Productive features of Holstein cows of different genetic lines

Abstract

Abstract. The purpose of the study is to investigate the productive features of Holstein cows of different genetic lines. Methods. The research was carried out in two breeding enterprises of the Sverdlovsk region on the livestock of Holstein cows. Groups of animals were formed by the method of pairs of analogues, taking into account the age of animals in lactation, physiological condition, live weight, lines of breeding bulls. The coefficient of milk content was estimated by the calculation method. The lactose, fat and protein content in milk was determined using a “Bentley 150” device. Somatic cells were determined on the “Somatos-M” device. Bacterial contamination was studied using a reductase assay. Prolactin was determined by enzyme immunoassay, cortisol by immunochemiluminescent method. Results. In terms of milk yield for 305 days of lactation and protein content in milk, Montwick Chieftain cows had an advantage with a significant difference between the groups (P < 0.05). The animals of the Reflection Sovering line were the best in terms of fat content, the difference between the groups was insignificant. The lowest content of somatic cells in milk and bacterial contamination was found in animals of the Reflection Sovering and Vis Back Idial lines. The best indicators of the leukocyte profile were determined in animals of the Vis Back Idial and Montwick Chieftain lines. In terms of glucose and total protein content in the blood, cows of the Montwick Chieftain line had an advantage, in terms of the amount of urea, animals of the Montwick Chieftain and Vis Back Idial line affiliation. The highest level of total lipids in the blood is typical for cows of the Reflection Sovering line. Scientific novelty. The research results indicate the relationship of biological characteristics and milk productivity with different lines of breeding bulls. The leukocyte profile of this herd of cows of different genetic lines in breeding enterprises of the Sverdlovsk region was studied for the first time. Practical significance. The results of the research can be used in breeding enterprises in order to increase the milk productivity of cows.