Topic:Breed Differences
Breed differences in horses encompass variations in physical characteristics, behavior, and physiological traits among different horse breeds. These differences arise from selective breeding practices aimed at enhancing specific attributes such as speed, endurance, strength, or temperament. Physical attributes can include variations in size, coat color, and conformation, while behavioral traits may involve differences in temperament and trainability. Physiological differences can affect metabolism, disease susceptibility, and performance capabilities. This topic includes peer-reviewed research studies and scholarly articles that explore the genetic, environmental, and historical factors contributing to breed differences, as well as their implications for equine management, health, and performance.
Genetic Evaluation of Barrel Racing Performance in Quarter Horses. Barrel racing is a competitive timed rodeo event that challenges horses and riders to complete a cloverleaf pattern around three barrels in the fastest time possible. In this study, we aimed to estimate the genetic parameters of barrel racing time (BRT) and evaluate the most suitable statistical model for its analysis. We compared a repeatability model and three random regression models (RRM) to analyse the longitudinal BRT data in Brazilian Quarter Horses. A total of 356,877 BRT records from 14,108 horses that competed in various events held across Brazil between 2010 and 2024 were analysed. ...
Identification of Genetic Relationships and Group Structure Analysis of Yanqi Horses. The Yanqi horse is a distinguished local breed in China, known for its robust physique and strong adaptability. However, due to insufficient breeding populations and a loosely structured breeding system, the number of Yanqi horses has been declining annually. To protect its genetic resources and develop scientific breeding strategies, this study aimed to analyze the genetic diversity, parentage relationships, and genetic structure of the Yanqi horse conservation population using microsatellite markers. A total of 117 Yanqi horses were selected for genotyping analysis using 16 microsatellite ...
Genomic Insights into Post-Domestication Expansion and Selection of Body Size in Ponies. Horse domestication revolutionizes human civilization by transforming transportation, agriculture, and warfare patterns. Despite extensive studies on modern domestic horse origins, the intricate demographic history and genetic signatures underlying pony size remain unexplored. Here, a high-quality genome assembly of the Chinese Debao pony is presented, and 452 qualified individuals from 64 horse breeds worldwide are extensively analyzed. The authors' results reveal the conservation of ancient components in East Asian horses and close relationships between Asian horses and Western pony lineages...
Genetic testing as a tool for diagnosis of congenital stationary night blindness (CSNB) in white spotted breeds in Poland. Congenital stationary night blindness (CSNB) has been connected to the leopard complex spotting phenotype (LP) in various horse breeds. CSNB associated with LP is thought to be caused by a 1378 bp insertion in TRPM1, with homozygotes being nightblind and having few to no spots of pigment in their white patterned area. This study aimed to assess the prevalence of CSNB alleles in tarant-colored horses in Poland through a three-primer system for an allele-specific Polymerase Chain Reaction (PCR). The TRPM1 gene insertion was genotyped in 221 horses belonging to Małopolska, Felin and Shetland Pon...
Age is associated with the requirement for surgery in horses with nephrosplenic ligament entrapment of the large colon at a single UK equine referral hospital. Conservative and surgical management of left dorsal displacement and nephrosplenic ligament entrapment of the large colon (NSLE) is well described in horses. Whilst breed factors predispose the development of NSLE, it is unknown if breed affects the likelihood for surgical intervention. Objective: To compare the incidence of surgical intervention and differences in pre-operative parameters between Thoroughbred and non-Thoroughbred horses. The authors hypothesise a higher proportion of Thoroughbreds require surgical intervention. Methods: Retrospective cross-sectional study. Methods: Case recor...
Healthy as a Horse? Characterising the UK and Ireland’s Horse Owners, Their Horses, and Owner-Reported Health and Behavioural Issues. This study focuses on recreational horse owners in the UK and Ireland to explore the relationship between horse characteristics and welfare issues. An online questionnaire was distributed to 1501 horse owners to collect data on the owners, horses, and health/behavioural issues. Most respondents were female (98%), lived in England (56%), and did not insure their horses for veterinary costs (51%). Horses were typically over 5 years of age (96%), taller than 154 cm (55%), and mostly geldings (65%). Common welfare issues reported included lameness (26%), handling problems (11%), antisocial behavio...
Effect of the intrinsic and extrinsic factors on the growth and development of young foals under subtropical conditions of Pakistan. This study was designed to explore the impact of intrinsic (breed of foal, age of dam, and age of foal at weaning) and extrinsic (season of birth and housing type) factors on the growth and survival of foals in the subtropical conditions of Pakistan. For the growth study, retrospective data analysis of foals (n = 150) born from purebred brood mares of Thoroughbred, Arabs, and Percheron breeds (n1, n2, and n3 = 50 each) was made. Six hundred and twenty-four (n = 624) foals born between 2020 to 2022 were observed for the study of foal survival rate. The survival of these foals till the age of on...
