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 were analyzed the peculiar features of morphology of bursa of Fabricius of turkeys broad-breasted white turkeys at the stage of postnatal ontogenesis. Research results showed that postnatal ontogenesis of bursa of Fabricius of turkeys developed irregularly with preservation of organ up to 220 days. At turkeys in 300-day old age the organ preserved only in 45% of bird units. Form, colour and consistency of bursa of Fabricius depended on bird age. The absolute weight of the organ increased up to 220 days. The relative weight was maximum at 20-day old age. The sexual peculiar features of the organ morphology were insignificant; they revealed after the beginning of sexual maturity and expressed by some difference in weight and linear dimensions.

Investigation of acute sub-acute toxicity of preparative forms (herbal infusion, tincture liquid extract and pulvis) of marsh cinquefoil (Comarum palustre) by the example of laboratory animals was realized in the conditions of the Republic of Belarus. White mice of both sexes with body weight of 18-20 g and white rats with body weight of 180-200 g were used in the experiment. Experimental preparations were administrated on empty stomach after 12 hours of absolute diet. The animals were supervised in course of 14 days. All changes in behavior were registered. Calculations of parameters of acute and average toxicity of all analyzed forms were presented. Research results showed that all analyzed preparative forms could be referred to the substances hazard category 4 (low-hazardous substances) with lethal dose 50 more than 5000 mg/kg of live weight. It was determined that the analyzed preparative forms proved to be highly effective against strongylatosis (Strongylata) of gastro-intestinal tract of sheep and calves

Results of studies of acute and chronic toxicity of control samples of long acting boluses on the basis of fenbendazole for the treatment of strongylatosis (Strongylata) of gastro-intestinal tract of cattle realized in the conditions of the Republic of Belarus were presented. White rats and mice were used for studying of acute and chronic toxicity of the prolonged anthelmintic. The preparation was tested in doses of 400; 800; 1200; 1600; and 2000 mg/kg of body weight. Prolonged anthelmintic was administrated introgastrally in the form of suspension. Preparation was reduced to fragments before application. White rats with body weight of 80-100 g were divided in three groups and were used for testing. Bolus of prolonged activity was reduced to fragments and mixed with feed before application. Rats ate the preparation during 30 day in dozes of 250 mg/kg, 375 mg/kg, and 500 mg/kg. Study of acute toxicity of preparation established that LD0 for white mice was 400 mg/kg; LD16 - 620 mg/kg; LD50 - 1080 (1062,7 / 1097, 3) mg/kg; LD84 - 1660, LD100 - 200 mg/kg. Signs of animal toxicosis were revealed in shakiness, depression, whiteness of visually accessible mucous coat, cramps. Catarrhal-haemorrhagic gastroenteritis and numerous effusions of blood on mucous coat of digestive tract were established at postmortem examination. There were no morphological changes in tissues of lungs, heart, liver and nephros. Eating of prolonged anthelmintic with feed during 30 days did not render toxicological influence on rats. There were no signs of intoxication, physiological deviations and no animal death. Research results showed that the analyzed prolonged anthelmintic could be referred the substance hazard category 3

After immunization of 30-35 day old piglets against a salmonellosis, pasteurellosis and streptococcosis (SPS) with special produced in the Republic of Belarus SPS vaccine in combination with immunostimulant sodium thyosulfate and vitamin C there was observed an activation myeloblastic hemopoiesis and lowering of erythropoeisis.

Analysis of morphological characteristic and parameters of a thyroid gland of a thyroid gland of growing cattle stock made it possible to specificate the age-specific and species-specific parameters of adaptation of cattle in concrete conditions of environment was realized in the conditions of cattle breeding complexes of the Republic of Belarus. As a result of studies there were obtained new data on form-building processes, macromorphology, topography and referential parameters of thyroid gland of cattle breeds.

While studying biochemical values that characterize rumen digestibility based on research agricultural experiment some results were obtained. These results prove that studied diets with increase of energy and raw protein concentration levels in dry matter influence positively at nitrous substances concentration activate micro flora motions and promote bio-synthetic processes in rumen fluid of experimental animals

The historical and modem data on morphology of adrenal glands were analysed on the basis key historical manuscripts of XVII and XIX centuries were analyzed in the conditions of the Republic of Belarus.

After the pathomorphological and histological studies of innards of fallen experimental animals in all realized experiments it was found that sheep and lambs infected with pneumoviral infections (Parainfluenza-3, Adenoviridae, respiratory streptococcosis infection) with their additional infestation with radioactive substances there was stated the acceleration of infectious process, and disease recrudesced up to 2-5 and more times (depending on irradiation doze). The immunity of sheep and lambs decreased caused by reproduction of viruses, and in acute cases animals died but in cases of mild forms the disease transformed into chronic form and caused animal death.

Determination of chronic toxicity of a new selenium-containing preparation Aesel was realized in the conditions of the Republic of Belarus. There was realized endermatic administration of the experimental preparation to laboratory white mice. Studying of sensitivity of some organs and systems of mice and revelation of a degree of reversibility of processes caused by active substances of the drug was realized. The main clinical, pathomorphologic, biochemical, hematological changes in the organism of laboratory animals with induced chronic toxicity were determined.