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Topic:Horse Breeds
Horse breeds represent the diverse genetic and phenotypic variations found within the species Equus ferus caballus. These breeds are categorized based on characteristics such as size, conformation, coat color, and temperament, which have been selectively bred over centuries to fulfill specific roles and functions. Common classifications of horse breeds include light horses, draft horses, and ponies, each serving different purposes ranging from riding and racing to work and companionship. This page aggregates peer-reviewed research studies and scholarly articles that explore the genetics, history, and functional attributes of various horse breeds, as well as their impact on equine management and breeding practices.
Connective tissue disorders in domestic animals. Though soft tissue disorders have been recognized and described to some detail in several types of domestic animals and small mammals for some years, not much progress has been made in our understanding of the biochemical basis and pathogenesis of these diseases in animals. Ehlers-Danlos syndrome described in dogs already in 1943 and later in cats affects mainly skin in these animals. The involved skin is thin and hyperextensible with easily inflicted injuries resulting in hemorrhagic wounds and atrophic scars. Joint laxity and dislocation common in people are less frequently found in dogs. No...
Genetic and environmental analysis of dystocia and stillbirths in draft horses. Genetic parameters and environmental factors were estimated for foaling ease (FE) and stillbirths (SBs) in four breeds of draft horses based on 11 229, 38 877, 35 764 and 13 274 FE and SB scores recorded between 1998 and 2010 for Ardennais (A), Breton (B), Comtois (C) and Percheron (P), respectively. Incidences for the three FE categories were: easy or without help 91.0% (A) to 95.4% (B), difficult 3.4% (B) to 7.1% (A) and intervention of a veterinarian 1.1% (B) to 1.9% (A). The frequency of SB ranged between 5.4% (B) and 9.4% (A). A multiple-trait threshold animal model was used that included...
Abdominal wall mass and hemoabdomen in a Haflinger mare. A 6-year-old Haflinger mare was presented with a history of recurrent hemoabdomen. On necropsy, a firm infiltrative multinodular yellow mass was observed in the wall of the posterior abdomen. Histopathologic examination revealed a proliferation of fibroblastic cells, which were positive for α-smooth muscle actin and vimentin.
Genetic polymorphism of Hucul horse population based on 17 microsatellite loci. Short tandem repeat (STR) loci, i.e. microsatellites are a class of genetic markers commonly used for population studies and parentage control. This study determined the usefulness of microsatellite markers recommended by International Society for Animal Genetics (ISAG) for identification and pedigree analysis in horses based on the example of Polish Hucul horse population (Equus caballus). The set of seventeen microsatellites loci was tested (AHT4, AHT5, ASB2, HMS2, HMS3, HMS6, HMS7, HTG10, HTG4, HTG6, HTG7, VHL20, ASB17, ASB23, CA425, HMS1, LEX3) for 216 individuals. All samples were genotyp...
Sequence analysis of the equine ACTN3 gene in Australian horse breeds. The sarcomeric α-actinins, encoded by the genes ACTN2 and ACTN3, are major structural components of the Z-line and have high sequence similarity. α-Actinin-2 is present in all skeletal muscle fibres, while α-actinin-3 has developed specialized expression in only type 2 (fast, glycolytic) fibres. A common single nucleotide polymorphism (SNP) in the human ACTN3 gene (R577X) has been found to influence muscle performance in elite athletes and the normal population. For this reason, equine ACTN3 (eACTN3) is considered to be a possible candidate that may influence horse performance. In this stud...
Primer effect in the detection of mtDNA heteroplasmy: insights from horse Cytochrome b gene. Heteroplasmy, the presence of bi-allelic mtDNA types within an individual, has been previously detected in the D-loop region and Cytochrome b gene (Cytb) of mitochondrial DNA using PCR-RFLP. However, heteroplasmy was absent in thousands of equine mtDNA sequences deposited in GenBank. To address whether heteroplasmy widely exists in mitochondria of Chinese indigenous horses, we generated the data set of the target sites in Cytb region with Sanger sequencing and PCR-RFLP method as well. In this study, 23 heteroplasmic individuals were detected in 430 Chinese local horses. Both site and length he...
During cooled storage the extender influences processed autophagy marker light chain 3 (LC3B) of stallion spermatozoa. To investigate the role of the processed autophagy marker light chain 3 (LC3B) protein in sperm survival in stallion semen processing during cooled storage, split ejaculates were diluted in two different extenders, KMT and INRA 96, and LC3B processing and sperm quality evaluated during incubation at 5°C for five days. After 3 days of incubation there was a drop in total motility in both extenders, although the percentage of progressive motile sperm was greater (P<0.05) in samples extended in INRA96. On Day 5 of cooled storage all sperm parameters decreased significantly independent of the ...
