Interaction between spatial and temporal instabilities of rainfall on milk production in the Brazilian semi-arid region

Abstract

The overall objective of the research was to evaluate the synergy between annual rainfall and the defining variables of milk production in the twenty largest producing municipalities in Ceará between the years 1973 and 20209. The research used annual rainfall data taken from the Ceara Meteorology and Water Resources Foundation (FUNCEME) as well as from the IBGE's Municipal Livestock Surveys (PPM) during the investigated period. The rainfall of the municipalities was organized into drought, normal and rainy periods, observing statistical criteria: average and standard deviation. It was used the coefficient of variation (CV) to measure the instabilities of the variables. It was created the instability index (INST) to capture the synergy between the annual precipitation of the municipalities with the number of lactating cows, the daily productivity of milk per cow and the average price of milk received by producers, in each municipality. To construct the INST, it was used the Factor Analysis, with the technique of decomposition in principal components. The results confirmed the high temporal instabilities of rainfall in the municipalities that were also observed in the defining variables of milk production in the studied municipalities. It can also be inferred from the results that, in all municipalities, the estimated INST for the rainy periods were always higher than those observed in the other periods (drought and normal), which confirms the great importance of rainfall for gauge good economic results in milk production in Ceara. The estimated INST confirmed the assumptions that guided the conduct of this research, that there is significant synergy between rainfall, the number of lactating cows, daily productivity and the price of milk received by farmers, in the largest milk producing municipalities in Ceara between the years 1973 and 2020.