Determination of possible relations between some metabolic activity indexes of Large White pregnant sows (with various pregnancy stages) and their offspring was realized in the conditions of the Republic of Belarus. In the experimental animals there was taken blood for hematologic and biochemical tests. In peripheral blood there was analyzed the average content of hemoglobin, total number of erythrocytes, leukocytes, thrombocytes and corpuscular volume. Content of total protein, albuminolesterin, concentration total kalium and nonorganic phosphorus, magnesium, iron, zinc, activity of alanine- and aspartate transaminase were evaluated in blood serum. Blood tests were made on 84th day of pregnancy, in 30 days before farrowing, on the 2-nd lactation day and on the 2-nd and 35-th days of piglet life. Research results showed high degree of persistence of iron and zinc deficiency of pregnant sows in the conditions of modern national swine production. The obtained results proved the presence of close relationship between metabolic processes of sows and piglets that was revealed in low degree of stores supply with elements which had been in deficit for their mothers

Determination of a degree and stages of metabolic disorders of aborted sows and sows which gave birth to dead fetus was realized in the conditions of the Republic of Belarus. Analysis of biochemical profile of blood of experimental sows was given. Typical deviations of biochemical status indexes in the conditions of reproduction pathology were determined. The highest degree of deviations of biochemical blood profile (indexes of fat, protein and mineral metabolism) was stated at aborted sows. At sows which gave birth to dead fetus there were stated abnormalties functional state of kidneys and liver, indexes of carbohydrate and mineral metabolism.

Comparison of morphological changes in placenta in the conditions of physiological pregnancy and pregnancy complicated acute asphyxia in farrow with deadborn piglets was realized in the conditions of the Republic of Belarus. There were realized complex clinical and morphological studies of placenta of pregnant sows. The experimental group was formed by pegnant sows with intranatally dead fetus because of acute asphyxia in course of farrowing caused by abnormality in placental circulation(prolapse of funis or loop of cord). The second (control) group consisted of healthy bred sows with physiological farrowing and alive newborn piglets. The groups were comparable to age, number of farrowings (no more two) and housing conditions. Detailed macrographic examinations of placenta (form, size, square, weight, volume, fetus-plecentary coefficient, amnion status and so on) and cord were realized. The research result showed that in the conditions of a complicated pregnancy in the thickness index placenta there were visualized a lot of connective tissue changed locus, infarcts as well as areas, and changes in morphometric indexes. All mentioned above factors proved to be a morphological substrate of fetoplacental insufficiency, which subsequently caused asphyxia, hypoxia, small-for-gestational-age fetus, and dead birth

Results of estimation of metabolic processes state in pregnant sows at different stages of sow pregnancy realized in the conditions of the Republic of Belarus were presented. Research results showed that there were changes in the analyzed indexes (total protein; albumins; total lipids; triglycerids; lactate; urea; creatinine; glucose; cholesterin; bilirubin; ALP; AAT; SGPT; amylase; gamma GTP; calcium; phosphorous; magnesium; iron) of biochemical blood profile at different stages of sow pregnancy. The most expressed divergences of the analyzed indexes were stated at pregnant sows on the 90-th day of pregnancy (10 out of 19 indexes) which were caused first of all by feeding uncertainty. It was established that level of total lipids was low during all analyzed pregnancy days, notably that the lowest indexes were registered on the 60-th day period (2,81+/-19 g/l). The lowest level of triglyceride (0,12+/-0,04 mmol/l) was stated at the same period ,too. At a later stage, this index was within the limits of physiologic standard. High level of urea in blood was registered on the 80-th day of pregnancy. Low indexes of glucose were stated on the 90-th and 100-th days of pregnancy (3,44+-/0,63 and 3,38+/-0,26 mmol/l, respectively). High level of cholesterol was stated in course of all pregnancy stages. There was low content of protein in blood in 20% of pregnant sows at the second stage of pregnancy. High indexes of creatine were registered in 80% of animals, urea – in 20% of animals. High content of bilirubin was noted in 23% of pregnant sows, high concentration of lactic acid – in 100% of animals; low content of glucose – in 38%, low level of lipids in blood – in 61%; low level of triglyceride – in 23%

Determination of influence of polymorphism of gene of erythropoetin receptor (EPOR) on productive qualities of sows and reproductive characters of boars of Belarusian meaty breed was realized in the conditions of the Republic of Belarus. Research results proved the possibility of EPOR gene application as a genetic marker which determined productive abilities of swine of Belarusian selection breed. Frequency of undesirable allel EPOR**c of EPOR gene in the analyzed swine stock balanced within the frames of wide range: from 44% for Belarusian meaty breed sows up to 78% for Belarusian Kripnaya Belaya breed sows. Analysis of influence of genotype with EPOR gene on multiple fetation of sows of Belarusian meaty breed showed that sows with the preferred genotype (EPOR**tt) statistically reliable (P less than 0,01) exceeded sows with undesirable genotype (EPOR**cc) in accordance with number of alive birth piglets on 1,7 heads. Among sows of Belarusian Kripnaya Belaya breed with genotype EPOR**ct there were stated multiple fetation indexes exceeding the sows with genotype EPOR**tt on 0,5 heads. Desirable EPOR**tt genotype irrespective of sow age rendered the positive influence on their multiple fetation. It was recommended to realize genetic testing on determination og polymorphism of gene of erythropoetin receptor among the animals of Belarusian meaty and Belarusian Kripnaya Belaya breeds. Selection of parental pairs of the selection nucleus was recommended to realize taking into consideration genotypes, giving preference to animals with EPOR**t allel

In the conditions of the Agricultural Complex Belaya Rus the highest productive values of sows are obtained in period of the fourth-sixths farrowings. The highest level of reproductive traits is shown by sows of Landrace and Belorusian meaty breeds

In course of a long-term selection breeding activities in the conditions of the Republic of Belarus on the basis of Belarusian Large White breed of swine there were created two high-productive lines - Delfina 37755 and Svitanka 3884. Individual selection of animals was realized in accordance with the main indexes of productive ability, development and conformation type. There were selected parent lines, there were used methods of intrastrain breeding and hybrid between lines, mild inbreeding on parental line. Bores and breeding sows were evaluated in accordance with their posterity productivity by means of a control feeding method. Productive indexes for Delfina 37755 line were 11,7 piglets, for Svitanka 3884 line – 11,9 piglets; age of live weight gain of 100 kg – 189 and 182 days, respectively; average daily weight gain – 735 gram and 749 gram; forage expenses – 3,5 and 3,51 fodder units; backfat thickness – 27,2 and 26,2 mm; ham weight – 10,9 and 11,2 k, respectively

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

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.

The analysis of data on a complex of reproductive qualities crossing sows has shown, that the combinations used in the classical scheme of variable crossing have appeared are less effective in comparison with the combinations including foreign meat breeds. It is recommended to change the traditional scheme of variable crossing, having excluded from it the Belarus black-motley breed and having entered foreign breeds of L and D and also to use hybrid male pigs (D x P)