Valentine Dzitsiuk, Svitlana Kovtun
Institute of Animal Breeding and Genetics of M.V.Zubets of the National Academy of Agrarian Sciences of Ukraine, Kiev 08321, Ukraine
Dzitsiuk, V., & Kovtun, S. (2019). Cytological characteristics of blood of cows with different levels of milk productivity, Bulgarian Journal of Agricultural Science, 25(Supl 1), 37–40
The article studies the content variability of erythrocytes, leukocytes, hemoglobin, ESR-index as well as numerous versions of micro-nucleus test and NOR (Nucleus Organizing Regions) Index. The studies were held for the inter-phase lymphocytes nuclei of the blood of heifers of the Ukrainian Red-and-Black breed that have various level of milk productivity. The studies displayed that the higher the productivity of heifers is the higher the erythrocyte and leukocyte values are. The direct and positive correlation between the milk production of cows and level of erythrocytes and hemoglobin is established. However, there was no connection found between the milk productivity level and the content of leukocytes in the blood. It is stated that the lowest level of erythrocytes that contain micro-nuclei is registered for the cows with yield level 3000-4000 kg. For the groups of cows that has the yield level 6000 kg and above an abrupt increase of erythrocytes with micro-nuclei was detected, comparing to the groups with the lower milk productivity. The frequencies of the lymphocytes with micro-nuclei are slightly higher for the groups that have the productivity level of 3000-4000 kg of milk, comparing to the groups of productivity of 4000-6000 kg and is lower for the groups of heifers with productivity of 6000 kg and above. By the coloration of the samples with silver nitrate it is stated that the least NOR number in inter-phase lymphocytes nuclei is found for the heifers with milking level of 3000-4000 kg, while the highest number is noticed for the cows with the productivity level of 5000-6000 kg. The average NOR Index among all researched groups of animals is 2.36.