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.

Climatic variations directly affect the animals, changing their physiology. Several factors such as species, breed, sex, age, nutrition, diseases, physiological stage, and seasonal variations can affect the pattern of haematological values. Quantitative and morphological changes in blood cells are associated with higher temperatures and humidity. Sixty-seven sheep (3 years old, not pregnant, clinically healthy) were used in the study to determine the effect of the temperature-humidity index (THI) and breed on morphological blood indices and β-hydroxybutyrate (BHB). The sheep were divided into groups by the breed (4 breeds) and the THI (2 classes). The blood samples from each animal were collected monthly. Significant differences between the values of leukocytes (WBC), neutrophils (NEU), erythrocytes (RBC), haemoglobin (HGB), haematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), lymphocytes (LYM), monocytes (MON) and platelet count (PLT) in THI groups were observed. In THI 1, the mean values of MCHC (5.68%, P < 0.05), MCH (0.52%), and HCT (4.90%, P < 0.05) were higher compared to those in THI 2. Multivariate test showed a significant effect of breed on NEU ( P < 0.05), RBC ( P < 0.05), HGB ( P < 0.05) and MCHC ( P < 0.05). The concentration of BHB in group THI 2 was by 12.9% higher ( P < 0.05), compared to group THI 1. A significant effect of the breed ( P < 0.05) and THI class ( P < 0.05) on BHB was determined, whereas the impact of breed interaction with the THI was found to be non-significant. The observations reported in this study suggest that the response to temperature is dependent on animal breed. It was found that both morphological blood indices and BHB were affected by the temperature-humidity index.

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 greater than temperature-humidity index greater than 10 and 3) temperature-humidity index less than 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.

Background: Copper supplementation in ruminants deserves special attention because of the narrow margin between deficiency and toxicity. The aim of the study was to analyse the relationship between the Cu concentration and other blood parameter values having taken into consideration their physiological limits based on the variation of copper concentration in the three different sheep breeds. Methods: Sixty sheep (35±5 kg) kept on the same farm were studied: the Suffolk (n = 20), the Merino (n = 20) and the Lithuanian blackhead (n = 20). The sheep were selected according to the following parameters: 3.5±0.3 years old, not pregnant during the entire investigation period, clinically healthy. All sheep were kept under the same conditions and throughout the year, were fed at the same time the same ration balanced according to their physiological needs. Individual blood samples were collected on the same day, on monthly basis for the period of one year (April 2018 to May 2019). Blood biochemical parameters as well blood haematology and cortisol concentration were analysed.Result: The highest average value of copper concentration was found in the Merino breed. The study has shown that the lowest number of blood samples with the levels of copper meeting the physiological limit values was found in the native Lithuanian blackhead sheep at the end of the grazing period and in the Merino and the Suffolk breeds - during the coldest winter months. The increase in copper concentration could be related to the stress caused due to the changes in dietary conditions, the variations of ambient temperature and different breed response to these factors.