Health traits in dairy cattle have crucial meaning to produce high quality milk. Despite of fertility problems and metabolic disorders in cows, the mastitis has a bigger economic losses influence to include it as selection criteria in cattle breeding. Somatic cell count (SCC) in that case are the good predictor for monitoring udder health cows under whole population level or separate herd. The aim of our study was to assess genetic and genomic components for SCC and their scores (SCS) using experimental dataset by seven herds with the subsequent QTL identification. For six-month observation the 5824 cows with 19786 test-day records were included into analysis. Then EBVs by offspring assessing of 139 genotyped Holstein sires were calculated trough TD Model (BLUPF90) and then it adopted as pseudo-phenotypes for GWAS. After quality control using Plink 1.90, we used ≈39K SNP (Illumina 50K). The average values for SCC and SCS were 351±7 thousands cells/ml and 2.86±0.02 score respectively. Heritability coefficients revealed low genetic variation for SCC – 0.119 and moderate for SCS – 0.211. Daily yield for cows with SCC >1000×103 cells/ml was low by -4.0 kg milk to compare individuals with SCC < 100×103 cells/ml. At the same time lactose content and freezing point were decreasing by 4.93 to 4.69% and -0.635 to -0.618°C. By Cattle QTLdb we identified some causal genes for SCC on BTA3 (ROR1), BTA9 (EZR), BTA13 (OSBPL2,DNAJC5,ZBTB46,MTG2), BTA14 (KHDRBS3) and BTA22 (RBMS3). But more relevant GWAS calls were found for SCS by BTA14 (KCNB2, ZFAT) as QTL associated to the milking speed that has unfavorable genetic correlation with clinical mastitis or SCS. Thereby, genes detected under experimental study, are the valuable and informative markers to implementation genomic selection methods for cattle health in creating Russian bulls’ reference population. The study was funded by RFBR within project No. 20-316-90050

Milk fatty acids (FA) derived from infrared spectra are a new type of traits that allow fast and predictability use their in dairy breeding and herd cattle management. The Holstein animals feature are the high milk yield, but milk composition traits can be different according to population or country origin. The purpose of our study was to find out genetic variation for milk FA and detect QTLs associated with Holstein sires’ EBV in Russian cattle population. For this analysis, we used an experimental dataset for 36982 milk test records from 14 breeding herds in the Moscow region. Individual milk samples per animal analyzed routinely by MilkoScan7 for different FA types: C14:0, C16:0, C18:0, C18:1, saturated, mono- and polyunsaturated, short-, medium- and long-chain. Total number of bulls consisted 778 individuals including 222 animals with genotypes (39051 SNP, Illumina 50K). For calculating EBV by Sire Model, we applied BLUPF90. Plink 1.90 performed quality check control and GWAS procedure. Heritability coefficients were 0.071–0.155 for C14:0-C18:0 levels, 0.196 for C18:1, 0.083 for SFA, 0.018 for PUFA, 0.176 for MUFA, 0.114–0.155 for SCFA-LCFA levels. GWAS revealed most significant (P < 0.001-0.00001) frequently QTLs associated with FA content that were cited in articles previously for BTA5 (CHST11,C18:1), BTA6 (KCNIP4,C18:1; PPRAGC1A,C18:0), BTA11 (NRXN1,LPIN1,C18:1; NBAS,C18:0), BTA26 (PCDH15,PUFA; PRKG1,C18:1). These genes were responsible for synthesis milk fat, fertility, udder conformation traits, lauric, myristic, myristoleic, palmatoleic, oleic and other types of FA. In addition, we identified several QTLs for C14:0, C16:0, SFA, MUFA, SCFA, LCFA on BTA1 (137.32 Mb), BTA10 (5.50 Mb, 9.79 Mb), BTA14 (44.35 Mb), BTA19 (17.57–17.89 Mb) and BTA22 (14.02–14.06 Mb, 20.29–20.45 Mb). Our results are the first steps toward to understanding genetic and genomic mechanisms for using FA in selection processes to improve milk quality for Holstein cattle in Russia. The study was funded by RSF (project No. 21-76-20046)

