Estimativa da produção leiteira e consumo de alimentos de vacas a partir da ocorrência de ondas de calor no Triângulo Mineiro e Alto Paranaíba, MG

Abstract

Thus this research has as objective to evaluate the effects of heat waves in the Triangle Mineiro and Alto Paranaíba - MG on milk production and feed intake and map this influence through a bioclimatical zoning based on temperature and humidity index (THI) medium. Therefore it was determined the THI frequency of occurrence above the critical level determined in THI ≥ 81. The concept of heat waves used was proposed by period of more than three consecutive days of maximum temperature equal to or greater than 32°C. Nine weather stations was analyzed to represent the Triângulo Mineiro and Alto Paranaíba, having at least one representing each micrometeorological station. A historical of heat wave occurrence was developed based on climatic data in an interval of four to eleven years was made in the database of the National Institute of Meteorology (INMET) with dry bulb temperature data and relative humidity at three times of day (09:00, 15:00, 21:00). Also simulated to quantify the decline in milk production (DMP) and decline in feed intake (DFI) in cities that have been identified heat wave periods. The results showed that the cities of Ituiutaba and Frutal were those with the largest number of flashes per year and have the cities of Patrocínio, Araxá and Sacramento, did not present heat waves during the study period. By simulating DMP and DFI and bioclimatic differences were found between the cities of Uberaba, Ituiutaba and Frutal, the first with the lowest estimates of production losses. The best cities for the creation of specialized breeds in milk production are Sacramento, Patrocínio, as presented THI out of hazard, THI night below 76 and did not have heat waves. The study of the occurrence of heat waves more effectively shows the effect of heat stress on milk production, which can hardly be seen in the study of the occurrence of THI average.