Navegando por Autor "Santos, Alexandre Leseur dos"

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    Estimation of genetic parameters for weaning and yearling weights in a composite population used to form the Purunã breed
    (Brazilian Journal of Animal Science, 2021-06) Otto, Pamela Itajara; Santos, Alexandre Leseur dos; Perotto, Daniel; Oliveira, Sheila Nogueira de; Granzotto, Fernanda; Gobo, Diego Ortunio Rosa; Souza, Felipe Eduardo Zanão de; Thomazini, Guilherme
    We aimed to evaluate the effects of sex and the linear and quadratic components of age of dam at calving, as well as apply a mixed model including maternal effect for the genetic evaluation of weaning (WW) and yearling (YW) weights. The phenotypic database was composed by Charolais, Caracu, Aberdeen Angus, and Canchim purebred and crossbred animals. Single-trait analyses were performed using models that included the maternal effect for WW and YW traits, and a model ignoring this effect on YW (YWNM). The Deviance Information Criterion (DIC), model posterior probabilities (MPP), accuracy of breeding values (ACC), and Spearman’s rank correlation were applied to compare the models including and ignoring the maternal effect on YW. Sex and age of dam at calving had significant effects on WW and YW. The direct heritability estimates were 0.21±0.03 and 0.05±0.02, and the maternal heritabilities were 0.11±0.02 and 0.02±0.01 for WW and YW, respectively. The heritabilities estimated for YW may have been influenced by the several genetic groups in the population and by used conventional animal model, which may not have been the better fit model to evaluate YW in this population. The DIC, MPP, and ACC values indicated that YW outperformed the YWNM model, but the rank correlation and percentages of individuals selected in common suggested that the best animals would be selected independently of the model chosen.
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    Genetic characterization of egg weight, egg production and age at first egg in quails
    (Revista Brasileira de Zootecnia, 2010-08-06) Hidalgo, André Marubayashi; Martins, Elias Nunes; Santos, Alexandre Leseur dos; Quadros, Thays Cristina Oliveira de; Ton, Ana Paula Silva; Teixeira, Rafael
    The objective of this research was to estimate genetic parameters for the traits egg weight, egg production in 189 days and age at first egg in three laying quails and one meat line of quails. Data was analyzed by Bayesian procedures using Gibbs sampling. The heritability estimates for egg weight, egg production in 189 days and age at first egg, were, respectively, for yellow line, 0.31, 0.84 and 0.53; for blue line, 0.14, 0.82 and 0.60; for red line, 0.70, 0.96 and 0.75; and for meat line, 0.73, 0.96 and 0.72. Genetic correlation between egg weight and egg production in 189 days, egg weight and day at first egg and egg production in 189 days and day at first egg were for yellow line, 0.58, -0.77 and -0.90; for blue line, 0.09, -0.01 and -0.95; for red line, 0.09, 0.03 and -0.76 and for meat line, -0.18, 0.19 and -0.91, respectively. Based on the probabilities of posterior parameter distribution overlap, the lines are divided in two different groups: one group with the yellow and blue lines and another with the red and meat lines.