Previsões para a produção de leite sob instabilidade pluviométrica no Ceará no período de 1974 a 2019

Abstract

The livestock sector is strongly influenced by weather phenomena and rainfall instability becomes an obstacle to productive capacity, especially in municipalities belonging to the semiarid region. Producers plan and organize their production based on past experiences, and from these experiences, they create their expectations for the future. This work evaluated how exogenous variables (rainfall and prices) interfere in the forecasts of dairy farmers in Ceará in the period from 1974 to 2019. Projections are generated about the endogenous variables over which dairy farmers have decision-making power (herd and productivity). Although they do not have decision-making power over the average price, which is exogenously determined by the market, the study estimated the forms of projections for this variable as well. It was also estimated how rainfall likely affects the predictions of variables associated with milk production. The ARIMA method proposed by Box and Jenkins (1976) was used to capture the behavior of variables based on their historical series (1974-2019). The results confirmed the indirect impact of rainfall and prices on the endogenous decision variables. The trajectories of production expectations and projected values, as well as the statistical tests performed, indicated the robustness of the adjustments made in the survey.