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.
A genome-wide investigation of insidious uveitis in Appaloosa horses. Equine recurrent uveitis (ERU), an inflammatory eye disease, is the leading cause of blindness among horses. Insidious uveitis, a form of ERU, is especially pervasive within the Appaloosa breed and is highly heritable (h = 0.68-1.0). To date only one risk locus, leopard complex (LP), has been identified, and it explained 0.16-0.33 of the heritability estimate, suggesting that insidious uveitis is a complex genetic disease within the Appaloosa horse breed with multiple unknown predisposing loci. Results: A genome-wide association study (GWAS) using relatedness, LP genotype, sex, and age as ...
Cryptorchidism in Equid: A Retrospective Study on Diagnostic Approach, Anaesthesia Management, Surgical Treatment and Outcomes. Over the years, various diagnostic and surgical techniques have been developed to recognise and treat cryptorchidism in equid. This study retrospectively analysed cases of cryptorchidism referred to two centres between 2012 and 2025. Clinical data collected included species, breed, age, gender, location of retained testis, diagnostic approach, anaesthesia plan and surgical treatment, perioperative medical treatment, intra-operative complications and outcomes. A total of 37 clinical cases were included, 1/37 was a donkey and 1/37 was an intersex female. Most of the horses were three years old a...
Risk factors for equine strangulating lipoma colic: An international, case-control study. Obstruction by strangulating lipoma (SLO) is one of the most common causes of small intestinal strangulation in horses and is fatal without surgery. Current knowledge of risk factors for SLO is limited to horse signalment features. To date, other risk factors have not been investigated. Objective: To investigate horse- and management-level risk factors for SLO using a population of healthy horses as controls. Methods: Matched, case-control study. Methods: A prospective, international multicentre study was conducted in the UK and USA between January 2022 and May 2024. Cases were horses with SLO...
Prediction Values for the Influence of Fetal Sex on Plasma Progesterone Concentration in Crioulo Breed Mares: A Preliminary Investigation. In equine reproduction, determining foetal sex is of economic and strategic importance, but currently available methods are often invasive, costly, or require specialised expertise. This study aimed to assess whether plasma progesterone concentrations could serve as a predictive tool for foetal sex determination in Criollo mares between the 4th and 8th months of gestation and to determine whether these measurements could identify foetal sex. Blood samples were collected at 30-day intervals from 17 Crioula mares between 114 days and 240 days of gestation. Maternal plasma progesterone concen...
Hematological and blood biochemical parameters of Tokara horses in Kaimon Foothills Nature Park. The Tokara horse is a breed of native Japanese horse, for which hematological and biochemical data are lacking. The aim of this study was to obtain current hematological and biochemical data on Tokara horses. We enrolled 90 Tokara horses kept at the Kaimon Foothills Nature Park (Kagoshima) that underwent physical examinations and blood sampling between 2022 and 2024. All horses in this study were regarded as clinically healthy, based on physical examinations. Hematological and biochemical parameters also showed no abnormal values. Based on the above results, we consider that the data from this...
Connections Between Gene Polymorphism and Fetlock and Hock Measurements in Polish Sport Horses. Finding the causative mutations for musculoskeletal system development and health status is of a higher priority for all sport horse breeders' associations. Of the regulating proteins involved in animal ossification, 15 gene polymorphisms were chosen to be identified as connected with the nine fetlock and 14 hock bone structures measurements of 198 horses. All measurements were taken using X-rays of the limbs, which were available at the beginning and end of the horse training. The analysis of variance (GLM, SAS program) was performed taking into account identified training and horse-connected...
Bridging Breeds: Transcriptomic Insights into Immune Traits of Yili, Thoroughbred, and Kazakh Horses. Studying the genetic characteristics and molecular mechanisms of immune regulation in horses is of great significance for protecting their genetic resources, improving breeding strategies, and enhancing their disease resistance, thereby ensuring their healthy performance in both sports and production. Objective: This study investigates the genetic characteristics and molecular mechanisms underlying immune regulation in Yili horses, comparing them with Thoroughbreds and Kazakh horses. Methods: Blood samples from each breed were analyzed for physiological, biochemical, and immune indices alongsi...
Assessment of thermal imaging to objectively body condition score mature horses and multiparous gestating beef cows. This study explored whether thermal imaging could provide an objective means of body condition scoring (BCS) horses and multiparous, gestating beef cows. This study consisted of two parts: one part assessed BCS in horses of the Quarter Horse or Thoroughbred breed types while the other evaluated BCS of gestating beef cows. Ground truth BCS were assigned by five to eight trained scorers for each animal. Thermal images were also collected from one or both sides of the body and analyzed for surface temperature. Surface temperature and BCS were evaluated with the whole body, and for five (cows) or ...
