Introduction. The main direction of increasing the productivity of milk is to increase the proportion of heredity of the Holstein breed in the genotype of cows. Industrial breeds in Ukraine are improving due to the increase in the Holstein inheritance in the genotype of cows. The "holsteinization" of the most widespread domestic Black-and-White diary breed is intensively conducted. Currently, the percentage of heredity from Holstein is 90% or more. The negative effect of "holsteinization" appeared in reducing the resistance of animals to diseases that led to the spread of necrobacterial pathology. The control of the spread of necrobacteriosis can be based on genetic markers. Important markers can be the allele of the BoLA-DRB3.2 gene responsible for the formation of adaptive immunity. Due to the ambiguity of the results of "holsteinization", the following tasks were solved: To study the genetic structure of the herd for the BoLA-DRB3.2 gene at the beginning of the "holsteinization" and now. To compare the detected genetic structures with the alleles spectrum of North American Holstein and identify quantitative and qualitative changes in the structure of the herd genotype. To determine the effect of "holsteinization" on the dynamics of milk production and the state of morbidity by necrobacteriosis. Materials and methods of research. Comparison of alleles of population of the Ukrainian Black-Pied Dairy (UBPD) breed and Holstein breed was conducted to detect the consequences of "holsteinization" on milk yield and incidence of necrobacteriosis. The data of the allelic polymorphism of the BoLA-DRB3.2 gene of the UBPD10 (2010, n = 162), UBPD15 (2015, n = 114) and two Holstein populations of the USA and Canada were collected. The allelic spectrum was determined by the PCR-RFLP method. The amplification of the BoLA-DRB3.2 gene was performed using 2-step PCR with the use of primers HLO-30, HLO-31 and HLO-32 and allele-specific PCR. Restriction analysis was performed with endonuclease RsaI, HaeIII, BstYI (XhoII). Restriction fragments were separated by electrophoresis in 4% agarose gel. Counting of allele frequencies was performed taking into account the number of homozygotes and heterozygotes found for the corresponding alleles. To determine the phylogenetic relationships between the populations of the studied herds, genetic distance and genetic similarity were determined by the M. Nei method. Individual dairy productivity of cows was estimated for all lactation (regardless of its duration). Average milk yields were determined as the total volume of milk produced divided by the number of dairy cows. Results and discussion. The breeding measures carried out led to the accumulation of alleles characteristic of the Holstein breed. For Holstein, there are eight alleles with a frequency of more than 4%. It is alleles *03, *07, *08, *11, *16, *22, *23, *24. A high degree of consolidation of weighty alleles can be outlined. In total they occupy 84,6% of allele spectrum of the population. Consolidation of such alleles in the herd of the Ukrainian Black-and-White diary breed is much lower - only 52.2%, although it increased by 6.2% over 5 years. Alleles *10, *13 and *28 are "weighty" for the Ukrainian Black-and-White diary breed, but they are almost non-existent in Holsteins. The genetic similarity of the herd UBPD15 and Holstein increased by ΔI = 0,085, and the genetic distance between the herds of the UBPD increased by ΔD = 0,085 for 5 years. The comparison of the allele spectrum of Holstein and the Ukrainian Black-and-White diary breed shows both the accumulation and the elimination of alleles associated with high productivity. The largest consolidation is typical for alleles *24 (+ 6.75%) and *16 (+ 4.65%). The frequency of "milk" alleles *22 and *08 decreased, respectively, by 4.14 and 1.27%. Alleys, which cause low milk productivity, have the following dynamics: * 23 + 2.53%, *11 – 0.67 and *28 – 0.26. The accumulation of alleles *16 and *23 (7.18%) was found that are associated with predisposition to necrobacteriosis and elimination of *03 and *22 alleles (4.75%) that influence on this disease. Conclusions. It is determined that the role of alleles characteristic for Holstein is increasing in the the Ukrainian Black-and-White diary herd. Breeding measures for holsteinization are conducted in the right direction. There is accumulation of alleles associated with high milk productivity and predisposition to necrobacteriosis. It positively affects the growth of milk production and negatively affects the incidence of necrobacteriosis.

