Possibility of increasing of meat productivity of ducklings of Temp cross after application of duck parental forms of German selection was studied in the conditions of the Republic of Belarus. In course of study there was revealed the dynamics of changes of live weight and feed expenses for live weight gain of linear and hybrid ducklings; as well as their meat qualities were determined. In course of studied there were used linear and hybrid ducklings obtained after crossbreeding of parental forms of Belarusian and German crosses of Peking breeds. There were formed 8 groups of one-day old ducklings. In the father's line the first (control) group was presented by pure bred line T1 of Temp cross; in the second group – by hybrid NT1 x T1, obtained after the direct crossing of male ducks of NT1 with female ducks of T1 lines; in the third group – by hybrid T1 x NT1, obtained after the backcrossing of male ducks of T1 with female ducks of NT1 lines; in the fourth group the combination NT1 was obtained by NT1 x NT1. In fifth group the maternal line was presented by pure line of T2 Temp cross (control); the sixth group was presented by hybrid T2N x T2 obtained after direct crossing of male ducks of T2N line with maternal ducks of T2 line; in the eighth group the combination T2N was obtained by T2N x T2N. Research results showed that application of Germal ducks in schemes of crossbreeding rendered the positive influence on live weight increasing of ducklings of father's line. In the carcasses of hybrid ducklings of all studied crossbreeds there was stated the decreasing number of skin with adipose layer and increasing number muscles including the pectoralis

Determination of genetic structure of different population lines of Belarusian white-and-black breed in accordance with locus of kappa-casein gene (CSN3) was realized in the conditions of the Republic of Belarus. In course of study there were used DNA samples of Belarusian white-and-black breed cows (380 samples) and bioprobes of servicing bulls (83 samples). With the help of endonuclease Hindill there were revealed two alleles of kappa-casein (A and B) in DNA preparations. As a result of genetic typing of breeding animals by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods there were revealed three genotypes CSN3**AA, CSN3**AB, and CSN3**BB. The frequency of occurrence of desirable genotype CSN3**BB of Belarusian white-and-black breed of cows depending on breed and linear pertain varied from 2,2% up to 7,69%, for servicing bulls – from 0 up to 11,1% . The majority of homozygotic cows with undesirable cow genotype CSN3**AA belonged to the following lines: of Ruties Edward (2,31646 - 92,3%), Niko (86,0%), Vis Ajdal (933122 - 71,9%), Reflection Sovereign (198998 – 63,9%). The desirable CSN3**BB genotype in most of the cases was stated at Annas-Adema (30587) and Hiltes-Adema (37910) lines. Presence of heterozygote genotype predominated in Annas-Adema (46,1%) and Montvik Chiftein (36,3%) lines. Realized analysis of cow population lines of Danish and Holstein breeds showed that the average frequency of occurrence of CSN3**B allel was 17%, but lower concentration (15%) of CSN3**b allel was typical for the Danish breeds. Frequency of occurrence of CSN3**B allel in Holsten lines was 18%. In was revealed that in 86,6% of cases bulls were the genetic carriers of CSN3**A allel and only 11,4% of animals had the desirable allel CSN3**B in their genotype

Determination of a degree of manifestation of immunomorphological changes in immune system organs of piglets vaccinated against salmonellosis, pasteurellosis and streptoccocusis with SPS vaccine (against salmonellosis (Salmonella), pasteurellosis (Pasteurella) and streptococcus) in combination with immunostimulative drugs and without them was realized in the conditions of the Republic of Belarus. Piglets of 30-35 days old were divided into 4 groups according to the analogue principle. Piglets of the first group were vaccinated against salmonellosis, pasteurellosis and streptoccocusis by SPS vaccine. Piglets of the second group were vaccinated by SPS vaccine with vitamin C. Piglets of the third group were vaccinated by SPS vaccine with immunotstimulant sodium thiosulphate. The fourth (control) group of animals was administrated with normal saline. Animals were immunized twice, intramuscularly with 7 day interval in dose of 4 ml (primary), and 5 ml (secondary). Vitamin С was administrated in dose of 0,05g per head. Sodium thiosulfate was administrated in combination with the vaccine in 30% concentration. The research results showed that immunization with SPS vaccine in combination with sodium thiosulphate and vitamin С promoted the activation of morphological reactions in tissues at locus of vaccine administration, lymphodnudus and lien. Immunization of piglets by SPS vaccine with sodium thiosulphate and with vitamin С activated the limphiod, micro- and macrophage reactions at locus of vaccine administration, as well as in organs and cells there was stated the well-marked vitamin C and glycogen distribution. Sodium thiosulphate showed higher immunostimulate influence in comparison with vitamin C

