Platelet Parameters of Holstein Newborn Calves

The activity of cattle’s platelets is mostly connected with the level of their metabolic processes. It is especially important at the beginning of ontogenesis and can differ in different breeds. The aim of the study is to estimate platelets’ activity of healthy Holstein calves during the newborn phase. The study used 35 Holstein calves which were received from healthy cows with the normal course of in-calf state. The calves were observed and examined on the 1st-2nd, 3rd-4th, 5th-6th, 7th-8th and 9th-10th days of life. We used biochemical, hematological and statistical methods of investigation. During the newborn phase the calves had a trend to weakening of platelets’ aggregation in response to all the applied inductors. Discocytes’ content in blood of Holstein calves during the newborn phase had an upward trend. The sum of platelets’ active forms in their case had an inclination for lowering on 7.6%. The number of freely moving little and large platelets’ aggregates in blood also had a downward trend during the first 10 days of ontogenesis. It was evidently provided by a trend to weakening of thromboxane synthesis in platelets of calves and decreasing of adenosine phosphates’ content in them at inclination for weakening of their secretion. The quantity of actin and myosin in platelets of observed calves on the 1st-2nd days of life was little and had an inclination for lowering in the course of the newborn phase. Having conducted the given study, we can consider that Holstein newborn calves are characterized by high functional perfection of platelet hemostasis. Low intravascular activity of platelets in Holstein newborn calves provides optimum of perfusion and metabolism in all the internals which are necessary for fast growth and development of animals.