To determine whether an anti-Salmonella bacterium is involved in control of pathogen load in persistently infected cattle herds. 24 Holstein calves experimentally infected and 39 Holstein cows naturally infected with Salmonella spp. An Escherichia coli (designated as P8E5) that possessed anti-Salmonella activity was isolated from Salmonella-negative bovine feces obtained from a herd with endemic Salmonella infection. In vitro analysis involved enumerating Salmonella enterica serovar Typhimurium coincubated with E coli P8E5. In vivo analysis involved coadministration of Salmonella spp and E coli P8E5 or an E coli control strain to neonatal Holstein calves. Fecal samples were collected on multiple days after inoculation, and quantitative PCR assay was performed by use of Salmonella-specific primers. E coli P8E5 reduced viability of Salmonella spp in vitro. Shedding of Salmonella organisms was diminished in calves administered E coli P8E5, whereas the control strain of E coli had no effect on shedding of Salmonella organisms. In this study, an E coli strain was identified that possessed bacteriocin-like activity and was able to decrease viability of Salmonella organisms in vitro and in vivo. Therefore, it is possible that this organism could be representative of native microbiota that dampen Salmonella spp in persistently infected cattle herds.

Investigation of method of gastroenteritis treatment of stores by means of application of enterosorbents was realized in the conditions of the Republic of Belarus. For the experiment there was used preparation Lactofiltrum containing 80% of hydrolyzed lignin and 20% of lactulose applied in dose of 0,3 g/kg once a day during 7 days. Efficiency of application of Lactofiltrum was compared with enterosorbent SV-2, which contained alcaline hydrolyzed lignin applied in dose of 1 g/kg once a day during 7 days. Four experimental groups piglets sick with gastroenteritis in the age of 1,5-2 months, with body weight of 15-17 kg were used in the experiment. The first group piglets were entered 0,3 g/kg body mass of Lactofiltrum once a day during 7 days. The second group piglets were entered enterosorbent SV-2 in dose of 1 g/kg in course of 7 days. For the piglets of the third group there was applied the complex of analysed preparations in same course of treatment. The fourth group of piglets was entered enrotim 10% in dose of 1 ml/ 20 kg of body mass. All animals had the same conditions of feeding and keeping. Research results showed that application of Lactofiltrum, SV-2 and their complex provided high antioxidative, detoxification, gepathoprotective activities. These preparations proved to be effective means of pathogenetic therapy for the treatment of gastroenteritis of piglets, both as individual preparations, and complex application. Comparative estimation of treatment methods of gastroenteritis showed that these preparations (except enrotim 10%) made it possible to regulate the metabolic processes due to elimination of intoxication, positive influence on hematopoiesis. The preparations lowered the duration of clinic manifestation of a disease and facilitated its duration, had gepathoprotective and antioxidative activity

A description of a method of chemical inactivation of Aujeszky's disease virus by teotropin was studied in the conditions of the Republic of Belarus. The developed inactivated viral suspension was tested for its antigenic activity. On the basis of realized experiments there were determined the optimal parameters of inactivation of Aujeszky's disease virus y means of 0,1% solution of teotropin under temperature of 37 deg C, pH 7,8 and duration of exposition of 24 hours. There were studied indexes of antigenic activity of inactivated virus

Investigation of histomorphological characteristics, organoleptic and physicochemical parameters of sheep meat and slaughter products, their biological value and bacterial number was realized in the conditions of the Republic of Belarus. Research results established that administration of liquid extract of common St.-John's wort (Hypericum perforatum) made it possible to obtain the substantial degree of sheep carcass bleeding, as well as the formation of a drying crust on a carcass surface. At a cut there was revealed the firm texture meat of light red or red color. Cut surface was wet and had specific flavour for the observed type of meat. Fat was solid, white or with yellow colour tone; tendons were elastic and solid. Analysis of boiled meat of sheep which were administrated by amber liquid essence showed that the cooking water was clear, without foreign odor. Meat of sheep, which were administrated by 2,5 % albazen suspension and were killed at 2 and 7 investigation days, had light medical odor in cooking water. In control variants the organoleptic parameters of sheep carcasses corresponded to fresh meat parameters of healthy animals. Realized physical-chemical analysis established the positive qualitative reaction to activity of peroxydase ferment in all meat samples, as well as the negative reaction to determination of primary protein breakdown products. Organoleptic and physical-chemical parameters of sheep meat after administration of amber liquid essence did not have any differences from animal meat of the control group

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.

Results of treatment and preventive maintenance of mastitis of lactating nonmilking cows and heifers with the help of a new probiotic preparation Lactosan realized in the conditions of the Republic of Belarus were presented. The developed new environmentally safe antimastitis preparation Lactosan contained lactic acid bacteria Lactobacillus plantarum and Lactobacillus acidophilus in amount not less than10E7 CFU/cm3 did not render irritating action on mucous membranes, did not cause a sensitization and according to its toxicity indexes could be concern to low-hazardous substances. Therapeutic effectiveness of Lactosan against subclinical mastitis was 84,2-94,1%; in case of serous and catarrhal mastitis – 63,2-68,4%; and after two therapy regimen – 79,0-84,2%.

It is established, that application of laser radiation of low intensity of infra-red area of a spectrum together with a constant magnetic field (an exposition 180 seconds) promotes correction of immunity of an organism of newborn calves that leads to increase in intensity of growth, and decrease in disease of young growth