Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in

  1. Vol. 87 No. 2, p. 496-506
     
    Received: Jan 03, 2008
    Published: December 5, 2014


    2 Corresponding author(s): lgalb@fcav.unesp.br
 View
 Download
 Share

doi:10.2527/jas.2008-0845

Comparison of different nonlinear functions to describe Nelore cattle growth1

  1. S. Forni*,
  2. M. Piles,
  3. A. Blasco,
  4. L. Varona§,
  5. H. N. Oliveira#,
  6. R. B. Lôbo|| and
  7. L. G. Albuquerque*2
  1. Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista “Julio de Mesquita Filho,” Jaboticabal, São Paulo, 14884900, Brazil;
    Institute of Agro-Food Research and Technology, Unidad de Cunicultura, Caldes de Montbui, 68140, Spain;
    Departamento de Ciencia Animal, Universidad Politécnica de Valencia, 46071, Spain;
    Centre University of Lleida-Institute of Agro-Food Research and Technology, Lleida, 25198, Spain;
    Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista “Julio de Mesquita Filho,” Botucatu, São Paulo, 18618000, Brazil; and
    Faculdade de Medicina, University of São Paulo, Ribeirão Preto, São Paulo, 14049900, Brazil

Abstract

This work aims to compare different nonlinear functions for describing the growth curves of Nelore females. The growth curve parameters, their (co)variance components, and environmental and genetic effects were estimated jointly through a Bayesian hierarchical model. In the first stage of the hierarchy, 4 nonlinear functions were compared: Brody, Von Bertalanffy, Gompertz, and logistic. The analyses were carried out using 3 different data sets to check goodness of fit while having animals with few records. Three different assumptions about SD of fitting errors were considered: constancy throughout the trajectory, linear increasing until 3 yr of age and constancy thereafter, and variation following the nonlinear function applied in the first stage of the hierarchy. Comparisons of the overall goodness of fit were based on Akaike information criterion, the Bayesian information criterion, and the deviance information criterion. Goodness of fit at different points of the growth curve was compared applying the Gelfand’s check function. The posterior means of adult BW ranged from 531.78 to 586.89 kg. Greater estimates of adult BW were observed when the fitting error variance was considered constant along the trajectory. The models were not suitable to describe the SD of fitting errors at the beginning of the growth curve. All functions provided less accurate predictions at the beginning of growth, and predictions were more accurate after 48 mo of age. The prediction of adult BW using nonlinear functions can be accurate when growth curve parameters and their (co)variance components are estimated jointly. The hierarchical model used in the present study can be applied to the prediction of mature BW in herds in which a portion of the animals are culled before adult age. Gompertz, Von Bertalanffy, and Brody functions were adequate to establish mean growth patterns and to predict the adult BW of Nelore females. The Brody model was more accurate in predicting the birth weight of these animals and presented the best overall goodness of fit.

Copyright © 2009. Copyright 2009 Journal of Animal Science