Physiological and biochemical status of highly productive dairy cows of different genetic value level in the first phase of lactation

Studies on the complex improvement of milk production characteristics and functional qualities of dairy cattle allow us to reveal mechanisms of physiological regulation of animals. The work was aimed at analyzing relationship between a milk productivity level, milk composition of Holstein cows and a state of fatness and biochemical blood parameters of highly productive animals during lactation. The data of zootechnical control, milk yield for 100 days of lactation, fat and protein weight percentage (on the Bentley 150 device), milk fat and protein yield were taken into account. Fatness was assessed by a 1-5 rating scale. In serum the biochemical analyzer Chem Well (USA) identified a number of biochemical values. The experimental data were processed (Excel 2007). Reliability was assessed by Student’s t-test. Four groups of animals with different productivity were selected. The first group included productivity of 6,500-7,000 kg of milk, the second - 7,000-7,500, the third - 8,000-8,500 and the fourth - 8,500-9,000 kg. For 100 days of lactation in the third group the yield was 3,761 kg, which is by 48.2 kg more than in the fourth, and by 218.5 and 748 kg more than in the second and first groups. Fatness in the first month in the first group amounted to 3.67, in the fourth - 3.44 points (P function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }