Using infrared thermography to measure the body surface temperature of crossbred cows and calves in the semi-arid region of Minas Gerais, Brazil

ABSTRACT

This study aimed to evaluate the body surfacetemperature of crossbreed cows and calves managed in thesemi-arid region of Minas Gerais (Brazil), using the infraredthermography technique. The thermal environment wascharacterized by daily collections of meteorological variablesand subsequent calculation of thermal indices. Body surfacetemperature (BST) was measured at 600, 1200 and 1600hours, at 1.0, 1.5, 2.0 and 4.0 meters distances from theanimals to measure the right and left flank temperature andcompare with the different information obtained in theliterature. The thermal environment was classified as anemergency from 1200. There was no significative differencebetween the distances studied, where the body surfacetemperature of cows and calves was 36.8 °C and 38.2 °C,respectively. There was significative interaction between thehours and the laterality of the body, where at 700 the BSTwas higher in the left flank due to the more intense ruminalactivity and at 1600 there was no difference in the BST, butin this period the higher BST values were observed due to thethermal environment. It is possible to obtain BST by means ofthermographic camera reliably up to a distance of 2.0 m. Thethermal environment elevates BST in the afternoon period, butthe adaptability of the animals obtained through heterosis doesnot expose them to the heat stress condition. The microclimateof the shaded environment and in full sun does not interferewith the calves' preference of accommodation.