Изучение фенотипической и генетической детерминации мастита крупного рогатого скота представляет особый интерес в контроле состояния здоровья молочных коров. Целью настоящей работы был поиск полногеномных ассоциаций с количеством соматических клеток и их дифференциацией в молоке коров голштинизированной черно-пестрой породы. Изучено 2814 образцов сырого молока, полученных при проведении контрольных доек. Для определения количества соматических клеток и дифференциации их по морфологическим видам (лейкоциты и полиморфно-ядерные нейтрофилы) использовали автоматический анализатор Fossomatic 7 DC. Для генотипирования 144 коров применяли биочип высокой плотности GGP Neogen 150K. После проведения контроля качества генотипов отобрали для дальнейшей работы по 110884 однонуклеотидных полиморфизма на каждое животное. Проанализирована динамика изменения суточного удоя и оценки количества соматических клеток в молоке коров в течение лактации. Показано, что полиномиальный тренд для соматических клеток имел обратную зависимость с аналогичным трендом для суточного удоя молока. При GWAS-анализе для количества соматических клеток, их нормированной (логарифмической) оценке и дифференциации наблюдались общие полиморфизмы на хромосомах 1, 5, 8, 9, 14, 20, 21, 23, 26 и 29, при этом число аннотированных генов составило 56. Сопоставление собственных результатов и подтвержденных другими авторами позволило установить, что 12 генов (P=0,000003—0,003130) имели непосредственную сопряженность с соматическими клетками в молоке, скоростью молокоотдачи и устойчивостью к маститу. Кроме того, эти гены были сопряжены с показателями молочной продуктивности, репродуктивными качествами, экстерьером, продуктивным долголетием и восприимчивостью к заболеваниям, что указывает на генетическую взаимосвязь данных признаков с показателями здоровья вымени коров. Наибольшее число локусов количественных признаков, ассоциированных с соматикой, обнаружено на хромосоме 20 крупного рогатого скота, в которых находились 6 наиболее значимых генов: NPR3, ANKRD55, PTGER4, ADAMTS12, CTNND2, PDZD2. Полученные результаты после апробации на большем поголовье молочных коров могут быть использованы в программе разведения скота. Ключевые слова: крупный рогатый скот, молоко, соматические клетки, дифференциация соматических клеток, однонуклеотидный полиморфизм, GWAS. The research of the phenotypic and genetic determination of mastitis in cattle is of particular interest in the control of the health in dairy cows. The aim of this work was to search genome-wide associations with the somatic cells count and their differentiation in the milk of Holsteinized Black-and-White cows. 2814 samples of raw milk obtained during control milkings were studied. To determine the number of somatic cells and their differentiation by morphological types (leukocytes and polymorphonuclear neutrophils), automatic analyzer Fossomatic 7 DC was used. For genotyping of 144 cows, a GGP Neogen 150K high-density biochip was used. After quality control of genotypes, 110884 single nucleotide polymorphisms per animal were selected for further work. The dynamics of changes in daily milk yield and assessment of the number of somatic cells in the milk of cows during lactation was analyzed. It is shown that the polynomial trend for somatic cells had an inverse relationship with a similar trend for daily milk yield. GWAS analysis for the number of somatic cells, their normalized (logarithmic) evaluation and differentiation, showed common polymorphisms on chromosomes 1, 5, 8, 9, 14, 20, 21, 23, 26, and 29, while the number of annotated genes was 56. Comparison of our results and those confirmed by other authors made it possible to establish that 12 genes (P=0.000003— 0.003130) were directly related to somatic cells in milk, milk flow rate and resistance to mastitis. In addition, these genes were associated with milk production traits, reproductive features, conformation, productive longevity and susceptibility to diseases which indicates a genetic relationship of these traits with cow udder health. The largest number of quantitative traits loci associated with somatic cells (score) was found on Bos Taurus Autosome 20 which included 6 genes: NPR3, ANKRD55, PTGER4, ADAMTS12, CTNND2, PDZD2. The results obtained after testing on a larger number of dairy cows can be used in a livestock breeding program.

