In the conditions of the Republic of Belarus there were studied the aetiology factors in development of dermatoses of productive cows taking into account the hygienic aspects. Structural defects of floors of cattle livestock buildings in animals of an experimental group promoted higher (on 35%) development of mattery dermhelminthiasis of distal areas of hindlegs in comparison with animals of a control group. Occurrence of skin dermhelminthiasis, especially in distal areas of hindlegs, was caused by various primary traumas of soft parts with the subsequent introduction into them of pathogenic microbial flora. The imperfect design of floors, an unsatisfactory microclimate in cow cattle houses, hypodynamia in the absence of constitutional walk made the preconditions for it. The reasons of purulent dermatosis of cows were two interconnected etiological factors: mechanical damages of tissues and development of a surgical infections in affected areas against the background of unsatisfactory microclimate that led to decrease in dairy efficiency on 4,51%. Therefore in a complex of the actions directed towards the preventive maintenance of surgical diseases, it is necessary to include the strict control over designing, building and operation of cattle-breeding premises, traumatism prevention, creation of an optimum microclimate and observance of zoohygienic norms of cattle maintenance.

In the conditions of the Republic of Belarus taking into consideration the hygienic aspects there were studied the aetiological factors in dermatosis development in productive cows. As a result of realized research it was established that aetiology of skin diseases in the area of a mammary gland were traumas, and following affects were more often marked: skin rhagades of mammillars; wound in the area of a mammary gland and mammillars; fistulas of milk tank vessels; and also sporadic damages of sphincter muscle of teat canal caused by machine milking. This in its turn gives made it possible to consider, that traumas of various character were a contributing factor for occurrence of udder garget - mastitis. In course of the realized analysis there was proved a high therapeutic efficiency of 1% aethonium gel for the treatment of various traumas of mammary gland and udder mammillars of cows. Clinical recovery of animals after administration 1% aethonium gel was stated on 3,2 days earlier, than after administration of Burenushka cream in the postoperative period. Healing and restoring action of 1% aethonium gel for udder tissues was proved by changes in number of somatic cells in milk. The quantity of somatic cells in 7 days after administration of 1% aethonium gel came back to the level which was typical healthy animals, while in the control group the quantity of somatic cells per 1 ml of milk did not decrease essentially.

In the conditions of the Republic of Belarus there were determined the parameters of acute and subacute toxicological characteristics of the developed in the Vitebsk State Academy of Veterinary Medicine anthelmintic preparations of durable action Febolvetum-О for control of sheep strongylatosis and Febolvetum for control of strongylatosis of cattle young stock. Data on determination of toxicological parameters of the prolonged action bolus were presented. Research results showed that the preparations did not render negative influence on laboratory animals (white mice). According to the parameters of acute oral toxicity the Febolvetum was qualify as the third hazard class. In accordance with the results of study of subacute toxicity parameters of the preparations, it was concluded, that in the conditions of free feeding of Febolvetum boluse in combination with forages in course of 30 days in doses of 200 mg/kg; 150 mg/kg; 100 mg/kg of body weight in animals there were found no signs of intoxication; there were not stated any is not fixed deviations in physiological state; and were stated no mice death.

In the conditions of the Republic of Belarus there was studied a comparative efficacy of methods of drug administration for diseased animals with respiratory diseases. It was stated that enteral (internal) administration of Tromexin in a complex therapy of calves with respiratory pathology possesses rendered low therapeutic efficacy and could have a lethal outcome. Parenteral (intramuscular) administration of Enrotil and Dexafort for a complex therapy of calves with respiratory pathology rendered a moderate therapeutic efficacy and could lead to animal's state improvement. Parenteral (intravenous) administration of hypertonic solutions of norsulfazol, calcium chloride, sodium chloride and glucose in complex therapy of calves diseased with a respiratory pathology proved to render a high therapeutic efficacy and may lead in a complete clinical recovery.

