Conforto térmico para búfalas em exposição durante feira agrícola no Nordeste do Brasil

Abstract

At agricultural fairs, it is common for animals to face accommodation conditions with limited thermal comfort, which can impact their ability to maintain homeothermy. Thus, the objective was to characterize and evaluate the effects of the thermal environment at an agricultural fair on the physiological parameters of dairy buffaloes. In this study, five Murrah breed buffaloes were housed in collective sheds with a north-south orientation, a 3.0-meter height, fiber-cement roofing, and a sand bed. The animals had free access to the feeder and were led to the watering trough three times a day during the LXVI Agricultural and Industrial Exhibition of Ceará (EXPOECE). Surface temperatures of the ocular, forehead, head, neck, trunk, and rump were obtained from these animals using a thermal imaging camera, along with their respiratory rates at 7 AM, 12 PM, and 6 PM. Additionally, the temperature and humidity index (THI; Thom, 1959) was calculated to assess environmental discomfort. The data were subjected to ANOVA at a 5% probability level. A higher air temperature was recorded at noon, being milder at 6 PM (32.9 vs. 27.9 °C; p<0.05), providing a thermally uncomfortable environment, especially at 12 PM (THI: 82.6). The animals showed a significant increase in respiratory rate at noon (27.5 breaths/min). Infrared thermography highlighted changes in the animals' body surface temperature throughout the day, with variations close to 1.5 °C (7 AM: 34.4 °C; 12 PM: 35.5 °C; 6 PM: 33.6 °C; p<0.05). Thus, it can be concluded that environmental parameters have a direct influence on the thermal comfort of animals, causing physiological changes in Murrah buffaloes, with increased respiratory rate and surface temperature during the hottest hours of the day.