The Major Histocompatability Complex (MHC) determines the immune response to pathogens, and its genes are promising candidates for the search of associations with diseases. A special role is played by BoLA-DRB3 gene, the product of which directly participates in the binding of alien antigens and conditions the specificity of the immune response. The second exon of this gene codes β1-domain of class II antigens, which is necessary for binding a broad spectrum of alien antigens. Exon 2 of BoLA-DRB3 gene is extremely polymorphic, giving the possibility to search the associations of its alleles with various diseases. The article provides the results of the study on polymorphism of alleles of BoLA-DRB3.2 gene for detection of its associations with sensitivity to fusobacteriosis (necrobacteriosis) of cows. The survey was performed using PCR-RFLP method with DNA of blood from 176 cows of two herds of Ukrainian black-and-white dairy breed. As a result of the studies, in the first herd, 25 BoLA-DRB3.2 alleles were found. In the selections of nectobacteriosis susceptible and resistant cows, we found 22 and 21 variants respectively. In the second herd, in the general selection and group of healthy animals, 27 alleles were typed, and 22 in the group of susceptible cows. BoLA-DRB3.2*22 allele was the commonest in both herds in both general selections and groups of nectobacteriosis-resistant cows. In the selection of susceptible animals, the commonest was the variant BoLA-DRB3.2*16. We determined statistically significant associations of BoLA-DRB3.2 alleles with sensitivity to nectobacteriosis of cattle. BoLA-DRB3.2*03 and *22 alleles associate with nectobacteriosis-resistant, while *16 and *23 – with nectobacteriosis-susceptible cows of the both studied groups. Also, in the first herd, another allele was found – *24, indicating close relationship with the disease. The studies of polymorphism of BoLA-DRB3 gene expand the knowledge about genetic peculiarities of the Ukrainian black-and-white dairy breed. The identified molecular-genetic markers could be useful for breeders whose work is oriented towards the formation of herds which are resistant to diseases of the limbs in cattle.

The application of techniques for effective cleaning of milking routes in milking machines is an important way to improve the quality of milk and increase labor productivity in dairy farming. The object of research was the system of washing the milk line of the milking machine with the upper milk line. The problem of rational use of energy resources was solved in the implementation of a routine operation – washing the milking machine. Experimental studies were carried out according to the Box-Benkin plan of the second order for 3 factors (the speed of movement of the washing solution, V; the temperature of the washing solution, T; the duration of the rinsing phase, t). In this case, a mathematical apparatus for planning a multivariate experiment according to the D-optimal plan was used. It was found that with an increase in the speed of movement of the washing solution and temperature, as well as the duration of the rinsing phase, the number of microorganisms on the surfaces of the nodes and elements of the milky line decreases. Milk lines of the milking machine made of any material are better cleaned with a hotter washing solution (40 °C) than with a cold one (20 °C). Thus, when cleaning with a solution of 40 °C of stainless steel and food aluminum, the reduction of microorganisms is 4.3 times, glass – 4 times, and rubber – 4.7. The essence of the experiment was to establish patterns when cleaning the milk line from various materials. The influence of the regime parameters (the speed of movement of the washing solution, V; its temperature, T; and the duration of the rinsing phase, t) on the energy consumption of the milking machine, E, was determined. The compromise problem of rationalizing the washing modes of the milk lines of the milking machine has been solved. Thus, rational mode parameters for the washing system were established: V=2.4 m/s, T=38.2 °C, t=3.2 minutes. With these parameters, the optimization criteria are: N=79 thousand CFU/cm3, Q=23.3 l, E=8.08 kWh

