The population dynamics of horses refers to the study of changes in horse populations over time, influenced by factors such as birth rates, death rates, immigration, and emigration. These dynamics are shaped by environmental conditions, resource availability, predation, and human intervention. Understanding population dynamics is essential for managing wild horse populations and ensuring sustainable practices in breeding and conservation efforts. This page compiles peer-reviewed research studies and scholarly articles that explore the factors affecting horse population dynamics, including genetic diversity, habitat utilization, and the impact of management strategies on population stability and growth.
Mouncey R, de Mestre AM, Verheyen KL.Analyses of industry-level data suggest that around one-third of the UK and Ireland Thoroughbred foal crop fail to enter training. Prospective follow-up of individual horses could provide additional insight, particularly around individuals not attaining specific career milestones. Methods: A Thoroughbred birth cohort was established on stud farms across the UK and Ireland. Training, race performance, sales, export data, destinations and reasons for individuals failing to meet career milestones were collected from stud records, follow-up with owners, stud book and racing authorities' databases,...
Luštrek B, Šimon M, Turk K, Bogičević S, Potočnik K.In small, closed populations such as the Lipizzan horse, maintaining genetic diversity while limiting inbreeding is a key challenge in conservation breeding. The Lipizzan is an indigenous Slovenian breed with a small population and restricted gene flow from other subpopulations. Inbreeding is traditionally monitored with pedigree-based coefficients, but these often underestimate realised autozygosity, particularly when pedigree depth is limited. This study compared pedigree-based inbreeding (F_PED) with four genomic estimators (F_HOM, F_ROH, F_HBD, F_GRM) in 329 Slovenian Lipizzan horses genot...
Williams JM, Jordan S, Friend L, Kay E, Edmunds M, Flynn H, Wensley S.Horse welfare within/after racing is often questioned by the public. British Racing's Horse Welfare Board's "A life well-lived" strategy provides a blueprint for Thoroughbred welfare, advocating accurate lifetime traceability of horses as essential to achieve this. The Census aimed to establish a population density model for British Thoroughbreds, not actively engaged in racing. Equestrians who owned/kept a Thoroughbred were asked to complete the Census between May and December 2023. Frequency analysis identified patterns in passport compliance, knowledge and understanding of current systems, ...
Karlau A, Azcona F, Molina A, Trigo P, Sánchez-Serrano JP, Demyda-Peyrás S.The Peruano de Paso is a horse breed renowned for its smooth gait, traditionally selected based on breeders' empirical knowledge. Recently, the frequency of chestnut horses, a recessive trait, has increased substantially within the official studbook. This study evaluated whether preference for chestnut coat colour has influenced morphological traits and genetic diversity within the breed. A total of 8376 records of seven morphological traits, collected by the Peruano de Paso Breeders Association over eight years, were analysed, along with a pedigree including 41,357 individuals. Morphological ...
Kim D, Lee S, Oyungerel B, Cho G.This study aimed to generate information for parentage testing in horse breeds using microsatellites (STRs) and single-nucleotide polymorphisms (SNPs). Genotype data were obtained from 189 horse hair root samples, including 38 Thoroughbreds (TBs), 17 Jeju horses (JHs), 20 Quarter horses (QHs), 21 American Miniatures (AMs), and 93 Mongolian horses (MHs), using 15 STR markers and 71 SNP markers. Comparative analysis revealed that the mean expected heterozygosity ranged from 0.468 (AM) to 0.491 (JH) for SNPs and from 0.695 (TB) to 0.791 (MH) for STRs. The mean observed heterozygosity ranged from ...
Hou L, Sulayman A, Zeng Y, Zhou L, Aimaier A, Kader A, Shi L.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...
Kassymbekova SN, Bimenova ZZ, Iskhan KZ, Sobiech P, Jastrzebski JP, Brym P, Babis W, Kalykova AS, Otebayev ZM, Kabylbekova DI, Baneh H, Romanov MN.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...
Duderstadt S, Distl O.Dülmen wild horses are kept in a fenced wooden and marsh area around Dülmen in Westphalia, Germany, since 1856. Previous analyses supported early genetic divergence from other domesticated horse populations and the Przewalski horse. Therefore, the objective of this study was to evaluate genetic diversity using high-density genomic data. Methods: We collected 337 one-year-old male Dülmen wild horses, captured at 12 annual auctions, for genotyping on the Illumina GGP Equine Plus Beadchip. All analyses were performed for 63,123 autosomal SNPs. Results: On average, each horse had 27.96 ROH with...
Taylor WTT, Delsol N, Oelze VM, Mitchell P, Stricker L, Lavin M, Ogundiran A, Hosek L, Barrón-Ortiz CI, Ojediran O, Quintero-Bisono D....Domestic equids were central to the initial colonization of the Atlantic coast of the Americas, a process partially chronicled by historical records. While Spanish colonists brought horses to the Caribbean decades earlier, settlement of the English colony at Jamestown, Virginia, was among the first dispersals of horses to the eastern seaboard. Archaeozoological analysis of identifiable domestic equid remains from two contexts associated with the initial occupation of Jamestown demonstrates intense processing and consumption of the first Jamestown horses during the "Starving Time" winter of 160...
Furukawa R, Tozaki T, Mizukami K, Iwasaki Y, Kawate K, Kikuchi M, Ishige T, Momozawa Y, Fukui E, Kakoi H.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...
Science (New York, N.Y.)August 28, 2025
Volume 389, Issue 6763 925-930 doi: 10.1126/science.adp4581
Liu X, Jia Y, Pan J, Zhang Y, Gong Y, Wang X, Ma Y, Alvarez N, Jiang L, Orlando L.Horsepower revolutionized human history through enhanced mobility, transport, and warfare. However, the suite of biological traits that reshaped horses during domestication remains unclear. We scanned an extensive horse genome time series for selection signatures at 266 markers associated with key traits. We detected a signature of positive selection at -known to be a modulator of behavior in mice-occurring ~5000 years ago (ya), suggesting that taming was one of the earliest steps toward domestication of horses. Intensive selection at began ~4750 ya with the domestication bottleneck, leading ...
Turcotte G, O'Sullivan TL, Rossi TM, Spence KL, Winder CB, Greer AL.Horses are frequently transported, creating opportunities for the spread of pathogens. Disease transmission models for equine infectious diseases face limitations on their generalizability due to challenges in describing equine movement and the structure of their contact networks beyond simplistic assumptions. This study aimed to combine a stochastic, agent-based, SEIR model for equine influenza disease dynamics with an observed Ontario, Canada equine contact network structure to quantify the potential magnitude of equine influenza outbreaks in Ontario competition horses under different condit...
Mukhanbetkaliyev Y, Yessembekova G, Mukhanbetkaliyeva A, Akmambayeva B, Kadyrov A, Uskenov R, Bostanova S, Ashirbek A, Korennoy F, Abdrakhmanov S.Equine herpesvirus 1 (EHV-1) is one of the most dangerous viral diseases affecting ungulates, and is characterized by a wide range of clinical manifestations in horses, including rhinopneumonia, abortion, neonatal death, and myeloencephalopathy. It is well known for causing mass abortions in mares and respiratory diseases in young animals. Once introduced into a horse breeding farm of any type, EHV-1 tends to establish as a persistent infection. The disease is reported on nearly all continents and causes substantial annual economic losses to horse breeding operations. In Kazakhstan, 34 EHV-1 o...
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 ...
Everts RE, Caron R, Foster G, McLoone K, Simiele L, Martin K, Brooks SA, Lafayette C.Roan coat color is described as the dispersion of white hairs within an otherwise solid background-color coat. This phenotype is primarily expressed on the body of the horse, with the head and legs exhibiting few or no white hairs. Previous studies mapped the locus for roan to the region and observed linked variants in a small number of breeds. Recently, we reported evidence for two independent haplotypes, and , in the region, which account for approximately 38% and 36% of roan horses, respectively. In the current report, using whole genome sequencing for unknown roan samples. We present a ...
Sharif MB, Mohaseb AF, Orlando L, Saliari K, Kunst GK, Czeika S, Mashkour M, Cucchi T, Peters J, Trixl S, Mohandesan E.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...
