Mercado de carnes. Aspectos descritivos e experiências com o uso de modelos de equilíbrio parcial e de espaço de estados

Abstract

This article presents some descriptive aspects of the world meat (beef, pork and poultry) market emphasizing the Brazilian participation. A partial equilibrium model for the meat market, derived from the Aglink model developed by OECD, is fit to Brazilian data. The consistence of Aglink is investigated in two contexts: the agreement between estimated and pre-specified values of elasticities and the agreement of the outlook or forecast of economic variables relative to observed and predicted values obtained via state space modeling. It is concluded from this analysis that sizable differences exist in both dimensions. There are relevant instances in which the observations do not support the specifications of the elasticities and the outlook proposed by OECD. In the long run, as more observations become available it is believed that time series methods such as state space modeling would be more expeditious for the purpose of ad hoc forecasts than partial equilibrium models. These should be adjusted better to the reality of the available observations through the use of more acceptable specifications of supply and demand elasticities. Only in this context partial equilibrium models become interesting from the point of view of assessing the effects of exogenous shocks and of specific sector policies.