Genetics of Muscle Disease. In the field of equine muscle disorders, many conditions have a genetic basis. Therefore, genetic testing is an important part of the diagnostic evaluation. Validated genetic tests are currently available for 5 equine muscle disorders: hyperkalemic periodic paralysis, malignant hyperthermia, glycogen branching enzyme disease, type 1 polysaccharide storage myopathy, and myosin heavy chain myopathy. These diseases should be tested for in the appropriate breeds with clinical signs of disease or as part of breeding management. Genetic testing in veterinary medicine is not regulated, and therefore,...
Inherited non-syndromic polydactyly in a Berber and Arabian-Berber horse family. Supernumerary digits, or polydactyly, have been described in various species including humans, wild and domestic animals. In horses, it represents the most common congenital limb malformation, which has only been described in isolated cases or nuclear families. Molecular aetiology has not been reported. Objective: To characterise the phenotype of a non-syndromic pre-axial polydactyly in a horse family and to decipher the inheritance pattern. Methods: Retrospective study. Methods: Forty-three members of the family including a previously reported polydactyl case were recruited. Available clinica...
Skin Barrier in Normal and Allergic Horses: What Do We Know? Information on skin barrier in horses is limited. A study on the epidermal ultrastructure of normal and allergic horses documented disorganized amorphous intercellular lipids in the stratum corneum of allergic samples. These findings are similar to atopic canine and human skin. Currently, there is no published study comparing skin barrier function parameters between normal and allergic horses; thus, the functional implications of the ultrastructural changes are unknown. In normal horses, body location, gender, breed, and ambient conditions affect skin barrier parameters, such as Transepidermal...
Dynamic Adaptation of Hematological Parameters, Albumin, and Non-Esterified Fatty Acids in Saddlebred and Standardbred Horses During Exercise. The response to exercise following a rest period may vary among horse breeds based on the importance of the hematological and hematochemical profiles of athletic horses. Ten Standardbred and ten Italian Saddlebred mares were subjected to a 4-week training program after a seasonal rest, and hematological parameters (red blood cells-RBCs; hemoglobin-Hb; hematocrit-Hct; platelets-PLTs; platelet aggregation-AG; aggregation slope-Slope; fibrinogen-Fb), as well as Albumin (Alb) and non-esterified fatty acids (NEFAs), were analyzed. Blood samples were obtained each week during the training program fo...
Genome wide landscaping of copy number variations for horse inter-breed variability. Copy number variations (CNVs) have become widely acknowledged as a significant source of genomic variability and phenotypic variance. To understand the genetic variants in horses, CNVs from six Indian horse breeds, namely, Manipuri, Zanskari, Bhutia, Spiti, Kathiawari and Marwari were discovered using Axiom™ Equine Genotyping Array. These breeds differed in agro-climatic adaptation with distinct phenotypic characters. A total of 2668 autosomal CNVs and 381 CNV regions (CNVRs) were identified with PennCNV tool. DeepCNV was employed to re-validate to get 883 autosomal CNVs, of which 9.06% were...
Serum 25(OH) Vitamin D Concentrations in Horses: Effects of Age, Gender, Breed, Skin Colour and Season. The optimal amount of vitamin D required for the proper functioning of the immune system differs from the amount necessary for bone homeostasis. Furthermore, vitamin D metabolism varies among horses. Nevertheless, there is a dearth of information regarding reference values for vitamin D in horses, particularly in the Turkmen breed. The primary objectives of this study were to determine the concentrations of 25-hydroxyvitamin D (25(OH)Vit D) in Turkmen, Thoroughbred and mixed Turkmen × Thoroughbred horses and to explore the effects of various factors on it and its relationship with serum bio...
Evaluating Forelimb and Hindlimb Joint Conformation of Morna Racehorses (Equus caballus). Measuring limb joint angles is crucial for understanding horse conformation, performance, injury diagnosis, and prevention. While Thoroughbred horses have been extensively studied, local Pakistani breeds (e.g., Morna racehorse) have not received scientific attention. This study aimed to quantify normal angles of limb joints in the Morna breed. Limb joint angles of standing horses (n = 50) were quantified using a measuring tape, height stick, protractor scale, and goniometer. The mean and standard deviation (Mean ± SD) values for the forelimb joint angles were 123.02 ± 3.46° for elbow, 171.5...
Factors associated with the selling price of sport horses in public auctions in Ireland. Sale prices at auction significantly impact the economic return of sport horse production. This study aimed to determine factors associated with auction sales prices of sport horses at four maturity stages: foals, juveniles, young horses, and older horses. A total of 42,799 sales records from 2003 to 2022 were obtained from two Irish equine auction companies. A univariate regression model was used, and significant variables underwent multivariate analysis. Within each maturity category, factors associated with above-mean-priced horses differed from those associated with below-mean-priced horse...
