Effects of Climate Variations on the Mechanisms of Thermoregulation in Sheep in the Southern State of Piauí, Brazil

The sheep breeds commercially exploited in northeastern Brazil are mostly hardy, but even being considered adapted animals, they suffer physiologically to the climatic conditions of this region. The objective of this study was to evaluate the variation of physiological parameters of animals and correlate them with meteorological data on different shifts and periods of the year. The design was DBC with 10 sheep, five Santa Inês and Morada Nova five. Data were collected in the dry and rainy season every three days , being measured in animals- respiratory frequency (RF), rectal temperature (RT), heart frequency (HF) and rate of sweating (RS) and at the same time were recorded environmental variables- air temperature (AT) and humidity (HA) was calculated index Globe Temperature and Humidity (IGTH). The AT showed a range of 10.48 ºC, with superiority in the dry season, the HA and the IGTH show significant difference (P < 0.05) between periods, since the RR showed a significant difference for the shifts of the period. The HF also significantly different for the two periods and the two rounds of each period. However it was found that in the late shifts of the two periods studied sheep suffered heat stress.