In the conditions of the Republic of Belarus there was realized the evaluation of genetic inheritance indexes of producing bulls at a cattle breeding enterprise in Belarus depending on a selection source (in accordance with an average productivity of female ancestors) in order to use them properly for the increasing of genetic potential of black-and-white Belarusian cows in Gomel region. The carried out analysis allowed to draw a conclusion, that bulls of national breeding lines according to the indexes of cow milk yields concede foreign bulls, i.e. delivered of Sweden on 2744 kg of milk or on 27,5% and from Russia and Hungary - on 1272-2906 kg of milk or 12,7-29,1% (Р less than 0,001). In accordance with butter-fat yielding capacity of bull mothers obtained at breeding farms of Belarus and in accordance with groups delivered from the other countries there were stated no essential distinctions (0,05). Butter-fat yielding capacity percentage of bull mothers varied within 3,99-4,10%. However, the yield of dairy fat per lactation the difference was in favour of bull mothers delivered from Sweden (114 kg or 27,9%) at P less than 0,001. Distinctions on milk producing ability of bull mothers from various cattle breeding enterprises of Belarus were revealed. It was established, that at mothers of bulls delivered from Hungary the variability of milk yield was the highest (3032 kg or 23%). Low variability indexes of milk yield and butter-fat yielding capacity percentage was typical for bull mothers of the Belarusian selection. The standard deviation at them made 872 kg of milk yield with 9% variability coefficient, and 0,03% - for butter-fat yield and 7% respectively. Variability on all indicators of dairy efficiency of bull mothers from various cattle breeding enterprises of Belarus in most of the cases was low - from 2,3 to 13%.

In the conditions of the Republic of Belarus there was determined the therapeutic efficacy of combined application of a complex antibacterial veterinary drug (containing lincomycin and spectinomycin) and Trivitim for the treatment of calves with respiratory diseases. In course of the study of 12 1-1,5 month old calves with respiratory diseases there were analyzed the hematological blood indexes, white blood cell differential and content of total protein in blood serum before the beginning of treatment and on the seventh and fourteenth days after beginning treatment. Research results showed that application the antibacterial veterinary drug in complex therapy with Trivitim in treatment of calves proved to be efficient. Their administration shortened the terms of recovery and prevented animal death as well as promoted the normalization of hematological and biochemical blood indexes.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application of organic form of selenium Sel-plex in feeding of producer bulls. In course of the study there was showed the dynamics of live weight and average daily weight gain of producer bulls; blood indexes of analimals by the end of the experiment; sperm quality of experimental bulls. As a result of research it was established, that application of organic form of selenium Sel-plex in feeding of breeding bulls during the summer and winter periods in a dose of 0,4 mg/kg of dry matter of a ration promoted the increasing of daily average live weight gain on 6,4-8,1%, improvement of morphological and biochemical blood structure, increasing of indices of natural resistance on 0,5-6,1% and sperm production quality - on 7,3-28,0%.

In the conditions of the Republic of Belarus there was analyzed the influence of the following paratypical factors on cow productive longevity: age of the first calving; milk yield at the first lactation; and a birth season. At the experimental animals there studied the indices of dairy efficiency: a lifelong milk yield (kg); a lifelong yield of dairy fat (kg); the total duration of the lactation period (days); duration of practical use (lactations). There was noted a tendency of increasing of a term of productive use and lifelong productive efficiency at the animals the practical economic use of which was begun in later terms. The insemination of these animals was approximately realized at the age older than 21 months. Also it was stated that in accordance with all investigated indices (except for a milk yield per one day of lactation) the highest indexes were typical for cows which had the least milk yield at the first lactation.

In the conditions of the Republic of Belarus there was realized a scientific and economic experiment on studying the influence of a multi-enzyme feed additive on productivity, viability, growth and development of calves. The multi-enzyme additive contained in its formula xilanaza; glucanase; cellulose; and dolomite (as a filling agent). It was determined that young growth of cattle which were fed with the multi-enzyme additive in dose 1 gram per 6 kilogram of milk by the end of the experiment had a live weight gain on 13,6% higher than in a control group. Calves which were fed with the additive were characterized by more stretched constitution, had well developed thorax and good development of skeleton in comparison with analogues from the control group.

In the conditions of the Republic of Belarus there was studied the efficiency of application of granulated and extruded lupine (Lupinus) in feeding of bull claves. It was determined that after lupine extruding the quantity of sugar in it increased on 45% due to lowering of starch content. The inclusion of extruded lupine into bull calves diets made it possible to increase the digestibility of dry and organic substances, protein and nitrogen-free extractive substances. The highest average daily weight gain (842 gram) was stated at claves which were fed with mixed fodder with 15% of extruded lupine; this was on 7,5% than in a control group. In the conditions of feeding with the granulated lupine the average daily weight gain increased on 5,3% in comparison with crushed one. In course of study there was analyzed the dependence chemical composition of lupine on the processing method; blood composition of the studied animals; diets of experimental animals; digestibility of nutrient substances of forages; balance and intake of nitrogen; biochemical blood composition; changes of live weight and average daily weight gain.