Beef production in the Republic of Belarus could be competitive only in case of development of the specialized beef cattle breeding. Therefore, for the increasing of beef production and improvement of its quality in Belarus there was noted the necessity to use cattle beef breeds both in case of straightbred breeding, and in crossing with low income-earning Black-and-White cow stock. Research results showed that hybrid Gereford x Black-and-White breeds of the first and second filial generations showed higher reproductive abilities which were manifested in 105-120 days age reduction at the stage of the first insemination, 18-44 days reduction of service period, 0,07-0,1 times increasing of breeding efficiency index, 9,8-14,4% increasing of calf crop per 100 dams, and 14,4-16,4% increasing of young stock livability in comparison with the Black-and-White breeds calves. Research results showed that the non-heating season of the mongrel Gereford x Black-and-White heifer breeds of the first and second filial generations was 396-400 days, breeding efficiency index (rate of fertilization) - 1,29-1,32, breeding performance index - 85,4-90,0%, while for the at Black-and-White heifer breeds the same indices were 425 days, 1,29 and 75,6%, respectively

For the first time in the Republic of Belarus there were developed the effective methods of marker-dependent selections directed towards increasing the performance traits and preventive measures of pig diseases of the Belarusian Large White breeds. Application of the presented techniques in practice made it possible to increase the multiple fetation of sows on 0,5-1,5 piglets, increase livability of stores on 1,1-5,7%, increase the average daily weight gain on 17g, lower feed expenses on 0,04 FU. In course of the realized studies there was studied the polymorphism of Ryr-1, ESR, E.Coli (ECR F 18) FUT 1 and IGF-2 genes, there was developed the efficient methods of marker-dependent selection. Research results showed that application of methods of molecular gene diagnostics proved to be economically feasible. In the conditions of rather low expenses for testing of boars and sows there was stated the considerable increases in economic efficiency of pork production. Creation of reserve populations with a desired genotype breed will make it possible to accelerate the breed-forming process

Development of a new method of boar evaluation taking into account their beef-making and fattening qualities as well as their posterity viability for the further selection of the best ones and for the culling and ranking of the worst ones was realized in the conditions of a large pig-breeding complex of the Republic of Belarus. Scientific and economic experiment was realized at the JSC Sozh, Gomel region (Belarus) at the pig-breeding complex with 108 thousand livestock heads of annual fattening. At a finishing stage of sow hybridization the combinations of Large White х Landrace and Large White х the Belarusian Meaty breeds were inseminates by boars of 990 synthetic lines (N11151 and N11146), the Belarusian Meaty breed (N3495), Landraces of the Polish (N40, N37, N78) and German selection (N11262, N11263, N11266), and also by a hybrid boar of 990 lines х Petren (N11145). Sow insemination was realized in three technological groups. Sows were selected taking into account their breed, age and last productive ability in order to avoid inbreeding. At the same time, each boar was checked up on the breeding stock for identical quality. The final estimation of boars was stated at the stage of achievement by their posterity of selling weight (before sending to a meat processing plant). The offered method made it possible to get an objective comparative estimation of breeding characteristics of tested boars in the conditions of a complex

Influence of 33 imported heads Landrace breed boars of foreign selection on feeding performance and meat productivity of swine of the Belarusian Meaty breed was studied in the conditions of the Republic of Belarus for the enhancement of Belarusian breeds genealogical structure. There was stated the positive influence of Landrace Breed on feeding performance and meat productivity of mixed bred stores obtained after the introductive crossing with sows of Belarusian Meaty breed which was expressed in the predominancy of mixed bred hogs over the purebred ones at the stage of fattening performance test: at the age of reaching 100 kg body weight – on 0,7%; at average daily weight gain - on 1,5%; at feed consumption - on 1,2%. Mixed bred stores also had thinner back fat (on 0,9 mm) and bigger loin (on 0,4 square cm). There was stated the one-sided influence of boars of Landrace Breed on feeding performance and meat productivity indices of mixed breeds. It was established, that hybrids of four lines (Zaboj, Zalet, Zont and Bison) with regard to control groups showed the effect of heterosis at age of achievement of body weight of 100 kg, at a daily average weight gain and at forage consumption in the following rates: 1,5% (Р less than 0,05), 2,8% and 1,5% (Р less than 0,05) for Zaboj line; 2,3%, 4,9% and 2,1% (Р less than 0,01) for Zalet lines; 1,4%, 3% and 1,5% (Р less than 0,05) for Zont lines; 3% (Р less than 0,001), 6,7% and 2,7% for a line of Bison. In meat productivity indices there was stated the in-between character of inheritance which caused the decreasing of fat thickness and increasing of loin eye area at descendants of trial groups of lines: Zaboj, Zalet, Zenit, Zont on 0,88 mm (Р less than 0,05) and 0,6 square cm, 1,7 mm (Р less than 0,01) and 2,1 square cm (Р less than 0,001), 1,3 mm (Р less than 0,01) and 0,9 square cm, 1,4 mm