Index of thermal stress for cows (ITSC) under high solar radiation in tropical environments.

This paper presents a new thermal stress index for dairy cows in inter-tropical regions, with special mention to the semi-arid ones. Holstein cows were measured for rectal temperature (T R), respiratory rate (F R) and rates of heat exchange by convection (C), radiation (R), skin surface evaporation (E S) and respiratory evaporation (E R) in the north eastern region of Brazil, after exposure to sun for several hours. Average environmental measurements during the observations were air temperature (T A) 32.