Holstein Breed Research Articles

Innovative solutions used in Holstein breeding by Osnabrück livestock association (OHG)

The article analyzes the dairy farming industry in Russia and the Samara region, presents the experience, achievements and strategy of innovative technologies in the breeding of the Holstein breed - the selection of the Osnabrück livestock breeding association in Germany. The aim of the research is to study the efficiency of selection and genetic work with cattle of German selection and transfer the experience gained to the conditions of the Samara region. In Germany, the main goal is to achieve the following indicators: to obtain from each bull at least 100 daughters in at least 80 farms for the indicator of productive breeding value and at least 80 daughters in at least 60 farms for the indicator of exterior breeding values. The use of the German genomic selection of the Holstein breed in Russia puts all selection and breeding work on a new intensive path of development of dairy cattle breeding, resulting in an increase in the number of pedigree animals and an increase in their milk productivity. The study and application of the experience of creating a German breeding service in the Russian Federation and the Samara region will significantly increase milk production, improve the genetic quality of pedigree livestock, and reduce the unit costs for breeding due to the timely identification and removal of animals with low genetic potential from reproduction.

Proposta de um iELISA para diagnóstico de Mycoplasma bovis em bovinos leiteiros e fatores de risco associados

ABSTRACT Mycoplasma bovis is a highly contagious agent associated with several pathologies in cattle. The detection of reactive antibodies to M. bovis by Indirect Enzyme-Linked Immunosorbent Assay (iELISA) identifies if there was an exposure to the microorganism. The current study aimed to optimize an iELISA from M. bovis total cell antigen, applying it to bovine serum samples, and to evaluate risk factors. Serum samples were obtained from 400 cows from 17 herds from Southeast Brazil. In the optimization of iELISA, the following was established: 2 μg/mL of antigen, sera dilution 1:300, and conjugate dilution 1:15000. The frequency was 62.3% (249/400) of reactive animals and 100% (17/17) of reactive herds. Risk factors were: herds with more than 100 animals (OR= 3.1; CI= 95%); Holstein breed (OR= 72.5; CI= 95%); cows (OR= 29.7; CI= 95%); intensive breeding system (OR= 3.3; CI= 95%); associated small ruminant production (OR= 4.4; CI= 95%); milk production above 500L (OR= 2.9; CI= 95%); no quarantine (OR= 1.5; CI= 95%); mechanical milking (OR= 5.5; CI= 95%) and cases of mastitis (OR= 5.5; CI= 95%). The proposed iELISA was able to detect antibodies reactive to M. bovis in bovine serum. Knowledge of these risk factors can assist in the implementation of prophylactic measures.

Influence of the genotype of breeding bulls on the quality of sperm production

The article presents the studies carried out at JSC “Krasnoyarskagroplem” during 2012-2015 years. The object of research is breeding-bulls of red-mottled and Holstein breeds and their sperm production. We compared two groups of bulls, a red-mottled breed (n = 18 heads) and the Holstein red-and-white suit (n = 18 heads) at the age of 24.3 months at the beginning of the study. The quality of sperm production was evaluated in accordance with the current GOST 23745-79 “Undiluted freshly obtained sperm of breeding bulls”. The fertilizing ability of sperm was evaluated by the insemination index. The authors revealed the dependence of the quantitative and qualitative indicators of the seed on the breed of bulls. The period of bull’s sexual functions formation of the Holstein breed ends at the age of four. The period of bull’s sexual functions formation of the red-mottled breed ends at the age of five. The insemination index of red-mottled bulls is on average 1.3, in Holstein bulls it is 1.7. It confirms that the quality of the sperm is good. Breeding bulls with a low insemination index were identified, e.g., Discont 29590 of the red-mottled breed has index of 2.4, Kozir 1676 and Snaiper 1802 of Holstein breed have indexes of 3.9 and 6.03, respectively.