The main objective of research "BoLA and disease" is the need to develop approaches and obtain reliable criteria which would allow to judge about animal genetic predisposition to the disease and about change of its immunological status in the development of pathological process. Genes of class II of main histocompatibility complex have the greatest association to diseases. Now 54 alleles of BoLA-DRB3.2 have been described by PCR-RFLP. The high level of allelic diversity of the gene is caused by necessity of tying a wide range of foreign antigens, which leads to the possibility of its use as a marker for various diseases of cattle. This article presents the results of detecting alleles of BoLA-DRB3.2 gene, which have the expressed relationship with the disease of Ukrainian Black-and-White Dairy cows on necrobacteriosis and can be used as DNA markers of this disease. Diagnosis of necrobacteriosis was set at the basis of clinical, pathological and epizootic data and laboratory results. The blood samples were taken from 114 cows, 43 of which had the disease. Spectrum of alleles of exon 2 of BoLA-DRB3 gene was studied by PCR. 54 alleles were determined in total. Alleles, which have a close relationship with susceptibility or resistance to necrobacteriosis and can be used as DNA markers, were established on indicators of frequency and relative risk (RR) with test on Pearson criterion (χ2). 32 alleles were determined in the experimental group of animals. There were seven alleles with a frequency greater than 5%. The most often determined allele of BoLA-DRB3.2 was *24. It is present in 18% of the animals. And often determined alleles were *22 (7,9%) and *28 (7,5%). Limit higher than 5% was for alleles *08 and * 09 (6,1%), *03 and *16 (5,3%). The lowest frequency of detection was for alleles *06, *25, *31 and *41 (0,4%). Alleles of BoLA-DRB3.2*24 (16,9%), *22 (10,6%), *28 (8,5%), *03 (7,7%), *08 and *10 (6,3%) were often determined in the group of healthy cows. Alleles *06, *14, *19, *25 and *51 weren’t determined in this group. The animals with necrobacteriosis had often alleles *24 (19,8%), *16 (12,8%), *23 (8,1%), *8, *10 and *28 (5,8%). Alleles *01, *11, *21, *31 and *41 weren’t in general. In the three experimental groups 8 alleles were determined with a frequency of over 5% (all herd, healthy and diseased animals respectively). There are four alleles among them presented in all three samples: *08, *10, *24 and *28. Two "informative" alleles (*03 and *22) were found in every the 20th animal simultaneously in two groups of cows – healthy animals and in the total sample. Also two "informative" alleles *16 and *23 were simultaneously in the diseased cows and in the total sample. 11 alleles have significant association with susceptibility or resistance to necrobacteriosis on criterion of relative risk. There are 4 alleles *16 (24,1%), * 18 (5,25%), *25 (5,04%) and *23 (4,41%), indicating the relationship with disease (RR ≥ 2). Four alleles of BoLA-DRB3.2 are significant on criterion χ2 and have a sufficient test of validity for the studied biological objects. Allele *16 shows a very high level test of validity P = 0,999 (χ2 = 16,6). Three alleles *03 (4,93), *23 (4,86) and *22 (4,03) have a minimum acceptable test of validity for χ2 for P = 0,95. 8 alleles: *3 (-7,7), *21 (- ,44), *36 (-3,87), *22 (-3,57), *12 (-3,18), *1 and *11 (-3,13) and *26 (- 2,51) indicate neсrobaсteriosis resistance (RR ≤ -2). Allele would be associated with the disease if the condition performed RR ≥ 2 і χ2> 3,8. There are two such alleles: *16 (RR = 24,1; χ2 = 16,6), *23 (RR = 4,41; χ2 = 4,86). Also "negative" alleles on risk of disease manifest are *18 (5,25) and *25 (5,08), but with insufficient validity of Pearson criterion (respectively 2,45 and 1,66). Allele would be associated with the resistance to disease if the condition performed RR ≤ -2 і χ2> 3,8. There are 2 alleles associated with resistance to necrobacteriosis: *03 (RR = -7,7; χ2 = 4,93) and *22 (RR = -3,57; χ2 = 4,03). Also six alleles (* 01, * 11, * 12, * 21, * 26 and * 36) detected resistance to neсrobacteriosis on high level of relative risk, but with insufficient validity. It should be noted, that allele BoLA-DRB3.2*22, which proved to be a "positive" marker of resistance to necrobacteriosis, has a strong correlation with resistance to mastitis in cows of Ukrainian Black-and-White Dairy (RR = -2,52; χ2 = 5,02) and Ukrainian Red-and-White Dairy breeds (RR = -4,66; χ2 = 11,11) in previous studies. The study of the distribution of alleles of exon 2 of BoLA-DRB3 gene at the Ukrainian Black-and-White Dairy cows, which were healthy and diseased by necrobacteriosis, revealed the alleles which had a close relationship with penchant to this disease (* 16 and * 23) and two alleles associated with resistance (* 03 and * 22). Given the fact that the research was conducted directly on animal blood DNA the detected alleles BoLA-DRB3 should be used as DNA markers in the analysis of susceptibility or resistance to necrobacteriosis of cows.