Horses have inhabited Iberia (present-day Spain and Portugal) since the Middle Pleistocene, shaping a complex history in the region. Iberia has been proposed as a potential domestication centre and is renowned for producing world-class bloodlines. Here, we generate genome-wide sequence data from 87 ancient horse specimens (median coverage = 0.97X) from Iberia and the broader Mediterranean to reconstruct their genetic history over the last ~26,000 years. Here, we report that wild horses of the divergent IBE lineage inhabited Iberia from the Late Pleistocene, while domesticated DOM2 horses, nati...
Bazvand B, Rashidi A, Zandi MB, Moradi MH, Rostamzadeh J, Mahmoudi P.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...
McGlennon AA, Verheyen KL, Newton JR, van Tonder A, Wilson H, Parkhill J, de Brauwere N, Frosth S, Waller AS.Strangles (Streptococcus equi infection) remains endemic in the UK, with ~300 laboratory diagnoses annually. Sub-clinically infected long-term carriers are considered a key driver of endemicity. Analysing genomes of circulating strains could provide valuable transmission insights of this pathogen. Objective: To determine the population structure and diversity of UK S. equi isolates and to model transmission using epidemiological and whole genome sequencing data. Methods: Retrospective cross-sectional epidemiological and genomic surveillance. Methods: A dated phylogenetic tree derived from 511...
Ding W, Gong W, Bou T, Shi L, Lin Y, Shi X, Li Z, Wu H, Dugarjaviin M, Bai D.The core objective of racehorse breeding is to enhance the speed and endurance of the horses. The Grassland-Thoroughbred is an emerging horse breed developed in northern China in recent years, characterized by excellent speed performance, enduring stamina, and strong environmental adaptability. However, research on the genetic characteristics within this breed and the genes associated with athletic performance remains relatively limited. We conducted whole-genome resequencing of Grassland-Thoroughbred F1, F2, F3, and the crossbred population (CY) and obtained a total of 4056.23 Gb of high-qual...
Mutillod C, Buisson E, Tatin L, Mahy G, Dufrêne M, Morvan N, Mesléard F, Dutoit T.The urgency of restoring ecosystems over vast areas has placed rewilding using wild herbivores at the forefront. However, few scientific studies address its effects on biodiversity and ecosystem functioning compared to more traditional conservation interventions with domestic herbivores. Equus ferus przewalskii horses introduced 30 years ago in the National Park of Cévennes, France - as a step of a conservation program of the species for its reintroduction in Mongolia - now occur as a semi-wild horse population, socially natural (i.e., management is based on natural selection). This introduct...
Scupham AJ.Many viruses mutate rapidly to adapt to host defenses, and for some of these viruses, the result is long-term infection in individual hosts. The work described here examines the infection and long-term maintenance of a newly identified virus, equine parvovirus-hepatitis (EqPV-H), in an individual horse. This description is possible because of a hypervariable region in the capsid gene; sequence variants were tracked by high-throughput sequencing of serum samples taken over a 16-year period. The data support the hypothesis that EqPV-H infection resulted in a sequence variant bottleneck. The cont...
de Carvalho CN, Cunha PP, Belo J, Muñiz F, Baucon A, Cachão M, Figueiredo S, Buylaert JP, Galán JM, Belaústegui Z, Cáceres LM, Zhang Y....Multiple sources of evidence for the systematic use of coastal ecosystems and resources by Neanderthals are known. Fossil hominin footprints offer direct portraits of individual or social group presence and locomotor behavior, and interspecific interactions, in the coastal ecospace. Here we describe the first two hominin tracksites found in the southwestern most region of Europe. At Monte Clérigo, dated to 78 ± 5 ka, trackways of three individuals demonstrate how Neanderthals navigated dune landscapes. These behaviors suggest route planning, with dune systems serving as advantageous set...
Avila F, Esdaile E, Bellone RR. Standardbreds, a breed of horses used in harness racing at either the trot or the pace, established a closed studbook in 1973. Concerns about genetic diversity within the breed led the United States Trotting Association (USTA) to establish a limit of mares bred per stallion (i.e., a studbook cap) in 2009. Here, we aimed to evaluate the impact of the breeding restrictions on genetic diversity between and among subpopulations. : Sixteen short tandem repeats (STRs) were analyzed across a dataset of 176,424 Standardbreds foaled in the United States between 1998 and 2021. We examined allelic richn...
