Determination of adaptation and compensation abilities of larval forms of cestodes (cysticercus and echinococci) was realized by means of evaluation of biochemical composition of their internal environment. There was realized the following estimation of biochemical composition of internal environment: Cysticercus tenuycollis from sheep - 34, Cysticercus tenuycollis from swine - 17, Echinococcus granulosus L. from swine - 23. Estimation of biochemical composition of custodies larvaceous forms was realized on the basis of the standard veterinary methods. Research results revealed that osmotic volumetric concentration of internal environment of custodies larval forms was lower than of osmolarity of blood serum. The average value of osmolarity of blood serum for both sheep and swine was 296,63 mmol/l. Research results showed presence of large quantity of specific lipo- and glycoproteins in custodies larva forms. Cysticercotic liquid administrated into suspended matter of microorganism Micrococcus lysadeicticus and leads to lyzing up to 5% of microbal bodies. It was possible to testify the presence of lyzing activity in liquid of larval forms of cestodes. The research results showed that the analyzed larval forms of cestodes had a lot of different and strong defense mechanisms. Adaptation and compensation abilities of larval forms of cestodes had nonspecific character and contained the following: physical mechanisms; humoral immunocompetent factors; and biochemical adaptation

Determination of influence of long acting antihelminthics (Aversictini boluses and boluses with albendazole) and influence of usual antihelminthics (farmatsin, alverm, fenbendavet) on first stomachanimal digestion, as well as on quantity and quality composition of microflora and microfauna in first stomach and large bowel was realized in the conditions of the Republic of Belarus. In course of the experiment there were used 6 groups of calves infested with helminths (Neoascaris vitulorum, Strongylata sp.). Research result showed that different antihelminth preparations to a greater or lesser degree rendered negative influenced on quantity and quality composition of microorganisms in first stomach and large bowel of cattle. Alverm and boluses with albendazole rendered the least influence on microflora and microfauna that could be explained by low toxicity of active substance (albendazole) of the above preparations. Aversictini boluses, fenbendavet, and farmastin changed the composition of microorganisms. It could be explained by high toxicity of preparations containing aversictini which rendered influence not only of gastro-intestinal tract but also on the whole organism. Active ingredient of mentioned above preparations (Aversektin C), being the product of microbial synthesis, rendered the antagonist action on the normal microflora of digestive tract. Negative influence of fenbendavet was caused by the chemical composition of the preparation and neurotoxic action of fenbendazol

On the basis of analysis of literary sources and realized studies there was realized an evaluation of the degree of losses caused by ruminant monieziasis in the conditions of modern agricultural production in the Republic of Belarus; the strategy of medical and preventive measures was presented. In course of studies there were analyzed sheep and cattle of different classes bred in farm holding of Belarus and imported from abroad, as well as different anthelmintic agents. Studying of antihelminthefficiency was tested on lambs with body weight 20 kg. Lambs were infested with moniezia (Moniezia expansa). Analysis of anthelmintic agent Alverm efficiency was realized by the example on infested heifers. Albazen was administrated once in dose of 0,8 mg/1 kg. Prazikvantel was administrated once in dose of 5,0 mg/1kg. Alverm was administrated once in dose of 80,0 mg/1 kg. Research results showed 100% extencefficiency and intencefficiency of albazen and prazikvantel. Alverm administrated once in dose of 80,0 mg/1 kg gly had 100 % 100 % extencefficiency and intencefficiency

Studying of efficiency of application of a natural biological control agent BioLAD obtained as a result of cultivation of Fusarium sambucinum fungus in feeding of broiler chickens was realized in the conditions of the Republic of Belarus. There were studied 100 broiler chickens of Ross-308 cross. Broiler chickens of the first (control) group were fed with standard diet with PK-5-1. Broiler chickens of the experimental groups starting from one day old age till the end of the growing period (41 days old) were fed with feed supplement BioLAD in different doses: 0,25 ml/head (second group), 0,5 ml/head (third group), 1 ml/head (fourth group). Research results showed that natural biological control agent BioLAD in dose of 0,5 ml/head made it possible to increase chicken live weight on 11,2 %, viability - on 4,2%. Feeding charges per 1 kg of live weight gain were1,89 kg (second group), 1,81 kg (third group), 1,90 kg (fourth group). It made it possible to decrease the combined feed charges on 6,4% (second group), on 10,4% (third group), and on 5,9% (fourth group). Application of biological control agent BioLAD had an effect on poultry growth activity, promoted high level of chickens viability, increased the indices of general and local protection, stimulated metabolic processes

Possibility of increasing of natural resistance of young livestock animals and productivity of piglets after application of experimental feed additive including dolomite powder was realized in the conditions of the Republic of Belarus. In course of study there were analyzed housing conditions of piglets; the hygienic examination of feeding rations; influence of dolomitic meal on piglet resistance and productivity. Piglets of the first (control) group were fed with standard total ration. Animals of the second and the third experimental groups were given dolomite powder in ratio of 1% and 2% of combined feed mass. Chemical content of dolomite powder, hematological indexes, disease incidence and piglet productivity were analyzed. The research results showed that in feeding rations of piglets in the analyzed swine breeding complex there was stated the deficit of calcium (14%), phosphorous (26%), magnesium (15%), cuprum (9%), zinc (27%) and manganese (27%). Research results showed that application of dolomite meal is efficient for the prophylaxis of mineral deficiency, and made it possible to increase the level natural resistance: serum bactericidal activity - on 16,4% and hemoglobin - on 19%. The optimal dolomite dose of dolomite was 2% and it promoted the lowering of disease incidence, increasing of viability and average daily weight gain