Dairy productivity of cows - daughters of bull producers

In the Sverdlovsk region, in herds of Holstein black-and-white cattle of the Ural type, up to 98% of cows are descended from bull producers of foreign selection. Assessment of the influence of a bull producer on the productive qualities of daughters is relevant and of practical importance, especially in conditions of increased blood in the Holstein breed. The daughters of the breeding bull Gavano had the highest indicators in terms of milk production, the daughters of the breeding bull Das were in second place. It should be noted that the milk yield for 305 days of lactation in all studied animals was within the range of 6583 (daughter of bull Cassio) - 8106 (daughter of bull Gavano) kg, which indicates a high potential for productivity in the cows of this herd. The superiority of the daughters of bull Gavano in milk yield ranged from 445 to 1523 kg or 5.5 - 18.8% and was reliable in favor of the former (P≤0.05 - P≤0.01). The highest rates for fat mass fraction in milk were found in the daughters of bull De-Su. 4,0 and 4,01% of fat was in milk of cows-daughters of the Sayan, Mers and Cassio bulls. In terms of protein mass fraction in milk, cows differed from bull De-Su for the worse. In the milk of cows-daughters of other bull producers the protein mass fraction was in the range of 3.13-3.17%. The yield of milk fat and milk protein was more influenced by milk yield in 305 days of lactation. Most of the nutrients were obtained from the milk of the cows-daughters of bull Gavano. The daughters of bull Sayan were in second place, only slightly inferior to them were the daughters of bulls Das and De-Su. Less nutrients were obtained with milk from the daughters of bull Cassio. All cows had a dairy production direction, as evidenced by a high milk yield ratio from 1186 to 1432 kg of milk per 100 kg of live weight of a cow. The farm uses daughter cows from Holstein bull producers with a high genetic potential for productivity.

Efficiency of Implementing a New System for Feeding Cows of Holstein Breed

Feed makes up to 70% of the total cost of feeding livestock. Therefore, high-quality feeding, based on the satisfaction of animals with the necessary level of nutrients and nutrients, is the key to the quality and profitability of the final product. It is known that ruminants have fundamental differences in the physiology of digestion and metabolism, when, due to the enzymatic activity of microorganisms, not only quantitative, but also qualitative characteristics of almost all components of the feed change. In this regard, we conducted production experience in introducing a new feeding system for Holstein cows, first-calf cows. For this, two groups of cows were formed on the basis of analogues and placed in different sections. The cows of the first group were fed according to the old feeding system, i.e., the feed was prepared in SILOKING feeders. Cows of the second group were fed from KONGSKILDE feeders. At the end of the experiment, data were obtained on obtaining the greatest amount of milk productivity of cows of the second group, which were fed 628.0 kilograms according to the new feeding technology.

МЕХАНИЗМ ЭНДОКРИННОЙ РЕГУЛЯЦИИ ПОЛОВОГО ЦИКЛА И НОРМАЛИЗАЦИЯ РЕПРОДУКТИВНОЙ ФУНКЦИИ У ТЕЛОК ГОЛШТИНСКОЙ ПОРОДЫ

In a large dairy company in the Ryazan region, studies of the mechanism of endocrine regu-lation of the estrial cycle were carried out, as well as ways of normalization of reproductive function were studied. Experimental data were obtained on the heifers of the Holstein breed of the same age. In a comparative aspect, the economic efficiency of the methods used is assessed. The drugs and methods used differed qualitatively from each other. For the first time, the combined use ofPGF Wakes Forte and Sedimin drugs has been proven to increase the probability of pregnancy in heifers of the same age by an average of 30 %.

Growth and development of replacement heifers depending on the origin

For insemination of cattle’s broodstock, the bulls’ seed is used, both domestic and foreign selection, that is, the increase in blood count of received heifers for the Holstein breed continues. The growth of animals, despite general growth patterns, is influenced by many factors, including their origin. The research aim is to assess weight growth characteristics of replacement heifers, depending on their origin, namely the father – the servicing bull. It was found that the difference in live weight at birth between heifers of different seed bulls was insignificant and amounted to 1.4 kg or 4.7%. The highest live weight at 18 months of age had heifers from the Sayan bull – 425.3 kg, slightly 3.6-5.3 kg inferior to them were the heifers from the Cassio and Mers bulls. Heifers grew unevenly over the periods. The uneven growth of heifers of different seed bulls, although it has a general pattern, but differs in groups. If in the period from 6 to 12 months of age there is a decrease in absolute growth in all groups, then already in the next period we can note the peculiarities in absolute growth change. So, the absolute growth of the heifers from the Das bull remained at the same level; the absolute growth of the heifers from the Sayan, De-Su, Tuareg, Cassio bulls continued to decline, and the absolute growth of the heifers from the seed bulls Havano, Mers and Bentley increased. On average, for the entire growing period, it ranged from 21.0 to 22.0 kg per month. Thus, the culture system of replacement heifers on the farm allows to get good results. The age of the first heifers’ insemination, depending on belonging to the seed bull, ranges from 14.3 to 16.9 months, which allows us to speak about using early terms of the first heifers’ insemination. The live weight at the time of the first insemination meets the requirements.

