Novos modelos de curvas de crescimento para bovinos de corte

Abstract

The use of mathematical models to study the growth curves of cattle is a practice which may assist in choosing the best method of exploitation and, therefore, contribute to increase the producer's profit. The most widely used mathematical models are the nonlinear functions which enable us to synthesize the growth curve in a small set of parameters that enhance relevant features of animal growth. Among the nonlinear models most commonly used for this purpose, we find those from are Richards, Gompertz, von Bertalanffy, logistic and segmented, of the spline type and of response plateau. New models are being proposed mainly due to the demand from producers who desire a better characterization of the growth curves because of the strong competitiveness of beef cattle market. Thus, the objective of this dissertation is to propose a new nonlinear model and a Von Bertalanffy model with response plateau. The new models are adjusted to growth data of beef cattle of the Nelore breed and compared to the classic nonlinear and response plateau models, cited in literature. The results show that the new models are suitable to relate weight and age of beef cattle of the Nelore breed by means of parameters which are biologically interpretable.