Cryopreservation of epididymal stallion sperm. Any event that makes semen collection or mating impossible, such as death, castration, or injury, may terminate a stallion's breeding career. Fortunately, stallion sperm which are capable of fertilization can be harvested from the epididymis, and frozen for future use. However, the fertility of frozen-thawed epididymal sperm has been found to be lower than that of ejaculated sperm. Therefore, this study aimed to optimize the fertility of frozen epididymal stallion sperm by investigating the effects of different cryoprotectants and freezing protocols on sperm quality. Dimethylformamide was test...
Physiological response to a breed evaluation field test in Icelandic horses. This study examined the response in terms of heart rate (HR), respiratory rate (RR), haematocrit (Htc), rectal temperature (RT), and some plasma variables in Icelandic horses of different sexes and ages performing the riding assessment in a breed evaluation field test (BEFT). The study was conducted in Iceland on 266 horses (180 mares and 86 stallions, divided into four age groups; 4, 5, 6 and ≥7 years old). RT and RR were recorded and blood samples were taken before the warm-up and after the riding assessment. Horse HR, velocity and distance were recorded during the warm-up, the riding asse...
Impact of colic surgery on return to function in racing Thoroughbreds: 59 cases (1996-2009). To determine the effect of colic surgery on return to function in Thoroughbred racehorses, identify clinical variables associated with successful return to racing, and compare racing performance between horses undergoing colic surgery and an untreated cohort. Methods: Retrospective cohort study. Methods: 59 Thoroughbred racehorses 2 to 5 years of age that underwent colic surgery and survived to hospital discharge and 90 untreated Thoroughbred racehorses equivalent in class. Methods: Medical records of patients evaluated for colic between January 1996 and July 2009 were reviewed, and horses wit...
Thiol-disulfide proteins of stallion epididymal spermatozoa. Thiol groups of cysteine residues represent redox centers involved in multiple biological functions. It has been postulated that changes in the redox status of mammalian epididymal spermatozoa contribute to the sperm maturation process. The present work shows the thiol-disulfide protein profile of stallion epididymal spermatozoa achieved by two-dimension electrophoresis and MALDI-TOF/TOF mass spectrometry of proteins labeled with a thiol-reactive fluorescent tag, monobromobimane. Our results have shown the formation of disulfide bonds in several sperm protein fractions during the epididymal ma...
Hematological and biochemical reference values for the endangered kiso horse. To establish blood and biochemical references for the endangered Kiso horse, blood samples were collected from 111 adult Kiso horses, 74.5% of the existing breed. The samples were analyzed for 23 hematological and biochemical parameters to determine their means and standard deviations (SD). We compared the mean ± 2SD with the reference values cited in one of the most commonly used veterinary textbooks in Japan. The hematology of Kiso horses is characterized by lower erythrocyte count and hematocrit and hemoglobin levels. In addition, their serum biochemistry showed lower levels of aspartate t...
Case-Study Investigation of Equine Maternity via PCR-RFLP: A Biochemistry Laboratory Experiment. A simple and robust biochemistry laboratory experiment is described that uses restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR) products to verify the identity of a potentially valuable horse. During the first laboratory period, students purify DNA from equine samples and amplify two loci of mitochondrial DNA. During the second laboratory period, students digest PCR products with restriction enzymes and analyze the fragment sizes through agarose gel electrophoresis. An optional step of validating DNA extracts through realtime PCR can expand the experiment to th...
Single nucleotide polymorphisms of myostatin gene in Chinese domestic horses. The myostatin gene (MSTN) is a genetic determinant of skeletal muscle growth. Single nucleotide polymorphisms (SNP) in MSTN are of importance due to their strong associations with horse racing performances. In this study, we screened the SNPs in MSTN gene in 514 horses from 15 Chinese horse breeds. Six SNPs (g.26T>C, g.156T>C, g.587A>G, g.598C>T, g.1485C>T, g.2115A>G) in MSTN gene were detected by sequencing and genotyped using PCR-RFLP method. The g.587A>G and g.598C>T residing in the 5'UTR region were novel SNPs identified by this study. The g.2115A>G which have pr...
