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Background: Climatic factors, such as high temperature, high relative humidity, can induce a thermal stress in animals. The phenomenon of mammalian sensitivity to thermal stress, especially in small ruminants, is widely reported in the literature. The present study aimed to analyze temperature and humidity effects on serum metabolic profile and cortisol concentration in sheep. Methods: The experiment was conducted on 40 adult, non-lactating and non-pregnant Suffolk sheep from December 2018 to December 2019. The subgroups were formed by age (two groups): twenty sheep were about 1.5 years old (Group 1) and other twenty - about 3 years old (Group 2). Based on the value of the temperature-humidity index, the following three subgroups were formed: 1) temperature humidity index ≥20; 2) 20> temperature-humidity index >10 and 3) temperature-humidity index <10. Blood cortisol concentration and biochemical parameters were measured once per month on the same day, in identical animals. Result: The analysis of biochemical parameters revealed that Group 2 showed significantly higher values for creatinine, phosphorus, zinc and cortisol. All blood indicators, except iron, phosphorus and total bilirubin, were dependent on THI concentration. The highest positive correlation coefficient of cortisol was calculated with urea and total protein. It is concluded that both cortisol and biochemical parameters play a significant role in thermal stress reactions in the Suffolk sheep. [ABSTRACT FROM AUTHOR]

Fédération Equestre Internationale (FEI) has described equine endurance racing as the second largest discipline in the world, above which is only show jumping. The Žemaitukai is an ancient indigenous Lithuanian horse breed known since the 6th or 7th century. The Arabian horse breed is one of the oldest human-developed horse breeds in the world. Compared with other race horse breeds, the muscle tissue of Arabian horses is characterized by significant differences in structure-a predominance of oxidative fiber type I is observed in Arabians, making them the prevailing breed in endurance racing. The Arabian horses are recognized as the leading breed in endurance competitions. Speed, pace, and total time in the race strategy have been extensively studied in human sports, and in contrast, this strategy appears to have been virtually ignored in equestrian sport, despite the potential for contributing to performance optimization. In relation to speed and total time in the race, there are limited data on postrace physical, biochemical, and blood gas parameters of endurance horses. Thus, this study was carried out to investigate the effects of speed on the blood parameters of the Arabian and Žemaitukai horses during an endurance race. Blood samples were taken before and immediately after the exercise. Biochemical and blood gas indicators were analyzed. The study showed significant increases in mean blood gasometrical indicators, such as partial carbon dioxide pressure (8.09-15.18%, p < 0.001); base excess in the extracellular fluid (14.01%, p < 0.001 in the Arabian horses and 172.01% in the Žemaitukai breed, p = 0.006); decreases of the blood electrolyte ionized calcium (4.38-8.72%, p < 0.001) and the hematocrit and hemoglobin values (20.05-20.12%, p < 0.001 in the Arabian horses and 6.22-6.23% in the Žemaitukai breed, p = 0.003-0.004); and decreases in the base excess in the blood values (29.24-39.38%, p < 0.001) and lactate (13.45-31.97%, p < 0.001) in the blood of both breeds in the post-competition horses. Significant increases after competition were determined for the values of creatinine (21.34-30.82%, p = 0.001-0.004), total bilirubin (50.84-56.24%, PH < 0.001), and albumin (2.63-4.48%, p = 0.048-0.001) for both breeds. For the faster Arabian horse breed, recovering after racing took half the time that the local Žemaitukai breed did.