In course of a long-term selection breeding activities in the conditions of the Republic of Belarus on the basis of Belarusian Large White breed of swine there were created two high-productive lines - Delfina 37755 and Svitanka 3884. Individual selection of animals was realized in accordance with the main indexes of productive ability, development and conformation type. There were selected parent lines, there were used methods of intrastrain breeding and hybrid between lines, mild inbreeding on parental line. Bores and breeding sows were evaluated in accordance with their posterity productivity by means of a control feeding method. Productive indexes for Delfina 37755 line were 11,7 piglets, for Svitanka 3884 line – 11,9 piglets; age of live weight gain of 100 kg – 189 and 182 days, respectively; average daily weight gain – 735 gram and 749 gram; forage expenses – 3,5 and 3,51 fodder units; backfat thickness – 27,2 and 26,2 mm; ham weight – 10,9 and 11,2 k, respectively

In the conditions of the Republic of Belarus there was realized a morphological study of bone marrow aspirates at different terms chicken of immunization against Gumboro disease which made it possible to analyze the state of immune system for the objective evaluation of immunological status. Research results showed that chicken immunization with a national liquid chick embryo viral vaccine produced on the basis of KMIehV-13 strain against Gumboro disease (infectious bursal disease) promoted the development of immunomorphological remodeling of bone marrow. Application of immunostimulants Alveozan and Nukleovit for poultry vaccination caused more expressed changes revealing in statistically reliable increasing of total number of myeloblastic cells in the majority of cases by means of increasing of immature cells, and then mature cells of granulocytic series, as well as quantity of lymphocytes and plasmacytes

Factors which increased milk productivity (age and continuance of service period) were studied in the conditions of an educational establishment of the Republic of Belarus by an example of cows of black-and-white breed. Dynamics of growth of milk productivity in course of 8 research years was presented. Analysis of interrelation between cow productivity and cow age was given. Mathematical calculation of relations between cow productivity indexes (milk yield, fat content, butter fat) and service period duration was given. Research results showed that increasing of an average term of economic use of cows and decreasing of duration of service period up to 90 days made it possible to increase dairy effiiemcy and herd reproduction, as well as obtain higher economic efficiency

Determination of influence of polymorphic variants of genes of kappa casein, beta-lactoglodulin and alpha-lactoalbumin on indexes of milk producing ability (milk yield, fat and protein content) of brood cows of Belarusian white-and-black breed was studied in the conditions of the Republic of Belarus. In course of analysis of polymorphism of kappa casein gene there was revealed the exceeding of frequency index of allel CSN3**a over the index of allel CSN3**b (0,795 and 0,205 respectively). Studying of polymorphism of beta-lactoglodulin gene showed that the frequency indexes of allel variants formed in the following way: BLG**a - 0,489 and BLG**b - 0,511. There were revealed three genotype variants of alpha-lactoalbumin among which the highest frequency indexes were stated for heterozygous genotype LALBA**aa *(32%) and LALBA**bb (14%). There was calculated the genetic equilibrium for loci of studied genes: x2 value for all studied loci was 0,008 – 1,96. Analysis of milk producing ability data in groups with different genotypes by locus of CSN3 gene showed that the highest indexes of milk yield were stated for group of cows with genotype CSN3**aa. Animals with genotype CSN3**bb had the highest fat percent, animals with genotype CSN3**aa - the lowest. Analysis of milk yield indexes showed that animals with homozygous genotypes BLG**aa and BLG**bb showed lower average milk yield than animals with genotype BLG**ab on 130 and 570 kg, respectively

During the investigation of nuclear DNA of boas of Belarusian meaty breed there was studied the polymorphism of EPOR, MUC4 and IGF-2 genes with the further determination of frequency of alleles and genotypes. Among boars tested for the polymorphism EPOR gene there was stated high percentage of heterozygous samples (EPOR**st): 43,3% for Belarusian meaty breed boars and 66,7% for Belarusian Kripnaya Belaya breed. In course of analysis of the genetic structure by MUC4 gene there was revealed the predominance of animals with the desirable d allele combination (MUC**cc): 60% for Belarusian Kripnaya Belaya breed and 82,2% for Belarusian meaty breed; by IGF-2 gene with homozygotic manifestation of recessive alleles: 46,4% and 63,4%, respectively. In the conditions of the Republic of Belarus there were determined the preferred boar genotypes with EPOR, MUC4 and ICF-2 genes and combinations which made it possible to increase the fattening and meaty qualities of posterity. The research results showed that in the selection breeding schemes it was necessary to consider not only maternal genotype, but also male genotypes giving preference to EPOR**st, MUC4**ss and ICF-2**qq genotypes