Relationship between cow milk yield and milk quality indicators

In the Sverdlovsk region, purebred bull producers of the Holstein breed of German, Danish and Canadian selection and the breeding stock of the domestic black-and-white breed of the Ural offspring were used for improvement. The Ural offspring of the black-and-white breed was distinguished by high milk yield and fat mass fraction and protein mass fraction in milk. In 2002, the Ural type of the Holstein black-and-white cattle was officially registered in the Ural region. This type has significant differences from the original rocks. The purpose of the article is to study the relationship between milk yield and milk quality indicators in cows-daughters of the Holstein black-and-white cattle of the Ural type from different Holstein bulls. It is established that the relationship of indicators depends on the belonging of cows-daughters to a particular bull producer. However, it can be noted that there is a positive relationship with an average and high level of correlation between milk yield for the first lactation and fat mass fraction in milk, milk yield for lactation and protein mass fraction in milk, and between fat mass fraction and protein mass fraction in milk in the groups of bull daughters from producers Emen and Reverse. For the group of daughters of the bull Jesmen, a high negative correlation was found between milk yield per lactation and fat mass fraction in milk, an average negative correlation between milk yield and protein mass fraction in milk, and a low positive correlation between fat mass fraction and protein mass fraction in milk. Correlation coefficients change with age. For the second lactation, the correlation coefficients differed from those established for the first lactation. So, they went to negative between milk yield and fat mass fraction in milk in the daughters of all evaluated bulls, between milk yield and protein mass fraction in milk remained the same, but decreased. The correlation coefficient between the quality indicators of milk in bull’s daughters changed to negative. Selection of cows by milk yield for the first lactation will allow you to get an increase in milk yield for full-age lactation.

Marker selection and genomic prediction of economically important traits using imputed high-density genotypes for 5 breeds of dairy cattle

Marker sets used in US dairy genomic predictions were previously expanded by including high-density (HD) or sequence markers with the largest effects for Holstein breed only. Other non-Holstein breeds lacked enough HD genotyped animals to be used as a reference population at that time, and thus were not included in the genomic prediction. Recently, numbers of non-Holstein breeds genotyped using HD panels reached an acceptable level for imputation and marker selection, allowing HD genomic prediction and HD marker selection for Holstein plus 4 other breeds. Genotypes for 351,461 Holsteins, 347,570 Jerseys, 42,346 Brown Swiss, 9,364 Ayrshires (including Red dairy cattle), and 4,599 Guernseys were imputed to the HD marker list that included 643,059 SNP. The separate HD reference populations included Illumina BovineHD (San Diego, CA) genotypes for 4,012 Holsteins, 407 Jerseys, 181 Brown Swiss, 527 Ayrshires, and 147 Guernseys. The 643,059 variants included the HD SNP and all 79,254 (80K) genetic markers and QTL used in routine national genomic evaluations. Before imputation, approximately 91 to 97% of genotypes were unknown for each breed; after imputation, 1.1% of Holstein, 3.2% of Jersey, 6.7% of Brown Swiss, 4.8% of Ayrshire, and 4.2% of Guernsey alleles remained unknown due to lower density haplotypes that had no matching HD haplotype. The higher remaining missing rates in non-Holstein breeds are mainly due to fewer HD genotyped animals in the imputation reference populations. Allele effects for up to 39 traits were estimated separately within each breed using phenotypic reference populations that included up to 6,157 Jersey males and 110,130 Jersey females. Correlations of HD with 80K genomic predictions for young animals averaged 0.986, 0.989, 0.985, 0.992, and 0.978 for Jersey, Ayrshire, Brown Swiss, Guernsey, and Holstein breeds, respectively. Correlations were highest for yield traits (about 0.991) and lowest for foot angle and rear legs-side view (0.981and 0.982, respectively). Some HD effects were more than twice as large as the largest 80K SNP effect, and HD markers had larger effects than nearby 80K markers for many breed-trait combinations. Previous studies selected and included markers with large effects for Holstein traits; the newly selected HD markers should also improve non-Holstein and crossbred genomic predictions and were added to official US genomic predictions in April 2020.

