Uso de simulação para estimar o consumo voluntário de ovinos em pastagens

Abstract

Modeling is a technique for using and applying models (conceptual, physical or mathematical) to describe a system. It permits or make feasible predict, simulate and estimate behaviors that would be difficult to measure or that would take considerable time for its determination in a real system.The objective of this research was to compare models of sheep voluntary intake and show using it would be more representativeon a pasture based animal production system and use it on farm planning. For this, a database was set up consisting of articles, dissertations and theses with information on the characteristics of the animals (live weight, reference weight of an adult animal, average daily gain and consumption) and pastures (pre and post feed mass - pasture, forage supply, accumulation and rate of accumulation). Mathematical models chosen to estimate the sheep voluntary intake use live weight (kg) and weight gain of animals (kg / head / day) (model 1);besides this data, the model 2 also use the weight of adult animal as an a input variable. The model that made the best prediction of voluntary consumption was model 1, since there were no significant differences between this model and the database used on validation. After the choice of the model, a simulation was performed using (pre and post grazing mass, forage allowance, forage accumulation rate and pasture stocking rate) to determine the forage budget of the production system and which would be the best alternative with 3 different levels of forage allowance: 4%, 8% and 12%. Using this data, three different scenarios of production was simulated was build.The analysis of the model output in the three scenarios evaluated, indicated that the system with 12% of forage allowance has the highest gain per animal / day and the highest gross margin among the evaluated options.