OLE! Dairy model: Description and evaluation of the biophysical components of a whole farm simulation model for pastoral-based dairy systems

The process of intensification of the dairy sector has been characterized in recent decades by the increase in milk production per hectare, the increase in livestock density, the inclusion of more concentrates in the diet, and the improvement of the genetic merit of dairy cows. The use of models has productive, environmental, and economic advantages. The objectives of the study were to describe a new model, “OLE! Dairy model”, to (a) simulate the biophysical performance of a pasture-based dairy production system; (b) evaluate the predictive capacity of the model with a set of statistical parameters, comparing its results with the biophysical performance of experimental studies of dairy farm systems, and (c) calibrate by adjusting the technical coefficient. The experimental design combines two feeding strategies with a different proportion of pasture in the diet and two animal genotypes. We make a description of the biophysical component and the calculations proposed in the “OLE! Dairy model”. Then a variety of parameters was calculated for model testing, including the Mean Squared Error, the Relative Prediction Error, the square root of the MSE, the Concordance Correlation Coefficient, and the Model Efficiency. The model presented a good predictive capacity for stocking rate and concentrate, pasture, and reserve intake. The predictive capacity of the model for individual production and area production improves after performing a rapid calibration, which allows for avoiding overestimations or underestimations that generate erroneous measurements in the planning and management of milk production systems, and can be adjusted to different conditions of production of the region. El proceso de intensificación del sector lechero se ha caracterizado en las últimas décadas por el aumento de la producción por hectárea, el aumento de la carga animal, la inclusión de más concentrados en la dieta y la mejora del mérito genético de las vacas. El uso de modelos tiene ventajas productivas, ambientales y económicas. Los objetivos del estudio fueron describir un nuevo modelo, “OLE! Modelo lechero”, para (a) simular el desempeño biofísico del sistema de producción lechero basado en pastos; (b) evaluar la capacidad predictiva del modelo con un conjunto de parámetros estadísticos, comparando sus resultados con el desempeño biofísico de un estudio experimental, y (c) calibrar ajustando el coeficiente técnico. El diseño experimental combina dos estrategias de alimentación con di