Изменение показателей собственной продуктивности быков-производителей голштинской породы в зависимости от сезона года и возраста

Abstract. Purpose of research. To estimate the impact of the season and age of the breeding bulls during the period of sperm collection on the main indicators of the own productivity of Holstein bulls. In studies of these indicators and productivity 229 bulls of Holstein breed have studied the effect of age (year of birth), season of the year, as well as the degree of influence of these factors on the value of indicators of productivity of bulls. Methods. Data on the main indicators of own productivity of breeding bulls are analyzed: the volume of ejaculate, the amount and concentration of spermatozoa in 1 ml. The research results were classified by season: winter, spring, summer, and autumn. The values of quantitative indicators of sperm production are given as deviations from the average value for the sample. Statistical analysis was performed using a boxplot diagram with average values and standard deviation (±σ) applied to it. The analysis of variance was performed using the following statistical model: yijk = µ + agej + seasonk + eijk + si. Fischer’s F-test was used to check the significance. Results. Regardless of the season, the values of the ejaculate volume and the total number of sperm in the ejaculate increase with age, and the concentration of sperm in 1 ml decreases. In the spring and summer period, 77–83 % and 66–79 % of observations had high values of the indicator volume of ejaculate and the number of spermatozoa in the ejaculate. In the spring and autumn periods, 62–64 % of observations had high values of sperm concentration in the ejaculate. The year of birth of the producer bull and the producer bull itself have a high degree of influence on the indicators of their own productivity: the volume of ejaculate – 14.94 and 18.22 %; the number of sperm in the ejaculate and their concentration – 8.53–27.88 and 4.51–15.82 %, respectively. Scientific novelty. The data obtained on the influence factors of season, age of the bull-the manufacturer’s figures for their own productivity.

Genotype by environment interaction for fat and protein yields via reaction norms in Holstein cattle of southern Brazil.

Our objective was to evaluate the genetic merit of Holstein cattle population in southern Brazil in response to variations in the regional temperature by analyzing the genotype by environment interaction using reaction norms. Fat yield (FY) and protein yield (PY) data of 67 360 primiparous cows were obtained from the database of the Paraná Holstein Breeders Association, Brazil (APCBRH). The regional average annual temperature was used as the environmental variable. A random regression model was adopted applying mixed models with Restricted Maximum Likelihood (REML) algorithm using WOMBAT software. The genetic merit of the 15 most representative bulls, depending on the temperature gradient, was evaluated. Heritability ranged from 0.21 to 0.27 for FY and from 0.14 to 0.20 for PY. The genetic correlation observed among the environmental gradients proved to be higher than 0.80 for both traits. Slight reranking of bulls for both traits was detected, demonstrating that non-relevant genotype by environment interaction for FY and PY were observed. Consequently, no inclusion of the temperature effect in the model of genetic evaluation in southern Brazilian Holstein breed is required.

Breed, heterosis, and recombination effects for lactation curves in Brazilian cattle

The objective of this study was to estimate the breed, heterosis, and recombination effects on different components of the lactation curve of Girolando cattle. The dataset used consisted of 12,121 purebred cows of Holstein (H) and Gyr (G) breeds, and six H×G crossbred cows (Girolando). The model used presents random effects of herd and cow, regression coefficient associated with linear effect of proportion of H breed, regression coefficient associated with the linear effect of heterosis between H and G [...]