Experimental application of a vaccine against salmonellosis, pasteurellosis, and streptococcosis (SPS) for piglets of 30-35 days was realized in the conditions of the Republic of Belarus. Research results showed that administrationof sodium thyosulphate and vitamin С in combination with SPS vaccine promoted the statistically-valid increasing of preventive properties of blood serum of piglets and increasing of titers of specific antibodies to agents of pasteurellosis and a salmonellosis in 1,3-2 times, as well as increasing in blood serum of quantity of immunoglobulins and to reduction of quantity of globulins.

Results of studying the efficiency of iodine containing preparation Jodon which was applied to highly productive cows with hypovarianism and to servicing bulls in order to increase their reproductive function realized in the Republic of Belarus were presented. On the basis of realized studies there was proved the considerable efficiency of Jodon preparation.

The historical and modem data on morphology of adrenal glands were analysed on the basis key historical manuscripts of XVII and XIX centuries were analyzed in the conditions of the Republic of Belarus.

Economic efficiency of immunization of piglets with a vaccine against a salmonellosis, pasteurellosis and streptococcosis in combination with 20% solution of sodium thiosulfate and Vitamin С as immune stimulators was analyzed in the production conditions of the Republic of Belarus.

Evaluation of efficiency of chelate forms of trace elements in rations of pregnant sows as a factor of improvement of their production indices and quality of obtained litter. It was determined that introduction into pregnant sows rations of chelate forms of zinc and iron starting from the 84th day of pregnancy and till farrowing led to authentic increasing of milk yield, weight of a litter at birth and at weaning periods, to increasing of live weight of obtained litter, and also proved to be a form of hypothrophics prevention in piglets.

In the conditions of the Republic of Belarus there was developed a production technology and there were produced samples of lyophilizated live vaccine against Aujeszky's disease of swine which corresponded to all parameters of control. The vaccine had an expressed phylactic power, induced the development of long-lived immunity of vaccinated piglets.

Morphological and structural changes in bone marrow of piglets which were immunized with produced in the Republic of Belarus SPS vaccine (against salmonellosis (Salmonella), pasteurellosis (Pasteurella) and streptococcus) in combination with immunostimulants and without them were analyzed in the conditions of the Republic of Belarus. Piglets of the first group were vaccinated against salmonellosis, pasteurellosis and streptoccocusis by SPS vaccine. Piglets of the second group were vaccinated by SPS vaccine with vitamin C. Piglets of the third group were vaccinated by SPS vaccine with immunotstimulant sodium thiosulphate. The fourth (control) group of animals was administrated with normal saline. Animals were immunized twice, intramuscularly with 7 day interval in dose of 4 ml (primary), and 5 ml (secondary). Vitamin С was administrated in dose of 0,05g per head. Sodium thiosulfate was administrated in combination with the vaccine in 30% concentration. Alongside with myelogram there were derived formulas of different cell groups of bone marrow: leucoerythroblastic index; intramedullary index of neutrophil maturity; intramedullary index of eosinophile maturity. Detailed myelogram of piglets on the 14-th day after the second immunization was presented. Research results showed that in all groups of vaccinated animals there was noted the activation of myeloblastic hematogenesis and decreasing of erythropoeisis. Piglet immunization was accompanied by strengthening of myeloblastic hematogenesis, increased number of lymphocytes and plasma cells in bone marrow