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The article presents the findings on the dynamics of the live weight of calves of various breeds in similar climatic conditions in arid regions of the Stavropol Krai of Russia and the steppe zone of Ukraine. It has been established that the live weight of calves of the Hereford, Kazakh white-headed and Kalmyk breeds when raised according to the traditional technology of beef cattle breeding when calves are sucked under cows up to 6-7 months of age, is in relationship with the milk qualities of mothers. At the same time, the live weight of the gray Ukrainian calves was interrelated regarding the live weight at birth and the feeding technology. A positive relationship was shown in the live weight of calves at birth and during their implementation at 15 and 18 months of age. Most effectively animals used pasture fodder in spring and summer. In an arid climate, it is more appropriate to breed specialized cattle belonging to the Hereford breed and then sell them for breeding in other farms in the region.

The aim of this study was to investigate the influence of the MyoD1 gene polymorphisms on some body parameters in sheep. MyoD1 polymorphisms were detected using NimbleGen sequencing tech-nology (Roche, USA). The effect of polymorphisms identified was investigated in Stavropol sheep breed rams (n=30). In coding and regulatory parts of gene 26, single nucleotide polymorphisms (SNP) were detected. These were the substitutions: c.-2112C>G, c.-1806A>G, c.-1687T>C, c.-1608C>T, c.-1603G>T, c.-1578G>A, c.-1235G>A, c.-910G>T, c.-909G>T, c.-880G>A, c.-637C>T, c.-412G>T, c.244C>T, c.246G>T, c.253G>T, c.259G>C, c.261C>T, c.269C>G, c.274C>A, c.276C>G, c.277C>A, c.279C>T, c.281C>A, c.287C>A, c.325T>C and c.483C>T. Sixteen of these SNPs have been identified for the first time. The complex of the four SNPs c.-1578, c.-880, c.-637, c.325 and c.-1235 occurred in Stavropol sheep breed only together. The study of the influence of these SNPs on the body parameters of rams showed the absence of significant correlation between their presence and the body size of the animals. The SNPs c.-910 and c.-909 were associated with improved body parameters, but they were found in a very small numbers of animals, which does not allow making definitive conclusions.

The aim of this research was to study the myostatin gene (MSTN) in Russian Stavropol Merino sheep and compare them with Merino sheep from New Zealand (NZ). Thirty rams of the Stavropol Merino breed and ten NZ Merinos were investigated. In order to detect sequence variation in MSTN, enrichment and sequencing of targeted DNA fragments was undertaken using NimbleGen technology. Nucleotide sequence variations (n = 31) were found in MSTN, including 29 single nucleotide polymorphisms (SNPs), one deletion and one insertion. Of these, 21 of the SNPs, the insertion and the deletion, were found in the Stavropol Merino sheep and 17 were found in the NZ Merinos. Eight variations in MSTN are described for the first time: c.373+396T>C, c.374-362A>T, c.374-16delT, c.747+185C>A, c.748-194C>A, c.782_783insT, c.940G>T and c.*310G>T, and these were unique to the Stavropol Merinos. The presence of SNP c.940G>T leads to the formation of a stop-codon (GAA>TAA) and thus truncated protein at amino acid position 314, while the insertion c.782_783insT changes the reading frame and would cause an amino acid sequence change from amino acid position 263 onwards, with the formation of a stop-codon at position 265. The study confirms the presence of additional variability in both non-coding and coding regions of ovine myostatin, which might subsequently be analysed to ascertain whether it affects meat production.

Increase in the degree of consanguinity of Holstein breed identified to the best-cultivated dairy breeds is one of the major ways to improve the genotypes of the dairy cattle in many countries all over the world. The widespread biotechnology and large-scale selection adoption reduced the range of the used bull sires in dairy stockbreeding, which resulted in the occurrence of different abnormalities associated with the inheritance caused by gene mutations and chromosomal disorders in the newborn calves. Since the main part of such abnormalities has a recessive inheritance pattern, they represent a hidden genetic load, which is not always expressed in a phenotype. In recent years, the cytogenetic and karyotyping approaches have become more widespread and are required for both the detailed theoretical prerequisites and the applied problem solutions to prevent losses in agricultural production. The results of the cytogenetic analysis of the North- Caucasian population of Holstein cows having problems in reproduction have been reported. The aberrant cells are detected (frequency of occurrence is 5.35%); the number of aberrations per analyzed cell (0.05/1.0) is determined; the absence of the reciprocal translocations in a karyotype in the analyzed livestock is revealed. The genealogical interrelations of ancestors of the lines of Montivik-Chifteyn no. 95679 and Reflekshn- Sovering no. 198998 bull sires with the values for stillbirth incidence among their progeny have been traced.

One of the new promising candidate genes defining productive qualities of sheep is MEF2B. Protein from the MEF2 group encoded by it affects the production of myostatin and the expression of the genes responsible for the growth of skeletal muscle fibers. Thus, the knowledge of the MEF2B gene structure is important for genomic selection. We have studied the structure of the MEF2B gene at sheep of Severokavkazskaya breed bred in Russia. To detect alleles we use NimbleGen sequencing technology by Roche (USA). As a result, it was revealed 14 single nucleotide polymorphisms (SNP) at the given breed. The discovered SNPare located in not coding areas. From them 7 polymorphisms are in the area of 5' upstream gene in loci: c.-1713, c.-1319, c.-839, c.-321, c.-246, c.-161, c.-3; 6 polymorphisms are in introns, loci: c.55-51, c.258+312, c.258+380, c.259-52, c.452+95, c.452+ 103, 1 SNP is in 3' downstream gene, c.*252. Two of the identified SNPs are significantly connected with high indices of meat productivity: c.55-51 and c.259-52. At the same time it was not possible to find out the impact on productivity of c.-1713 polymorphism. Our investigation is a base of next research of affection of different MEF2B gene alleles on meat quality and can be used to prepare PCR test-system for genomic selection.

