Turning a cow into a goat with a teleonomic model of lifetime performance

Abstract

Predicting nutrient partitioning throughout lifespan is a major issue in modelling dairy female performance. A general framework has been proposed for dairy cattle. The key concept of this framework is to consider lifetime performance as a trajectory, goal directed towards reproductive success, genetically scaled and potentially altered by environment. The framework is based on two sub-models, namely a regulating model describing a time base pattern of priority for physiological functions and an operating sub-model driving energy partitioning. The objective of this work is to assess the suitability of the model to represent dairy goat lifetime performance. Eight parameters were modified to ‘turn a cow into a goat’: two parameters were related to foetal growth, three parameters were related to reproductive events timing, two parameters related to the scaling of body weight at maturity and milk potential and a parameter related to labile body mass mobilization. Individual records of the INRA experimental herd were used to assess the model suitability to simulate dairy goat performance. The result shows that the simulated body weight and milk production dynamics over three lactations were globally consistent with the data. Hence, adapting eight parameters from the dairy cow model was sufficient to simulate the performance of a dairy goat. This work opens perspective for the development of a generic animal model.