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

In course of realized in the conditions of the Republic of Belarus evaluation of growing intensity and level of meat productivity depending on cattle sex there was conducted the scientific and economic experiment by an example of two groups of white-and-black bull-calves and heifer calves. In the first growing period the animals of experimental groups were fed with milk substitute. At the stage of completion of growing and fattening the bulls and heifers of experimental groups obtained ration containing haylage, plus 2 kg of flattened grains and 2 kg mixed fodders. Results of linear and weight indexes analysis showed that in changes of exterior of bulls and heifers of black-and-white breed there was noted a certain regularities in their growth and development. The most intensive growth and development of analyzed young cattle was stated at age from 6 till 12 months. At the same time, bulls exceeded heifers according to the main exterior indexes. According to the visual evaluation of bulls and heifers there were determined the differences in constitutional type

An effort to demonstrate the mechanism of homeostatic alteration of high-producing cows at the period of increasing milking capacity and peculiar features of its changing in the conditions of introduction into cattle diets of carbohydrate containing and carbohydrate compensative additives was realized in the conditions of the Republic of Belarus. In course of the experiment there were used white-and-black breed cows of 3-4 lactations with body weight of 700 kg and milk yield over the last lactation of 7000-8000 kg of milk. Experimental cows in two weeks before the supposed calving were administrated with 50 ml of propylene glycol, 6 g of niacin and 50 ml of glycerin; and in course of 60 days after calving the administration of the additives was realized in doses of 125 ml; 6 g; 50 ml, respectively. Research results showed that application of mentioned above additives rendered the positive effect on cow liver that was proved by the improved hemic function of experimental cows: increasing of quantity of erythrocytes, hemoglobin, and hematocrit

Investigation of peculiar features of productive and reproductive qualities (milk producing ability; reproductive qualities; live weight at different ages) of milking cows of white-and-black breed was realized in the conditions of CJSC Lipovtsy of Vitebsk region of the Republic of Belarus. On the basis of obtained results there was calculated the selective differential of milk yield and butter-fat yielding capacity which were increased by means of maternal and father's cattle; genetic progress through selection in reliance on generation and target standard for the analyzed herd, as well as the minimal requirements to first-calf heifer productivity.Research results showed that average milk yield in the analyzed herd was 5204 kg with average butterfat percentage 3,59%; for first-calf heifers – 4838 kg with butter-fat yield of 3,47%. Productivity of first-calf heifers and cows was higher than the standard valuation requirements to milk yield on 1350-1588 kg

Determination of regular variations of macromorphological and topographical characteristics of thymus gland, spleen, thyroid gland, and atrabiliary capsules of swamp beavers (Myocastor coypus) at the postnatal ontogenesis was realized in the conditions of the Republic of Belarus. Taking into consideration active participation of immune and endocrine system organs in metabolic processes and vicarious and adaptive reactions there were revealed species and age-specific anatomical peculiar features of thymus gland, spleen, thyroid gland, and atrabiliary capsules of swamp beavers that made it possible to broader knowledge in the sphere of species, age-specific, breed and topographic anatomy

In the conditions of the swine breeding complex in the Republic of Belarus where had been applied the three-way crossing and self-replacement of swine herd there was studied the productivity of swine depending on duration of their embryonic development. There was developed new method of selection replacement gilts which made it possible to select a breeding swine flock with high adaptation abilities to the industrial housing conditions. Research results showed that the duration of pregnancy in the conditions of three-way rotational crossbreeding and self-replacement of swine herd was 114,5 +/- 0,03 days with variance between 103 and 121 days. In the majority of breeding sows (93%) the duration of pregnancy period was within the limits from 112 up to 117 days. Season of a year rendered influence on the duration of sow pregnancy: the longest one was in winter and spring, the shortest – in summer and autumn. With advancing age there was stated the increased duration of pregnancy period. Difference in duration for first-pregnant sows and sows with 8 farrows was 0,51 days. With increase of pregnancy duration there was noted the lowering of multiple fetation, but there was the increasing of live weight of piglets at birth, their growth energy and viability

Analysis of the main indexes of embryo productivity of cow donors with a view to application of progestagenic intravaginal devices in technology of cattle embryo transplantation was realized in the conditions of the Republic of Belarus. Research results showed that application of progestogenic implants independently of the day luteal phase of sexual cycle in schemes of animal treatment made it possible to regulate the folliculogenesis of cows by mean of formation of new wave of follicles growth that could be used in increasing the efficiency of technology of transplantation of cattle embryos. Application of intravaginal devices in schemes of superovulation treatment of cows made it possible to obtain high-grade results of the main indexes of embryo production of donors in technology of cattle embryo transplantation. The technology of application of implant PRID in course of 7 and 9 days in the luteal phase of sexual cycle of donors proved to be the most optimal. It was determined that the indexes of quality composition of embryos, transplantability of fresh and frozen embryos obtained from cows induced by superovulation with application intravaginal devices corresponded to the control indexes. Application of progesterone extracting implants in the schemes of donor cows treatment schemes did not render influence on obtaining of viable animal yield after transplantation of biological material to recipients

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

Studying of palatability of bait blisters applied for oral immunization of wild carnivores against rabies was realized in the conditions of the Republic of Belarus by an example of foxes which were administrated with liquid viral vaccines against rabies. Foxes were divided into 5 groups with 8 animals in each. Animals of the first group were immunized with a liquid viral vaccine in blister baits Lisvulpen-VBF which was produced from an attenuate strain of rabies virus SAD-BERN (Belarus). Animals of the second group were immunized with liquid viral vaccine Belvak TM BP produced from the cultural living strain KMIEhV-V101 (Belarus). Animals of the rest three groups were immunized with liquid viral vaccine in blister baits which was produced from a modified strain of a fixed attenuate rabies virus KMIEV-94. Foxes of the forth group were additionally fed with ascorbic acid with baits in the doze of 0,1 g, and foxes of the fifth group were fed with 5 ml immune response modifier Nuklevit. All mentioned blister baits were studied in accordance with the following parameters: bait flavor and attraction to animals; form and size of bait; bait consistency; blister and its size in relation to bait; palatability of bait; degree of damage of bait containing a vaccine; quantity vaccine which was got into animal oral cavity; postvaccinal complication. Palatability of liquid viral vaccines in blister baits Lisvulpen-VBF was 96%, Belvak TM BP - 94%, KMIEV-94 - 80%

Influence of potassium orotate on hematological, immunomorphological indexes and and marrowy myelopoiesis of broiler chickens in the process of oral associated immunization against infectious bronchitis and poultry Newcastle disease was investigated in the conditions of the Republic of Belarus. There were studied 60 broiler chickens divided into 3 groups: one control group and two experimental ones. Research results established that potassium orotate application in combination with associated poultry immunization against infectious bronchitis and Newcastle disease increased the number of leucocytes and the volume of adenoid tissue as well as raised the lymphocytes density in thymus and bursa of Fabricius. In the bone marrow aspirates in 7 days after immunization in the control group there was stated the increasing of basophilic myelocytes number in comparison with the second experimental group. In 14 days in the control group there was noted the increasing of a total number of basophiles. In 21 days after immunization there were stated no considerable changes in the composition of basophil cells in the experimental groups. Research results showed that potassium orotate intensively stimulated the development of plasmocytic reaction in the conditions of multipartial immunization