Effects of seasonal ambient heat stress (spring vs. summer) on physiological and metabolic variables in hair sheep located in an arid region

• Published in: International journal of biometeorology Vol. 60; no. 8; pp. 1279 - 1286
• Main Authors: Macías-Cruz, U., López-Baca, M. A., Vicente, R., Mejía, A., Álvarez, F. D., Correa-Calderón, A., Meza-Herrera, C. A., Mellado, M., Guerra-Liera, J. E., Avendaño-Reyes, L.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-08-2016; Springer Nature B.V
• Subjects: Animal Physiology; Animals; Arid regions; Arid zones; Biological and Medical Physics; Biophysics; Blood; Blood Glucose - analysis; Body Temperature; Chlorine; Cholesterol; Cholesterol - blood; Climate; Data processing; Earth and Environmental Science; Electrolytes; Environment; Environmental Health; Female; Hair; Heat; Heat stress; Heat Stress Disorders - blood; Heat Stress Disorders - physiopathology; Heat Stress Disorders - veterinary; Heat tolerance; Hot Temperature - adverse effects; Humidity; Metabolism; Metabolites; Meteorology; Original Paper; Physiological effects; Physiology; Plant Physiology; Potassium; Potassium - blood; Respiratory Rate; Seasons; Sheep; Sheep - blood; Sheep - physiology; Skin; Spring; Stress, Physiological; Summer; Temperature effects; Time measurement; Triglycerides; Triglycerides - blood; Urea; Urea - blood; Wind; Circadian rhythms; Heat tolerance; Hair breed; Glucose; Body temperature
• ISSN: 0020-7128; 1432-1254
• DOI: 10.1007/s00484-015-1123-6

Twenty Dorper × Pelibuey primiparous ewes were used to evaluate effects of seasonal ambient heat stress (i.e., spring vs. summer) on physiological and metabolic responses under production conditions in an arid region. Ten ewes experiencing summer heat stress (i.e., temperature = 34.8 ± 4.6 °C; THI = 81.6 ± 3.2 units) and 10 under spring thermoneutral conditions (temperature = 24.2 ± 5.4 °C; THI = 68.0 ± 4.8 units) were corralled together to measure rectal temperature, respiratory frequency, and skin temperatures at 0600, 1200, 1800, and 2400 h on four occasions over 40 days. Blood metabolite and electrolyte concentrations were also measured at 0600 and 1800 hours. Data were analyzed with a completely randomized design using repeated measurements in time. Rectal and skin temperatures, as well as respiratory frequency, were higher (
P
 < 0.01) in summer than spring at all measured days. Blood serum glucose, cholesterol, triglycerides, and chlorine concentrations were lower (
P
 < 0.01) in summer than spring at 0800 and 1800 hours. In contrast, summer heat stress increased (
P
 < 0.01) blood urea and potassium concentrations at 0800 and 1800 hours. Compared with spring thermoneutral conditions, summer heat stress affected the physiological and metabolic status of hair breed ewes in an arid region, which included blood metabolite and electrolyte adjustments to efficiently cope with summer heat stress.