Analysis of Genetic Diversity and Race Genetic Structure of Major Horse Breeds in Xinjiang, China. The study of horse genetic diversity is imperative for informing conservation strategies, safeguarding ancestral lineages, and enhancing breed adaptability to environmental and disease pressures. This study employed 13 microsatellite markers with fluorescent-labeled capillary electrophoresis to analyze the genetic diversity of the Kyrgyz horse ( = 30) and Barkol horse ( = 30) for the first time, comparing them with three other indigenous horse breeds ( = 30 per breed) from Xinjiang, China. A total of 208 alleles were detected. The Polymorphic Information Content (PIC) results from GenAlEx 6.51...
Uncovering Genetic Diversity and Adaptive Candidate Genes in the Mugalzhar Horse Breed Using Whole-Genome Sequencing Data. Mugalzhar horses are a relatively young native breed of Kazakhstan, prized for meat and milk production and adaptation. This study was conducted to investigate genetic diversity and pinpoint genomic regions associated with selection signatures in this breed using whole-genome sequence data. Variant calling yielded a total of 21,722,393 high-quality variants, including 19,495,163 SNPs and 2,227,230 indels. Most variants were located in introns and intergenic regions, while only 1.94% were exonic. Estimates of genetic diversity were moderate, with expected and observed heterozygosity and nucleot...
Sexual arousal intensity modulates copulatory behavior and semen quality in Arabian stallions: Effects of age, origin, and collection method. Stallion sexual behavior during semen collection can be influenced by multiple factors, yet the role of sexual arousal intensity remains underexplored. Understanding how arousal modulates behavioral and physiological reproductive traits is essential for improving artificial insemination (AI) efficiency and semen quality. This study aimed to evaluate the effects of sexual arousal intensity, age, origin, and semen collection method on stallion sexual behavior and the quality of fresh and frozen semen. Unassigned: Thirteen Arabian stallions (7 Tunisian, 6 foreign parentage) aged 6-20 years (total...
Behavioral Assessment of Equine Relaxation Following Manual Therapy: A Pilot Study. The aim of this pilot study was to evaluate the relaxation, stress reduction and behavioral changes observed after manual therapy applied to horses exposed to racing and physical training stimulus. This descriptive approach is aimed at veterinary clinicians to evaluate the therapy process more effectively with behavioral feedback. For this purpose, the study was conducted in two different equestrian clubs in Adana (Adana Mediterranean and Suvari Equestrian Clubs) between 2023 and 2024. A total of 32 racehorses (16 Thoroughbred, 16 Arabian; 16 female, 16 male) of different ages, genders and bre...
High-quality, haplotype-resolved reference genomes of the Dutch warmblood horse and Friesian horse using trio binning. In horses, genetic diversity is predominantly observed between breeds, with little variation within breeds. The studbooks of the two largest horse populations in the Netherlands, the Dutch Warmblood horse and Friesian horse population, have ongoing conservation projects including collecting large-scale genotype and sequence data. The current reference genome, derived from a Thoroughbred horse can lead to bias in genetic analyses of other horse breeds. Therefore, the aim of this study was to create high-quality breed-specific reference genomes of Dutch Warmblood and Friesian horses. We performe...
Mutation rate and spectrum of germline de novo mutations in a closed population of Thoroughbred horses. Thoroughbreds have been maintained as a closed breed for over 300 years since the crossbreeding between Arabian stallions and English mares. Despite interest in germline de novo mutations across species, their frequency in horses, particularly in Thoroughbreds, remains largely unexplored. Objective: This study aimed to identify de novo mutations in Thoroughbreds and estimate their frequency within a genetically closed population. Methods: We performed deep whole-genome sequencing (≥230× depth, 150 bp paired-end reads) and Sanger validation in a Thoroughbred trio (sire, dam, and foal). Reads...
Retrospective Evaluation of Cryptorchid Sidedness at Colorado State University Between 1984 and 2014 and Oakridge Equine Hospital Between 2008 and 2023. Cryptorchidism is a common congenital disorder in male horses characterized by the failure of one or both testes to descend into the scrotum. This developmental anomaly has important clinical, surgical, and economic implications, particularly in breeding animals. This retrospective study investigates the prevalence and laterality of cryptorchidism in a large equine population presented to two veterinary referral hospitals-Colorado State University Veterinary Teaching Hospital (CSU VTH, 1984-2014) and Oakridge Equine Hospital (OEH, 2008-2023). Medical records were reviewed to identify affected ...
