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Topic:Animal Studies
Animal studies involving horses encompass a range of research focused on understanding equine biology, behavior, and health. These studies often investigate various aspects of horse physiology, genetics, nutrition, and disease pathology. Researchers utilize animal studies to explore the effects of different treatments, management practices, and environmental factors on horse welfare and performance. The findings from such studies contribute to the development of improved care strategies and health interventions. This page gathers peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of animal studies conducted on horses, providing insights into their application in advancing equine science.
Assessment in mice of vapA-DNA vaccination against Rhodococcus equi infection. There is a need to produce a vaccine against Rhodococcus equi pneumonia in foals in which immunity against infection is largely based on a type 1, cell-mediated, immune response. The VapA protein of the virulence plasmid of R. equi is highly immunogenic. To assess the potential of vapA-DNA to produce immunity, C57BL/6 and BALB/c mice were immunized with a DNA vaccine constructed from vapA incorporated into pcDNA3.1. The plasmid construct expressed VapA in a COS-7 cell line. Intramuscular immunization of mice resulted in enhanced clearance of R. equi from the liver of intravenously challenged m...
[Sequence comparing of mtDNA D-Loop varied region in Chinese Mongolian horse and External Thoroughbred horse]. Mitochondrial DNA D-Loop varied region 400 bp sequence variations in 4 Chinese Mongolian horses and 4 External Thoroughbred horses were analyzed in this experiment. The results showed that the average nucleotide mutational rate of mtDNA D-Loop varied region in 4 Chinese Mongolian horses was 3.69%, while External Thoroughbred horses were 4.00%. Three types of mutations including transition, transversion and deletion were all found in the investigated mtDNA D-Loop regions, of which transition was the most frequent. Nucleotide mutational loci were abundant, length mutations were found and great d...
The role of the extrinsic thoracic limb muscles in equine locomotion. Muscles have two major roles in locomotion: to generate force and to absorb/generate power (do work). Economical force generation is achieved by short-fibred pennate muscle while the maximum power output of a muscle is architecture independent. In this study we tested the hypothesis that there is an anatomical and structural separation between the force-generating anti-gravity muscles and the propulsive (limb/trunk moving) muscles of the equine forelimb. Muscle mass and fascicle length measurements were made on the thoracic limb extrinsic muscles of six fresh horse cadavers. Physiological cros...
Blood-oxygen binding in healthy Standardbred horses. The purpose of this study was to determine the effect of regulating factors on the oxygen equilibrium curve (OEC) under standard conditions and then to calculate the oxygen extraction between arterial and jugular venous blood in healthy Standardbred horses. The results were compared to those previously obtained in humans and cattle, using the same experimental method. The partial oxygen pressure at 50% saturation of haemoglobin, measured under standard conditions (standard P50), was 24.8+/-2.0 (SD of mean) mmHg. This value was similar to the cattle standard P50 (25.0+/-1.4 mmHg, SD of mean) bu...
Establishment of pregnancies after serial dilution or direct transfer by vitrified equine embryos. Experiments were conducted to determine viability of equine embryos in vivo after vitrification. In a preliminary study (Experiment 1), embryos were exposed in three steps to vitrification solutions containing increasing concentrations of ethylene glycol and glycerol (EG/G); the final vitrification solution was 3.4 M glycerol + 4.6 M ethylene glycol in a base medium of phosphate-buffered saline. Embryos were warmed in a two-step dilution and transferred into uteri of recipients. No pregnancies were observed after transfer of blastocysts >300 microm (n = 3). Transfer of morulae or blastocyst...
Effect of feeding a DHA-enriched nutriceutical on the quality of fresh, cooled and frozen stallion semen. Eight stallions were used in 2 x 2 crossover study to determine if feeding a nutriceutical rich in docosahexaenoic acid (DHA) would improve semen quality. Stallions were randomly assigned to one of two treatment groups (n = 4 per group). Stallions were fed their normal diet (control) or their normal diet top-dressed with 250 g of a DHA-enriched nutriceutical. Feeding trials lasted for 14 week, after which a 14-week washout period was allowed and the treatment groups were reversed for another 14 week feeding trial. Feeding the nutriceutical resulted in a three-fold increase in semen DHA levels ...
