Age dynamics of hematological indices in dry cows
Abstract
The requirement for the study of blood parameters is determined by its physiological significance and changes that occur in different physiological and pathological conditions. The hematological profile is an important criterion that shows the physiological condition of animals. The physiological changes of blood in cows have been established concerning the conditions of keeping and feeding, hygienic parameters, in the dynamics of the dry season, in different seasons of the year, etcetera. We have not found any information on studies of the dynamics of blood parameters in pregnant animals, depending on their age, in the study of literary sources in recent years. The purpose of our work was to study the age-related dynamics of hematological blood parameters in cows during the dry period. Our studies aimed to determine the hematological indices of Holstein breed cows in the physiological course of the prenatal period during the dry period, depending on the number of deep calving. Control and experimental groups were formed on the principle of group-analogues (by breed, age, sex, physiological state, weight, milk productivity). Animals kept in typical rooms with satisfactory microclimate parameters (in winter) and at camps (in summer). Laboratory studies were carried out in the laboratory of the Dnipro State Agrarian and Economic University. Hematologic studies were performed according to the following indicators: erythrocytes, hemoglobin, color index, erythrocyte sedimentation rate, leukocytes, monocytes, lymphocytes, neutrophils with rod-like shape and segmented nucleus, basophils and eosinophils according to conventional methods. The results of our studies indicate that the lowest number of erythrocytes was detected in the cows of the sixth calving and the highest hemoglobin content, which led to the rise of the color index – in cows of the fifth pregnancy present the reverse tendency; increase to the maximum values of the number of leukocytes in cows of the third body (1.32 times), which is a reflection of the greater reactivity of the body of cows of this age group; a probable decrease (by 10.59 %, P < 0.05) of lymphocyte counts was found in sixth-calf cows, indicating a weakened immune response; also increased eosinophils almost 1.75 times (P < 0.05) compared to fifth pregnancy; the trend of a gradual decrease in the number of segmented neutrophils in calving cows is followed by a second to fifth pregnancy and a significant reduction in the number of stab neutrophils in cows of the fifth pregnancy of up to 1.33 %.
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