A dead calf with cranial duplication removed by cesarean section under local infiltration anaesthesia. The cow made uneventful recovery after surgery without complication.

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

Analysis of synchronization of oestrus of cows by means of Ovsynch and Pre-Synch methods was realized in the conditions of the Republic of Belarus. Research results showed that estrus synchronization by means of Pre-Synch method proved to be more efficient by means of higher percentage of fertilization after the first and second insemination in comparison with Ovsynch method. Treatment of cows with the substances Surfagon and Tetravit for synchronization of oestrus did not render negative effect on milk quality and safety.

Development of a new national preparation for the preventive maintenance of cow mastitis, fissures of milking tubes skin of cow udder was realized in the conditions of the Republic of Belarus. The preparation Maz' Solnechnaya ("Unguent Solnechnaya") did not contain antibiotics, hormones and other synthetic components. Natural components of a preparation provide long anti-inflammatory action, stimulate local blood circulation, regeneration of epidermis and accelerate processes of healing of microtraumas. Besides it possesses high efficiency at preventive maintenance of mastitises at cows.

Using macro and microelements, vitamins A and D in correspondence with norms of Institute of Animal Husbandry (1992) per 1 kg of dry substance of a diet: phosphorus - 5,29 g, calcium - 7,46, sodium - 5,59 g, copper - 12,64 mg, zinc - 77,26, magnesium - 77,26, vitamins A and D correspondingly - 23,74 and 1,02 thousand ME for highly productive lactating cows with average daily milk yield of 32 kg at summer feeding compared to Agricultural Academy norms (1985) promotes increase of the so called relative products outcome and profit from basic fatness (3,4%) milk sale per 1 animal at 411 rubles

Determination of the optimal doses of monocomponents of the developing vaccine against rotavirus infection and cattle colibacillosis was realized in the conditions of the Republic of Belarus by the example of 80pregnant cows with body weight 400-450 kg. Immunological efficiency of the analyzed preparations was estimated in accordance with ascending rate of titres of specific antibodies before and after vaccination. Research results showed that the highest degree of expressed immunologic response to the monocomponents was stated for cows vaccinated in dose 2,5 cm3. Increasing of dose up to 5,0 cm3 did not render substantial influence on gain of specific antibodies level in blood serum of immunized cows. Decreasing of dose up to 1,0 cm3 caused to less intensive biosynthesis of antibodies, excluding animals which were administrated with antigen E. coli K88. In the majority of experimental groups of cows in blood serum there was stated the increasing of specific antibodies level after the second administration of the components. The obtained results proved the necessity of dualfold administration of the developing biological preparation. In course of study there was determined the choice of monocomponent doses of the vaccine. The optimal dose of monocomponent against cattle rotavirus in case of infection titre 7,0 lg 50% tissue cytopathic dose was 2,5-5 cm3 pr animal. The highest titres of the specific anticolibacillosis antibodies for E.coli with concentration of bacterial cells 10E9/ml for K99 and A20 in the conditions of antigen administration in dose 2,5 cm3, and for E.coli with adhesive antigens K88 - 1,0 cm3

Investigation of vitamin supply of cattle affected by fascioles in association with strongylatosis of gastro-intestinal tract was realized in the conditions of the Republic of Belarus by an example of white-and-black 3-8 year old cows. Analysis of blood and blood serum of experimental animals showed that content of B1, B2, and E vitamins was lower in group of animals sick with fascioliasis and strongylatosis of gastro-intestinal tract. There were stated no changes in A and C vitamins content. Content of pyroracemic acid exceeded control indexes and was 22,0 +/- 0,173 mg/l. Content of vitamin A did not change and was 0,011 +/- 0,0012 mg/l for sick animals and 0,013 +/- 0,0043 mg/l at healthy animals. Content of vitamin C was different for sick and healthy animals: 1,685 +/- 0,190 mg/l and 1,93 +/- 0,294 mg/l, respectively. Research results proved that treatment of cattle sick with helminth infestation should be realized in complex. It was proposed to apply premixes and vitamin preparations containing B1, B2, as well as A, E, and C vitamins for the increasing of natural protection and for the creation of unfavourable conditions for disease agents

Results of treatment and preventive maintenance of mastitis of lactating nonmilking cows and heifers with the help of a new probiotic preparation Lactosan realized in the conditions of the Republic of Belarus were presented. The developed new environmentally safe antimastitis preparation Lactosan contained lactic acid bacteria Lactobacillus plantarum and Lactobacillus acidophilus in amount not less than10E7 CFU/cm3 did not render irritating action on mucous membranes, did not cause a sensitization and according to its toxicity indexes could be concern to low-hazardous substances. Therapeutic effectiveness of Lactosan against subclinical mastitis was 84,2-94,1%; in case of serous and catarrhal mastitis – 63,2-68,4%; and after two therapy regimen – 79,0-84,2%.

Development of new compositions of premixes for cows with milk yield of 4-5 thousands kg per lactation depending on lactation stage and pregnancy was realized in the conditions of the Republic of Belarus. Efficiency of application of premixes in comparison with the standard ones was estimated. Experiment was realized by an example of 3 groups of cows of white-and-black breed; experimental period included beginning milking period (90 days) and the main lactation period (142 days). Cows of the first control group were given premix P60-6M with combined feed. Animals of the second group were fed with premixes created on the basis of carotene and microelements content. Cows of the third group were given premixes in accordance with recommended standards. The refined standards of cow vitamin and trace elements consumption were presented. Formulas of premixes for high-producing cows were presented. The research results showed that the developed formulas corresponded to the physiological needs and their application influenced on metabolism and milk producing ability. Application of experimental premixes made it possible to increase the digestibility of nutritive substancesoin 2,3-7,5%. Application of vitamins and trace elements in heightened doses (on 10-30%) caused the increasing of their uptake and increasing of cuprum, zinc, manganese and cobalt content in blood on 11,6-40,8%

Determination of influence of polymorphic variants of genes of kappa casein, beta-lactoglodulin and alpha-lactoalbumin on indexes of milk producing ability (milk yield, fat and protein content) of brood cows of Belarusian white-and-black breed was studied in the conditions of the Republic of Belarus. In course of analysis of polymorphism of kappa casein gene there was revealed the exceeding of frequency index of allel CSN3**a over the index of allel CSN3**b (0,795 and 0,205 respectively). Studying of polymorphism of beta-lactoglodulin gene showed that the frequency indexes of allel variants formed in the following way: BLG**a - 0,489 and BLG**b - 0,511. There were revealed three genotype variants of alpha-lactoalbumin among which the highest frequency indexes were stated for heterozygous genotype LALBA**aa *(32%) and LALBA**bb (14%). There was calculated the genetic equilibrium for loci of studied genes: x2 value for all studied loci was 0,008 – 1,96. Analysis of milk producing ability data in groups with different genotypes by locus of CSN3 gene showed that the highest indexes of milk yield were stated for group of cows with genotype CSN3**aa. Animals with genotype CSN3**bb had the highest fat percent, animals with genotype CSN3**aa - the lowest. Analysis of milk yield indexes showed that animals with homozygous genotypes BLG**aa and BLG**bb showed lower average milk yield than animals with genotype BLG**ab on 130 and 570 kg, respectively