Air temperature and humidity index for regionalization of dairy farming in Uruguay

Abstract

The aim of this study was to characterize the thermal environment of summer in Uruguay and to identify the meteorological conditions that can potentially cause heat stress on dairy cattle. We used an index including two meteorological variables: Temperature and Humidity Index (THI) to asses the frequency and duration of critical values. We worked with hourly, daily, and monthly data obtained from ten permanent meteorological stations distributed around the country. Average values above the critical level during January were found for the areas north of the Río Negro. In January, for six localities north of the Río Negro, we calculated probabilities of THI values above the critical level greater than 50 % in general and above 80 % for Salto and Artigas. The average daily duration of above critical values was greater than 10 h for the diurnal phase and 4 h for the nocturnal phase during January for those two localities.