Topic:Comparative Study
Comparative studies in equine research involve the systematic analysis of different horse breeds, management practices, or physiological responses to identify variations and similarities. These studies are instrumental in understanding how different factors influence health, performance, and behavior in horses. Common areas of comparison include genetic traits, nutritional requirements, disease resistance, and response to training. By evaluating these differences, researchers can develop targeted strategies for breeding, healthcare, and training. This page aggregates peer-reviewed research studies and scholarly articles that focus on the methodologies, findings, and implications of comparative studies in the context of equine science.
Complete genomic characterization of bovine papillomavirus type 1 and 2 strains infers ongoing cross-species transmission between cattle and horses. Infection with bovine papillomavirus (BPV) types 1 and 2 results in the most common skin tumor of horses, termed equine sarcoid. The persistent and recurrent nature of this tumor stands in contrast to the regressive nature of BPV-1/- 2 induced cutaneous papillomas in cattle. The circulation of horse-specific BPV-1/- 2 variants within equine populations has been suggested as a possible explanation for the difference in clinical presentation of BPV-1/- 2 infection between horses and cattle. In order to investigate this hypothesis, we identified 98 complete BPV-1/- 2 genomes using a Nanopore ...
Evaluation of recurrent laryngeal neuropathy in domestic and feral horse populations in Australia using histologic and immunohistochemical analysis: A pilot study. Little is known about potential differences in the left recurrent laryngeal nerve (Lrln) and left cricoarytenoideus dorsalis (LCAD) muscle between domestic and feral horse populations. If a difference exists, feral horses may provide a useful control population for research related to recurrent laryngeal neuropathy (RLN) and increase our understanding of potential population pressures influencing the incidence RLN. The objective of this study was to compare the Lrln and LCAD of domestic and feral horses using histological and immunohistochemical techniques (IHC). Sixteen horses, domestic (n = ...
Metagenetic Analysis of the Pregnant Microbiome in Horses. Placentitis is the leading cause of infectious abortion in the horse. Additionally, it can result in weak and/or growth restricted offspring. While the etiology of ascending placentitis is well described in mares, less is known regarding the pathogenesis of other types, such as nocardioform placentitis. This study aims to identify the microbial communities in different body sites of the pregnant mare in early gestation to establish a core microbiome that may be perturbed in pathologic pregnancies such as placentitis. We hypothesize that the equine placenta harbors a distinct resident microbiom...
Topical Bacteriophage Therapy for Staphylococcal Superficial Pyoderma in Horses: A Double-Blind, Placebo-Controlled Pilot Study. Increased antimicrobial resistance highlights the need for alternatives to antibiotics. Bacteriophages, which are benign viruses that kill bacteria, are promising. We studied the efficacy of topical bacteriophages for treating equine staphylococcal superficial pyodermas. Eight isolates were tested against a bacteriophage bank, and a cocktail consisting of two bacteriophages was prepared. Twenty horses with clinical and cytological evidence of superficial pyoderma and confirmed infection based on swabbed culture were enrolled in the study. Each horse received both the bacteriophage cocktail a...
In vitro antibacterial efficacy of autologous conditioned plasma and amniotic membrane eye drops. To determine the in vitro antibacterial efficacy of equine and canine autologous conditioned plasma (ACP) and amniotic membrane extract eye drops (AMEED) against aerobic bacteria common to the corneal surface. Methods: Canine (n = 4) and equine (n = 4) anticoagulated whole blood samples were sterilely collected, pooled for each species, and processed using the Arthrex ACP® Double-Syringe System. Platelet counts were performed on ACP and pooled blood. AMEED were obtained from a commercial source. An electronic medical records search (2013-2022) identified aerobic bacteria cultured from...