Real-time transrectal ultrasonographic measurement of the fetal eye (vitreous body) to predict parturition in bucking horse mares. Monitoring gestation and predicting parturition in mares with unknown breeding dates is challenging, especially in pasture bred herds of bucking horses. Transrectal ultrasonographic measurement of fetal vitreous body length is a validated predictor of foaling dates, but previous research suggested a need for breed-specific parameters to develop accurate indices for respective breeds. This study aimed to develop a scale associating fetal vitreous body length with days before parturition (DBP) in bucking horses. Biannual data collection over 2 years identified 199 pregnancies out of 240 reproduc...
Genomic-Inbreeding Landscape and Selection Signatures in the Polo Argentino Horse Breed. Analyzing genetic variability and inbreeding trends is essential for effective breed management in animal populations. To this, the characterization of runs of homozygosity (ROH) provides a good genomic approach to study the phenomena. The Polo Argentino (PA) breed, globally recognized as the best adapted to playing polo, is known for its strong influence of Thoroughbreds, intense selective breeding, and extensive use of reproductive biotechnologies. This study investigates the PA's genomic variability, by characterizing the ROH landscape and identifying ROH islands (ROHi) as potential genomic...
A Genetic Make Up of Italian Lipizzan Horse Through Uniparental Markers to Preserve Historical Pedigrees. Lipizzan is a famous horse breed dating back to 1580 when the original stud of Lipica was established by the Hasburg Archduke Charles II. Currently, the Italian State Stud of Lipizzan Horses (ASCAL) is a conservation nucleus managed through strict mating rules where mitochondrial DNA sequences are used to verify the correct assignment of mares to a historical pedigree maternal lineage. Here, we analyzed the D-loop sequences of Lipizzan horses from the ASCAL in Monterotondo (Rome, Italy) in order to confirm their pedigree assignment to known female founder families. The concurrent investigation...
Bayesian Recursive and Structural Equation Models to Infer Causal Links Among Gait Visual Scores on Campolina Horses. Gait visual scores are widely applied to horse breeding because they are a fast and easy phenotyping strategy, allowing the numeric interpretation of a complex biological process such as gait quality. However, they may suffer from subjectivity or high environmental influence. We aimed to investigate potential causal relationships among six visual gait scores in Campolina horses. The data included 5475 horses with records for at least one of the following traits: Dissociation (Di), Comfort (C), Style (S), Regularity (R), Development (De), and Gait total Scores (GtS). The pedigree comprised thre...
The Prevalence of Gastric Ulcer Syndrome in 395 Horses in Jiangyin City, China, Jiangsu Province. The aim of this study was to determine the prevalence and association of EGUS in horses of different ages, breeds and occupations. Gastroscopies were performed on 395 horses, and gastric ulcers were graded on a scoring system from 0 to 4. The relationship between age, breed, and work, along with the prevalence of gastric ulcers and their influences, were evaluated. The prevalence rate of ulcers in this herd was 78%. Older horses were prone to ulcers in both the glandular and squamous mucosal areas. Across the different jobs surveyed, 60% of the horses had a score of 2 or above. For the horses ...
Genetic composition of Kazakh horses of Zhabe type evaluated by SNP genotyping. Horses are animals traditionally playing prominent role as both food source and working animals for Kazakh people. Zhabe horses are traditional type of indigenous Kazakh horses characterized by versatility and adaptation to conditions of Central Asia. The present work focuses on examination of genetic structure of Zhabe horses using SNP genotyping with addition of previously published data. Total 1038 individuals including 403 new samples of Zhabe horses and 42 sample of white horses 'Zhetysu Asyly' have been considered. DNA was extracted from hair roots using commercial DNA isolation kit and ...
Study of Variation of ACOX1 Gene Among Different Horse Breeds Maintained in Iran. The gene is vital for fatty acid metabolism and is linked to environmental stress and physical exertion adaptation. The p.Asp237Ser variant (rs782885985) in is associated with increased enzyme activity and reactive oxygen species (ROS) levels. This study examined the polymorphism across six horse breeds in Iran: Arabian, Thoroughbred, KWPN, Caspian, Kurdish, and Turkmen. The goal was to identify differences in genotype distribution, potentially serving as genetic markers under selection pressure related to breed-specific traits. In a sample of 324 horses, genomic DNA was analyzed using PCR...