Population Structure and Genetic Diversity Among Shagya Arabian Horse Genealogical Lineages in Bulgaria Based on Microsatellite Genotyping. The Shagya Arabian horse breed was created to address the need of Imperial Hussars (Hungarian light horsemen) for a horse with the intelligence, essential characteristics, and endurance of the Arabian breed, but also of a bigger size and having a better weight-carrying capacity and jumping ability. The present study aimed to explore the genetic variability and population structure of the uninvestigated Shagya Arabian horse population in Bulgaria based on genotyping at 15 equine microsatellite markers. A total of 140 horses belonging to six genealogical lines (Dahoman, Gazal, Ibrahim, Kuhailan ...
Genotype concordance and trait mapping efficacy comparing data from the Equine 670 K SNP array with whole genome sequence in 21 horses. With advancing genomic technologies, single-nucleotide polymorphism (SNP) arrays and whole genome sequencing (WGS) have become essential tools in equine genetic research. In this study, we assessed the concordance in SNP calls and trait-mapping efficacy by comparing data of 21 horses both genotyped on the Equine 670 K SNP array and sequenced at either ~12× or ~30× depth. Our analysis revealed that higher sequencing depths were significantly associated with fewer discordant calls between platforms. Additionally, we investigated the most frequent no-call and discordant positions and identifi...
Late Iron Age and Roman equine breeding north of the Alps: Genetic insights and cultural implications. The Roman conquest of the northern Alpine foreland in 15 BCE introduced larger-sized horses and hybrid mules to the region. To investigate their genetic profiles and influence on local breeding, we analyzed our previously generated shallow shotgun DNA data from 402 Late Iron Age and Roman equids, supplemented with mitochondrial and nuclear capture data from 40 to 31 equids from the same regions and periods. Late Iron Age and Roman horses exhibit high matrilineal diversity, with unique haplogroups in the latter indicating exogenous animals. The preferred use of male mounts in army service menti...
Whole-Genome Resequencing Analysis of Athletic Traits in Grassland-Thoroughbred. Speed is not only the primary objective of racehorse breeding but also a crucial indicator for evaluating racehorse performance. This study investigates a newly developed racehorse breed in China. Through whole-genome resequencing, we selected 60 offspring obtained from the crossbreeding of Thoroughbred horses and Xilingol horses for this study. This breed is tentatively named "Grassland-Thoroughbred", and the samples were divided into two groups based on racing ability: 30 racehorses and 30 non-racehorses. Based on whole-genome sequencing data, the study achieved an average sequencing depth o...
Quantitative modeling reveals prolonged lactate clearance in young and unraced Jeju horses following high-intensity exercise under passive recovery conditions. To model lactate recovery kinetics in relation to sex, age, running speed, and racing experience, and to estimate blood lactate clearance time under passive recovery conditions that reflect current management practices in Jeju horses, a less well-characterized pony-sized indigenous breed. Unassigned: From October through December 2022, BLC was measured at baseline, 10 minutes after 800-m barrier trials (time [T]-1), and 50 minutes (T2) after 800-m barrier trials in 40 race-trained Jeju horses (2 to 4 years old). Lactate clearance was modeled using nonlinear regression with an exponential decay...
Variation in Four Horse Gait Categories Illustrated by Quantitative Analysis With ANALOC-E. Horse gaits are a trait highly selected and prized in diverse breeds. Meanwhile, gait classification relies mostly on subjective visual observations by evaluators. Noninvasive equipment able to track locomotion in horses and output quantitative gait parameters is not only helpful in evaluating locomotion but also in designating gait types and its variations. Equine locomotion pattern designation based solely on observer evaluation can be subjective; therefore, utilizing tools that provide quantitative results and track individual limb movements, especially during intermediate-speed gaits, can ...
Population structure and signature of selection for body size in some Iranian and exotic horse breeds. Iran is home to genetically distinct horse breeds shaped by geography and history. Breeds like the Kurdish, Caspian pony, and Turkmen reflect deep-rooted diversity and unique adaptive traits. Objective: This study aimed to identify genomic regions exhibiting signatures of selection and to detect candidate genes and biological pathways related to body size that may influence performance in various Iranian and exotic horse breeds. Methods: Samples were collected from three Iranian native breeds (Caspian pony, Turkmen, and Kurdish) and three exotic breeds (Fell pony, Arabian, and Akhal-Teke) orig...
Reference Intervals for Biochemical Analytes in Clinically Healthy Adult Lusitano Horses. To date, serum biochemical analytes reference intervals (RIs) in Lusitano horses have not been studied. This study aimed to establish the RIs for biochemical analytes following the American Society of Veterinary Clinical Pathology guidelines and to compare them with the general equine population's RIs. Blood samples were collected from 76 clinically healthy adult Lusitano horses, and RIs of 22 biochemical variables were determined using Reference Value Advisor software. Lusitano horse-specific RIs are proposed for the following variables: total protein (3.9-7.0 g/dL), albumin (2.5-3.8 g/dL), g...