Ryan CA, Berry DP, Bugno-Poniewierska M, Burke MK, Raudsepp T, Egan S, Doyle JL.Autosomal trisomy, a genetic disorder characterized by the presence of an extra autosome, is a rare but important chromosomal abnormality in horses, often associated with infertility, developmental abnormalities, and reduced life expectancy. This study represents the largest population-level screening for autosomal trisomy in horses; the analysis used single nucleotide polymorphism (SNP) panel genotype intensity data from 17,078 horses, 6601 of which were juveniles (i.e., ≤12 months of age) when genotyped. Using methodologies adapted from similar screening studies in cattle, the only aneuplo...
Ablondi M, Eriksson S, Mikko S.Fragile foal syndrome (FFS) is a disease caused by a recessive lethal missense mutation in the PLOD1 gene located on ECA2. Despite its harmful effect, a relatively high frequency of FFS carriers was observed in Warmblood breeds spanning from 7.4% in a random sample of Swedish Warmblood breed to 17% in the Hanoverian and Danish Warmblood, indicating potential heterozygous advantage. Balancing selection can be further studied based on haplotype blocks and via detection of heterozygosity-rich region (ROHet) around the target of selection. In this study we evaluated the presence of haplotype block...
Ding W, Gong W, Bou T, Shi L, Lin Y, Shi X, Li Z, Wu H, Dugarjaviin M, Bai D, Zhao Y.Speed and endurance are the primary goals in racehorse breeding. The Grassland-Thoroughbred is a newly developed breed in northern China that combines speed, endurance, and environmental adaptability. However, current research on the genetic background of this breed and the genes associated with athletic performance remains limited. We conducted whole-genome resequencing on Mongolian (MG), Thoroughbred (TB), Xilingol (XL), and Grassland-Thoroughbred (CY) horses, generating 3813.74 Gb of clean data after quality control. The number of transitions was significantly higher than that of transversi...
Asti V, Summer A, Ablondi M, Sartori C, Giontella A, Pilastro V, Mecocci S, Cappelli K, Mancin E, Oian A, Mantovani R, Capomaccio S, Sabbioni A.Horses have undergone extensive natural and artificial selection, shaping the diversity of breeds observed today. Native Italian breeds present unique traits influenced by natural selection, such as adaptation to harsh climates, or hoof strength, but face challenges due to population declines and the reduction of their original breeding purpose. This study focuses on five local Italian breeds: Bardigiano, Haflinger, Maremmano, Murgese, and Italian Heavy Draught Horse, to understand how selection has shaped their populations. A total of 1620 individuals were genotyped with a medium-density SNP ...
Science (New York, N.Y.)May 15, 2025
Volume 388, Issue 6748 748-755 doi: 10.1126/science.adr2355
Climate affects habitat, food availability, and the movement and sustainability of all life. In this work, we apply Indigenous and Western scientific methods, including genomics and isotope profiling, on fossils from across Beringia to explore the effect of climate change on horses. We find that Late Pleistocene horses from Alaska and northern Yukon are related to populations from Eurasia and crossed the Bering land bridge multiple times during the last glacial interval. We also find deeply divergent lineages north and south of the American ice sheets that genetically influenced populations ac...
Barsi B, Oláh J, Posta J.The Hungarian Coldblood horse was developed in the 1920s by crossing local mares with draft horses imported from Belgium and France, and was approved as an official horse breed in 1954. The aim of the study was to analyze the quality of the pedigree, generation interval, gene origin, and inbreeding. The pedigree information was received from the Hungarian Coldblood Horse Breeding Association. The studbook data of the registered animals up to 2023 were evaluated. Two reference populations were chosen: horses having offspring in 1989 and 2023. The final database contained 21,699 horses. Pedigree...
Linklater WL, Cameron EZ, Minot EO, Stafford KJ.Feral horse, Equus caballus, breeding groups, called bands, usually include one but sometimes up to five stallions. We found that mares were loyal to single-stallion (SS) or multistallion (MS) bands or were social dispersers (maverick mares, Mv). The spacing and social behaviour of mares and stallions in single- and multistallion bands was measured. Indices of mare well-being were also measured including activity budgets (feeding: MS>SS=Mv; resting: MSSS), maternal effort in maintaining contact with foals (MS=Mv>SS), parasite levels in faeces (MS>Mv>SS), body condition (MS=Mv<SS...