An in vitro biomechanical comparison of the breaking strength and stiffness of polydioxanone (sizes 2, 7) and polyglactin 910 (sizes 3, 6) in the equine linea alba. To determine failure strength, stiffness, and failure mode of 4 suture materials in equine linea alba. Methods: Randomized complete block design. Methods: Linea albas collected from 12 adult horses (mean weight, 475 kg; mean age, 10 years). Methods: The ventral abdominal fascia, including the linea alba, was collected and bisected along the linea alba into right and left halves. Each half was divided into four, 5-cm sections extending from the umbilicus cranially, and randomly assigned to 1 of 4 suture materials: 2 polydioxanone (2 PD), 3 polyglactin 910 (3 PG), 6 polyglactin 910 (6 PG), and 7...
An equine protozoal myeloencephalitis challenge model testing a second transport after inoculation with Sarcocystis neurona sporocysts. Previous challenge studies performed at Ohio State University involved a transport-stress model where the study animals were dosed with Sarcocystis neurona sporocysts on the day of arrival. This study was to test a second transportation of horses after oral inoculation with S. neurona sporocysts. Horses were assigned randomly to groups: group 1, transported 4 days after inoculation (DAI); group 2, at 11 DAI; group 3, at 18 DAI; and group 4, horses were not transported a second time (controls). An overall neurologic score was determined on the basis of a standard numbering system used by veteri...
Communications of normal nasal and paranasal cavities in computed tomography of horses. Heads from 15 male and female horses of various breeds and ages were examined with computed tomography under general anesthesia in dorsal recumbency. The main interest was the evaluation of the entire paranasal sinus system. Special attention was paid to the location, size, and shape of the conchomaxillary, nasomaxillary, frontomaxillary, and sphenopalatinal openings. The frontomaxillary opening was the largest aperture and was found to be age-dependent in size mostly. Orientation and shape of the openings were sagittal or horizontal; the narrowest of them was the slit-like nasomaxillary apert...
Evaluation of glucose tolerance and intestinal luminal membrane glucose transporter function in horses with equine motor neuron disease. To confirm whether the plasma glucose concentration curve obtained during oral glucose tolerance tests (OGTTs) in horses with equine motor neuron disease (EMND) is decreased, compared with that obtained in clinically normal horses, and determine whether that decrease is a result of defective glucose metabolism or intestinal glucose transport dysfunction. Methods: 8 horses with EMND and 44 matched control horses. Methods: Electromyography and OGTTs were performed in all 8 affected horses and 10 control horses. Intravenous GTTs (IVGTTs) were performed in 6 affected horses and another 11 control ...
Effect of prolonged use of altrenogest on behaviour in mares. Oral administration of altrenogest for oestrus suppression in competition horses is believed to be widespread in some equestrian disciplines, and can be administered continuously for several months during a competition season. To examine whether altrenogest has any anabolic or other potential performance enhancing properties that may give a horse an unfair advantage, we examined the effect of oral altrenogest (0.044 mg/kg), given daily for a period of eight weeks, on social hierarchy, activity budget, body-mass and body condition score of 12 sedentary mares. We concluded that prolonged oral ad...
High-resolution RH map of horse chromosome 22 reveals a putative ancestral vertebrate chromosome. High-resolution gene maps of individual equine chromosomes are essential to identify genes governing traits of economic importance in the horse. In pursuit of this goal we herein report the generation of a dense map of horse chromosome 22 (ECA22) comprising 83 markers, of which 52 represent specific genes and 31 are microsatellites. The map spans 831 cR over an estimated 64 Mb of physical length of the chromosome, thus providing markers at approximately 770 kb or 10 cR intervals. Overall, the resolution of the map is to date the densest in the horse and is the highest for any of the domesticat...
Influence of Ganoderma lucidum on blood biochemistry and immunocompetence in horses. The characteristic ingredients of Ganoderma lucidum, such as polysaccharides, triterpenoids, nucleic acids and small proteins, have been found and proved to have many special pharmacological properties. Mice and rats have been extensively used to investigate the effects of G. lucidum. Experiments with horses as an animal model for investigating the effects of G. lucidum have never been reported. The purpose of this investigation was to understand the influence of G. lucidum feeding on blood biochemistry and immunocompetence in horses. Complete blood count (CBC) and blood biochemistry were surv...
Osteonal effects on elastic modulus and fatigue life in equine bone. We hypothesized that recently formed, incompletely mineralized, and thus, relatively deformable osteons in the equine third metacarpus enhance in vitro load-controlled fatigue life in two ways. Macroscopically, there is a compliance effect, because reduced tissue elastic modulus diminishes the stress required to reach a given strain. Microscopically, there is a cement line effect, in which new osteons and their cement lines more effectively serve as barriers to crack propagation. We studied 18 4 x 10 x 100 mm beams from the medial, lateral, and dorsal cortices of metacarpal bones from 6 thorou...
