The climate and its implications for milk production in the Brazilian cerrado

Objective. To analyze the climate in the last thirty years in the Northwest of Minas and its impacts on dairy production. Materials and Methods. The database of the National Institute of Meteorology was used during the period from 1985 to 2017 in the cities of Unaí, Paracatu, Arinos and Formoso/MG. For each month and year, the average minimum temperature (Tmin), maximum temperature (Tmax), relative humidity (RH), Temperature and Humidity Index (THI), Wet-bulbe Globe Temperature Index (WBGT), estimate of the decrease in milk production (DMP) and DMP on critical days (DMPc) were calculated. Results. The results were evaluated using the lm function of R, and the t test to test the null hypothesis that the regression coefficient was equal to zero with a significance level of 5%. An increase in Tmax and Tmim values by 0.6-0.9°C respectively was observed. The THI and WBGT values in the municipalities show states of danger and emergency. The DMP obtained were 2.8 kg cow-1 day-1 (Paracatu and Formoso), 3.2 kg cow-1 day-1 in Unaí and between 3.7 and 4.6 kg cow-1 day-1 in Arinos. Conclusions. It is verified that the thermal condition in the studied cities is outside the considered thermoneutral zone, being necessary primary and secondary environmental modifications to guarantee the welfare of the animals and satisfactory livestock indexes.