Kirkpatrick JF, Lyda RO, Frank KM.Wildlife, free-ranging and captive, poses and causes serious population problems not unlike those encountered with human overpopulation. Traditional lethal control programs, however, are not always legal, wise, safe, or publicly acceptable; thus, alternative approaches are necessary. Immunocontraception of free-ranging wildlife has reached the management level, with success across a large variety of species. Thus far, the immunocontraceptive research and management applications emphasis have been centered on porcine zona pellucida and gonadotropin-releasing hormone vaccines. Contraceptive succ...
Cosgrove EJ, Sadeghi R, Schlamp F, Holl HM, Moradi-Shahrbabak M, Miraei-Ashtiani SR, Abdalla S, Shykind B, Troedsson M, Stefaniuk-Szmukier M....The Arabian horse, one of the world's oldest breeds of any domesticated animal, is characterized by natural beauty, graceful movement, athletic endurance, and, as a result of its development in the arid Middle East, the ability to thrive in a hot, dry environment. Here we studied 378 Arabian horses from 12 countries using equine single nucleotide polymorphism (SNP) arrays and whole-genome re-sequencing to examine hypotheses about genomic diversity, population structure, and the relationship of the Arabian to other horse breeds. We identified a high degree of genetic variation and complex ances...
Tenzin , Sharma B, Dhand NK, Timsina N, Ward MP.From January through July 2008, rabies reemerged in the Chhukha district of southwestern Bhutan. To clarify the distribution and direction of spread of this outbreak, we mapped reported cases and conducted directional tests (mean center and standard deviational ellipse). The outbreak resulted in the death of 97 animals (42 cattle, 52 dogs, and 3 horses). Antirabies vaccine was given free of charge to ≈674 persons suspected to have been exposed. The outbreak spread south to north and appeared to follow road networks, towns, and areas of high human density associated with a large, free-roaming...
Raudsepp T, Finno CJ, Bellone RR, Petersen JL.The horse reference genome from the Thoroughbred mare Twilight has been available for a decade and, together with advances in genomics technologies, has led to unparalleled developments in equine genomics. At the core of this progress is the continuing improvement of the quality, contiguity and completeness of the reference genome, and its functional annotation. Recent achievements include the release of the next version of the reference genome (EquCab3.0) and generation of a reference sequence for the Y chromosome. Horse satellite-free centromeres provide unique models for mammalian centromer...
Harris SR, Robinson C, Steward KF, Webb KS, Paillot R, Parkhill J, Holden MT, Waller AS.Strangles, the most frequently diagnosed infectious disease of horses worldwide, is caused by Streptococcus equi. Despite its prevalence, the global diversity and mechanisms underlying the evolution of S. equi as a host-restricted pathogen remain poorly understood. Here, we define the global population structure of this important pathogen and reveal a population replacement in the late 19th or early 20th Century. Our data reveal a dynamic genome that continues to mutate and decay, but also to amplify and acquire genes despite the organism having lost its natural competence and become host-rest...
Hill EW, Bradley DG, Al-Barody M, Ertugrul O, Splan RK, Zakharov I, Cunningham EP.Mitochondrial DNA (mtDNA) D-loop sequences (381 bp) from 100 thoroughbreds in 19 of the most common matrilineal female families were used to reconstruct a founder female population for the thoroughbred ( approximately 1650-1750 AD). Seventeen haplotypes were found to have contributed to the 19 female lineages. In order to place the reconstructed founder population in wider historical context, we examined, using both single strand conformation polymorphism and direct sequence analysis, variation in a 343 bp mtDNA fragment in that population and 13 other horse populations of disparate provenance...
McGivney BA, Han H, Corduff LR, Katz LM, Tozaki T, MacHugh DE, Hill EW.The Thoroughbred horse is a highly valued domestic animal population under strong selection for athletic phenotypes. Here we present a high resolution genomics-based analysis of inbreeding in the population that may form the basis for evidence-based discussion amid concerns in the breeding industry over the increasing use of small numbers of popular sire lines, which may accelerate a loss of genetic diversity. In the most comprehensive globally representative sample of Thoroughbreds to-date (n = 10,118), including prominent stallions (n = 305) from the major bloodstock regions of the w...