Behavior and misbehavior of the horse. For decades after the discipline of psychiatry had been established as an accepted specialty, many medical schools continued to fail to train their students in the fundamentals of this discipline. Medical students all have at least cursory exposure to psychiatric principles and basic psychology. Unfortunately, the veterinary profession has lagged behind human medicine in this regard. Until recently, veterinary students received no training in animal behavior, and there were no available residencies within our schools for developing board-certified behavioral specialists.
Prospects for whole genome linkage disequilibrium mapping in thoroughbreds. Linkage disequilibrium (LD) mapping is often used in searches for genes governing economically significant traits and diseases. The D' coefficient is a commonly used measure of the extent of LD between all possible pairs of alleles at two markers. This study aimed to test the utility of the D' coefficient for LD mapping of a trait in a thoroughbred population. Microsatellite genotype data and grey coat colour as a trait model in a thoroughbred population were used to assess the extent of LD. We demonstrated that LD mapping was a reasonable approach for initial genome-wide scans in a thoroughbr...
Genetic clustering of Borna disease virus natural animal isolates, laboratory and vaccine strains strongly reflects their regional geographical origin. The aim of this study was to gain more detailed insights into the genetic evolution and variability of Borna disease virus (BDV). Phylogenetic analyses were performed on field viruses originating from naturally infected animals, the BDV vaccine strain 'Dessau', four widely used laboratory strains and the novel BDV subtype No/98. Four regions of the BDV genome were analysed: the complete p40, p10 and p24 genes and the 5'-untranslated region of the X/P transcript. BDV isolates from the same geographical area exhibited a clearly higher degree of identity to each other than to BDV isolates from ot...
Determination of the stiffness of the equine spine. Mechanical properties of the equine back are the bases for realistic modelling of the back, which is recognised as an important step towards improved understanding of the pathogenesis of equine back conditions. Objective: The stiffness of the equine back depends on the direction of the applied force and on the position of the spine. Methods: Fourteen dissected spines were tested in a tensile testing machine. In 3 different positions, simulating dorsoventral, laterolateral and dorsoventral-30 degree rotated movement, force was applied on the dorsal spinous process of T12 to reach an excursion o...
Mepivacaine local anaesthetic duration in equine palmar digital nerve blocks. Perineural analgesics are used for lameness diagnosis but the duration of effect, knowledge of which would provide valuable information when performing subsequent blocks, is unknown. Objective: To evaluate the duration of a palmar digital nerve block using force plate measurements. Methods: Ten horses diagnosed with unilateral navicular syndrome were trotted at range of 3 +/- 0.15 m/sec over a force plate to record ground reaction forces for 5 trials of each forelimb. Data were recorded before nerve block, and then at 15 mins, 1, 2 and 24 h post nerve block. Results: Before nerve block, peak v...
Verification of skin-based markers for 3-dimensional kinematic analysis of the equine tarsal joint. Kinematic studies are usually based on tracking markers attached to the skin. However, complex joints, such as the tarsal joint, function in 3-dimensions (3D), and have therefore necessitated application of the invasive bone pin technique, limiting kinematic studies to the research laboratory. This study investigates the feasibility of using skin-based markers for 3D analysis of tarsal joint motion. Objective: Three-dimensional motions of the tarsal joint can be measured with an acceptable degree of accuracy using skin markers. Methods: Retroreflective markers were attached over the tibial and...
Influence of individual competition level on back kinematics of horses jumping a vertical fence. The costs and investments required for the purchase and training of showjumpers justify the need to find selection means for jumping horses. Use of objective kinematic criteria correlated to jumping ability could be helpful for this assessment. Objective: To compare back kinematics between 2 groups of horses of different competition levels (Group 1, competing at high level; Group 2 competing at low level) while free jumping over a 1 m vertical fence. Methods: Three-dimensional recordings were performed using 2 panning cameras. Kinematic parameters of the withers and tuber sacrale (vertical dis...
Effects of 6 degree elevation of the heels on 3D kinematics of the distal portion of the forelimb in the walking horse. Understanding of the biomechanical effects of heel elevation remains incomplete because in vivo studies performed with skin markers do not measure the actual movements of the 3 digital joints. Objective: To quantify the effects of 6 degree heel wedge on the 3-dimensional movements of the 4 distal segments of the forelimb in the walking horse. Methods: Four healthy horses were used. Kinematics of the distal segments was measured invasively with a system based on ultrasonic triangulation. Three-dimensional rotations of the digital joints were calculated by use of a 'joint coordinate system' (JCS...
