Age dynamics of morphological parameters of blood in mares of Hanoverian breed in the conditions of the North-West Region of the Russian Federation

The Hanoverian breed is one of the promising breeds of sport horse breeding. A quick and accurate assessment of the condition of the body of a sport horse is one of the factors for the success of its sport career. In this study, we conducted a clinical blood analysis of mares of different ages of the Hanoverian breed. This allowed us to expand the database for interpreting the results of laboratory tests of the blood of horses of the Hanoverian breed. Many authors note the importance of timely detection and elimination of metabolic disorders in horses and suggest using morphological parameters of blood to assess the functional state of their body. The interpretation of laboratory test results is carried out taking into account a variety of data, including age. The literature contains data on age-related changes in the blood of different animal species, different horse breeds, including the Hanoverian, as well as horses with different physical loads. The obtained information about the gerontology of Hanoverian mares kept in the Northwestern Federal District, namely the Leningrad Region, whose soils are poor in iodine, allows us to increase the accuracy of interpreting the results of laboratory studies, which makes our work relevant. Evolutionarily acquired adaptation mechanisms allow us to adapt to the natural and climatic conditions of the place of keeping. In view of this, there are studies of the blood of horses of aboriginal breeds There are not so many current data on the ecological and physiological adaptation of the Hanoverian breed today. Although the breed is one of the most promising in sports horse breeding according to the results of the Olympic Games of the 21st century. A more detailed study of its physiology is also a topical issue. Therefore, the aim of the study was to study age-related changes in the morphological parameters of the blood of Hanoverian mares in the Northwestern Federal District of the Russian Federation. The study was conducted on the basis of a stud farm in the Tosnensky District of the Leningrad Region, specializing in breeding Hanoverian horses. The horses are kept in a stable, receive the same diet in the form of dry fodder (harvested in the fields near the stable) and fresh grass, and walk on the pasture for 8-9 hours daily. For the study, 20 clinically healthy mares were selected, which were divided into 4 age groups of 5 horses each. Blood was collected in the summer 2 hours after the walk, an hour before feeding, taking into account the rules of asepsis and antisepsis in vacuum tubes for hematology with K3EDTA. The following parameters were determined in each sample: ESR (using Panchenkov pipettes), hemoglobin concentration (hemoglobin cyanide method using acetone cyanohydrin), the concentration of erythrocytes and leukocytes was counted using a counting chamber with a Goryaev grid. When analyzing the data obtained, it was found that the average erythrocyte sedimentation rate and the number of leukocytes exceed the upper limits of the reference values. A significant increase in the ESR level was found in the group of animals aged 16 years and older (p<0,05). The concentration of erythrocytes was significantly higher in the group of horses aged 2-4 years (p><0,05). The concentration of leukocytes in the group of horses aged 16 years and older was significantly (p><0,05) lower compared to the average value. Key words: blood morphology, horses, mares, age, Hanoverian horse, leukogram>˂0,05). The concentration of erythrocytes was significantly higher in the group of horses aged 2-4 years (p˂0,05). The concentration of leukocytes in the group of horses aged 16 years and older was significantly (p˂0,05) lower compared to the average value.