Dairy cattle breeding is one of the main suppliers of protein and animal fat, it is one of the most important branches of agriculture and plays a primary role in providing adequate nutrition for the population. During the purposeful work on harmonization of the national regulatory framework with international legislation, special attention is paid to scientific developments in the way of full implementation of Russian livestock production in the global trading system. The recommendations of the International Committee for Registration of Animals (ICAR) (Global Standard…, 2017; Trukhachev et al., 2017) are the methodological basis for the introduction of the generally accepted organizational principles for the recording and evaluation of the productive qualities of animals. One of the stages of this process was implementation in 2015-2017. in the Stavropol State Agrarian University of research projects, especially significant for the agro-industrial complex of the Russian Federation in the direction of ensuring import substitution in animal husbandry (genetic material), which envisage the development of a regional model for the formation and management of highly productive genetic resources for dairy cattle. The object of the research was cattle (cows) of the North Caucasian population of the Ayrshire breed (n = 550), from which, based on the analysis of the materials of the primary zooveterinary records, groups of cows with 3-fold milking were formed to study the daily dynamics of fat and protein content in raw milk samples I, II and III milking, n = 240) and 2-fold milking (I and II milking - 180 cows). In the process of performing monthly analyzes of the quality of individual milk samples obtained from pedigree cows taken for 2- or 3-fold milking, it was found that a certain pattern is observed in the diurnal dynamics of fat and protein content in milk, which probably has a general biological nature and largely depends on the technological factor - the multiplicity of milking cows, which coincides, basically, with the regularities described in the methodology of the International Committee for Registration of Animals (ICAR). The nature of the dynamics of the concentration of fat in milk at 2- and 3-fold milking has, though a different mathematical form, but they have a general tendency: the fat in milk for milking cows, as a rule, is 10.77–10.98 % lower, than II and III milking. The variability of the protein concentration in milk during the day is the same as the fat dynamics, though it is less expressed than of fat and accounts 0.88%. Keywords: milk cows, milk quality, Ayrshire cattle Article DOI: http://doi.org/10.15544/RD.2017.067

One of the ways of improving the genotypes of dairy cattle in Russia is to increase the proportion of the Ayrshire breed, which can be justly claimed to be one of the best dairy breeds in the world. However, due to the prevalence of large-scale breeding technologies, which involves the use of a limited contingent of dairy cattle bulls, including but not limited to the Ayrshire breed, the emergence of new-born calves with various anomalies, including chromosomal, which commonly have a hereditary basis attributable to gene mutations have been observed. Given that the bulk of these anomalies are acquired by recessive inheritance, they may not always manifest themselves in the phenotype and thus represent a hidden genetic load. In recent years, the significance of cytogenetic analysis and karyotyping is becoming increasingly important, not only when considering the theoretical assumptions, but also when solving applied problems aimed at preventing damage to agricultural production. This article presents the results of the cytogenetic analysis of Ayrshire cattle affected by reproductive problems. The following has been established: an absence of changes in the diploid set of the investigated dairy cattle (2n = 60); the presence of aberrant cells, whose frequency of occurrence amounted to 3.6% in the population of 440 head (number of aberrations per aberrant cell researched – 0.036 / 1.0); the absence of reciprocal translocations in the karyotype of the investigated population. It is suggested that the existing Ayrshire sires Hannulan Yaskiyri, Riihiviidan Urho Errant, O.R.Lihting and their descendants do not have a genetic load of chromosomal abnormalities. Keywords: chromosome, karyotype, mutation, Ayrshire cattle Article DOI: http://doi.org/10.15544/RD.2017.141

The Ayrshire dairy breed is renowned for producing large quantities of high quality milk and, therefore, is frequently used for crossbreeding. However, various hereditary anomalies caused by gene mutations have been recently recorded in calves produced by some Ayrshire sires. Most of these anomalies were shown to have a recessive inheritance pattern, thus imposing a threat of unpredictable dramatic changes in cattle genotypes under such factors as genetic drift, selection and inbreeding. The purpose of this study was to examine the susceptibility of the Ayrshire cattle bred in the North Caucasus to such hereditary abnormalities as complex vertebral malformation (CVM) and bovine leukocyte adhesion deficiency (BLAD). The investigation was carried out on 16 cows with various phenotype and reproduction disorders that were selected based on a three-year veterinary observation of 440 livestock animals. The target group cows were generally the descendants of Hannulan Yaskiyri, Riihiviidan Urho Errant and O.R. Lihting. The results demonstrated that no animals under study were the carriers of these genetic disorders, which proved the mutant alleles of BLAD and CVM to be absent from the Ayrshire cattle livestock bred in the North Caucasus. Therefore, the sires of these cattle can be successfully used for breeding. Keywords: complex vertebral malformation (CVM); bovine leukocyte adhesion deficiency (BLAD) ; Ayrshire cattle breed Article DOI: http://doi.org/10.15544/RD.2017.142