Physiologic parameters of the Dorper and Santa Ines sheep and their cross submitted to the climatic conditions of the tropic semi-arid northeasterner

The goal of this work was to evaluate physiological parameters (respiratory and cardiac frequencies, rumen movement and rectal temperature) in Dorper, Santa Ines and Dorper x Santa Ines crossbreed (F1) sheep submitted to typical weather conditions (tropic semi-arid) of Brazilian northwest. Were used 48 sheep, 16 animals from each of the three genetic groups (Dorper, Santa Ines and crossbreed), among them 8 were male and 8 were female. The experimental design was completely randomized in a 3 x 2 x 2 factorial scheme (3 genetic groups, 2 genders and 2 collecting shift). From the three variations sources considered, gender, genotype and shift, the last had a significant (P<0.05) effect on all physiological parameters evaluated without interaction with gender (P<0.05) in relation to respiratory and cardiac frequencies. It was concluded that the shift was the factor that had the higher influence on the sheep's answer to temperature environment, independently of genotype and gender. Evening shift conducted animals to a dangerous situation, in terms of thermal uncomfortable and heat stress. Considering the cardiac frequency of F1 males and Doper female and the respiratory frequency of Dorper males and females and of F1 males, they were more stressed. It demonstrated the reduced capacity of the exotic genotype and their crossbreed for adaptation.