Unraveling the maternal heritage: identifying the complex origins of indigenous Indian horse and pony breeds through mitochondrial genome analysis. This study explored the maternal genetic diversity of six indigenous Indian horse and pony breeds (Bhutia, Kathiawari, Manipuri, Marwari, Spiti, and Zanskari) using comprehensive mitochondrial genome (mitogenome) analysis. Blood samples from 53 horses across diverse agro-climatic zones of India were analyzed, revealing 36 distinct haplotypes, with a haplotype diversity of 0.889 and nucleotide diversity of 0.00347. These indices suggest significant maternal genetic diversity in Indian equines. A median-joining (MJ) network, based on the hypervariable region of the D-loop along with sequences of...
Y-chromosomal insights into the breeding history and sire line genealogies of two traditional Baroque horse breeds: Lipizzaner and Kladruber. The paternally inherited, male-specific part of the Y chromosome (MSY) is an ideal marker for studying the origin, genealogies, and historical connections of horse patrilines. Here, we performed fine-scaled MSY haplotype (HT) analysis in two Baroque horse breeds, the Lipizzaner and the Kladruber, both known for their long-standing tradition of sire line breeding and interconnected genealogies. We genotyped 95 MSY markers using KASP technology in 90 stallions representing all patrilines of both breeds. We identified 14 HTs across eight Lipizzaner sire lines and six HTs in eight Kladruber lines....
Prevalence of Taylorella equigenitalis in Icelandic mares and geldings in Southern Germany and Austria. Contagious Equine Metritis (CEM) caused by the bacterium Taylorella equigenitalis (T. equigenitalis), is a venereal infection of equids which is of international concern to the equine breeding industry. A recent study showed a high prevalence of T. equigenitalis in Icelandic stallions when compared to stallions of other breeds also using for natural breeding. Consequently, the objectives of the present study were to investigate the prevalence of T. equigenitalis in Icelandic mares and geldings and to determine factors associated with a T. equigenitalis-positive qPCR result. In total, 361 Icela...
Clinical and morphological features of corneal lymphoma in 26 horses (27 eyes). Little information describing the biologic behaviour and therapies for corneal lymphoma exist. Objective: To characterise histologically confirmed equine corneal lymphoma considering breed, age or sex predisposition, histologic and immunologic features, therapies and outcomes. Methods: Retrospective case series. Methods: A multicentre retrospective medical record review was used to identify horses that presented with corneal disease confirmed morphologically as corneal lymphoma from 2012 to 2022. Results: Mean age at diagnosis was 10.5 years. Males represented 18/26 cases. Warmblood (14) and...
Genomic insights into the genetic diversity, lateral gaits and high-altitude adaptation of Chakouyi (CKY) horses. Chakouyi (CKY) horses from the Qinghai‒Xizang Plateau are well known for their unique lateral gaits and high-altitude adaptation, but genetic mechanisms underlying these phenotypes remain unclear. This study presents a comparison of 60 newly resequenced genomes of gaited CKY horses with 139 public genomes from 19 horse breeds. Population structure analyses (admixture, PCA, and neighbor-joining tree) reveal a close genetic relationship between CKY and other highland breeds (Tibetan and Chaidamu horses). Compared with other Chinese breeds, CKY horses present reduced nucleotide diversity (θπ)...
Comparative analysis of racing performance following surgical correction of epiglottic entrapment in standardbreds and thoroughbreds. Epiglottic entrapment (EE) is a common cause of poor performance in racing standardbreds (STBs) and thoroughbreds (TBs). There is limited information published on the condition in STB racehorses and limited information on factors associated with return to racing available for either breed. Unassigned: This study investigated and compared the pre surgical findings, post-surgical complications and racing performance in STBs and TBs undergoing surgery for correction of EE. Associations between signalment and pre-surgical findings, and the presence of complications and racing post-surgery were com...
Estimation of Genetic Parameters for Racing Time and Ranking in Thoroughbred Horses. This study aimed to estimate genetic parameters for race time in seconds and final ranking, as well as to analyze the genetic trends associated with race time. The study utilized a dataset consisting of 23,290 records of race times and final ranks at distances of 1,000, 1,600, and 2,000 m from 6,213 Thoroughbred horses from the São Paulo Jockey Club. Our model considered the year of the run, animal sex, race class, track conditions, the linear effect of horse weight and age, and the quadratic effect of age as fixed covariates. Random effects included direct additive genetic, animal permanent ...
Genetic characterization of phenotypic traits in endangered Taishu horse breed and their breeding strategy. The Taishu horse is a native Japanese breed threatened with extinction. It is important to genotype the causative genes of rare phenotypes in endangered breeds because unique genetic traits might be lost unless a breeding strategy for conservation is constructed. In the present study, nine single-nucleotide variants and three indels of nine genes related to coat color, body composition, and gait were genotyped in 56 Taishu horses. Of these, only three genes were polymorphic. The observed coat color phenotypes coincided with the estimated phenotype from the genotypes, whereas black horses showe...