Imputed genomes of historical horses provide insights into modern breeding. Historical genomes can provide important insights into recent genomic changes in horses, especially the development of modern breeds. In this study, we characterized 8.7 million genomic variants from a panel of 430 horses from 73 breeds, including newly sequenced genomes from 20 Clydesdales and 10 Shire horses. We used this modern genomic variation to impute the genomes of four historically important horses, consisting of publicly available genomes from 2 Przewalski's horses, 1 Thoroughbred, and a newly sequenced Clydesdale. Using these historical genomes, we identified modern horses with high...
Preliminary study of heart rate variability in Criollo horses for the elucidation of their neurophysiological characteristics of autonomic nerve function. The Criollo is an Argentine horse breed with a calm temperament. Although its temperament is considered to be related to its neurophysiological characteristics, the details of this are unknown. Therefore, we analyzed the heart rate variability in Criollos as a preliminary study to deepen the neurophysiological understanding of their autonomic function. Electrocardiograms were recorded from Criollos and Thoroughbreds, and the power spectrum of heart rate variability was analyzed. Compared with Thoroughbreds, Criollos showed (i) a significantly higher high-frequency component, which is an index ...
Immunohistochemical markers for equine granulosa cell tumors: a pilot study. Sex cord-stromal tumors (SCSTs), generally referred to as granulosa cell tumors (GCTs) or granulosa-theca cell tumors (GTCTs) in equids, show complex compositions and variable numbers of hormone-producing cells. These tumors can be difficult to diagnose, especially in early stages. Therefore, we tested a panel of antibodies for vimentin, smooth muscle actin, laminin, Ki-67, E-cadherin, calretinin, moesin, p-ezrin, AMH, and aromatase, markers used for tumor composition and classification, progression, and prognosis in human SCSTs, on an exemplary grapefruit-size equine GCT within the left ovary...
Transmural Ultrasonography in the Evaluation of Horse Hoof Internal Structures: Comparative Qualitative Findings-Part 1. Ultrasonography is commonly used to evaluate equine lameness-related structures, but traditional hoof approaches cannot adequately visualize internal structures such as the lamellar layer. To address this limitation, we used 62 healthy hooves without digital radiographic abnormalities, made up of thirty anatomical pieces (phase 1) and thirty-two hooves from living horses (phase 2). In both phases, half of the digits were submerged in water (group 1) and the other half in water and ice (group 2) for 24 h. Ultrasonographic views and temperature and humidity measurements were taken every two hour...
Ancient segmentally duplicated LCORL retrocopies in equids. LINE-1 is an active transposable element encoding proteins capable of inserting host gene retrocopies, resulting in retro-copy number variants (retroCNVs) between individuals. Here, we performed retroCNV discovery using 86 equids and identified 437 retrocopy insertions. Only 5 retroCNVs were shared between horses and other equids, indicating that the majority of retroCNVs inserted after the species diverged. A large number (17-35 copies) of segmentally duplicated Ligand Dependent Nuclear Receptor Corepressor Like (LCORL) retrocopies were present in all equids but absent from other extant peris...
Cerebellar axonopathy in Shivers horses identified by spatial transcriptomic and proteomic analyses. Shivers in horses is characterized by abnormal hindlimb movement when walking backward and is proposed to be caused by a Purkinje cell (PC) axonopathy based on histopathology. Objective: Define region-specific differences in gene expression within the lateral cerebellar hemisphere and compare cerebellar protein expression between Shivers horses and controls. Methods: Case-control study of 5 Shivers and 4 control geldings ≥16.2 hands in height. Methods: Using spatial transcriptomics, gene expression was compared between Shivers and control horses in PC soma and lateral cerebellar hemisphere w...
Comparison of radiography and CT for the evaluation of third carpal bone slab fractures in Thoroughbred racehorses. Slab fractures of the third carpal bone (C3) are a common cause of lameness in Thoroughbred racehorses. Information on fracture morphology is commonly obtained from radiographs or CT. This retrospective, methods comparison aimed to explore the agreement between radiography and CT for imaging C3 slab fractures and discuss the contribution of the latter to clinical case management. Thoroughbred racehorses with a slab or incomplete slab fracture of C3 identified on radiographs that subsequently underwent CT examination were included. Fracture characteristics (location, plane, classification, disp...
