Índice de temperatura e umidade aplicado à vacas leiteiras no noroeste do Rio Grande do Sul

Abstract

The present work aims to demonstrate how temperatures, both high and low, have an influence on milk production. The dairy cattle exposed to the sun's rays during the strong summer, suffers from thermal stress causing its food and production to be negatively affected. Data for analysis were collected in summer and winter, in the morning (6 hours) and in the afternoon (15 hours), during 11 days in the months when the seasons will be more intense. In the winter, the lowest value of THI was obtained (37.1) and in the summer the highest value (92.34), showing the worst situation of comfort for the cows, in which the milk productivity was 36428 liters in the month of July and 30095 in the month of January, a reduction of around 18.4% in relation to winter and summer. It was concluded, therefore, that high values of UTI (above 75) provided conditions of stress and decreased milk production. Keywords: Thermal comfort, production, Milking.