Antiaggregation vascular wall control of the major blood cells in calves during the phase of milk feeding

Blood cell aggregation is known to influence significantly a blood rheology in animals, particularly in cattle, during each period of ontogenesis, of which the milk feeding is important for development of a number of physiological mechanisms, including effective vascular control of gemostasis. Here we report the results of studying effect of vascular walls to blood cell aggregation in 39 Black-and-White calves. Blood samples were analyzed in 11, 15, 20 25 and 30 day old animals. A lipid peroxidation was estimated based on thiobarbiturate concentration (TB), the parameters of antioxidation activity in blood plasma were assessed, and antiaggregation properties of the blood vessels were investigated in the test of vein occlusion. Erythrocyte aggregations, free erythrocytes and the number of erythrocytes per aggregation were counted. Also the formation of platelet and neutrophil aggregations was considered. There were calculated the indexes of vascular control of erythrocyte number per aggregation, aggregation number, and free erythrocyte number. Also the antiaggregation activity of blood vessel wall and an inhibition of neutrophil aggregation by vascular wall were indexed. During investigation the lipid peroxidation in calves’ blood plasma was low, the acyl hydro-peroxide level varied from 1.44±0.17 to 1.47±0.25 D 233/ml, and the concentration of TB-active compounds changed from 3.59±0.15 to 3.64±0.28 mmol/l, with an antioxidation activity changed slightly too. An increase was shown of blood cell aggregating coupled with a gradually growing antiaggregation effect of vascular wall due to activated N-oxide and prostacyclin production in the endothelium. A balance of observed pro- and antiaggregation activity provides optimal rheological blood parameters in milk-fed calves resulting in adaptation to the environmental factors.