In vitro analysis of equine, bone marrow-derived mesenchymal stem cells demonstrates differences within age- and gender-matched horses. Stem cell therapies are used routinely in equine practice. Most published reports characterise stem cells derived from younger horses; however, middle-aged horses are often in athletic performance, and experience degenerative medical conditions. Thus, mesenchymal stem cells (MSCs) from this group should be investigated. Objective: To describe differences in in vitro adherence, proliferation and potential for differentiation of equine bone marrow-derived MSCs (equine BMMSCs) harvested from middle-aged (10-13 years old) female donors. Methods: Descriptive study of stem cell characteristics. Meth...
Prediction of the elastic strain limit of tendons. The elastic strain limit (ESL) of tendons is the point where maximum elastic modulus is reached, after which micro-damage starts. Study of damage progression in tendons under repetitive (fatigue) loading requires a priori knowledge about ESL. In this study, we propose three different approaches for predicting ESL. First, one single value is assumed to represent the ESL of all tendon specimens. Second, different extrapolation curves are used for extrapolating the initial part of the stress-strain curve. Third, a method based on comparing the shape of the initial part of the stress-strain curve ...
CatSper and the relationship of hyperactivated motility to intracellular calcium and pH kinetics in equine sperm. In vitro fertilization does not occur readily in the horse. This may be related to failure of equine sperm to initiate hyperactivated motility, as treating with procaine to induce hyperactivation increases fertilization rates. In mice, hyperactivated motility requires a sperm-specific pH-gated calcium channel (CatSper); therefore, we investigated this channel in equine sperm. Motility was assessed by computer-assisted sperm motility analysis and changes in intracellular pH and calcium were assessed using fluorescent probes. Increasing intracellular pH induced a rise in intracellular calcium, w...
Use of two conventional staining methods to assess the acrosomal status of stallion spermatozoa. The acrosome is a highly specialised region of the spermatozoon that is essential for fertilisation. Defects or dysfunction of this structure have been associated with fertility problems in man and various domestic species including stallions. Current methods of evaluating the acrosome of stallion spermatozoa are time consuming and require specialised equipment, which is cost prohibitive to the average practitioner. Objective: To evaluate 2 conventional stains (Dip Quick and Spermac) and determine their usefulness in assessing acrosome integrity in stallions as compared with specific acrosomal...
Heritabilities and genetic correlations between fetlock, hock and stifle osteochondrosis and fetlock osteochondral fragments in Hanoverian Warmblood horses. The main objective of this study is to estimate genetic parameters for osteochondrosis (OC) and osteochondrosis dissecans (OCD) in fetlock, hock and stifle joints as well as for palmar or plantar osteochondral fragments (POFs) and dorsodistal osteochondral fragments (DOFs) in fetlock joints. For this purpose, the results of a standardized radiographic examination of 7396 Hanoverian Warmblood horses were used. Heritabilities and genetic correlations were estimated using residual maximum likelihood (REML) under a linear animal model. Heritability estimates for OC at the different joints were at ...
Megaesophagus in Friesian horses associated with muscular hypertrophy of the caudal esophagus. Friesian horses have a perceived high rate of congenital or hereditary diseases, including megaesophagus, that may lead to choke and death. A retrospective study was performed to determine the prevalence and pathologic characteristics of esophageal disease in 852 horses, including 17 Friesians, that had been necropsied over a 6-year period at the Diagnostic Center for Population and Animal Health. Forty-two horses had grossly described esophageal lesions (25 muscular hypertrophy, 7 hemorrhage, 6 megaesophagus, 4 erosion/ulceration, 3 obstruction, 2 tears, 2 secondary neoplasms, 2 lymphoid patc...
Genetic analysis of kinematic traits at the trot in Lusitano horse subpopulations with different types of training. The possibility of using quantitative kinematic traits as indirect selection criteria for sport performance could be beneficial to perform an early genetic evaluation of the animals. The genetic parameters for objectively measured kinematic traits under field conditions have been estimated for the first time, in order to potentially use these traits as indicators of gait quality in future selection of the Lusitano breed. The repeatability within three different types of training (dressage, bullfighting and untrained) was also discussed. A total of 176 males (4 to 14 years old) were recorded at...
Evidence of positive selection for a glycogen synthase (GYS1) mutation in domestic horse populations. A dominantly inherited gain-of-function mutation in the glycogen synthase (GYS1) gene, resulting in excess skeletal muscle glycogen, has been identified in more than 30 horse breeds. This mutation is associated with the disease Equine Polysaccharide Storage Myopathy Type 1, yet persists at high frequency in some breeds. Under historical conditions of daily work and limited feed, excess muscle glycogen may have been advantageous, driving the increase in frequency of this allele. Fine-scale DNA sequencing in 80 horses and genotype assays in 279 horses revealed a paucity of haplotypes carrying th...