Arthroscopically guided lag screw fixation of subchondral bone cysts in the medial femoral condyle in Thoroughbred racehorses: description of technique and comparative results. To describe an arthroscopically guided technique for lag screw placement across subchondral bone cyst (SBC) in the medial femoral condyle (MFC) and to compare postoperative racing performance with corticosteroid injection and cyst debridement. Methods: Retrospective cohort study. Methods: One hundred twenty-three horses with 134 MFC SBCs undergoing treatment at a single referral hospital in the UK between January, 2009, and December, 2020. Methods: Sex, age, limb affected, radiographic cyst dimensions, preoperative and postoperative lameness, surgical technique (lag screw placement, cyst debr...
Effects of a 10% dimethyl sulfoxide solution on radiocarpal joint amikacin pharmacokinetics during intravenous regional limb perfusion in standing sedated horses. To determine the effect of a 10% dimethyl sulfoxide (DMSO) solution on the peak concentration (C ) of amikacin in the radiocarpal joint (RCJ) during intravenous regional limb perfusion (IVRLP) compared with 0.9% NaCl. Methods: Randomized crossover study. Methods: Seven healthy adult horses. Methods: The horses underwent IVRLP with 2 g of amikacin sulfate diluted to 60 mL using a 10% DMSO or 0.9% NaCl solution. Synovial fluid was collected from the RCJ at 5, 10, 15, 20, 25, and 30 minutes after IVRLP. The wide rubber tourniquet placed on the antebrachium was removed after the 30 min sample. A...
Assessment and comparison of microcirculation and macrocirculation in horses undergoing emergency exploratory celiotomy versus elective surgical procedures. To assess oral buccal microcirculation by hand-held videomicroscopy in horses during colic surgery, comparing microcirculation values with macrocirculatory parameters and with those of healthy elective surgical horses. Methods: Clinical prospective study. Methods: Client-owned horses (nine in the colic group; 11 in the elective group). Methods: In the colic group, buccal mucosal side stream dark-field microscopy (DFM) videos, cardiac output (CO), mean arterial pressure (MAP), and lactate were obtained at three timepoints under general anesthesia (30, 90, and 150 min after induction). Video a...
Characterization of the Glycans of Equine κ-Casein. To study the protein-bound glycans of equine κ-casein, equine sodium caseinate was first obtained from raw mare's milk by acid precipitation and then fractionated by cation-exchange chromatography. The oligosaccharides of the obtained equine κ-casein were analyzed by RP-HPLC-UV-HRMS after β-elimination with simultaneous derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP). In addition to the acidic tetrasaccharide derivative Neu5Ac-Gal-[Neu5Ac]-GalNAc-2PMP known from bovine κ-casein, the acidic pentasaccharide derivative Neu5Ac-Gal-[Gal-GlcNAc]-GalNAc-2PMP was identified as the most ab...
Identification and kinetics of microsomal and recombinant equine liver cytochrome P450 enzymes responsible for in vitro metabolism of omeprazole. In humans, omeprazole is metabolised by cytochrome P450 (CYP450) CYP2C19 and CYP3A4 with differences in CYP2C19 genotypes leading to variable response to therapy. Despite a wide use of omeprazole in horses with evidence of variable therapeutic efficiency, information regarding enzymatic metabolism is not currently available. This study aims to describe the in vitro kinetics of omeprazole metabolism and determine which enzyme(s) are responsible for omeprazole metabolism in horses. Omeprazole (0-800 uM) was incubated with liver microsomes and a panel of equine recombinant CYP450s (eq-rCYP). Meta...
