Respostas fisiológicas e hematológicas de ovinos Soinga e Santa Inês sob estresse térmico

This study aimed to evaluate the adaptive capacity of Soinga and Santa Inês genotypes under different diets and thermal environments, using physiological and hematological parameters. Lambs were fed diets based on sorghum silage and concentrate (50:50 and 70:30 ratios). Environmental variables such as ambient temperature, relative humidity, and black globe temperature were recorded, and the black globe humidity index was calculated. Rectal temperature (RT), surface temperature (ST), respiratory rate (RR), blood glucose levels, and hematological parameters were assessed. Measurements were taken at 1:00 p.m. (pre-stress) and 3:00 p.m. (post-stress) every 15 days. A completely randomized factorial design was used. Environmental conditions exceeded ideal thresholds for sheep. There was a significant interaction between genotypes and environment for RT andST, with Santa Inês showing higher RT and ST under the 3:00 p.m. heat stress (P<0.05). Soinga had lower mean ST, RT, RR, and glucose levels, indicating better thermal stress adaptation. The 50:50 diet resulted in higher glycemia (P<0.05). Total plasma protein (TPP) levels varied by genotype, diet, and time. Santa Inês showed higher TPP and leukocyte levels (P<0.05). Significant differences were found in erythrocyte and leukocyte counts among evaluated factors. Soinga genotype showed greater adaptability tosemi-arid conditions, maintaining most physiological parameters within normal ranges, except for RR, which was elevated across all groups.