Investigation of quality and quantity indexes of sperm production of boars of Yorkshire, Landrace, Duroc breeds of Danish selection was realized in the conditions of the Republic of Belarus. Quality and quantity indexes were analyzed in accordance with ejaculate volume, spermium concentration and activity at different age-specific periods in the comparative aspect. Thorough analysis of quality indexes (ejaculate volume; spermium concentration; spermatozoon motility; sperm quantity) of semen production of studied breeds at different age-specific stages (before 7 months old; 7-10 months; 10-12 months; 12 months and older) was presented. Coefficients of variation of valuation indexes of semen production were stated. Research results showed that the lowest ejaculate volume was typical for boars of Duroc breed, but the quantity of spermium in ejaculate of this breed since 10-month old age was the highest – 92,6 milliard, that made it possible for this breed of boars to take premier place according to the index of spermium quantity in ejaculate. The same index for boars of Landrace and Yorkshire at age of 12 months old and older was 77,5 and 76,3 milliards, respectively. High variability of indexes of evaluation of semen production was due the reason that the research was taking place at the period of formation of productivity over the whole pig stock. Research results proved that indexes of semen production of producer boars of Yorkshire, Landrace, Duroc breeds of Danish selection depended on the breed and high variability indexes

Immunomorphological changes in young hens vaccinated with an associated inactivated emulsion vaccine against bursal disease, infectious bronchitis and Newcasle disease was realized in the conditions of the Republic of Belarus. Replacement young hens of 130-158 days old were divided into 2 groups with 200 head in each according the analogue principle. At the age of 130 days old the first experimental group of chickens was immunized against bursal disease, infectious bronchitis and Newcasle disease with a liquid inactive emulsion vaccine (produced in the republic of Belarus) in dose of 0,5 ml intramuscularly. In course of the experiment chickens from each group were killed on the third, seventh, fourteenth, twenty-first and twenty-eighth days. For the analysis of immunomorphological reaction there were tested tissue pieces from the places of vaccine administration, as well as thymus, bursa of Fabritius, lien, cecal tonsils and Garder's gland. Research results showed that in tissues in places of the vaccine administration there were developed hemorrhages, serous inflammatory edema, necrobiosis and necrosis of muscular fibers, inflammatory cellular infiltration, and moderate plasmocytic reaction. At a later stage at the places of damaged structures there was noted the development of granulation tissue with presence of some lymphoid nodules. In response to vaccination in the central organs of poultry immunity there was stated the sinuated changes of morphological indexes. Immunization of chickens against infectious bursal disease, infectious bronchitis and Newcasle disease promoted the increasing of absolute weight of lien, activation of blastic and plasmocytic reaction in bursa of Fabritius and lien and did not render substantial influence on immunomorphological indexes of cecal tonsils and Garder's gland

Determination of a degree of manifestation of immunomorphological changes in immune system organs of piglets vaccinated against salmonellosis, pasteurellosis and streptoccocusis with SPS vaccine (against salmonellosis (Salmonella), pasteurellosis (Pasteurella) and streptococcus) in combination with immunostimulative drugs and without them was realized in the conditions of the Republic of Belarus. Piglets of 30-35 days old were divided into 4 groups according to the analogue principle. Piglets of the first group were vaccinated against salmonellosis, pasteurellosis and streptoccocusis by SPS vaccine. Piglets of the second group were vaccinated by SPS vaccine with vitamin C. Piglets of the third group were vaccinated by SPS vaccine with immunotstimulant sodium thiosulphate. The fourth (control) group of animals was administrated with normal saline. Animals were immunized twice, intramuscularly with 7 day interval in dose of 4 ml (primary), and 5 ml (secondary). Vitamin С was administrated in dose of 0,05g per head. Sodium thiosulfate was administrated in combination with the vaccine in 30% concentration. The research results showed that immunization with SPS vaccine in combination with sodium thiosulphate and vitamin С promoted the activation of morphological reactions in tissues at locus of vaccine administration, lymphodnudus and lien. Immunization of piglets by SPS vaccine with sodium thiosulphate and with vitamin С activated the limphiod, micro- and macrophage reactions at locus of vaccine administration, as well as in organs and cells there was stated the well-marked vitamin C and glycogen distribution. Sodium thiosulphate showed higher immunostimulate influence in comparison with vitamin C

Investigation of immunity of broiler chickens of Kobb-500 cross vaccinated by national associated viral vaccine and foreign (ABIC, Israel; Vitex XXI vek Seva) vaccines against Newcastle disease and infectious bronchitis was investigated in the conditions of the Republic of Belarus. In course of studies there was analyzed the content of immunoglobulin in blood serum, as well as the influence of living vaccines on immunity formation. Research results showed that broiler chickens immunization against Newcastle disease and infectious bronchitis by national and foreign vaccine produced by ABIC company made it possible to increase the phagocytic activity of pseudoeosinophils, bactericidalal and lysozyme activity of blood serum, that proved the activation of nonspecific protection factors. At the same time in blood serum there was stated the increasing of immunoglobulin number in 1,5-3,0 times in comparison with control groups. Economic efficiency of all analyzed vaccines was analyzed

Selection of an optimal dose of Cryptosporidium parvum agents which were isolated from swine and could cause expressed changes in organs of experimentally infestated mice was realized in the conditions of the Republic of Belarus. Data about on persistence of homoxenous coccidia Cryptosporidium parvum at laboratory white mice and pathomorphological changes in the bodies of experimental animals were presented. In a mucous coat of intestines there was marked a catarrhal inflammation with mucous membrane necrosis and its infiltration by leukocytes and macrophages.

Results of studying the efficiency of iodine containing preparation Jodon which was applied to highly productive cows with hypovarianism and to servicing bulls in order to increase their reproductive function realized in the Republic of Belarus were presented. On the basis of realized studies there was proved the considerable efficiency of Jodon preparation.

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.

Research results showed that in the conditions of correct organization and application of technological methods of livestock breeding and feeding it was possible to achieve high livability rate of sheep and lambs up to 90%. Also it was possible to get a substantial break of infection chain of many sheep diseases (especially those which had a respiratory nature). Research results showed that simultaneous application of convalescent-phase serum against sheep acute respiratory diseases, as well as Nitox 200 and Invamek for treatment of sheep and especially 2-3 month old lambs with respiratory infectious diseases promoted the recovery of 80-100% of animals.

It was established that in blood serum of pigs vaccinated against leptospirosis there was an authentic increasing of alanine aminotransferase, alkaline phosphatase and gamma-glutamyltransferase that made proved the presence of residual reactogenicity of biological preparations. In course of the experiment there were used 4 groups of swine which were administrated with 4 types of vaccines: 1. polyvalent vaccine produced in Belarus; 2. experimental thiosulfate vaccine in which there was used 30% sodium solution; 3. experimental emulsified vaccine; experimental emulsified + sodium + thiosulfate vaccine.

Development of a production technology of a national anthelminthic preparation Triclafen (from benzimidazole group) on the basis of triclabendazole and fenbendazole was realized in the conditions of the Republic of Belarus. As a result of realized experiments it was found that the developed suspension corresponded the requirements of pharmacopoeial items and can be applied for veterinary practice. Composition of different components with wide action spectrum made it possible to apply it against ruminant animals.