State of immune system of broiler chickens after administration into their diets of nonspecific immunostimulative drugs – bacterial liposaccharide Alveozan and spore-forming aerobic bacterium Bac. Alvei (KMIEhV-11) and probiotic on the basis of lactic acid bacillus Dialakt was studied in the conditions of the Republic of Belarus. In course of the study there was proved that the analyzed preparations had expressed immunogenic activity, rendered the positive influence on natural resistance of broiler chickens. Under action of preparations Alveozan and Dialakt in broiler chickens there were stated the following changes: improvement of protein absorption from gastro-intestinal tract in chickens at the age up to 19 days; there was achieved a hepatic protection effect at birds at the age up to 36 days. The specified changes did not depend on application regimen of the given preparations.

Analysis of the epizootological situation in infectious diseases in the world and the Republic of Belarus was presented. The prevention and eradication control strategy of mentioned diseases in Belarus was defined. In Belarus there was stated no cases of special danger infectious diseases of cattle: bovine spongiform encephalopathy; highly pathogenic poultry flu; aphthous fever; since 1982 - Bang's disease; since 1980 - Newcastle disease; since 1999 – anthrax. Preventive maintenance of 30 infectious diseases was based on application of specific prophylaxis.

Data оn evaluations of therapeutic efficacy of albendazol and fenbendazol agaonst acute and chronic forms of larval cestodiasis of animals were studied in the conditions of the Republic of Belarus by an example of experimentally infested sheep and rabbits. Application of albendazol and fenbendazol both separately and in complex with antioxidant vitamin and mineral additive against the chronic forms of cysticercosis tenuicollis and cysticercosis pisiform was inefficient. But application of albendazol against acute form of cysticercoses caused the lowering of invasion intensity in shepp and rabbits in 3 times, fenbendazol – in 2,6 times. Application of anthelmintic agents in complex with vitamin and mineral composition promoted the lowering of invasion intensity (in 5 and 4,1 times, respectively) and prevented the disease development in 60% of animals.

The physical and biological properties of a produced in the conditions of the Republic of Belarus nonspecific blood serum of animals according to an improve technology corresponded to all necessary standards. The prophylactic efficiency of nonspecific blood serum of animals was 80%, that was on 10% higher than serum of convalescents. Therapeutic effectiveness of nonspecific blood serum was 90%, that was on 8% higher than serum of convalescents

Study of parasitocoenoses of digestive system of Ayrshire breeds of cows and heifers was realized in the conditions of the Republic of Belarus. In course of investigation there was presented a highly efficient universal sedimentation and flotation method with centrifuging for diagnostic of low intensity infestations of cattle. Heifers of Ayrshire breed the total infestation with parasites of gastro-intestinal tract was 100%. Species composition of parasites per one animal was 2,0 +/- 0,258. In winter period the components of parasitoses of a digestive tract were the following: eimeria, strongylats, fascioles, moniezia, nematodes, trematodes and cestodes. In cows of Ayrshire breed the total infestation was also 100%, mixed infestation – 70,0 %. Species composition of parasites per one animal was 2,55 +/- 0,170. In winter period the components of parasitoses of a digestive tract were the following: eimeria, strongylats, fascioles, and capillariasis

Data on development of an antigen on the basis of larvae of warble flies grubs (Hypodenna bovis) for diagnostic of spontaneous cattle hypodermosis by means of the indirect fluorescent (IFA) test and with application of blood serum and milk samples realized in the conditions of the Republic of Belarus were presented. Specificity and sensitivity of experimental sample of antigen for revealing of spontaneously infestated with larvae of warble flies with IFA test at hypodermotosis has made about 100%.

In the conditions of the Republic of Belarus there was studied a therapeutic effectiveness and influence on milk productivity of 22% Timbendazole after spontaneous infestation of cows with fascioliasis (Fasciola hepatica). As a result of studies the Timbendazole 22% proved to be highly efficient against Fasciola hepatica in cattle – from 92,9% up to 100% (in comparison with Albendatimum-100 granulated material the efficiency of which was 88-90%). As a result of cows treatment by anthelmintics – Timbendazole 22% and Albendatimum-100 against Fasciola hepatica there was stated the substantial increasing of milk productivity of animals (on 23,4 and 11,0%, respectively) in comparison with animals which were not administratec with mentioned above preparations.

Determination of interactions of monoinfestations and associations of parasites with the normal microflora of intestines of sheep was realized in the conditions of the Republic of Belarus. In the conditions of low associative infestations with Moniezia sp., Strongylata and Strongyloides nematodes, Eimeria protozoa there were stated changes in intestine microflora of sheep: sharp decrease of quantity of bifidus bacteria and lactic acid bacillus, colibacilli with the simultaneous presence of lactose-negative Bacillus coli, increasing number of aerobic bacteria. Recovery of monieziae in the conditions of presence in parasitocoenosis composition of nematodes of suborder Strongylata and Strongyloides species, Eimeria promoted the restoration of quality and quantity composition of microflora of sheep gastrointestinal tract

Problem of ruminant monieziasis is widely distributed in the Republic of Belarus. For the eradication of farm holdings and complexes there was proposed a complex of measures which included the application of highly efficient anthelmintic agents, including preparations for injection therapy and prolonged substances for intrajejunal administration (boluces).

A technology of application autolysis of fodder yeasts (AFY) for the production of products with higher protein content, digestible aminoacids and other nutritive and biologically active substances in comparison with the standard fodder yeasts (provit) was tested in the conditions of the Republic of Belarus by an example of three groups of swine. Animals of the first (control) group were fed with combined feed SK-26 with addition of 2% of provit. Animals of the second group were fed with combined feed SR-26with addition of 2% of AFY, the third group - with addition 4% of AFY. Provit and AFY were included into combined feed instead of excluded protein components in equivalent number. Research results showed that autolysis of fodder yeasts did not render negative influence on productivity of fattening stores. Average daily weight gain of stores was 637-674 g. Calculation of economic efficiency of combined feeding application of 2 and 4% of AFY showed that application of 2% AFY was more economically profitable