Firfty serum and fifty semen samples collected from cattle and buffalo bulls were subjected to ELISA and gB gene based PCR, respectively to detect antibodies in serum and viral DNA in the semen against BHV 1. Out of 50 bulls, 15 (30%) serum samples were detected positive by ELISA while 21 (42%) semen samples were positive by gB gene based PCR. While correlating the results of ELISA and PCR, some seronegative bulls revealed presence of viral genome in semen whereas few seropositive bulls could not reveal viral genome in semen, thus, suggesting application of combined serological assay and PCR assay to detect the presence of BHV-1 infection in bulls.

Influence of monocalcium phosphate on natural resistance and clinical indexes of blood of breeding bull calves of white-and-black breed was realized in the conditions of the Republic of Belarus. Bull calves of the first (control) group in the composition of their main ration were fed with mixed fodder K-66-b, hay, green mass and as a balanced phosphoric-potassium additive they were fed with8 grams of defluorinated phosphate per 1 kg of mixed feed. Bulls of the second, third and fourth experimental groups in combination with the standard ration instead of difluoridated phosphate were fed with 5; 10; and 15 grams monocalcium phosphate per 1 kg of combined feed, respectively. Research results showed that application of fodder monocalcium phosphate in addition to the main ration made it possible to increase calcium and phosphorus content in blood of experimental bull calves. In the control group phosphorous content was 2,17 micromole, in the experimental groups – 2,40-2,78 micromole; calcium content – 2,50 and 2,58-2,88 micromole, respectively. The analyzed additive rendered positive effect on protein exchange, increased the natural resistance, bacterial growth-inhibitory activity in blood serum in the third, fourth and second groups on 50,3%, 42,5%, and 40,3%, respectively; lysozyme activity – on 46,0%, 39,2%, and 32,3%, respectively; phagocytic activity of leukocytes – on 21,9%, 25%, and 19,1%

Studying of efficiency of application of modified scheme of hyperimmunization of bull-producers with a designer salmonella polyantigenin in comparative analysis with the production scheme of hyperimmunization was realized in the conditions of the Republic of Belarus. Research results showed that engineered polyvalent antigen for hyperimmunization of producer bulls contained in their formula the following serovariants of salmonella in 1:1 ratio: S. typhimurium 371, S. dublin 373, S. choleraesuis 370, and S. enteritidis CB. The obtained antigen was sterile, harmless and had pH 7,3. Hyperimmunization of producer bulls in the experimental scheme revealed in increasing of leukocytes quantity on 57,3 %, banded neutrophils on 86,7 %, B-lymphocytes - on 42,2 %, content of total protein - on 25,6 %, content of Ig G - on 77,8 %, lg M - on 51,6%. After the fifth administration of antigen there was stated the lowering of agglutinating activity of blood serum on 25%, content of Ig G - on 54,4%, Ig M - on 14,6 %, that indicated to the inefficiency of antigen administration and became the basis for termination of hyperimmunization cycle. Immunobiological reaction of bull-producers which were hyperimmunized by the suggested scheme differed from reaction of animals which were hyperimmunized by the production scheme: content of total protein increased on 10,1%, protein content - on 27,3 %, content of lg G - on 24,8 %, lg M - in 23,7%

Growth and development of mixed bred Charollais x white-and-black young stock and black-and-white bull-calves since 8-month old age till and 15-month old age were studied in the conditions in the Republic of Belarus. In course of studied there were analyzed linear growth; young stock growth intensity; forage consumption; efficiency of experimental results. On the basis of obtained data there was determined the absolute growth rate of bull-calves at certain growing periods. Research results showed that dramatic changing of technology of management and feeding of mixed bred Charollais x white-and-black young stock bulls after weaning period caused the decrease of daily average live weight gain from 8-month old age till and 15-month old age in comparison with white-and-black cattle on 99 grams or 14%. Analysis of exterior of experimental animals confirmed the priority of mixed bred young cattle over white-and-black herdmates. They were characterized by massive corpus, wider and deeper barrel, wide withers, back and coupling

Application in diets of breeding bull calves of an optimum dose of selenium (0,4 mg on 1 kg of a solid of a diet) renders positive influence on formation of reproductive ability of bull-calves: promotes increase daily average gains live weight on 7,1%, indicators of natural resistance – on 0,6-6,7% and to improvement of quality sperm production – on 16,4% during the winter period. During the summer period daily average gains live weight on 6,8%, indicators of natural resistance – on 0,5-13,9% and to improvement of quality sperm production – on 15,7% accordingly

The research in RUP Scientific and Practical Center of Animal Breeding of National Academy of Sciences on such parameters as consumption of forages, processes of rumen digestion, morphological and biochemical structure of blood has shown that usage of wet grain preserved with Kormoplus for young cattle fattening has a positive effect on physiological condition and digestibility of nutrients and promotes nitrogen usage by animals that increases at 7,0 and 1,6%

Feeding replacement calves of 369-460,8 kg of live weight with diets of non-degradable protein level that is 10% higher than approved norm increases metabolically energy transformation into weight gain energy from 19,10 to 20,81 MJ or at 9% that promotes increase of average daily weight gains at 5% and decrease of energy spends at 5% counted per 1 unit of energy for weight gain. Ejaculate volume is increased at 14% and sperm concentration – at 12%

Addition of 0,01 mg/ml epibrassinolid in 100 ml laktoza-gliceryn-yolky thinner during the autumn-winter period has resulted, on the average on groups of bulls, to mobility increase sperms on 10,6 %, the survival rate sperms has increased by 17,9 %, the quantity pathological sperms has decreased on 32,5 %, safety sperm cover has increased by 4,5 %, resistance sperms has raised on 15,6 %, discoloration time blues has decreased on 8,5 %, has allowed to raise percent insemination cows and the calf on 12%

In the conditions of the Republic of Belarus there was developed a method of surgical treatment of servicing bulls with penial tumors including tumor removal by means of gas docker Tail Docker and intravenous 0,5% novocaini solution injection during postoperative stage makes it possible to reduce the duration of surgical operation in 3-4 times, completely remove probability of bleeding, reduce the healing period on the average on 6 days and lower the probability of relapse of tumor.

It is determined that diets with protein digestibility of 61-66% in organism of a calve activate fermentative processes in rumen, increase digestibility of nutrients at 3,8-10,1% that allows to obtain the average weigh gains of 1036-1075 g, that is at 4,2-8,1% higher than that of control group at forage spends of 6,79-7,04 forage units