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

Analysis of the main indexes of embryo productivity of cow donors with a view to application of progestagenic intravaginal devices in technology of cattle embryo transplantation was realized in the conditions of the Republic of Belarus. Research results showed that application of progestogenic implants independently of the day luteal phase of sexual cycle in schemes of animal treatment made it possible to regulate the folliculogenesis of cows by mean of formation of new wave of follicles growth that could be used in increasing the efficiency of technology of transplantation of cattle embryos. Application of intravaginal devices in schemes of superovulation treatment of cows made it possible to obtain high-grade results of the main indexes of embryo production of donors in technology of cattle embryo transplantation. The technology of application of implant PRID in course of 7 and 9 days in the luteal phase of sexual cycle of donors proved to be the most optimal. It was determined that the indexes of quality composition of embryos, transplantability of fresh and frozen embryos obtained from cows induced by superovulation with application intravaginal devices corresponded to the control indexes. Application of progesterone extracting implants in the schemes of donor cows treatment schemes did not render influence on obtaining of viable animal yield after transplantation of biological material to recipients

Investigation of quality and quantity indexes of sperm production of boars of Yorkshire, Landrace, Duroc breeds of Danish selection was realized in the conditions of the Republic of Belarus. Quality and quantity indexes were analyzed in accordance with ejaculate volume, spermium concentration and activity at different age-specific periods in the comparative aspect. Thorough analysis of quality indexes (ejaculate volume; spermium concentration; spermatozoon motility; sperm quantity) of semen production of studied breeds at different age-specific stages (before 7 months old; 7-10 months; 10-12 months; 12 months and older) was presented. Coefficients of variation of valuation indexes of semen production were stated. Research results showed that the lowest ejaculate volume was typical for boars of Duroc breed, but the quantity of spermium in ejaculate of this breed since 10-month old age was the highest – 92,6 milliard, that made it possible for this breed of boars to take premier place according to the index of spermium quantity in ejaculate. The same index for boars of Landrace and Yorkshire at age of 12 months old and older was 77,5 and 76,3 milliards, respectively. High variability of indexes of evaluation of semen production was due the reason that the research was taking place at the period of formation of productivity over the whole pig stock. Research results proved that indexes of semen production of producer boars of Yorkshire, Landrace, Duroc breeds of Danish selection depended on the breed and high variability indexes

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

Selection of an optimal dose of Cryptosporidium parvum agents which were isolated from swine and could cause expressed changes in organs of experimentally infestated mice was realized in the conditions of the Republic of Belarus. Data about on persistence of homoxenous coccidia Cryptosporidium parvum at laboratory white mice and pathomorphological changes in the bodies of experimental animals were presented. In a mucous coat of intestines there was marked a catarrhal inflammation with mucous membrane necrosis and its infiltration by leukocytes and macrophages.

This article is devoted to a problem of biochemical interaction of selenium and antioxidational system of animals and people organism. The problem we have touched is about the efficiency of influence of organic and inorganic taking place on subcellular level. The advantages of organic selenium are proved, the degree of its bjochemical influence on an antioxidationi status of health are indicated.

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.

A method of development of highly purified antigen of a virus of classical swine fever (Sinlak strain) for definition of antibodies in enzyme multiplied immunoassay (ELISA) was tested in the conditions of the Republic of Belarus. There were determined parameters of sensitivity and specificity. There was developed a method of partial purification of the antigens by means of obtaining of infected leukoconcentrate, settling of virus by means of ammonium sulfate with the further ultrafiltration through a membrane

In the conditions of the Republic of Belarus after fasciolosis invasion of cattle for the biochemical diagnostics of liver pathologies there was composed a hepatospecific metabolic profile of blood serum of cattle into which there were included several enzymes (alanine aminotransferase; aspartate aminotransferase; gamma-glutamyl transpeptidase; alkaline phosphatase; and cholinesterase), content of total albumin, serum albumin, total cholesterin and total bilirubin, as well as colloid tests (thymol turbidity test and test for apoliproteins). There was revealed a intrahepatic cholestasis developed during fasciolosis infestation, as well as dysproteinemia as a compensatory mechanism of liver proteinsyntetic function.