Physiological and Metabolic Responses to Water Restriction in Ewes Under Semi-Arid Conditions

The aim of this study was to evaluate the effect of different water restrictions on the thermoregulation and blood hematological and metabolite parameters of crossbred Santa Inês ewes in a semi-arid climate. Thirty-two ewes were subjected to four water supply levels (100%, 80%, 60%, and 40%), in a completely randomized design with eight replications. The confinement period lasted 77 days, with 14 days allocated for adaptation. Respiratory rate, heart rate, and rectal temperature exhibited a quadratic response. There was an increase in red blood cells and urea. The enzyme alanine aminotransferase decreased linearly with water restriction. Urinary creatinine decreased along with water supply. Regarding urine color characteristics, all groups showed different colors, ranging from clear to cloudy. For the chemical characteristics of urine, a quadratic effect was observed for pH, with the highest value (8.75) at 60%. An increase was observed in total urine proteins and urobilinogen. Crossbred Santa Inês ewes in a semi-arid climate exhibit physiological adaptations to water supply reduction up to 40%. Following an 80% reduction in water supply, animals exhibit mild dehydration, characterized by increased serum urea levels and decreased alanine aminotransferase activity.