Abstract
Platelet activity in cattle can change under the influence of many factors. Their assessment in the second phase of their early ontogenesis is of great interest, taking into account the breed of calves. The purpose of the work is to evaluate platelet activity in black-and-white breed dairy calves. The study was conducted on 41 calf of black-motley breed, which was obtained from healthy cows as a result of 2–3 pregnancies. The calves were examined on the 11th, 15th, 20th, 25th and 30th day of ontogenesis. The study used biochemical, hematological and statistical methods. In animals, an increase in platelet aggregation with all tested inductors was detected during the milk feeding phase. The number of discoid platelets in the blood of calves observed during the second phase of early ontogenesis decreased by 10.5 %. Moreover, the total number of active platelets increased by 24.0 %. The levels of small, as well as medium and large aggregates of platelets present in the blood also increased during the milk feeding phase by 28.6 and 27.3 %, respectively. This was achieved in the observed calves by an increase of 9.6 % in the synthesis of thromboxane in platelets due to an increase in the activity of cyclooxygenase in them by 9.4 % and thromboxane synthetase by 9.3 %. This was also influenced by the increase in the platelet content of adenosine phosphates and the increase in their secretion. The levels of actin and myosin in inactive calf platelets increased during the milk feeding phase by 9.7 and 13.2 %, respectively. In animals, an increase in the additional generation of actin and myosin was revealed during platelet aggregation by 11.1 and 9.8 %, respectively. It is clear that calves of the black-motley breed of dairy food are characterized by a certain increase in the activity of platelet aggregation and secretion. This provides them with a high degree of preservation of blood volume in case of damage to blood vessels. The growth of intravascular platelet activity in these calves also contributes to the creation of the necessary conditions to minimize blood loss and ensure homeostasis.
Highlights
As the functionality of the hemostatic system seriously identifies hemocirculation [1, 2]
In platelets was assessed by the levels of adenosine triphosphate (ATP) and adenosine diphosphate (ADP), the intensity of their secretion when introduced into the environment of collagen and number of actin and myosin in the protein composition of the cytoskeleton of intact and exposed to platelet activation in response to ADP [20]
In the examined calves, on the 11th day of life, AP occurred with collagen for 31.8±0.10 s, accelerating by 30 days of ontogenesis to 28.6±0.15 s
Summary
As the functionality of the hemostatic system seriously identifies hemocirculation [1, 2] Great value in this belongs to platelets. There are some works devoted to the platelets of these productive animals in the individual age groups [18] These individual details do not allow having a holistic view on the issue and dictating the need to perform extensive research. The need for these works is due to the great importance of the functions of platelets for the flow of blood flow in the capillaries. Due to genetic differences between individual breeds of cattle and high physiological values of platelets activity in the realization of the potential productivity, it is necessary to evaluate the properties of thrombocytes in calves belonging to highly productive on the milk yield of black-motley breed in the second phase of their early ontogeny
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