter 2). In this study has used data of 2,146 females from a broiler chicken line, from a company located in the south of the country. The eggs production was evaluated by the number of eggs produced between the 25th and 64th weeks of age birds. For the bi-characteristics were formed four partial periods of the 25th until 31st (P31), 25th until 40th (P40), 25th until 48th (P48) and the 25th to 52nd (P52) weeks of age and period of total production (PTOTAL) of the 25th to 64th week of age. It was used for analyze the bicharacteristic animal model. P40, P48 and P52 showed values of the relative efficiency of the correlated responses with the period with PTOTAL greater than 1, with an indication of selection by correlated responses an efficient selection criterion. The selection in P40 can be recommended as it showed the highest heritability (0.40) and a value of 0.70 for the genetic correlation with PTOTAL this period, thus allowing a higher gain per unit time as a result of efficiency and on reducing the generation interval. The general random regression model proposed for the fixed effects of hatching, mean trend of production, and the random effects-additive, permanent environmental and residual effects. The model with Legendre polynomial of order three for the fixed effects and the fourth order for the random direct additive genetic and permanent environment of animal was the model that promoted a better fit for egg production. The likelihood ratio test (LRT) has indicateddifference (P<0.01) and best values for the log-likelihood function (LogeL) for the Akaike information criterion (AIC) and the Bayesian informationcriterion (BIC) for the best model. Genetic variances, permanent environmental and phenotypic variations presented with advancing age. The heritability estimates for the model that promoted the best fit were low to moderate, with the largest value(0.28), found near the peak of production. Estimates of additive genetic correlation and permanent environment varied widely.