Modelling beef cattle growth : models evolution and applications

Abstract

Mathematical models play nowadays an important role in research in biology. In the field of animal production, for instance beef cattle growth, many models have been elaborated. Their degree of complexity and their level of integration of knowledge on mechanisms vary according to the objectives they are assigned. Considering biological processes on a fine scale, leading to a low aggregation level of the model, which may generate uncertainty in the value of the parameters, hamper the future applications of a model.

This paper first deals with a classification and a description of the different types of beef cattle growth models. A dynamic and mechanistic model we have developed is then described. This model attempts to be simple enough in order to be used for the prediction of animal growth as a response to feeding, yet integrating a mathematical formalization of biological processes. Results from this model have been tested against experimental data on Salers heifers. This comparison shows globally a good agreement between simulated and observed data. However, for some variables, like lipids and adipose tissues, the model needs to be improved, for instance in the formalization of our knowledge. The integration of such models in feed allowances tools is also discussed.