Ablondi M, Dadousis C, Vasini M, Eriksson S, Mikko S, Sabbioni A.Horses are nowadays mainly used for sport and leisure activities, and several local breeds, traditionally used in agriculture, have been exposed to a dramatic loss in population size and genetic diversity. The loss of genetic diversity negatively impacts individual fitness and reduces the potential long-term survivability of a breed. Recent advances in molecular biology and bioinformatics have allowed researchers to explore biodiversity one step further. This study aimed to evaluate the loss of genetic variability and identify genomic regions under selection pressure in the Bardigiano breed ba...
McGahern A, Bower MA, Edwards CJ, Brophy PO, Sulimova G, Zakharov I, Vizuete-Forster M, Levine M, Li S, MacHugh DE, Hill EW.Equine mitochondrial DNA (mtDNA) phylogeny reconstruction reveals a complex pattern of variation unlike that seen in other large domesticates. It is likely that this pattern reflects a process of multiple and repeated, although not necessarily independent, domestication events. Until now, no clear geographic affiliation of clades has been apparent. In this study, amova analyses have revealed a significant non-random distribution of the diversity among equine populations when seven newly sequenced Eurasian populations were examined in the context of previously published sequences. The associati...
Seltenhammer MH, Simhofer H, Scherzer S, Zechner R, Curik I, Sölkner J, Brandt SM, Jansen B, Pehamberger H, Eisenmenger E.Equine melanomas occur most commonly in grey horses at age 5 years or more. Generally, benign and malignant melanomas are distinguished by microscopy, but a more distinct classification would be helpful. Objective: The objectives of this study were to gain further evidence concerning the occurrence of melanotic tumours, and to evaluate the impact of heredity on melanoma development. Methods: A clinical study was conducted on a defined population of 296 grey horses of Lipizzaner breed. Individuals were classified according to their stage of disease using a 0-5 scale. Heritability was estimated ...
Linklater WL.Socio-ecological explanations for intra- and interspecific variation in the social and spatial organization of animals predominate in the scientific literature. The socio-ecological model, developed first for the Bovidae and Cervidae, is commonly applied more widely to other groups including the Equidae. Intraspecific comparisons are particularly valuable because they allow the role of environment and demography on social and spatial organization to be understood while controlling for phylogeny or morphology which confound interspecific comparisons. Feral horse (Equus caballus Linnaeus 1758) p...
Lam KH, Parkin TD, Riggs CM, Morgan KL.This study was part of a programme to optimise the longevity and maximise the health and welfare of the Thoroughbred racehorses in Hong Kong. Injuries to the superficial digital flexor (SDF) tendon are the most common veterinary reason for premature retirement in this population. Objective: To describe the frequency and pattern of retirements associated with SDF tendon injuries in Thoroughbred racehorses and to compare the characteristics of these horses with those that retired for other reasons. Methods: A retrospective analysis of retirement records documented in the Hong Kong Jockey Club cl...
Cañon J, Checa ML, Carleos C, Vega-Pla JL, Vallejo M, Dunner S.Partition of the genetic variability, genetic structure and relationships among seven Spanish Celtic horse breeds were studied using PCR amplification of 13 microsatellites on 481 random individuals. In addition, 60 thoroughbred horses were included. The average observed heterozygosity and the mean number of alleles were higher for the Atlantic horse breeds than for the Balearic Islands breeds. Only eight percentage of the total genetic variability could be attributed to differences among breeds (mean FST approximately 0.08; P < 0.01). Atlantic breeds clearly form a separate cluster from th...
The climatic and cultural diversity of the Italian Peninsula triggered, over time, the development of a great variety of horse breeds, whose origin and history are still unclear. To clarify this issue, analyses on phenotypic traits and genealogical data were recently coupled with molecular screening. Methods: To provide a comprehensive overview of the horse genetic variability in Italy, we produced and phylogenetically analyzed 407 mitochondrial DNA (mtDNA) control-region sequences from ten of the most important Italian riding horse and pony breeds: Bardigiano, Esperia, Giara, Lipizzan, Maremm...