На основе анализа компонентного состава молока проведено изучение белковой и жировой фракций, метаболитов веществ и соматических клеток для голштинизированных черно-пестрых коров и карачаевских коз в сравнительном аспекте. Молоко коров предназначалось для переработки, а молоко коз использовалось для выкармливания козлят. В этой связи представляет интерес использование экспресс-метода инфракрасной (ИК) спектроскопии для исследования точности прогностической модели анализа молока от разных видов животных, в частности, для определения в образцах содержания жирных кислот (ЖК). Скрининг молока по 25 показателям выполняли с помощью анализатора CombiFOSS 7 DSCC. Установлено, что в молоке коз было достоверно больше жира и белка, насыщенных ЖК (69,59% против 65,67% в коровьем) и более значимых для питания человека полиненасыщенных ЖК (4,05% против 3,66% у коров). Коэффициент детерминации показал высокую значимость совокупных факторов, включенных в GLM-уравнение, для массовой доли лактозы (23,9%), короткоцепочечных ЖК (28,1%), ацетона (24,3%), бетагидроксибутирата (37,9%), точки замерзания молока (46,0%) и мочевины (85,1%). Корреляции между компонентами имели биологическую направленность, характерную для процессов синтеза молока в организме жвачных животных. Проведенный комплексный анализ показал перспективность ИК-спектров для использования как в менеджменте стада коров и коз, так и в накоплении информации для изучения генетической детерминации процессов образования молока у сельскохозяйственных животных. The protein and fat fractions, metabolites and somatic cells count for Holsteinized Black-and-White cows and Karachai goats were studied by in a comparative aspect. The cows’ milk was intended for processing, and milk of goats was used to feed the goatlet. In this regard, to use the express method of infrared (MIR) spectroscopy to study the accuracy of the predictive model for analyzing milk from different animal species, in particular, to determine the content of fatty acids (FA) was interesting. Milk screening for 25 parameters was performed using a CombiFOSS 7 DSCC analyzer. It was found that under the same paratypical conditions, there was significantly more fat and protein in goat milk, however, in terms of lactose content, milk pH values were higher in cows’ milk. Goat milk has a higher content of saturated FAs (69.59% opp. 65.67% in cow milk) and polyunsaturated FAs that are more significant for human nutrition (4.05% opp. 3.66% in cows). The determination coefficient showed the high significance of the aggregate factors included in the GLM equation for the lactose percentage (23.9%), short-chain FA (28.1%), acetone (24.3%), betahydroxybutyrate (37.9%), milk freezing point (46.0%) and urea (85.1%). The correlations between components had a biological orientation that characterized for the milk synthesis processes into the body of ruminants. The analysis showed that MIR spectra are promising for use in the management of a herd of cows and goats, and in the information accumulation for studying the genetic determination of milk processes synthesis in animals.

Mastitis is an inflammatory condition of the breast that can be caused by chemical, physical, traumatic injury or bacteria. In recent years, biomarkers for the mastitis diagnosis have been actively studied. The aim of the study was to assess the relationship between SCC and pathogenic bacteria in milk occurrence. The study carried out by milk samples collected in the experimental herd (Krasnodar region, Russia) from 85 Holsteinized Black-and-White cows. Healthy cows (HC; n = 4), cows at risk for clinical mastitis (RCM, n = 22), subclinical (SCM; n = 25) and clinical mastitis (CM; n = 34) groups were divided by a bacteriological cultivation and SCC level (Fossomatic7 DC). SCC results were logarithmically converted to SCS. Consequent groups were included animals with SCS level: HC (SCS < 4.1), RCM (4.2≤SCS≤5.3), SCM (5.4≤SCS≤6.3), CM (SCS >6.4). HC group of animals showed SCS equal to 3.11±0.28, 4.85±0.44 for RCM, 5.8±0.28 for SCM and 7.43±0.87 for CM. Identification of isolated bacteria species was carried out by conventional biochemical methods using the API20E, APIStaph, API20Strep tests (bioMerieux SA,France). Number of isolated pathogenic bacteria in CM group was 57 strains of which 33.3% were attributed to Enterobacteriaceae, 45.6% to coagulase-negative staphylococci (CONS), 12.3% to S.aureus and 8.8% to Ps.aeruginosa. In SCM group there were assigned 48 strains: 32.5% to Enterobacteriaceae strains, 42.5% to CONS, 20.0% to S.aureus, 5.0% to Ps.aeruginosa. The antibiotic susceptibility was determined according to NCCLS and EUCAST. S.aureus isolates showed the highest sensitivity to erythromycin (4.3% of resistant strains) and the highest resistance to ciprofloxacin (100%), tetracycline (95.0%), rifampicin (88.5%), benzylpenicillin (79.3%), novobiocin (69.2%) and fusidin (65.5%). The primary analysis of SCC and milk microbiological profile can be able to increase the accuracy of mastitis occurrence diagnosing that contributes to taking the right decision for choosing an antibiotic to preserve the cows’ health in Russian cattle population. The study was funded by RSF (project No.21-76-20046)