Assimetria na transmissão de preços na cadeia produtiva do leite no estado de Goiás

Abstract

The general objective of this research is to analyze the presence of asymmetries in the transmission of prices (ATP) in the milk production chain in Goiás, from January 2005 to December 2020. The work is structured in 7 sections. Introduction aims to make a general introduction, demonstrating that only Goiás, among the biggest milk-producing states, has increased the number of rural establishments producing milk in recent years. Through this motivation, explanations for this phenomenon are sought, verifying, as the literature suggests, if there is a dominance of a specific agent, which affects the dynamics of price transmission and, consequently, the economic sustainability of the activity of other agents in the milk production chain in the state of Goiás. Thus, the thesis built is that the processing agent has preserved margins of milk producers in Goiás to allow the maintenance and increase of these producers in the dairy activity, not configuring, therefore, as a dominant agent in this production chain. Chapter 1 shows an overview of milk production globally and Brazil, focusing on the main producing states. Even though the objective of the thesis is to deal with the empirical models of ATP for Goiás, the discussion of this chapter is relevant considering that the production of milk in Goiás and its advances are not disconnected from other producing regions in technological and competitive terms. The purpose of Chapter 2 is to introduce the discussion of price transmission in agricultural markets in general. It seeks to analyze the theoretical framework on ATP, but without using a method or protocol to separate and analyze articles, carried out in the subsequent chapter. Chapter 3 is written in article format and aims to raise state of the art on price transmission in milk markets. To this end, a systematic literature review was carried out, from 2010 to 2020, on the Web of Science database. The results point to many publications on price transmission, especially in the last ten years, with research showing great interest in analyzing milk markets. It was noticed that the greater interest by the analyzed literature was in the investigation of the vertical transmission of prices and that agents downstream of the chain tend to exert market power more frequently over agents upstream. Chapter 4 is also written in article format and aims to analyze asymmetries in the linear transmission of prices in the milk production chain in Goiás. For this purpose, the traditional Houck and Asymmetric Vector Error Correction (Avec) models were estimated using a series of average milk prices at the producer and wholesale level for the state of Goiás, and at the retail level for the city of Goiânia-GO. The results suggest that the processing industry does not benefit from asymmetries in the transmission of prices to producers or retailers. It also indicates some level of organization among rural producers in Goiás, sufficient to gain bargaining power. Finally, it means that retailers benefit from ATP processes. However, traditional linear models may not capture relevant points of asymmetry in the data so non-linear models, present in the current literature, become appropriate. Therefore, Chapter 5, also written in article format, aims to analyze asymmetries with thresholds in the transmission of prices in the milk production chain in the state of Goiás for the same data set. Thereunto, the estimated models were Threshold Autoregressive (TAR), momentum-TAR (MTAR), consistent TAR (CTAR), consistent MTAR (CMTAR) and Asymmetric Error Correction Models with thresholds. In the results, asymmetries were captured only by the CTAR and CMTAR models, suggesting that Chan's method (1993) is relevant for this type of investigation. In the long run, on the one hand, wholesalers benefit from small negative changes in producer prices; on the other hand, a change in the wholesale price trajectory, towards a negative trend, is not quickly adjusted in producer prices, suggesting that the wholesaler agent does not exercise dominance in the chain. Among wholesalers and retailers, the results indicate that retailers benefit from the ATP in the short run, but with limitations given the magnitude and direction of the long-run equilibrium shocks. Finally, it is concluded that there is not enough evidence to characterize the presence of a dominant agent in the milk production chain in the state of Goiás. This characteristic allowed some bargaining power for farmers, allowing their maintenance in the activity and confirming the thesis initially raised