Recent studies have shown that bovine leukemia virus (BLV) sequences can be classified into seven distinct genotypes based on full gp51 sequence. This classification was based on available sequence data that mainly represented the BLV population that is circulating in cattle from the US and South America. In order to aid with a global perspective inclusion of data from Eastern Europe is required. In this study we examined 44 BLV isolates from different geographical regions of Poland, Belarus, Ukraine, and Russia. Phylogenetic analysis based on a 444bp fragment of env gene revealed that most of isolates belonged to genotypes 4 and 7. Furthermore, we confirmed the existence of a new genotype, genotype 8, which was highly supported by phylogenetic computations. A significant number of amino acid substitutions were found in the sequences of the studied Eastern European isolates, of which 71% have not been described previously. The substitutions encompassed mainly the C-part of the CD4+ epitope, zinc binding peptide region, CD8+ T cell epitope, and overlapping linear epitope E. These observations highlight the use of sequence data to both elucidate phylogenetic relationships and the potential effect on serological detection of geographically diverse isolates.

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A b s t r a c tThe publications concerning the effects of atmospheric pressure on the general patterns of metabolism, reproduction and adaptive capability in animals and humans from 1970 to 2015 are reviewed. The analysis could show that all those investigations were carried out on different mammalia species in different years and were fragmentary. Colossal changes in the Earth's atmosphere occurred over the recent decades, which were caused by the anthropogenic factors; considerable changes in the environment affected the habitats of living organisms. In addition, the rapid development in the livestock farming on the basis of the accelerated selection processes could contribute to the formation of animal breeds characterized by the changed metabolic functions, the affected stress tolerance, and the lower adaptive capabilities. That enabled us to conduct a survey to ascertain the effect of atmospheric pressure variability on the qualitative and quantitative semen parameters for bull sires of a modern selection. The survey was carried out in the Center for Animal Biotechnology and Molecular Diagnostics, the L.K. Ernst All-Russia Research Institute for Animal Husbandry, on the basis of the Head Center for Reproduction of Farm Animals. The collection, evaluation, freezing, thawing, and the use of the pedigree bull sire semen were carried out according to the National Technology (edited by N.M. Reshetnikov and A.I. Abilov, 2008). A total of 472 ejaculates of bull sires aged 2 to 10 years were analyzed in January, 2012. The atmospheric pressure varied in that period as follows: lower 755 mm Hg, from 755 mm Hg to 765 mm Hg, and over 765 mm during the periods of 7 days, 9 days, and 15 days, respectively. The ejaculate volume (ml), concentration (milliard per ml) and motility of spermatozoa with the progressive forward movements (PFM) (grades) were analyzed after the collection, freezing, thawing, and in 5 hours of incubation at 38 С; the total number of spermatozoa per ejaculate (milliard), sperm defects (%), number of frozen semen doses per ejaculate, and the supposed loss of the semen doses caused by the sperm defects depending on both the variables of atmospheric pressure and the age of animals were examined comparatively. The obtained data were processed; the statistical reliability was calculated by the Stewdent's t-criterion. It is ascertained that the atmospheric pressure substantially affects the quantity and the quality of the obtained sperm products. These effects can be neatly traced by the number of sperm defects at sampling with defining a statistically valid value (P > 0.001). The bull sires aged 2.5 to 5 years are found to be more adaptive to the effects of various environmental factors. It is determined that the culling rate of the native semen samples by the activity parameter decreases with increasing the atmospheric pressure. The distinct dependency of the decrease in motility of sperm after the incubation at 38 С from the increase in the atmospheric pressure was revealed. The best value for the nu...

S u m m a r yThe association study of BLV status (carrier, non-carrier) with the level of milk productive traits in Black and White cows of different lactation periods was performed. The blood samples were derived from the whole herd including 382 cows of fist lactation period, 253 cows of second lactation period and 197 cows of third lactation period. The presence of provirus form of BLV in blood leuco-cytes was detected by nested PCR using developed system. Based on results of PCR analysis the cows received BLV + or BLV -status. The increase of the number of cows with BLV + status from 28.5 per cent of fist lactation period cows to 36.1 per cent of third lactation period cows was observed. The significantly higher BLV prevalence (+9.0…+ 21.7 per cent) in fist lactation period cows with the «mean» (within Xaverage±σ) and «high» (more than Xaverage+σ) levels of milk productive traits (milk yield, fat content, milk fat and protein yield) comparing to «low» productive cows (less than Xaverage-σ) was observed. The data analysis in aspect of different milk productive traits indicated the higher differences between the groups differed in milk fat yield (18.3-21.7 per cent, p < 0.999). The tendencies described above in the most of cases were observed in the second and third period lactations' cows. The increase of the level of most milk productive traits (milk yield, fat content, milk fat and protein yield) in cows of different genealogical lines with BLV + status comparing to BLV -status was observed.Keywords: Keywords: bovine leukemia virus, DNA diagnostics, milk productive traits.Breeding cattle for high milk production contributes to changes in animals' health (1). Higher output of milk extends the share of available energy utilized in the synthesis of milk, and thereby promotes a negative energy balance that can be restored for the expense of body reserves, which in turn, causes a partial decline of condition. Such metabolic load is peculiar to high yielding cows as specific type of metabolism associated with increased synthesis and secretion of milk; in most cases it results in metabolic stressviolation of some energetic processes related to, in particular, reproduction and health (2). Metabolic stress during lactation affects the nature of immune response, which was confirmed by K. Kimura et al. (3) who revealed differences in leukocyte patterns of Holstein cows after mastectomy and normally lactating ones. The changed immune profile of high yielding cows is seen as the cause of their susceptibility to diseases (4-9). For example, milk yield and susceptibility to mastitis are linked by the positive genetic correlation varying from 0,24 to 0,55 (5). K.L. Ingvartsen et al. (9) have detected undesirable genetic correlations between milk yield and the incidence of ketosis (0,26-0,65), ovarian cysts (0,23-0,42), mastitis (0,15-0,68), and lameness (0,24-0,48). Increased milk production is also associated with widespread occurrence of bovine leukemia virus (BLV) in dairy cattle. It was shown that Holstein cows of Cana...