ANALYSIS OF THE DIFASICS GROWTH CURVE OF HEREFORD FEMALES BY THE GOMPERTZ NON-LINEAR FUNCTION

Authors

  • Patrícia Neves Mendes Universidade Federal de Lavras (UFLA), Lavras, Minas Gerais, Brasil
  • Joel Augusto Muniz Universidade Federal de Lavras (UFLA), Lavras, Minas Gerais, Brasil
  • Fabyano Fonseca e Silva Universidade Federal de Viçosa (UFV), Viçosa, Minas Gerais, Brasil
  • Ana Rita de Assumpção Mazzini Universidade Federal de Pelotas (UFPEL), Pelotas, Rio Grande do Sul, Brasil
  • Natascha Almeida Marques da Silva Universidade Federal de Lavras (UFLA), Lavras, Minas Gerais, Brasil

Keywords:

modelo não-linear, erros auto-regressivos, heterogeneidade de variâncias

Abstract

This study had the objective to compare weight difasics Gompertz models applied in the study of Hereford females growth curves and to modeling  the errors structure inherent to each model. The non-linear difasic Gompertz growth models were adjusted with three different errors structures: independent errors (IE), first-class auto-regressive (AR (1)) and second-class auto-regressive (AR (2)) to weight-age data of 55 Hereford females, evaluated since birth till 675 days old.  The comparison between the models was carried out through on the biological interpretation basis of the parameters and in the adjustment of quality appraisers (adjusted determination coefficient, Durbin-Watson test, residual standard desviation, iterations number), beyond the Akaike information criteria (AIC) and the F test to model comparison. All studied functions, although showed good data adjustment, tend to sub estimate the adult animal weight.

KEY WORDS: Auto-regressive errors, heterogenety of variances, non linear model.

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Published

2009-07-02

How to Cite

MENDES, P. N.; MUNIZ, J. A.; SILVA, F. F. e; MAZZINI, A. R. de A.; SILVA, N. A. M. da. ANALYSIS OF THE DIFASICS GROWTH CURVE OF HEREFORD FEMALES BY THE GOMPERTZ NON-LINEAR FUNCTION. Brazilian Animal Science/ Ciência Animal Brasileira, Goiânia, v. 10, n. 2, p. 454–461, 2009. Disponível em: https://revistas.ufg.br/vet/article/view/2249. Acesso em: 9 apr. 2025.

Issue

Vol. 10 No. 2 (2009)

Section

Animal Production

License

Copyright (c) 2009 Brazilian Animal Science/ Ciência Animal Brasileira

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