Babesiosis is a common disease in dogs. Babesia canis (Piana & Galli-Valerio, 1895) (Sporozoa, Babesiidae) causes the destruction of erythrocytes, resulting in hypotensive shock and total tissue damage due to lack of oxygen. Because of babesiosis, anemia develops in dogs, and in the first hours of the disease it is normocytic, normochromic and nonregenerative, and on the 2–3rd day of the course, macrocytic, hypochromic anemia with reticulocytosis develops. Scientists have studied the most common indicators of evaluation of erythrocytopoesis during babesiosis (the number of red blood cells, hemoglobin, hematocrit index, indices of “red” blood MCH and MCV), but the age structure of erythrocytes, their acid resistance and the ferrum-transferrin complex for this parasitic pathology have not been sufficiently studied. We carried out research on dogs of service breeds, which were divided into two groups: the first (6–18 months old, n = 10) and the second (2–8 years, n = 15). According to the conducted studies, in dogs of different age groups with babesiosis revealed oligocythemia with anisocytosis and poikilocytosis, oligochromia, decreased hematocrit index and macrocytosis. Significant changes in the morpho-functional state of erythrocytes in dogs of both groups have been revealed, in particular, changes in the population (age) composition of red blood cells: the number of “old” erythrocytes increases (they are rapidly destroyed), the “young” forms of red blood cells decrease and the time for their hemolysis is reduced. As a result of the study of the ferrum-transferrin complex in dogs with babesiosis in both groups, an increase in the level of free ferrum (UIBC) and a decrease in the saturation of transferrin with the trace element was found, which makes it impossible to form a hemoglobin molecule in the bone marrow.

Regular physical exercise improves the cardiovascular system function, increases energy metabolism and antioxidant protection, provides greater muscle strength and physical endurance. However, exhaustive physical exercise can cause oxidative stress. During intense physical exercise, erythrocytes become more vulnerable to oxidative damage due to action of active oxygen forms, high concentration of polyunsaturated fatty acids. Physical loading of horses is accompanied by the development of tissue hypoxia, so one needs to study in detail changes of hematopoiesis indices, responsible for providing oxygen to tissues. When monitoring animal health, blood tests will detect a disease in early stages, because blood is a sensitive indicator of metabolic disorders, both of physiological and pathological body conditions. The purpose of present study was to examine changes of some hematopoiesis indicators (RBC, Hb, HCT, MCV, MCH), acid resistance of erythrocytesand population structure in trotting horses due to workloads of 1,600 m trot races (at rest, after race, after 90 min). In total, 20 clinically healthy horses of Orlovska and Russian trotting breeds, aged 2–3 years, were used in the study. The experimental animals included 5 mares, 15 stallions. All horses had active training. The horses were divided into two groups. The first animal group included animals that showed high results (2 min 04 s – 2 min 21 s); the second had trotters that covered the distance with worse time (2 min 28 s – 2 min 41 s). The erythrocyte couint in the leader horses after the loading increased, in the outsider horses it fell. After rest the leader horses’ erythrocytes returned to their original values, in the outsider horses they did not change. The outsider horses’ hemoglobin level after loading was lower than in the leader horses. The leader horses had higher hemoglobin content after rest (by 11.0% as compared with the values before the loading). The outsider horses had lower hemoglobin content. The leader horses hematocrit value increased, in the outsider horses ‒ decreased. The leader horses’ MCV after the loading was reduced, however after rest it recovered. The outsider horses showed MSV increase during the whole study period. The MCH in the leader horses did not change over the entire research period, in the outsider horses – it increased. The animals that showed better results, had an increasing number of “mature” and “old” erythrocytes due to their elimination from the depot. However, the outsider animals had an increasing number of “young” erythrocytes, resistant to hemolysis, but they were not able to provide tissues with needed oxygen.

Syndrome of anemia in foals manifests itself in the first weeks of their life, and occurs because of oxygen deficiency and excess of carbon dioxide after birth, and caused by a deficiency of trace minerals (iron, copper, cobalt, zinc, iodine, selenium), cyanocobalamin, and folic acid. For the experiment, we selected two groups of foals (age 20–30 days old) with pale conjunctiva. Animals of the experimental group were injected intramuscularly with Vitazal® 5 ml for 6 days. Foals of the control group received 6 ml of Ferrovet® intramuscularly, again after 10 days. The condition of erythrocytopoiesis was studied before drug administration and 30 days after treatment. It was found that 30 days after the administration of the drug in experimental group animals, the number of red blood cells increased by 31.4% (P < 0.001). In the control group, this indicator did not change significantly and did not differ from the values before the treatment. The hemoglobin content in experimental group foals after treatment significantly increased by 28.9% (P < 0,001). In contrast, 66.7% of animals in the control group showed oligochromemia. A similar trend of changes was noted in the determination of the hematocrit value. Changes were also found in the fractional composition of erythrocytes. In particular, after treatment in foals of both groups, the number of «old» erythrocytes decreased (P < 0.05). At the same time, the number of «mature» populations increased only in experimental group foals (P < 0.001). Regarding «young» erythrocyte populations, their number decreased in experimental animals by 8.3% (P < 0.001). However, in foals treated with Ferrovet® (control group), the proportion of «young» cells was increased after treatment, which apparently indicates the activation of proliferation and increased elimination of immature erythrocytes from the bone marrow. The iron content after the introduction of Vitazal® in foals of experimental group significantly increased by 45.6% and on average 26.8 ± 1.07 μmol/l (P < 0,01). In control animals after treatment, the content of this biometal did not change significantly. FTC values in the experimental group, namely TIBC and UIBC in 30 days after treatment significantly decreased (P < 0,001), while in foals of control group they remained unchanged. Iron metabolism directly depends on its transport form - transferrin protein. Throughout the study period, its content in control and experimental group animals was the same. However, the saturation of transferrin with iron in experimental group animals after the introduction of Vitazal® significantly increased by 19.8% and averaged 40.2 ± 1.26% (P < 0.001). In foals that received Ferrovet®, this indicator did not change 1 month after treatment. Thus, the study found a positive antianemic effect of the drug Vitazal® for anemic syndrome in foals.