Tolerância ao calor de caprinos e ovinos em regiões tropicais

An integrative study was conducted to analyze heat tolerance in sheep and goats raised in tropical regions, particularly in the Brazilian semiarid. Data from 537 animals, including 280 sheep and 257 goats, were compiled from 20 scientific studies carried out during morning and afternoon periods. The studies used the Black Globe Temperature and Humidity Index (BGHI) as an environmental indicator and rectal temperature (RT) and respiratory rate (RR) as physiological responses to heat stress. Heat tolerance was assessed using the Heat Tolerance Coefficient (HTC), calculated from the mean physiological variables. Mean BGHI values were 76 in the morning and 82 in the afternoon. Statistical analysis revealed a significant effect of species and period of the day on HTC, with goats showing lower values than sheep, indicating greater heat tolerance. Higher physiological stress was observed during the afternoon for both species. It is concluded that both goats and sheep from different genetic groups exhibit high tolerance to semiarid climatic conditions; however, sheep are less tolerant to heat, reinforcing the need for differentiated management strategies, especially during periods of higher thermal load. Keywords: Bioclimatology; Heat stress; Small ruminants; Brazilian semiarid region; Heat tolerance.