Development of a novel real-time PCR multiplex assay for detection of Streptococcus equi subspecies equi and Streptococcus equi subspecies zooepidemicus. Strangles is a contagious bacterial disease of horses caused by Streptococcus equi subspecies equi (SEE) that occurs globally. Rapid and accurate identification of infected horses is essential for controlling strangles. Because of limitations of existing PCR assays for SEE, we sought to identify novel primers and probes that enable simultaneous detection and differentiation of infection with SEE and S. equi subsp. zooepidemicus (SEZ). Comparative genomics of U.S. strains of SEE and SEZ (n = 50 each) identified SE00768 from SEE and comB from SEZ as target genes. Primers and probes for real-ti...
Common superficial and deep cutaneous bacterial infections in domestic animals: A review. The skin covers the external surface of animals, and it is constantly exposed to and inhabited by different microorganisms, including bacteria. Alterations in the skin barrier allow commensal and/or pathogenic bacteria to proliferate and penetrate deep into the lower layers of the skin. Being the first barrier to the external environment, the skin is prone to injuries, allowing the penetration of microorganisms that may lead to severe deep infections. Companion animals, especially dogs, are prone to bacterial infections, often secondary to allergic dermatitis. When environmental conditions are...
Relationship between quantitative real-time PCR cycle threshold and culture for detection of Streptococcus equi subspecies equi. To compare PCR and culture results for the detection of subspecies . Respiratory tract samples (N = 158) from horses being tested for Bacterial culture was carried out on samples from which was detected by quantitative real-time PCR. was isolated from 12 (7.6%) samples: 4/9 (44%) samples when the PCR cycle threshold (C) was ≤ 30, 7/30 (23%) when the C was 30.1 to 35, and 1/119 (0.8%) when the C was 35.1 to 40. The highest C sample from a sample that yielded a positive culture was 36.9. The optimal Youden's J value was at a C of 34.2, the same value as determined by number needed to misdi...
New genomic insights into the conformation of Lipizzan horses. Conformation traits are important selection criteria in equine breeding, as they describe the exterior aspects of the horse (height, joint angles, shape). However, the genetic architecture of conformation is not well understood, as data of these traits mainly consist of subjective evaluation scores. Here, we performed genome-wide association studies on two-dimensional shape data of Lipizzan horses. Based on this data, we identified significant quantitative trait loci (QTL) associated with cresty neck on equine chromosome (ECA)16 within the MAGI1 gene, and with type, hereby differentiating heav...
Novel Expression of GLUT3, GLUT6 and GLUT10 in Equine Gluteal Muscle Following Glycogen-Depleting Exercise: Impact of Dietary Starch and Fat. Horses have a slow rate of muscle glycogen repletion relative to other species for unknown reasons. Our aim was to determine the expression of glucose transporters () and genes impacting GLUT4 expression and translocation in the gluteal muscle. Five fit Thoroughbred horses performed glycogen-depleting exercises on high-starch (HS, 2869 g starch/day) and low-starch, high-fat diets (LS-HF, 358 g starch/d) with gluteal muscle biopsies obtained before and after depletion and during repletion. Muscle glycogen declined by ≈30% on both diets with little increase during repletion on LS-HF. Transcrip...
Histological comparison of the lamellar tissue of Iberian origin breed horses created in semi-feral conditions or in an intensive system. Although the external conformation of wild horse hooves has been proposed as an ideal model for domesticated modern horses, histological signs of laminitis have been reported among them. With the hypothesis that the lamellar tissue of horses of Iberian origin raised in semi-feral is healthier than those raised in an intensive management system (stall confinement and high-calorie diet intake), the objective was to compare their lamellar tissues. Lamellar tissue samples were taken from the forelimb hoof of eight domesticated Mangalarga Marchador (MM) horses and from six semi-feral Marajoara (MJ)...
In Vitro-Produced Equine Blastocysts Exhibit Greater Dispersal and Intermingling of Inner Cell Mass Cells than In Vivo Embryos. In vitro production (IVP) of equine embryos is increasingly popular in clinical practice but suffers from higher incidences of early embryonic loss and monozygotic twin development than transfer of in vivo derived (IVD) embryos. Early embryo development is classically characterized by two cell fate decisions: (1) first, trophectoderm (TE) cells differentiate from inner cell mass (ICM); (2) second, the ICM segregates into epiblast (EPI) and primitive endoderm (PE). This study examined the influence of embryo type (IVD versus IVP), developmental stage or speed, and culture environment (in vitro ...
