Critical points on growth curves in autoregressive and mixed models

Adjusting autoregressive and mixed models to growth data fits discontinuous functions, which makes it difficult to determine critical points. In this study we propose a new approach to determine the critical stability point of cattle growth using a first-order autoregressive model and a mixed model...

Full description

Bibliographic Details
Main Authors: Sheila Zambello de Pinho, Lídia Raquel de Carvalho, Martha Maria Mischan, José Raimundo de Souza Passos
Format: Article
Language:English
Published: Universidade de São Paulo 2014-02-01
Series:Scientia Agricola
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162014000100004&lng=en&tlng=en
Description
Summary:Adjusting autoregressive and mixed models to growth data fits discontinuous functions, which makes it difficult to determine critical points. In this study we propose a new approach to determine the critical stability point of cattle growth using a first-order autoregressive model and a mixed model with random asymptote, using the deterministic portion of the models. Three functions were compared: logistic, Gompertz, and Richards. The Richards autoregressive model yielded the best fit, but the critical growth values were adjusted very early, and for this purpose the Gompertz model was more appropriate.
ISSN:1678-992X