Herd life, lifetime production, and profitability of Viking Red-sired and Montbéliarde-sired crossbred cows compared with their Holstein herdmates

The first 2 generations from a 3-breed rotation of the Viking Red (VR), Montbéliarde (MO), and Holstein (HO) breeds were compared with their HO herdmates in high-performance commercial herds in Minnesota. The designed study enrolled pure HO females in 2008 to initiate a comparison of 3-breed rotational crossbreds with their HO herdmates. Sires of cows were proven artificial insemination bulls selected for high genetic merit in each of the 3 breeds. The first-generation cows calved for a first time from 2010 to 2014 and had 376 VR × HO and 358 MO × HO crossbreds to compare with their 640 HO herdmates. The second-generation cows calved for a first time from 2012 to 2014 and had 109 VR × MO/HO and 117 MO × VR/HO crossbreds to compare with their 250 HO herdmates. Collection of data ceased on December 31, 2017, and all cows studied had the opportunity for 45 mo in the herd after first calving. Production of milk, fat, and protein (kg) during lifetimes of cows was estimated from test-day observations with best prediction. The lifetime profit function included revenue and cost. Revenue was from production, calves, and slaughter of cull cows. Costs included feed cost during lactation, lactating overhead cost, dry cow cost (including feed cost during dry periods), replacement cost, health treatment cost, insemination cost, fertility hormone cost, pregnancy diagnosis cost, hoof trimming cost, and carcass disposal cost. For individual cows with herd life longer than 45 mo after first calving, survival of cows was projected beyond 45 mo after first calving to estimate herd life, production, and profitability. The 2-breed crossbreds had +158 d longer herd life and the 3-breed crossbreds had +147 d longer herd life compared with their respective HO herdmates. Also, 12.4% of the 2-breed crossbreds died up to 45 mo after first calving compared with 16.3% of their HO herdmates. Furthermore, approximately 29% of both the 2-breed and 3-breed crossbreds lived beyond 45 mo after first calving compared with approximately 18% of their respective HO herdmates. On a lifetime basis, the 2-breed and 3-breed crossbreds provided +$122 and +$134, respectively, more cull cow revenue compared with their HO herdmates. For lifetime replacement cost, the 2-breed crossbreds did not differ from their HO herdmates; however, the 3-breed crossbreds had -$28 less lifetime replacement cost compared with their HO herdmates because of their younger age at first calving. The combined 2-breed crossbreds had +$0.473 (+13%) more daily profit (ignoring potential differences for feed efficiency) and the combined 3-breed crossbreds had +$0.342 (+9%) more daily profit compared with their respective HO herdmates. This resulted in +$173 more profit/cow annually for the combined 2-breed crossbreds and +$125 more profit/cow annually for the combined 3-breed crossbreds compared with their respective HO herdmates.

Genetic characteristics of the Pechora type of Kholmogorsky cattle based on microsatellites and DNA markers

The Pechora zonal type (PH-1) was obtained by absorbing crossbreeding of local Northern komolog cattle with the Kholmogorsky breed. Currently, Kholmogorsky cattle are on the verge of extinction, which is due to the widespread metisation of domestic Holstein breeds. The paper presents the characteristics of the allelofond of the Kholmogorsky herd of the Pechora type (n=66) by 11 polymorphic loci of microsatellites. It was found that the polymorphism of tandem repeats in the Pechora type of Kholmogorsky cattle is observed in all 11 loci, the most polymorphic is the tgla53 locus (10 alleles). The most common allele SPS115 248 occurs with a frequency of 0.606. The average number of alleles for 11 loci was 6.2, and the number of effective alleles was 3.4. the obtained indicators were compared with the values published for Yakut [1], Holstein [2, 3] and Ayrshire cattle [4]. It was found that the Pechora type of Kholmogorsky breed has a higher number of effective alleles than Yakut cattle (by 1.0), and lower than other breeds (by 0.3...1.6). Analysis of F-statistics showed that on average, the deviation of the actual heterozygosity from the expected one is insignificant Fis=-0.004, while other breeds, excluding the sample of Holstein bulls, had a more significant excess of heterozygotes. The smallest genetic distance of the studied population was established with the Holstein breed (d=0.221 to cows and d=0.200 to bulls). A more detailed genetic analysis of individual loci showed that the frequency of occurrence of alleles BM2113 Pechora type is closer to the Yakut (r=0.935) and Ayrshire (r=0.875) than to the Holstein breed (r=316...357).

