In the conditions of the Republic of Belarus there was realized a determination of an optimal time for cow insemination with the help of oestrus detector by Draminsky's method. In course of the experiment there were used black-and-white nonpregnant cows at the stage of oestrus (sexual heat). In course of the study there were used clinical, biochemical and hematological research methods. Dynamics of changing of estrous cycle slime depending on a day of sexual cycle was analyzed. Indexes of the reproductive function of cows in experimental and control groups were compared. Research results showed that revelation of cows with oestrus with the help of oestrus detector by Draminsky's proved to be efficient and informative. Insemination of animals at the stage when the resisting of oestrus mucilage after the minimal indexes (180-200) rose sharply up to the indexes 300-320 proved to be efiicient. This made it possible to realize single insemination of animals.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application of an adsorbent mycotoxins Toxfin Dry (Belgium) for lowering of toxicity load on broiler chickens. In the course of the study there was given attention to poultry productivity, viability and forage expenses for broiler chickens breeding. There was developed a scheme of Toxfin Dry preparation feeding to broiler chickens. There were presented the results of weighing of control and experimental broiler chickens during the breeding periods; the basic zootechnical indices in the conditions of introduction Toxfin Dry; economic efficiency of its application. Research results showed that introduction of a mycotoxin adsorbent Toxfin Dry into diets of broiler chickens promoted the improvement of digestion and absorption of mixed fodder nutrients in a gastroenteric tract, that in its turn promoted the increasing daily average weight gain on 4,3%, broiler stock viability - on 2,6%; and to decrease the expenses for forages on 13,9%. On the basis of obtained experimental data it was recommended to include the mycotoxin adsorbent Toxfin Dry into rations of broiler chickens as a dry mix with mixed fodder in a dose of 5 g/kg of forage dry matter.

In the conditions of the Republic of Belarus there was analyzed the efficiency of feeding of a new protein vitamin and mineral additive containing national local protein and mineral raw material sources in diets of 12-16-month old heifers. Instead of sunflower extraction cake the heifers were fed with the protein-vitamin and mineral additive which contained rape grain (Brassica napus), lupine (Lupinus) grain as well as mineral and vitamin additives based on halites, phosphogypsum, phosphate, sapropel and premix in dose of 20-25% by weight as a part of mixed fodders. The additive was used against the background of rations with green mass from a cereal and leguminous mixture - 56-57%, mixed fodder - 36-37%, molasses - 6-7%. In accordance with nutritional value indexes the proposed additive rendered the positive influence on forage consumption, indexes of ruminal digestion, as well as on the morphological and biochemical blood composition. It application made it possible to obtain daily average weight gains of animals at the level of 812-827 grams within forage expenses of 7,0-7,2 сentner of fodder units. Inclusion of the protein vitamin and mineral additive with local protein and mineral raw materials in rations of calves made it possible to lower the mixed fodder cost price on 12-15% and the cost price of 1 centner of gain during the summer period - on 11-13%.

In the conditions of the Republic of Belarus it was determined that application of monocalcium phosphate in a dose of 10 gram per 1 kilogram of mixed fodder and specified doses of trace elements (cuprum; zink; cobalt; manganese; iodine) in diets of growing pedigree bull calves made it possible to increase indices of body weight of young cattle stock of the third experimental group in comparison with animals of the first and the second groups on 18,3 and 11 kg or respectively on 3,9 and 2,3%; as well as to increase the intensity of their growth. The highest daily average live weight gain was noted at animals of the third experimental group – 1062 grams. It was higher than at bull calves of the first and the second groups respectively on 31,3 and 12,8 grams, or on 3 and 1,2%. Application of monocalcium phosphate in a dose of 10 gram per 1 kilogram of mixed fodder favorably affected the formation of desirable type of sexual behavior and indices of semen production quality. Thus, in the third experimental group in comparison with animals of the first and the second groups the volume of ejaculate was on 0,2 and 0,1 ml higher (or on 5,8 and 2,9%); quantity of sperm in ejaculate - on 0,7 and 0,3 billion, or on 35 and 15%.

In the conditions of the Republic of Belarus there were analyzed the doses and efficiency of application of selenium in composition of a mixed fodder KP-2 in diets of bull calves of at their breeding for meat. In course of the study the was developed a formula of a mixed fodder with various doses (0,1; 0,2; 0,3 mg per 1 kg of a dry matter of a ration) of selenium; there was studied the influence of different selenium doses in mixed fodders on palatability of diets, their digestibility, use of nutritive elements and hematological indexes of animals. Also, there was analyzed the influence of different doses of selenium on bull calves growing intensity. There was given the zootechnical and economic evaluation of usage of selenium for bull calves. Selenium dose of 0.2 milligram per 1 kilogram of dry matter proved to be the most efficient and promoted the increasing of average daily body weight gain on 10.9%.

