Funções splines para estudo de curvas de crescimento em ovinos cruzados

• Ano de defesa: 2011
• Autor(a) principal: Oliveira, Diana Campos de
• Orientador(a): Carneiro, Antônio Policarpo Souza
• Banca de defesa: Santos, Gérson Rodrigues dos , Nascimento, Carlos Souza do
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Estatística Aplicada e Biometria
• Departamento: Estatística Aplicada e Biometria
• País: BR
• Palavras-chave em Português: Modelo não-linear; Funções splines; Identidade de modelos e qualidade do ajuste
• Palavras-chave em Inglês: Non-linear model; Splines functions; Identy of models; Quality of fit
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::PROBABILIDADE E ESTATISTICA::ESTATISTICA
• Link de acesso: http://locus.ufv.br/handle/123456789/4035

This study aims to describe growth curves in crossed sheeps through spline regression, to compare the goodness of the spline regression adjustment using usual non-linear models and, then, to apply a test for identity of models in order to verify if the curves of the groups presented differences. It was used, in this work, animals weighings informations from the followings cutting sheeps genetical groups: Dorper x Morada Nova (DMN), Dorper x Rabo Largo (DRL), Dorper x Santa Inês (DSI). It was adjusted growth curves through von Bertalanffy, Richards and Brody nonlinear models; and through linear-linear, linear-plateau and linear-linear-linear spline functions for each genetical group. The spline functions and the nonlinear models were compared by the following quality of fit evaluators: AIC (Akaike Information Criterion), BIC (Bayesian Information Criterion), Adjusted Determination Coeffi cient (R2 aj). The spline functions presented better adjustment than the non-linear models, and the linear-plateau was the best one to describe the weight-age relation of the sheeps studied. According to tests of models identity, the genetical group DSI presented greater precocity and higher daily weight gain; then, this group was the most suitable for meat production.