Economic efficiency of the use of dwarf pine and lichen in the diets of young cattle in the conditions of the Magadan region

For the first time, in the conditions of the Magadan Region, studies were carried out on the use of a feed additive (FA) prepared from dwarf pine (mountainpine) in combination with lichens in feeding young cattle of the Holstein breed and crossbred young animals of the Golstein and Hereford breeds. Over the period of the experiment, the absolute increase of the experimental bulls exceeded the indicators of the control groups: young Holstein breed by 2.15 kg (0.58%), hybrids by 6.35 kg (1.51%). The relative growth rate of experimental bulls according to Brody was higher than that of bulls in the control groups: bulls of the Holstein breed by 0.12%, crossbreeds by 0.77%. The use of crossing low-productivity dairy cattle with bulls of meat breeds makes it possible to obtain interbred hybrid animals of the I and II generations. The production of beef from crossbred young stock is characterized by greater economic efficiency in comparison with the fattening of super-renovated young Holstein breed. In the experimental group of a hybrid of the Holstein and Hereford breeds of the 1st generation, this indicator was 7.2 energy feed units (EFU), which is 7.7% lower than in the control one, and 13.25% lower than in the experimental group of the Holstein breed.

Генодиагностика мутации FANCIBY у представителей голштинской породы и ее помесей

The article is devoted to the development and use of a method for diagnosing the source of Brachyspina Syndrome, or short spine, in the Holstein breed and its crossbreeds. Representatives of this breed are the most highly productive animals in the world for milk. The development of a diagnostic method for breed-specific hereditary carriers is an important task in dairy farming. In this regard, the authors have proposed a Patent and a Reagent Kit for the detection of normal FANC1TY and mutant FANC1BY alleles in the Holstein breed and its crossbreeds. The frequency of occurrence of genotypes formed by these alleles in different sex and age groups of animals in the Holstein breed and its high-blooded hybrids was studied. Historical data related to the founders, from whom the spread of the mutant FANC1BY allele within the Holstein breed itself and its crossis in the USA, Canada and Russia began, has presented. The development of a diagnostic method for the mutant FANC1BY allele will make it possible to stop spreading of the Brachyspina Syndrome source. The proposed method will make it possible, in the early stages, to form healthy groups of breeding animals (bulls, replacement bulls, bull-reproducing cows), thereby laying the foundation for creating a high-quality livestock in the regions where the Holstein breed and its numerous crossbreeds are bred. cattle, Holstein breed, crossis, genotype, FANC1BY mutation, allele, Brachyspina syndrome

Technological properties of cow milk with the addition in their diet of silage prepared with bio-preservative “GreenGrass 3×3”

The completeness of the provision of the body of highly productive cows with the necessary set of nutrients depends on the set of feeds included in their diet, as well as on their quality. The purpose of the research is to study the effect of silage with the biological preservative “GreenGrass 3×3” on the technological properties of milk from cows of Holstein and Ayrshire breeds. It is found that the morphological and biochemical composition of the blood in the animals of the experimental groups significantly improves approaching the optimal parameters. Feeding lactating cows with silage in feed mixture from lucerne prepared with bio-preservative increases the average daily milk yield by 20.5% in the Holstein breed and by 26.9% in the Ayrshire breed. The quality of milk is improved by the increase in the mass fat fraction by 0.10-0.13% respectively, the mass protein fraction - by 0.10-0.14%, including casein - by 0.14-0.19%. In the general structure of milk proteins, the mass fraction of casein increases, while the mass fraction of whey proteins, on the contrary, decreased by 2.0-2.2%. It is very important that the proportion of γ-caseins, which do not clot under the influence of rennet, decreased by 0.5-0.9% in the test samples. As a result, the duration of clotting by rennet decreased by 13.8-12.1% and the loss of dry matter with whey - by 1.3-2.1%, the yield of casein clot increased by 5-4% and its density increased by 0,37-0.22 g / cm2. All these aspects show the increase in the technological properties of milk in cows from the experimental groups.

Frequency distribution of polymorphic variants of the beta-casein locus in Russian various breed cattle subpopulations

Using the author’s test system, 2607 Holstein, Ayrshire and Jersey breeds were genotyped at CSN2 locus. It was determined that the frequency of preferred genotype A2A2 is in Holstein, Ayrshire and Jersey groups of animals - 0.21; 0.25 and 0.60 respectively. The frequency of A2 allele in Holstein breed is 0.48; in Ayrshire - 0.51; in Jersey - 0.78. Thus, the Russian subpopulations of Ayrshire, Jersey, and Holstein cattle subpopulations according to frequencies of A2A2 genotypes (CSN2 locus), the Jersey breed has the best indicators (0.60). Russian breeding enterprises selling semen production of Ayrshire and Holstein bulls should increase the share of breeders with CSN2 genotypes A2A2.

