GROWTH DESCRIPTION OF PURE AND CROSSBRED TURKEYS USING NON-LINEAR MODELS IN HOT AND HUMID TROPICAL ENVIRONMENT

Abstract

This study was conducted to compare three non-linear growth models (Logistics, Gompertz and Von Bertalanffy) in describing the growth of 360 turkeys of three genotypes (exotic, crossbred and local). The growth curve parameters - A, B and K for each growth model were estimated for each turkey using the NLIN procedure (Marquart algorithm) for the Bayesian approach with a fixed-effect model. The best fit of the three models was also estimated. A comparison was done among the three models using Akaike Information Criteria (AIC) and the Bayesian Information Criteria (BIC). Pearson product-moment correlation coefficient (r), the correlation coefficient, was used to examine the linear relationship between two quantities, A and K growth model parameters. For comparison of growth models parameter predicted, the Von Bertalanffy's model predicted the smallest value in both criteria for all the male and local female turkeys, while Gompertz's growth model had the smallest predicted value in both criteria for the female exotic and female crossbred turkeys. Based on the goodness of fit using the Bayesian Model Choice Criteria (Deviance Information Criteria), Von Bertalanffy's growth model showed the best fit. However, the difference between Bertalanffy's and Gompertz's growth models is very minimal, thus, making both models suitable for modeling the growth curve of domestic turkey and to consider how this weight is attained.