Infrared thermography as a potential non-invasive tool to study seasonal stress in late gestation Sahiwal cows and their neonate calves

Abstract

Stress triggers a multitude of physiological responses including alterations in surface temperature aimed at maintaining homeostasis of animal. The present study was undertaken to evaluate the comparative seasonal effect of thermal stress on body surface temperature during the critical period of late gestation and early life. For this, late gestational Sahiwal cows (n=48) were selected and categorized into four groups: natural heat stressed (NHS), cooling treated (CLT), spring and winter groups, and their neonate calves born in summer (IUHS-intra uterine heat stressed and IUCL-intra uterine cooled), spring and winter season. The thermal profile obtained from infrared thermography (IRT) showed a trend of surface temperature for each region examined over varied THI (temperature humidity index). Body surface temperature in NHS was significantly higher, followed by spring, CLT and least in winter group cows. Within the group, study revealed numerically high surface temperature of eye, front and udder on the day of parturition, while slightly lower temperature of flank portion. NHS, CLT and spring cows had non-significant variations in udder temperature. Insulation breakage from the legs at a colder temperature was observed. In neonates, significantly high surface temperature was observed in IUHS, followed by IUCL and spring calves, while significantly low surface temperature in winter calves. Thus, cooling treatment in the late gestation significantly lowered body surface temperature in both dams and calves. Further, it is also concluded that out of different anatomical regions, eye and feet temperature is the most reliable indicator for assessing seasonal stress with changing THI.