Trends in the field of animal and of every pig production in particular are stipulated by the effectiveness of the chosen technologies an integral part of which are breeding methods. Working with pig lines is the main focus of selection in breeding herds aimed at consolidating and improving the productive and reproductive qualities of pigs. Ambiguity of comprehensive research as for the line breeding performance and functionality of its methodology outlines priorities for further study of lines, implementing of genetic potential productivity of pigs within the lines and their compatibility. Systematic research and use of the results in herds of large white pigs to determine population characteristics, evaluation of the effectiveness of selected breeding and increasing obtaining high quality piglets based on reasonable selection of breeding pair are especially important.

When combined with pigs of different genotypes, specialized for individual characteristics of parental and maternal lines within the same species the increase if performance of reproductive ability, growth energy, fattening qualities are observed. An important reserve for increasing productivity (5–15%) of different breed of plant types, lines and families in a production conditions is a rational use of methods of interbreed breeding and hybridization. Interline interbreed crosses compared with linear breeding help the increasing of productive qualities of sows for birthrate by 6–8 %, milk – by 1,1–2,4%.

 Using boars lines Douhol, Rekord, Spontus and Champion Turk of large white breed of English selection combined with sows  of domestic type of Large White breed ULW-1 birthrate was 10,3–11,8 piglets per farrow.

Recently, breeding farms in Ukraine engaged in cultivation of Large White pigs, an increase in the number of lines hogs, especially foreign selection is marked.

That is why, the purpose and objective of the study were to investigate the efficiency boars of Large White breed of different lines on reproductive performance of sows.

The analysis of the use of boars line of Large White breed pigs in the breeding nucleus in farm AJSC«AC «Kalyta» of Kyiv region. The material of research were the data of breeding and zootechnical account forms. Reproductive qualities of sows were evaluated according to the following criteria: period of pregnancy, days; general quality of piglets at birth, including live born, heads; nest weight at birth, kg; quality of piglets at weaning, heads; nest weight at weaning, including one head mass, kg; survival rate, %.

To restore breeding stock on the farm one uses most intensively the hogs of the following lines: Vayss (n = 16), Napoleon (n = 13), Royal Turk (n = 12) and Tyakki (n = 11). In all,  6,829 farrowings of sows including 437 emergency ones which is 6,84 % were analyzed. The smallest percentage of accidental litters were found in sows which were inseminated  with the male pig sperm of the following  lines: Danny (3,81 %), Kuyukka (3,52 %) and Champion Boy (2,38 %). The highest percentage of emergency litters were found in sows combined with Gneiss lines (8,39 %), lines of Napoleon (7,92 %), Vayss (7,75 %) and Knark (7,75 %).

The period of pregnancy has a low coefficient of variation in the sows. The figure was mostly 115 days while in the sows which were inseminated with the male pig sperm of two lines of Orion and Champion Boy it was 114 days.

The total number of piglets at birth in sows ranges from 11,51 to 12,30 piglets. The greatest number of piglets at birth, including live ones was found  in sows which were inseminated with the male pig sperm of two lines of  Royal Turk and Champion Boy, the smallest number was found  in sows which were inseminated  with the male pig sperm of the lines Marshall and Knark. The smallest percentage of live piglets at birth was found in sows which were inseminated with the male pig sperm of the lines Danny (92,04) and Knark (92,64), the largest – in sows which were inseminated  with the male pig sperm of the line Marshall (95,28). Live nest weight at birth in sows ranges from 15,92 (line of Denni) to 17,21 kg (line of Orion).

The smallest number of piglets at weaning was found in sows which were inseminated with the male pig sperm of the lines Knark (9,75) and Orion (9,94). The largest number of piglets at weaning was found in sows which were inseminated with the male pig sperm of the lines Champion Boy (10,41). The greatest nest weight at weaning was found in the offspring of lines Marshall (192,97 kg) and Champion Boy (196,35), the lowest – in descendants of line Royal Turk (173,79 kg). Live weight per head at weaning of piglets was the largest in the line Orion (19,38 kg), the lowest – in pigs of line Napoleon (17,19 kg). Piglet survival ranged from 85,17 (line Lafet) to 87,90 % (line Champion Boy).

The greatest number of piglets at birth, including live and at weaning were found in sows which were inseminated with the male pig sperm of the line Champion Boy. Also, the descendants of this line were characterized by the highest nest weight at weaning and nest survival. In females, which were inseminated with the male pig sperm of the line Danny the lowest percentage of live pigs and nest weight at birth was found. In sows which were inseminated with the male pig sperm of the line Orion the highest percentage of live pigs, nest weight at birth and the average weight per head at weaning was found. The descendants of line Napoleon were characterized by smaller nest weight including the average weight per head at weaning.

According to sows reproductive performance the analysis of boars usage efficiency of large white breed of different lines was made. Among 6,829 litters of sows 437 accident oncs were found which is 6,84%. The most intensively used in economy lines are the following: Vayss, Napoleon, Royal Turk and Tyakki. The total number of piglets at birth in sows ranges from 11,51 to 12,30 piglets. The highest percentage of live piglets at birth was found in sows which were inseminated with the male pig sperm of the line Marshall (95,28). Live nest weight at birth in sows ranges from 15,92 to 17,21 kg. The greatest nest weight at weaning was found in the offspring of lines Marshall (192,97 kg) and Champion Boy (196,35 kg). Piglet survival ranged from 85,17 (line Lafet) to 87,90% (line Champion Boy).

In further research combinatorial ability of pigs of Large White breed specific of genealogical lines and families will be studied.

Key words: Large White breed, pigs, boars, sows, line, survival, reproductive ability, farrowing.