In the conditions of the Republic of Belarus there was studied the clinical and biochemical status of pregnant cows, as well as the determination of the main reasons of disease incidence of new-born calves with dyspepsia (dyspeptic disorder). Realized clinical and biochemical studies showed that the inappropriate feeding of pregnant cows in animal breeding farms in housing season of husbandry caused the disorders of metabolic processes in the experimental animals. In blood there was noted the lowering of indexes of alkalinity reserve, glucose, phosphorous, carotine, disturbance of calcareous and phosphorous ratio. In other words, in pregnant cows there were stated the latent forms of osteodystrophia, hypovitaminosis A, hypoglycemia, and acidosis. All these factors caused the irritation and damage of liver and other organs. Mammary gland of diseased animals released colostrum milk of low quality and according to the content of nutritious and protective elements quantity it was of low quantity. Besides, derangements in calf feeding of pregnant nonmilking cows led to birth of calves with low resistance indexes to the influence of external environment factors.

In the conditions of the Republic of Belarus there was studied the morphology and growth dynamics of vomeronasal cartilage of swine at postnatal period. The vomeronasal cartilage covers the vomeronasal body outside. Lateral and medial bases of vomeronasal cartilage formed an antrum in which there was an organon vomeronasal. The most intensive growth of a cartilage of pigs occurred in the first two months of animal life. Arrangement of cartilage was dissymmetric - at the right it was sited more caudad than at the left; this fact caused the differences in its dimensions at the transverse sections.

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 were analyzed the efficiency of 13-18-month old young stock of cattle bred for meat in the conditions of various energy value nutrition levels with the determination of nutrients intake of a diet. It was established that use of rations with various level of metabolic energy and protein breakage rendered the positive influence on nutrient digestibility of rations. This made it possible to improve the digestibility of dry and organic substances, nitrogen-free extractive substances and fibre at the bull calves which were fed with 63% of cleavable protein, as well as to increase the metabolic energy up to 10% in the ration, surpassing the control indexes respectively on 3.1; 2.5; 2.8; and 2.9 items. Adjournment from the acquired nitrogen considerably increased and made up to 64-70%. Productivity of fattening young cattle stock made it possible to obtain 977.7-1011.0 gram of live weight gain. As a result, the growth energy was stated at the level of 15,90-17,33 МJ in the conditions of conversion of metabolic energy into growth of 13,81-14,26% and expenses of metabolic energy of the ration per 1 MJ in live weight gain of 4,72-5,46 MJ.

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 analyzed the efficiency of administration of nonconventional feed materials in diets of highly productive cows and its influence of indexes of natural resistance at different physiological stages of animals. In the process of studying of adaptation processes of highly productive cows at different stages of lactation it was determined that feeding with nonconventional melanoidin-humic additives at different physiological periods rendered a positive influence of highly productive cows, promoted the increasing of natural resistance of animals and improvement of immuno-humoral blood indexes. Administration of an additive Ehkolin in a ration of highly productive cows with stimulation for increasing milk flow in a dose of 100 ml per head promoted the increasing of blood serum bactericidal activity on 5,2%, beta-lysine activity - on 7,2%. Feeding of animals at a basic lactation period with 50 ml of preparation Ehkolin-2 provided the maximum increasing of lysozyme activity of blood serum (on 6,2%) and beta-lysine activity of blood serum (on 12,7%), and also promoted the activation of leukocytopoiesis. Addition of Ehkolin-3 in ration structure of dry cows in a dose of 750 ml increased the indexes of lysozyme activity of blood serum on 7-8,6%, bactericidal activity of blood serum - on 2,2-3,6% and beta-lysine activity of blood serum - on 2,2-3,6%.

In the conditions of the Republic of Belarus there were determined the doses of application of siliceous sapropel as well as there were studied the indexes of ruminal digestion and digestibility of diet nutrient substances by bull calves. The studied siliceous sapropel of the lake Pribylovichi (Belarus) occurence on 42% consisted of organic substances and on 58% - of mineral substances: calcium, phosphorus, magnesium, potassium, sodium, iron, zinc, manganese, and copper. The studied sample of sapropel did not render toxic action on test objects of infusorian Tetrahymena pyriformis in the conditions of its addition into the basic forage in number of 1%; 3%; 5%; and 10%. However, its higher concentrations (10%) retarded the development of Protozoa. Feed additives with the content of siliceous sapropel in mixed fodder in dose of 1%, 3% and 5% increased the relative biological value of forage in the experiments on test objects of infusorians Tetrahymena pyriformis in the average respectively on 5,4%, 5,0 and 2,6%. Higher concentrations of sapropel in mixed fodder (5 and 10%) lowered its nutritional value. Inclusion of siliceous sapropel in bull calve rations activated the enzymatic processes in farding bag and increased the digestibility nutritive elements on 2,3-3,6% except for protein, digestibility which was practically at identical level at animals of all groups.

In the conditions of the Republic of Belarus there was studied the efficiency of application of forage chemical preservatives Kormoplyus-1, Kormoplyus-2, and Kormoplyus-3 for grass fodder conservation. The analyzed preservatives contained acetous acid, urotropine and sodium acetate (only in Kormoplus-2). In course of the study there were established experimental batches with the studied sreservative; there was determined a chemical composition of prepared forages; in physiological and scientifical and economic experiment there was analyzed the feeding efficiency of cereal ensilage. Research results showed that application of preservatives Kormoplyus-1 and Kormoplyus-2 2 for preparation of cereal ensilage made it possible to receive a high quality ensilage and to increase the dry matter safety on 4,2-8,7% and protein on 12-9,4% on comparison with storage without preservatives. Also, it made it possible to increase the digestibility of dry matter in cattle diets respectively on 5.5% and3.7%; organic substance - on 5.5% and 4.0%; fibre - on 16,5% and 15,0%, and also to increase nitrogen deposition on 17,4 and 20,8%. Feeding with forages preserved with Kormoplyus-1 and 2 did not render negative influence on a health state and biochemical indices of animal blood.

In the conditions of the Republic of Belarus there was presented a characteristic of breeding stock of mares of Trakensky breed in accordance with body conformation and exterior. In course of the study there were taken measurements of height at the shoulder, heart-girth, metacarpus circumference at 1 year old and two year old age stages. There was calculated an index of massiveness which characterize the development of chest, index of bone which provided insight into skeleton development. Research results showed that in accordance with an exterior the breeding stock mares had a deep and massive barrel, good skeleton and developed muscle. The index of massivness was 118,4-120,5, bone index – 20,8-21,6, that corresponded to a type of riding horses. In accordance with the exterior, measurements and quality of posterity the mares of the bred lines obtained high grades and 93,5% were graded as elite class.