Comparative characteristics of the genetic structure of the Syrian cattle breed compared to Holstein and Aberdeen-Angus breeds.

Objectives:The objective of this study was to perform a comparative analysis of allelic diversity to reveal population-genetic characteristics of animal breeds, namely Shami (SH), Holstein (HLS), and Aberdeen-Angus (A-A).Materials and Methods:The genetic materials of SH breed animals represented by wool with hair follicles were collected from 39 SH heads in Syria. Also, genetic materials of HLS breed of American selection (n = 55, HLS) and bulls and cows of A-A breed bred at breeding enterprises in Russia (n = 30, A-A) were collected. Genetic differences between the cattle groups were studied using 11 microsatellite markers. Results:The cattle breed in Syria was characterized by high genetic diversity, 107 alleles, while the average number of alleles per microsatellite locus was 9.23, which is significantly higher than that in the animals of HLS (6.18) and A-A (5.00). When analyzing the genetic equilibrium for individual locus in SH breed, a deviation from equilibrium at four loci was revealed: TGLA227, SPS115, TGLA122, and ETH225; at one locus in HLS breed: SPS115, for A-A breed: at two loci, i.e., TGLA122 and ETH225. When assessing the level of genetic consolidation, a deficiency of heterozygotes was observed in two of the three studied breeds: 4.8% for SH and 8.0% for A-A. A slight excess of heterozygotes was found in the HLS breed at the level of 0.2%. The average comparative measurement of genetic variation in different populations value for 11 loci for all breeds was 0.069, which indicates that 93.1% of the total variability is due to the intra-breed diversity, and only 6.9% is due to the differences between breeds. Conclusion:The analysis of the animals belonging to their breed has shown a 100% genetic consolidation and the compliance of individual animals with the respective breeds. The study of genetic distances, adjusted for small samples, revealed the smallest genetic distance between the SH breed and HLS breed, equaling 0.107. The A-A breed, which has its separate origin and has never been imported into the Syrian Arab Republic, adjoins this cluster as an independent branch. Microsatellites can be used as an essential criterion for assessing the population-genetic characteristics of groups of cattle of various breeds (degree of polymorphism, level of heterozygosity, fixation indices, genetic group membership).

Популяционно-генетическая характеристика, оценка геномного инбридинга и гомозиготности крупного рогатого скота черно-пестрой и голштинской пород по STR и SNP маркерам в России

The object of the study was sires of the Black-and-White and Holstein breeds, which had STR profiles and passed the genotyping procedure for SNP markers. The subject of the study was the level of genomic inbreeding and homozygosity, as well as population-genetic characteristics based on them. With an increase in Fx based on pedigree data, an increase in the level of genomic inbreeding (FROH) calculated from SNP markers was also noted. The results for 9 STR markers record a wavelike increase in homozygosity from group I to group IV with a subsequent increase from group V to group VII inclusive. During the study of the average FROH values in accordance with the years of birth of sires, a significant difference was found between the last two groups (2009-2011; 2012-2014) from all the others in a pairwise comparison. The results of calculating the FROHand Ca9 of bulls from different countries of origin indicate a statistically significant differentiation of the group of animals from Russia (RF) from animals, born in German and Canadian. A significant difference was noted for the highest FROH level in the samples in the Holstein Black-and-White breed from the Red-and-White Holstein and Black-and-White breeds. The Fst values between the SNP and STR species of the animals had insignificant differentiation (0.008-0.027). Differences in STR calculation between the Black-and-White Holstein and Red-and-White Holstein breeds were insignificant, less than 20%, while the rest of the values differed many times. Fst between RF and Germany, RF and the Netherlands according to STR data is 0.006 and 0.008, according to SNP data 0.005 and 0.006, respectively. A mutual increase in the value of Fst and the year of birth of the sires was noted, emphasizing the greatest remoteness of the population of 1983-1997 from the populations of recent years, when new genotypes of bulls were obtained. The similarity of Fst values between genealogical lines is replaced by a significant scatter in the indicators when they are compared in pairs.