Treatment and long-term follow-up of distichiasis, with special reference to the Friesian horse: a case series. Distichiasis is very uncommon in horses and treatment options and outcome remain unknown. Objective: To describe treatment and long-term follow-up of distichiasis in the horse. Methods: Retrospective clinical study. Methods: Case records of horses admitted for diagnosis and treatment of uni- or bilateral distichiasis between 2003 and 2012 were reviewed. Long-term (>6 months after last treatment) follow-up was by telephone conversation with the owner or referring veterinarian. Data were analysed using a Chi-squared test. Results: Eighteen cases were identified, of which 17 were Friesians. All h...
Evidence for a retroviral insertion in TRPM1 as the cause of congenital stationary night blindness and leopard complex spotting in the horse. Leopard complex spotting is a group of white spotting patterns in horses caused by an incompletely dominant gene (LP) where homozygotes (LP/LP) are also affected with congenital stationary night blindness. Previous studies implicated Transient Receptor Potential Cation Channel, Subfamily M, Member 1 (TRPM1) as the best candidate gene for both CSNB and LP. RNA-Seq data pinpointed a 1378 bp insertion in intron 1 of TRPM1 as the potential cause. This insertion, a long terminal repeat (LTR) of an endogenous retrovirus, was completely associated with LP, testing 511 horses (χ(2)=1022.00, p<<...
Use of cholesterol-loaded cyclodextrin: an alternative for bad cooler stallions. During the cooling process, sperm may suffer irreversible damage that compromises the fertility rate. Incorporating cholesterol-loaded cyclodextrin (CLC) represents a strategy to increase sperm resistance at low temperatures; however, high levels of cholesterol in the cell membrane can interfere with sperm capacitation. The goals of this study were to determine the CLC concentration and cooling temperature that produce optimal kinetic parameters and viability of sperm from stallions identified as bad coolers (BCs) and good coolers (GCs), as well as the effect of adding CLC on the occurrence of...
Empirical growth curve estimation considering multiple seasonal compensatory growths of body weights in Japanese Thoroughbred colts and fillies. Thoroughbred horses are seasonal mating animals, and their foals are born yearly in spring seasons. In northern regions or countries, the foals generally show a typical seasonal compensatory growth pattern, where their growth rate declines in winter and increases in the next spring. In this study, a new empirical approach is proposed to adjust for this compensatory growth when growth curve equations are estimated, by using BW of Japanese Thoroughbred colts and fillies raised in Hidaka, Hokkaido. Based on the traditional Richards growth curve equation, new growth curve equations were developed ...
Breed Differences in Dopamine Receptor D4 Gene (DRD4) in Horses. Genetic polymorphisms in genes related to neurotransmitters or hormones affect personality or behavioral traits in many animal species including humans. In domestic animals, the allele frequency of such genes has been reported to be different among breeds and it may account for breed differences in behavior. In this study, we investigated breed differences in horses in the dopamine receptor D4 gene (DRD4), which has been reported to affect horse personality. We collected samples from seven horse breeds including those native to Japan and Korea, and compared the sequence of the DRD4 exon3 regio...
Accuracy of MRI technique in measuring tendon cross-sectional area. Magnetic resonance imaging (MRI) has commonly been applied to determine tendon cross-sectional area (CSA) and length either to measure structural changes or to normalize mechanical measurements to stress and strain. The ability to reproduce CSA measurements on MRI images has been reported, but the accuracy in relation to actual tendon dimensions has never been investigated. The purpose of this study was to compare tendon CSA measured by MRI with that measured in vitro with the mould casting technique. The knee of a horse was MRI-scanned with 1.5 and 3 tesla, and two examiners measured the pate...
Development of postural balance in foals. This study used stabilographic analysis to measure and describe changes in stability during standing in foals from birth to 5 months of age. Stabilographic analysis was performed on newborn foals immediately after first suckling then daily until 1 week of age, weekly until 1 month of age and monthly until 5 months of age. Ground reaction force (GRF) data were collected for periods of 8s with the foal standing on one or two force plates recording at 1000 Hz. Stabilographic variables describing the amplitude, velocity and frequency of center of pressure (COP) movements were derived from the GRF ...
