Thermoregulation and performance of Sind and Guzera young bulls in 'Agreste' region of Paraiba State

The objective of this study was to evaluate the bioclimatic indices that influence physiological variables, performance and nutrient intake by Gir and Guzera young bulls. The work was conducted at the Experimental Station of Alagoinha/EMEPA-PB in Alagoinha town in 'Agreste' region of Paraiba state, Brazil, using 16 young bulls of Sind and Guzera breeds (8 animals of each breed), with a mean 31.5 +/- 1.5 months of age, kept under confined conditions. The statistical design used was randomized blocks with eight replications in split plot with breed in the main plot and time (6, 12 and 16 h) as subplots. Rectal temperature, respiratory rate and surface temperature of the animals remained within the normal range for the bovine species. There was no negative influence on food intake and the animals had weight gain higher than expected, demonstrating that they are adapted to the conditions of northeastern Brazil, since there were no changes in their physiological parameters considered within the normal range and still showed excellent growth performance and nutrient intake.