The Journal of heredityJanuary 3, 2018
Volume 109, Issue 4 384-392 doi: 10.1093/jhered/esx114
Druml T, Neuditschko M, Grilz-Seger G, Horna M, Ricard A, Mesaric M, Cotman M, Pausch H, Brem G.Within the scope of current genetic diversity analyses, population structure and homozygosity measures are independently analyzed and interpreted. To enhance analytical power, we combined the visualization of recently described high-resolution population networks with runs of homozygosity (ROH). In this study, we demonstrate that this approach enabled us to reveal important aspects of the breeding history of the Haflinger horse. We collected high-density genotype information of 531 horses originating from 7 populations which were involved in the formation of the Haflinger, namely 32 Italian Ha...
van Beest FM, Uzal A, Vander Wal E, Laforge MP, Contasti AL, Colville D, McLoughlin PD.Density is a fundamental driver of many ecological processes including habitat selection. Theory on density-dependent habitat selection predicts that animals should be distributed relative to profitability of habitat, resulting in reduced specialization in selection (i.e. generalization) as density increases and competition intensifies. Despite mounting empirical support for density-dependent habitat selection using isodars to describe coarse-grained (interhabitat) animal movements, we know little of how density affects fine-grained resource selection of animals within habitats [e.g. using res...
Ning T, Xiao H, Li J, Hua S, Zhang YP.Mitochondria play a crucial role in energy metabolism through oxidative phosphorylation. Organisms living at high altitudes are potentially influenced by oxygen deficits and cold temperatures. The severe environmental conditions can impact on metabolism and direct selection of mitochondrial DNA. As a wide-ranging animal, the domestic horse (Equus caballus) has developed various morphological and physiological characteristics for adapting to different altitudes. Thus, this is a good species for studying adaption to high altitudes at a molecular level. We sequenced the complete NADH dehydrogenas...
Landman MA, de Blaauw JA, van Weeren PR, Hofland LJ.A population of 805 horses (70 per cent dressage, 20 per cent show jumpers and 10 per cent trotters) with orthopaedic problems was examined for signs of lameness and back problems, irrespective of their original complaints. In the horses with a back problem the prevalence of lameness was 74 per cent, and back problems were diagnosed in 32 per cent of the lame horses. These percentages were significantly higher than those recorded in a control population of 399 horses, of which 20 per cent were lame and 12 per cent had back problems. In the group of horses with orthopaedic problems there was a ...
The Journal of heredityFebruary 28, 2013
Volume 104, Issue 3 386-398 doi: 10.1093/jhered/est003
Khanshour A, Conant E, Juras R, Cothran EG.The Arabian horse ignites imagination throughout the world. Populations of this breed exist in many countries, and recent genetic work has examined the diversity and ancestry of a few of these populations in isolation. Here, we explore 7 different populations of Arabians represented by 682 horses. Three of these are Middle Eastern populations from near the historical origin of the breed, including Syrian, Persian, and Saudi Arabian. The remaining Western populations are found in Europe (the Shagya Arabian and Polish Arabian) and in America (American Arabian). Analysis of genetic structure was ...
Tozaki T, Kakoi H, Mashima S, Hirota K, Hasegawa T, Ishida N, Miura N, Choi-Miura NH, Tomita M.Microsatellite 15 TKY System was characterized for parentage verification of horse registry. The Microsatellite 15 TKY System was constructed by using 15 microsatellites, TKY279, TKY287, TKY294, TKY297, TKY301, TKY312, TKY321, TKY325, TKY333, TKY337, TKY341, TKY343, TKY344, TKY374, and TKY394, to provide stringent PCR-based microsatellite typing specifically optimized for multicolor fluorescence detection. The Microsatellite 15 TKY System showed good resolutions for 250 unrelated Thoroughbred horses, and the probability of exclusion (PE) at each microsatellite ranged from 0.437 to 0.621, resul...
Aberle KS, Hamann H, Drögemüller C, Distl O.We compared the genetic diversity and distance among six German draught horse breeds to wild (Przewalski's Horse), primitive (Icelandic Horse, Sorraia Horse, Exmoor Pony) or riding horse breeds (Hanoverian Warmblood, Arabian) by means of genotypic information from 30 microsatellite loci. The draught horse breeds included the South German Coldblood, Rhenish German Draught Horse, Mecklenburg Coldblood, Saxon Thuringa Coldblood, Black Forest Horse and Schleswig Draught Horse. Despite large differences in population sizes, the average observed heterozygosity (H(o)) differed little among the heavy ...