An iterative approach to identify key predictive features of fear reactivity and fearfulness in horses (Equus caballus). This study extends previous findings by applying artificial intelligence (AI) methods to a larger dataset to identify key features that predict fear reactivity (i.e., immediate reaction to fear inducing stimuli) and fearfulness (i.e., a stable personality trait) in 101 Lipizzan horses. The analysis included 221 morphological, kinematic, behavioral and management measurements per horse. Previous findings were confirmed, as body and head size were identified as promising predictors of aspects of fear-related trait. Using an iterative AI approach, six key features for fear reactivity and nine for...
Epidemiological Patterns of Gastrointestinal Parasitic Infections in Equine Populations from Urumqi and Ili, Xinjiang, China. Gastrointestinal parasitic diseases pose significant health risks to equine populations. This study investigated the epidemiological patterns of equine gastrointestinal parasites in Xinjiang by analyzing 83 fecal samples collected from Ili ( = 62) and Urumqi ( = 21) between August and November 2024. The modified McMaster technique was employed to quantify fecal egg counts (EPG) and was complemented by morphological identification to assess infection dynamics related to geography, breed specificity, and management practices. The results demonstrated an overall infection prevalence of 66.3% (55/...
Meat Production Potential of Local Horse Breeds: Sustainable Conservation Through Valorization. Local horse breeds, particularly cold-blood types, are often marginalized in economic and social contexts, primarily due to the neglect of their economic, genetic, and cultural potential, as well as their role in preserving the identity of rural areas, local communities, and ecosystems. The valorization of these breeds is a crucial prerequisite for their economic repositioning. The Croatian Posavina horse is a local breed, well adapted to harsh, extensive production systems. Its sustainability is achieved through pasture-based meat production, primarily targeting foreign European markets. Ensu...
Physiological response to weight carrying and associations with conformation traits in Icelandic horses used for tour riding. Weight carrying capacity is an important trait in riding horses and it may be associated with conformation. This study examined the physiological response to a ridden incremental weight carrying test in 16 adult Icelandic horses used for tour riding. Horses carried 20% (BWR20%), 25% (BWR25%), 30% (BWR30%) and 35% (BWR35%) of their body weight (BW) in tölt (~ 5.7 m/seconds, 640 m/step), and associations with body measurements and back conformation (score) were examined. Horses were divided into two groups (narrow or broad back) and body measurements were collected. Plasma lactate was analy...
The Effects of the Lactation Period, Mare Age, and Foaling on the Chemical and Physical Composition of Milk from Kazakh Mares Kept Under Natural Pasture Conditions. This study aimed to evaluate the chemical composition of milk from Kazakh mares kept under free-grazing conditions on natural pasture without supplementary feeding. Fifty Kazakh mares were aged 3 to 13 years, kept in herds, and categorized by age, number of foalings, and lactation stage for statistical analysis. Milk samples were collected, chilled, and analyzed on the same day using a Milkoscan FT2. The composition of fat, protein, lactose, total solids, casein, and other components was examined. Statistical analyses, including ANOVA, PCA, CDA, and Pearson correlation analysis, were performed...
The Thoroughbred Theory: Influence of Breed on Performance at the CCI5*-L Level of Eventing. Breed bias exists within many of the top disciplines of equestrian sport. Therefore, the objective of this study was to evaluate the influence of breed on performance at the CCI5*-L level of eventing. To do so, the results of all CCI5*-L events from 2014 to 2024 were assessed. Initially, Thoroughbreds were compared to all non-Thoroughbreds, and this was followed by assessing the ten primary breeds. Data included penalties accrued in dressage, cross country, show jumping, and overall. Additionally, the likelihood of completing each phase was assessed. It was found that Thoroughbreds accrued mor...
Prevalence and risk of orthopedic diagnoses in insured Swedish Warmblood horses. Sweden has a strong tradition of insuring horses for veterinary costs, and orthopedic diagnoses are the most common for insurance claims. The aim of this study was to investigate differences in prevalence and risk of orthopedic diagnoses for Swedish warmblood (SWB) horses classified as jumping (J) or dressage (D) horses. Also, other factors that may influence orthopedic health were investigated, i.e., sex, birth cohort, and participation in young horse tests and competition. The data consisted of 15,619 insured SWB horses born between 2010 and 2020. Horses were classified as J or D horses acco...