A method to generate capture baits for targeted sequencing. Hybridization capture approaches allow targeted high-throughput sequencing analysis at reduced costs compared to shotgun sequencing. Hybridization capture is particularly useful in analyses of genomic data from ancient, environmental, and forensic samples, where target content is low, DNA is fragmented and multiplex PCR or other targeted approaches often fail. Here, we describe a DNA bait synthesis approach for hybridization capture that we call Circular Nucleic acid Enrichment Reagent, or CNER (pronounced 'snare'). The CNER method uses rolling-circle amplification followed by restriction dige...
Genetic variation and domestication of horses revealed by 10 chromosome-level genomes and whole-genome resequencing. Understanding the genetic variations of the horse (Equus caballus) genome will improve breeding conservation and welfare. However, genetic variations in long segments, such as structural variants (SVs), remain understudied. We de novo assembled 10 chromosome-level three-dimensional horse genomes, each representing a distinct breed, and analysed horse SVs using a multi-assembly approach. Our findings suggest that SVs with the accumulation of mammalian-wide interspersed repeats related to long interspersed nuclear elements might be a horse-specific mechanism to modulate genome-wide gene regulato...
Horse serum or equine platelet lysate increases total vascular endothelial growth factor A concentrations and correlates with vascular growth in an equine facial arterial ring assay. To evaluate ex vivo angiogenesis of equine arterial rings in response to various growth media. Methods: Facial arteries were dissected from 11 horses post-euthanasia. Equine platelet lysate (ePL) was harvested from 6 horses. Methods: Arteries were exposed to endothelial growth media (EGM) + horse serum (HS) for first sprout (FS), vascular regression (VR), and (basement membrane matrix [Matrigel]) lysis (ML) evaluation. Additional rings supplemented with (1) EGM, (2) EGM + EDTA, (3) endothelial basal media (EBM), (4) EBM + HS, or (5) EBM + human VEGF were compared for vascular network area (VNA...
Novel equid papillomavirus from domestic donkey. Papillomaviruses can be of great medical importance as they infect humans and animals such as Equus species, other livestock and pets. They are responsible for several papillomas and benign tumours in their host. Objective: To describe a novel equid papillomavirus detected in oral swab samples collected from donkeys (Equus asinus) found on the Northwest plateau of China. Methods: Cross-sectional. Methods: Swab samples collected from the oral mucosa of 32 donkeys in the Gansu Province of China, were subjected to viral metagenomic analysis to detect the presence of Papillomavirus. After de novo ...
Adaptive Response of Estrogen-Iron Axis in Pregnant Purebred Spanish Mares of Different Age. The maintenance of iron (Fe) homeostasis is vital for the physiological function along life. In sexually mature humans and experimental animals, estrogens downregulate hepcidin (Hpc) expression, in order to improve the intestinal absorption and to mobilize Fe stores for maternal erythropoietic expansion and placental development. However, changes of these mechanisms related to regulation of Hpc on the availability of Fe during gestation with advancing age in mares, remain unknown. The objective of this study was to evaluate the interrelationships between serum Fe, Ferritin (Ferr) and Hpc with ...
Plasma Estradiol Profile After Administration of Different Types of Estradiol Esters in Acyclic Mares. Although the use of different estradiol esters has been extensively studied in hormonal protocols in cows, such information is lacking in mares. The present study aimed to assess the effects of treatment with the same doses and administration frequency of estradiol cypionate, estradiol benzoate and 17β estradiol on plasma estradiol (E2) concentrations of acyclic mares and correlate the E2 profile to the endometrial edema score. Sixteen treatments were performed in 14 mares randomly divided into three groups: EB (n = 5), EC (n = 5), and 17β (n = 6), receiving 10 mg on day 0 (D0), 6 mg o...