Physiological and biochemical blood parameters of Even breed domestic reindeer during early postnatal ontogenesis

The relevance of this study is due to the fact that, despite numerous studies on the type and composition of feed consumed by reindeer throughout the year, seasonally changing blood biochemical parameters, which serve as markers of calf growth potential, remain insufficiently studied. This article presents the results of physiological and biochemical studies of the blood of Even domestic reindeer during early postnatal ontogenesis, depending on the season, with a particular emphasis on age. The biochemical parameters of blood, such as alkaline phosphatase and creatine phosphokinase activity in serum, thyroxine, calcium and inorganic phosphorus content and glucose level were assessed dynamically, starting from the first day after birth (1 day, 6 days, 1, 4, 7, 10 months); the number of calves in each age group was 10 heads. The established (p<0.01 ) correlation relationships between the activities of alkaline phosphatase (r = -0.81) and creatine phosphokinase (r = -0.67) in the blood and the age of the calves are associated with the intensive growth of bone tissue in young animals, when there is a high need for inorganic phosphates, as well as the growth and development of muscle and nervous tissues rich in creatine phosphokinase. Thyroxine (T4) levels in reindeer blood are highest during the neonatal phase, which is due to the body’s adaptation to a new rhythm of functioning, accompanied by stress on endocrine regulatory mechanisms during the first months of life. It has been established that heliogeophysical environmental factors significantly influence both the level of enzymatic activity and the level of inorganic phosphorus in the animals’ blood. The identified seasonal and age-related variations in the physiological and biochemical parameters of blood of Even reindeer, combined with the authors’ existing data, may serve as markers of calf growth potential and characterize the animals’ metabolic profile.