Lei CZ, Su R, Bower MA, Edwards CJ, Wang XB, Weining S, Liu L, Xie WM, Li F, Liu RY, Zhang YS, Zhang CM, Chen H.To obtain more knowledge of the origin and genetic diversity of domestic horses in China, this study provides a comprehensive analysis of mitochondrial DNA (mtDNA) D-loop sequence diversity from nine horse breeds in China in conjunction with ancient DNA data and evidence from archaeological and historical records. A 247-bp mitochondrial D-loop sequence from 182 modern samples revealed a total of 70 haplotypes with a high level of genetic diversity. Seven major mtDNA haplogroups (A-G) and 16 clusters were identified for the 182 Chinese modern horses. In the present study, nine 247-bp mitochondr...
Kim KI, Yang YH, Lee SS, Park C, Ma R, Bouzat JL, Lewin HA.Historical records suggest that horses inhabiting the island of Cheju in Korea are descendants of Mongolian horses introduced in 1276. Other studies, however, suggest that horses may have been present on the island prior to the Mongolian introduction. To determine the origin of the Cheju horses we used a phylogenetic analysis of sequences of the mitochondrial DNA (mtDNA) D-loop region, including tRNA Pro and parts of tRNA thr and tRNA Phe sequences (1102-bp excluding the tandem repeat region). Maximum parsimony and neighbor-joining trees were constructed using sequences determined for seven Ch...
Grilz-Seger G, Druml T, Neuditschko M, Dobretsberger M, Horna M, Brem G.The sample ascertainment bias due to complex population structures remains a major challenge in genome-wide investigations of complex traits. In this study we derived the high-resolution population structure and levels of autozygosity of 377 Lipizzan horses originating from five different European stud farms utilizing the SNP genotype information of the high density 700 k Affymetrix Axiom™ Equine genotyping array. Scanning the genome for overlapping runs of homozygosity (ROH) shared by more than 50% of horses, we identified homozygous regions (ROH islands) in order to investigate the gene ...
Orlando L.The horse was essential to past human societies but became a recreational animal during the twentieth century as the world became increasingly mechanized. As the author reviews here, recent studies of ancient genomes have revisited the understanding of horse domestication, from the very early stages to the most modern developments. They have uncovered several extinct lineages roaming the far ends of Eurasia some 4000 years ago. They have shown that the domestic horse has been significantly reshaped during the last millennium and experienced a sharp decline in genetic diversity within the last...
Solé M, Ablondi M, Binzer-Panchal A, Velie BD, Hollfelder N, Buys N, Ducro BJ, François L, Janssens S, Schurink A, Viklund Å, Eriksson S....Copy Number Variation (CNV) is a common form of genetic variation underlying animal evolution and phenotypic diversity across a wide range of species. In the mammalian genome, high frequency of CNV differentiation between breeds may be candidates for population-specific selection. However, CNV differentiation, selection and its population genetics have been poorly explored in horses. Results: We investigated the patterns, population variation and gene annotation of CNV using the Axiom® Equine Genotyping Array (670,796 SNPs) from a large cohort of individuals (N = 1755) belonging to eight ...
Hall SJ.Accurate measures of effective population sizes (Ne ) in livestock require good quality data and specialized skills for their computation and analysis. Ne can be estimated by Wright's equation Ne =4MF/(M+ F) (M, F being sires and dams, respectively), but this requires assumptions which are often not met. Total census sizes Nc of livestock breeds are collated globally. This paper investigates whether estimates of Ne can be made from Nc ; this would facilitate conservation monitoring. Some Ne methodologies avoid the assumptions of Wright's equation and permit measurement, rather than estimation,...
Lazary S, Antczak DF, Bailey E, Bell TK, Bernoco D, Byrns G, McClure JJ.Six laboratories participated in the Fifth International Workshop on Lymphocyte Alloantigens of the Horse, testing 132 alloantisera against lymphocytes of 880 horses chosen to represent different families and breeds. Most of the alloantisera were produced by lymphocyte immunization between horses matched at the ELA-A locus. All horses were also tested with antisera contributed to the workshop by participating laboratories which identified ELA specificities A1-A10 and W12-W21. Previously identified workshop specificities ELA-W14, W15 and W19 were accepted as products of the ELA-A locus based on...