In the conditions of the Republic of Belarus there was analyzed the productivity of 13-18-month old young stock of cattle which was bred for meat with various levels of energy value nutrition. Also, there were noted their slaughter qualities and chemical composition of meat. Administration of diet rations with an increased level of exchange energy and the best indices of protein fissility rendered a positive influence on productivity of young stock of fattening cattle and made it possible to obtain 1103-1100 gram of body weight gain. As a result, the energy value gain was 22,9-22,6 MJ along with conversion of metabolizable energy at a gain - 24,7-25,3%. Consumption of metabolizable energy per 1 MJ along with body weight gain were within 4,7-5,0 MJ. Feeding of rations with various levels of the studied factor rendered the positive influence on slaughter qualities, made it possible obtain slaughter yield of 53,6-54,6% at an optimum ratio of nutrients in meat. Feeding of bull calves with diets with excessive content (up to 10%) of metabolizable energy made it possible to lower the prime cost of obtained breeding products on 0,55%.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application multi-enzyme preparations (drugs) Ehkozim (contained beta-glucanases; endo-xilanase; cellulose) and Vitazim (contained complex of enzymatic carbohydrases: xylanase; cellulose; beta-glucanases) in diets of lying hens. Vitazim was applied for destruction of complex structures: dietary fibre, protein, starch. Ehkozim was applied for albuminolysis of the main nonstarch polysaccharides of fodders. It was established that application of preparations in feeding of lying hens promoted the increasing of biological value of poultry meat, and prove to be economically expedient. Poultry meat of analyzed samples in accordance with physical, chemical and bacteriological indices, as well as in accordance with biological value and harmlessness was not worse than meat of control samples. As a result of the realized bacteriological research of all experimental samples of meat and internal organs there were not stated microorganisms Е. coli, S. aureus, bacteria of sort Proteus, B. сеreus and sulfate-reducing clostridium, salmonellas.

In the conditions of the Republic of Belarus there was studied the possibility of increasing of meat yield productivity of ducklings of Temp cross in the conditions application of parental lines of Peking ducks of German breeding Stolle Seddin Vital (SVV) cross. In course of the study there was realized a comparative evaluation of linear and crossbred ducklings in accordance with meat qualities and blood indexes. There were presented the results of morphological composition of liner and crossbred duck carcasses; dynamics of changes of lipid exchange (total lipids; cholesterine; triglyceride) of ducklings; morphological composition of carcasses of father and mother combinations; blood indexes of ducklings; blood indexes of crossbred ducklings of final combinations. Research results showed that crossbred ducklings had high meat properties which exceeded the purebred ones. In ducklings with lower indexes of fattiness of carcasses there was noted the lowering of concentration of total lipids, cholesterine and triglyceride in blood.

In the conditions of the Republic of Belarus there was analyzed the interrelation between the main indexes of cattle milk performance of dairy cattle of Large Red Belarusian breed and Belarusian Black-and-White breed with different genotypes of kappa casein gene. In course of the study there was determined the frequency of occurrence of genotypes and alleles by kappa-casein gene in population of cows of mentioned above breeds. Values of correlation coefficients between some indexes of milk performance of the studied breeds were analyzed. Correlation factors between the basic indexes of milk performance of cows with different genotypes of kappa casein. Research results showed that milk protein content and butter-fat yielding capacity were in negative association with the main breeding trait of dairy cattle – amount of milk yield. Butter-fat yielding capacity and milk protein content correlated positively. Thus, selection breeding in accordance with one of this traits will promote increasing of the other. Besides, it is necessary to realize DNA-diagnostics of cattle according to kappa casein gene and to select animals having in their genomes allele CSN3**B connected with higher milk protein content.

In the conditions of the Republic of Belarus there was determined the influence of different rates of lithium addition into mixed fodders for sows feeding on hematological indexes and their reproductive qualities. In course of the study there was analyzed the dynamics of body weight of sows over the reproductive period; indexes of productivity of sows (number of born piglets; weight of 1 piglet; litter weight; weight of weanling piglets; number of weanling piglets; etc.); hematological indexes of sows; state of humoral factors of immunity of sows. Research results showed that in case of lithium application in diets of sows there was stated an improvement of hematological indexes and immunity functions and resistance. The optimal level of lithium in rations was 15 milligram per 1 kilogram of dry matter of a diet. This dose essentially promoted the increasing of reproductive performance, piglets weight and milking capacity of sows as well as better viability of piglets.