In the conditions of the Republic of Belarus the seasonal derangements of metabolic processes at high-producing cows usually take place in the period from March till May. Analysis of efficiency of application of national preparation CMP (complex-mineral preparation -iron (15 mg/ml); iodine (6,8 mg/ml); magnesium (6,0 mg/ml); selenium (0,32 mg/ml) and vitamin preparation Trivitim (vitamin A – 30000 IU; , vitamin D – 40000 IU; vitamin E – 20 mg) for the preserving of high milking yielding capacity and prevention of metabolic processes disorders was realized. Four groups of high productive cows were formed. First group was entered 10 ml of CMP intramuscular; cows of the second group were entered 10 ml of Trivitim intramuscular; cows of the third group were entered CMP and Trivitim in the same doses; and the fourth group was a controlled one. On the 1-st, 7-th and 15-th days there was realized evaluation animal clinical state, hematologic and biochemical blood indexes (leukocytes; erythrocytes; hemoglobin; thrombocytes; ESR; total protein; albumins; urea; creatinine; glucose; calcium; phosphorous; magnesium; iron), and average daily milk yield. There was also analyzed the phagocytic activity of neutrophilic leukocytes. Research results showed that content of leukocytes and ESR in blood in all experimental groups was within the standard limits. In the first experimental group there was state the increasing of hemoglobin (from 91,4 +/- 4,38 up to 111,83 +/- 4,3 g/l (P less than0,05) ) and erythrocytes (from 4,48 +/- 0,21 up to 5,97 +/- 0,45 10E12/l) content. The same changes were stated in cows of the 2-d and 3-d experimental groups. Content of hemoglobin and erythrocyte in blood of cows which were administrated with CMP and Trivitim increased from 90,6 +/- 0,06 to 99,83 +/- 3,61 g/l and from 4,51 +/- 0,27 to 5,55 +/- 0,28 10E12/l, respectively. Analyze of biochemical indexes of cow blood showed that content of total protein, calcium, phosphorus, magnesium and iron increased. On the 15-th day there was stated the decrease of urea. Research results proved that the combined application of CMP and Trivitim was efficient and prevented subclinical disorders of metabolic processes

Investigation of peculiar features of productive and reproductive qualities (milk producing ability; reproductive qualities; live weight at different ages) of milking cows of white-and-black breed was realized in the conditions of CJSC Lipovtsy of Vitebsk region of the Republic of Belarus. On the basis of obtained results there was calculated the selective differential of milk yield and butter-fat yielding capacity which were increased by means of maternal and father's cattle; genetic progress through selection in reliance on generation and target standard for the analyzed herd, as well as the minimal requirements to first-calf heifer productivity.Research results showed that average milk yield in the analyzed herd was 5204 kg with average butterfat percentage 3,59%; for first-calf heifers – 4838 kg with butter-fat yield of 3,47%. Productivity of first-calf heifers and cows was higher than the standard valuation requirements to milk yield on 1350-1588 kg

The necessity of creation of the optimal conditions for production of high-quality dairy products was conditional upon the fact that milk is very unstable by its chemical and physical indicators biological liquid. There is no point in improving milk quality after the realized production. Results of the realized in the conditions of the Republic of Belarus evaluation of milk according to the sanitary and hygienic indices for the further improvement of its quality were presented. According to the data on milk purchasing it noted that in Belarus there was stated a noticeable reduction of milk quality in accordance with its grade of quality. Throughout the last years the relative density of realization of the premium quality milk was less than 50% (46,5% - in 2005, 48% - in 2006), and at the same time, the volume of sales of the second second-rate quality milk reduced on 7,6%, and volume of off-grade milk - on 0,7%. Milk quality at the studied in course of investigation dairy farms in the majority of cases was conditional upon such indicators as base-titratable acidity, bacterial number and quantity of somatic cells in milk. Titrate acidity indices in over than 36% of milk does not correspond in to standards of the Republic of Belarus. Evaluation of bacterial number in the produced milk showed that its main production volume (65,2%) corresponded to the first and second grades and 6,7% were off-grade quality. Somatic cells content in the studied milk samples in 27% corresponded to the extra fine grade, and only about 2% of the analysed milk samples corresponded to off-grade milk

In the conditions of the Republic of Belarus there was realized a comparative study of peculiar features of influence of combined application of Khelavit preparation and protein-vitamin-mineral feed supplements Khendriks and Spaeta-kontsentrat on health status of cows and quality of obtained cow milk after application of these preparation for the preventive treatment of osteodystrophy. In course of study there were analyzed haematologic and biochemical blood indexes of cows after application of the experimental preparations. Results of physical and chemical indexes of milk were presented. Research results showed that the analyzed protein, vitamin and mineral feed supplements caused the normalization of biochemical blood indexes in comparison with animal of a control group. Besides, application of mentioned above drugs promoted the increasing of veterinary and sanitary quality and technological properties of produced milk.

Factors which increased milk productivity (age and continuance of service period) were studied in the conditions of an educational establishment of the Republic of Belarus by an example of cows of black-and-white breed. Dynamics of growth of milk productivity in course of 8 research years was presented. Analysis of interrelation between cow productivity and cow age was given. Mathematical calculation of relations between cow productivity indexes (milk yield, fat content, butter fat) and service period duration was given. Research results showed that increasing of an average term of economic use of cows and decreasing of duration of service period up to 90 days made it possible to increase dairy effiiemcy and herd reproduction, as well as obtain higher economic efficiency

An effort to demonstrate the mechanism of homeostatic alteration of high-producing cows at the period of increasing milking capacity and peculiar features of its changing in the conditions of introduction into cattle diets of carbohydrate containing and carbohydrate compensative additives was realized in the conditions of the Republic of Belarus. In course of the experiment there were used white-and-black breed cows of 3-4 lactations with body weight of 700 kg and milk yield over the last lactation of 7000-8000 kg of milk. Experimental cows in two weeks before the supposed calving were administrated with 50 ml of propylene glycol, 6 g of niacin and 50 ml of glycerin; and in course of 60 days after calving the administration of the additives was realized in doses of 125 ml; 6 g; 50 ml, respectively. Research results showed that application of mentioned above additives rendered the positive effect on cow liver that was proved by the improved hemic function of experimental cows: increasing of quantity of erythrocytes, hemoglobin, and hematocrit

Analysis of supply of first-calf heifer diets with the mineral substances and their blood level at the first period of lactation as well as the development of the optimal feed formula of the mineral premix which could make it possible to neutralize the possible deficit of nutritive elements was realized in the conditions of the Republic of Belarus. It was stated that in animal diets against the background of protein and carbon misbalance there was noted the deficit of a number of trace elements such as manganese, copper, cobalt and zinc. In spite of sufficient content of calcium and phosphorus in cow diets, their concentration in blood plasma in first-calf heifers did not correspond to standard criteria, that was probably caused by vitamin D deficiency in cow rations. There was marked a low level of zinc, cobalt and manganese in whole blood of the majority of cows. With the purpose of correction of the first-calf heifer rations and for the prevention of possible hypomicroelementoses there was developed the composition of premix taking into account the necessary of cow feeding standards