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Topic:Experimental Methods
Experimental methods in equine research encompass a variety of techniques and procedures used to investigate physiological, behavioral, and health-related aspects of horses. These methods are designed to collect data that can enhance the understanding of equine biology and inform veterinary practices. Common experimental approaches include controlled trials, observational studies, and laboratory-based experiments. Techniques may involve the use of non-invasive imaging, biochemical assays, and physiological monitoring to assess parameters such as metabolic function, locomotion, and disease progression. This page compiles peer-reviewed research studies and scholarly articles that explore the application, development, and evaluation of experimental methods in the study of equine science.
Structure and collagen crimp patterns of functionally distinct equine tendons, revealed by quantitative polarised light microscopy (qPLM). Structure-function relationships in tendons are directly influenced by the arrangement of collagen fibres. However, the details of such arrangements in functionally distinct tendons remain obscure. This study demonstrates the use of quantitative polarised light microscopy (qPLM) to identify structural differences in two major tendon compartments at the mesoscale: fascicles and interfascicular matrix (IFM). It contrasts functionally distinct positional and energy storing tendons, and considers changes with age. Of particular note, the technique facilitates the analysis of crimp parameters, in w...
Interaction between the sequence of feeding of hay and concentrate, and boiling of barley on feed intake, the activity of hydrolytic enzymes and fermentation in the hindgut of Arabian mares. The interaction between the sequence of feeding of hay and concentrate and the hydrothermal processing of barley in alleviating concentrate effects on intake, and hindgut fermentation in horses was tested. Six Arabian mares (4-10 years of age, 410 ± 35 kg body weight) were used to evaluate the effects of feeding sequence (FS) and type of barley (TB) on intake, and faecal volatile fatty acids (VFA), activities of α-amylase (AA: EC 3.2.1.1), carboxymethyl cellulase (CMCase: EC 3.2.1.4), microcrystalline cellulase (MCCase: EC 3.2.1.91) and general filter paper degrading activity (FPD). Mare...
Evaluating the electrical impedance and mucus-related gene expression of uterine endometrial tissues in mares. We investigated the electrical impedance of the reproductive tracts (vagina and uterine endometrial tissues) and the expression of mucus-related genes to identify the stage of the estrous cycle in mares. We first examined vaginal impedance in native Hokkaido mares during their estrous cycle and found no significant differences. However, impedance levels tended to decrease towards ovulation. Furthermore, we investigated the estrous cycle by measuring the electrical impedance of the uterine endometrial tissues obtained from carcasses of mares. We found that impedance levels in the endometrial ti...
Novel dry cryotherapy system for cooling the equine digit. Digital cryotherapy is commonly used for laminitis prophylaxis and treatment. Currently validated methods for distal limb cryotherapy involve wet application or compression technology. There is a need for a practical, affordable, dry cryotherapy method that effectively cools the digit. The objective of this study was to evaluate the hoof wall surface temperatures (HWSTs) achieved with a novel dry cryotherapy technology. Methods: Repeated-measures in vivo experimental study. Methods: Experimental intervention at a single site. Methods: 6 systemically healthy horses (3 mares, 3 geldings). Method...
Vitrification of germinal-vesicle stage equine oocytes: Effect of cryoprotectant exposure time on in-vitro embryo production. Previous studies have found low rates of blastocyst development (0-11%) after vitrification of germinal vesicle (GV)-stage equine oocytes. In this study, we systematically evaluated a short (non-equilibrating) system for GV-stage oocyte vitrification. In Exp. 1, we assessed oocyte volume in cumulus-oocyte complexes (COCs) exposed to components of a short protocol, using 2% each of ethylene glycol and propylene glycol in the first solution (VS1); 17.5% of each plus 0.3 M trehalose in the second solution (VS2); and fetal bovine serum as the base medium. Based on the time to oocyte minimum volu...
Pharmacokinetics of the anticonvulsant levetiracetam in neonatal foals. Seizures are a common manifestation of neurological disease in the neonatal foal and are an important cause of morbidity and mortality in this population. Current antiepileptic options are effective, but often have undesirable adverse effects, short duration of action and high cost. Levetiracetam has an ideal safety and pharmacokinetic profile in multiple species, including the adult horse, and may be a safe and cost-effective alternative anticonvulsant in neonatal foals. Due to differences in drug disposition and clearance dosages in neonates, dosing recommendations in other species or adult ...
Estimation of dietary threonine requirement using plasma amino acid concentrations in mature thoroughbreds. The experiment was conducted to estimate dietary threonine (Thr) requirement using plasma amino acid concentrations as a criterion in mature thoroughbreds. Four adult thoroughbreds were used, and a 4 × 4 Latin square design was used for four dietary Thr levels. