This study evaluated the antibacterial effects of a mixture of Sophorae radix and Glycyrrhiza uralensis Fischer (1 : 1) ethanol extracts (SGE) on mice infected with Streptococcus (S.) pyogenes. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration of SGE necessary for antibacterial effects against S. pyogenes were 20§¡/mL. Based on the time-kill curves for S. pyogenes, SGE was effective at 4 ¡¿MIC after 16 h. On Day 12 after challenge, the survival rate of mice treated with 2.0 mg/kg SGE was 60%. In conclusion, SGE had potent in vitro and in vivo antibacterial activities against S. pyogenes.

In the evaluation of anthelmintic efficacy by fecal egg counts for cattle naturally infected with helminths, the reasonable technique of fecal egg counts and the reliable guidelines were determined. Modified technique of Harashigeru and Kim's sedimental tube was the most reasonable in fluke egg counts. Universal egg counting technique was preciser than McMaster egg counting technique and was lower in coefficient variation. Fecal egg counts of pretreatment should be carried out twice and mean of the egg should be calculated

In the conditions of the Republic of Belarus there was studied the influence of various doses of dolomite on productivity, egg quality and a mineral metabolism of laying hens. The research was realized by an example of laying hens of Highsex Brown. The experimental hens at the age of 250 days old were divided into 4 groups on 60 heads in each by means of analog method. Laying hens of the first (control) group were fed with a basic diet including 5% of a soya cake (cockle-shell), and hens of the second, third and fourth (experimental) groups instead of a soya cake were fed with a mixed fodder with addition of a mineral additive of dolomite. Hens of the second group were fed with the additive at a rate of 2%, the third group - 3%, and the fourth group - at a rate of 5% of weight of dry matter of forage. During the experiments there were maintained optimum parameters of microclimate, recommended temperature and light regimes and a sufficient ultra-violet irradiation. As a result of the realized research it was established, that use of the mineral dolomite additive in feeding of laying hens proved to be possible as a substitute of an expensive import cockleshell. Use of various doses of dolomite promoted improvement of mineral metabolism, increasing of productivity and improvement of egg quality of laying hens.

In the conditions of the Republic of Belarus there was realized a comparative study of meat productivity of mongrel Gereford х black-and-white heifers ad purebred black-and-white heifers in the conditions of different levels of concentrated feedstuff in cattle diets; and determine the most efficient and long-term method of animal breeding for meat. Research results showed that breeding of meaty of hybrids of Gereford х black-and-white heifers of the second generation without using the feeding concentrates in their diets or on using rations with a low rate of feeding concentrates (10-20%) proved to be more effective, than breeding of purebred black-and-white herdmates (for which specific density of the concentrated forages in diets made up 20% through pregnancy). Hybrids on Gereford breed in accordance with meat productivity level surpassed the purebred black-and-white animals. The most considerable results were marked at hybrid heifers with relative density of concentrates in a ration of 20% which in accordance with slaughter weight indexes surpassed the herdmates of black-and-white breed on 39,1 kg or on 23,68%, in accordance with slaughter yield - on 8,2%, in accordance with fresh carcass weight - on 37,9 kg or on 23,8%, in accordance with weight of inner porc - on 1,19 kg or on 20,62%.

In the conditions of the Republic of Belarus there were analyzed productivity indexes of sows of different families and family groups and their compatibility with male pigs of different lines of Belarusian meaty breed and Landras. On the basis of the realized research it was marked, that according to the number of piglets in a litter and multiple pregnancy distinctions between breeding sows of Landras breed and Belarusian meaty there was not observed. From sows of both breeds in average per farrowing there was obtain 11,0 - 11,2 piglets, including 10,4 - 10,5 live piglets, that exceeded requirements of the first class of the instruction on evaluation of pigs on 4,0 - 5,0%. At the same time, sows of the Belarusian meaty breed had litter weight at weaning in 40 days of 104 kg, that was authentically higher on 8 kg or on 8,3% (Р less than 0,001), than sows of Landras breed. In each breed there were some distinctions in sow productivity by families and in breeding with boars of different lines.

In the conditions of the Republic of Belarus there was analyzed the efficiency of application of an adsorbent mycotoxins Toxfin Dry (Belgium) for lowering of toxicity load on broiler chickens. In the course of the study there was given attention to poultry productivity, viability and forage expenses for broiler chickens breeding. There was developed a scheme of Toxfin Dry preparation feeding to broiler chickens. There were presented the results of weighing of control and experimental broiler chickens during the breeding periods; the basic zootechnical indices in the conditions of introduction Toxfin Dry; economic efficiency of its application. Research results showed that introduction of a mycotoxin adsorbent Toxfin Dry into diets of broiler chickens promoted the improvement of digestion and absorption of mixed fodder nutrients in a gastroenteric tract, that in its turn promoted the increasing daily average weight gain on 4,3%, broiler stock viability - on 2,6%; and to decrease the expenses for forages on 13,9%. On the basis of obtained experimental data it was recommended to include the mycotoxin adsorbent Toxfin Dry into rations of broiler chickens as a dry mix with mixed fodder in a dose of 5 g/kg of forage dry matter.

In the conditions of the Republic of Belarus it was determined that application of monocalcium phosphate in a dose of 10 gram per 1 kilogram of mixed fodder and specified doses of trace elements (cuprum; zink; cobalt; manganese; iodine) in diets of growing pedigree bull calves made it possible to increase indices of body weight of young cattle stock of the third experimental group in comparison with animals of the first and the second groups on 18,3 and 11 kg or respectively on 3,9 and 2,3%; as well as to increase the intensity of their growth. The highest daily average live weight gain was noted at animals of the third experimental group – 1062 grams. It was higher than at bull calves of the first and the second groups respectively on 31,3 and 12,8 grams, or on 3 and 1,2%. Application of monocalcium phosphate in a dose of 10 gram per 1 kilogram of mixed fodder favorably affected the formation of desirable type of sexual behavior and indices of semen production quality. Thus, in the third experimental group in comparison with animals of the first and the second groups the volume of ejaculate was on 0,2 and 0,1 ml higher (or on 5,8 and 2,9%); quantity of sperm in ejaculate - on 0,7 and 0,3 billion, or on 35 and 15%.

In the conditions of the Republic of Belarus there were analyzed the doses and efficiency of application of selenium in composition of a mixed fodder KP-2 in diets of bull calves of at their breeding for meat. In course of the study the was developed a formula of a mixed fodder with various doses (0,1; 0,2; 0,3 mg per 1 kg of a dry matter of a ration) of selenium; there was studied the influence of different selenium doses in mixed fodders on palatability of diets, their digestibility, use of nutritive elements and hematological indexes of animals. Also, there was analyzed the influence of different doses of selenium on bull calves growing intensity. There was given the zootechnical and economic evaluation of usage of selenium for bull calves. Selenium dose of 0.2 milligram per 1 kilogram of dry matter proved to be the most efficient and promoted the increasing of average daily body weight gain on 10.9%.

In the conditions of the Republic of Belarus there was analyzed the productivity of 13-18-month old young stock of cattle which was bred for meat with various levels of energy value nutrition. Also, there were noted their slaughter qualities and chemical composition of meat. Administration of diet rations with an increased level of exchange energy and the best indices of protein fissility rendered a positive influence on productivity of young stock of fattening cattle and made it possible to obtain 1103-1100 gram of body weight gain. As a result, the energy value gain was 22,9-22,6 MJ along with conversion of metabolizable energy at a gain - 24,7-25,3%. Consumption of metabolizable energy per 1 MJ along with body weight gain were within 4,7-5,0 MJ. Feeding of rations with various levels of the studied factor rendered the positive influence on slaughter qualities, made it possible obtain slaughter yield of 53,6-54,6% at an optimum ratio of nutrients in meat. Feeding of bull calves with diets with excessive content (up to 10%) of metabolizable energy made it possible to lower the prime cost of obtained breeding products on 0,55%.