Evaluation of pressure distribution under an English saddle at walk, trot and canter. Basic information about the influence of a rider on the equine back is currently lacking. Objective: That pressure distribution under a saddle is different between the walk, trot and canter. Methods: Twelve horses without clinical signs of back pain were ridden. At least 6 motion cycles at walk, trot and canter were measured kinematically. Using a saddle pad, the pressure distribution was recorded. The maximum overall force (MOF) and centre of pressure (COP) were calculated. The range of back movement was determined from a marker placed on the withers. Results: MOF and COP showed a consistent ...
Ground reaction forces and limb function in tölting Icelandic horses. Gaited horses employ 4-beat stepping (singlefoot) gaits that extend into speeds typical of trots. Ground reaction force (GRF) patterns of these specialised gaits have not been reported; therefore, appraisal of these gaits using nongaited horse kinetics may lead to clinical misjudgements. Objective: GRFs of tölting Icelandic horses will be comparable in profile and magnitude with those of trotting horses. Methods: Forelimb and hindlimb GRFs were obtained for 10 Icelandic horses ridden at a tölt. These data were evaluated across 3 speed ranges: <2, 2.5-5 and >5 m/sec. Results: Virtually all ve...
Relationships between fore- and hindlimb ground reaction force and hoof deceleration patterns in trotting horses. The transmission of shockwaves following hoof impact is proposed to be one major source of stress to the limb. In the forelimb, there are indications that the period of horizontal deceleration of the hoof is related to the attenuation of shockwaves. In the hindlimb, information about the hoof deceleration has been lacking. Objective: To compare hoof deceleration patterns between the fore- and hindlimbs. Methods: Seven Standardbreds were trotted by hand over a force plate covered with sand, with triaxial accelerometers mounted on the fore and hind hooves. Variables representative of deceleratio...
Three-dimensional carpal kinematics of trotting horses. Descriptions of 3D kinematics assist in understanding joint function and dysfunction, and are an essential step toward 3D inverse dynamic analysis. Objective: To measure 3D carpal joint motion during trotting. Methods: Three-dimensional trajectories of bone-fixed markers on the radius and third metacarpus of the right forelimb of 3 healthy horses were recorded at 120 Hz using a 6-camera analysis system. Joint kinematics were calculated in terms of helical angles between the 2 segments using a spatial attitude method. Results: All horses showed carpal extension and internal rotation of the meta...
Dynamic pressure measurements for the detailed study of hoof balance: the effect of trimming. Studies on hoof balance have, so far, only assessed the effects of strong and relatively unrealistic interventions due to technical limitations of measuring equipment. For the assessment of more subtle interventions, other techniques are necessary. Objective: To test a sensitive pressure measurement system during locomotion and to set a standard for further studies by using the system to evaluate the effects of trimming. Methods: Eighteen horses were measured before and after trimming with an interval of 4 weeks. Trimming was standardised to a straight hoof-pastern axis. The horses trotted ove...
The effect of bilateral glossopharyngeal nerve anaesthesia on swallowing in horses. Dysfunction of the glossopharyngeal nerve has been implicated as a cause of dysphagia in horses. However, recent studies have indicated that this is not the case. Objective: To determine whether bilateral glossopharyngeal nerve anaesthesia would cause dysphagia in horses or result in measurable alterations in the timing, function, or sequence of swallowing. Methods: Swallowing was evaluated in 6 normal horses with and without bilateral glossopharyngeal nerve anaesthesia. Swallowing dynamics were assessed subjectively and objectively based on time from prehension of food until swallowing, numbe...
SNARE proteins and caveolin-1 in stallion spermatozoa: possible implications for fertility. Proteins implicated in the "SNARE hypothesis" for membrane fusion have been characterized in the acrosome of several mammalian species, and a functional role for these proteins during the acrosome reaction has been proposed. We have investigated the presence of SNAREs in equine sperm, using semen samples obtained from stallions with varying fertility. Immunocytochemical analysis revealed that members of different SNARE families can be detected on the acrosome of equine sperm, notably in the acrosomal cap and equatorial segment. These proteins include the t-SNARE syntaxin, the v-SNARE synaptobr...
cDNA AFLP-based techniques for studying transcript profiles in horses. The identification of differentially expressed genes is a fundamental prerequisite for understanding the molecular regulation of most physiological and pathological processes. Among the procedures employed to compare mRNA populations, those that are gel-based appear to hold great promise and are considered excellent tools for studying gene expression in species, such as the equine one, for which little genomic information is available. In the present study, we evaluated two techniques for studying mRNA profiles in horse tissue, one referred to the cDNA-amplified fragment length polymorphism (A...
