Navegando por Autor "Oliveira, Sheila Nogueira de"

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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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    Multivariate analysis using morphometric and ultrasound information for selection of tilapia (Oreochromis niloticus) breeders
    (Brazilian Journal of Animal Science, 2019-03-14) Oliveira, Sheila Nogueira de; Ribeiro, Ricardo Pereira; Oliveira, Carlos Antonio Lopes deAngela Rocio; Lopera-Barrero, Nelson Mauricio; Aspilcueta Borquis, Rusbel Raul; Zardin, Aline Mayra da Silva Oliveira; Souza, Felipe Pinheiro de; Poveda-Parra, Angela Rocio
    This study evaluated morphometric and ultrasound information of tilapia (O. niloticus) breeders through multivariate analysis. We applied correlation, clustering, and principal component analysis to a dataset composed of information from 222 male and female breeders of the improved GIFT strain. The body weight, objective of the breeding program, showed a high positive correlation with most of the morphometric parameters. The formation of clusters indicated characteristics responsible for muscle composition and carcass weight. Some characteristics showed a high correlation, such as body weight and fillet weight (0.98 and 0.94 for females and males, respectively), and a high contribution to the explanation of data variability; of the total characteristics evaluated for females, two explained 75% data variability and four explained 72% for males. We concluded that it is possible to reduce the number of characteristics measured, as well as use information of average daily weight gain and body weight to select female and male breeders, respectively, to drive genetic gains favoring more productive generations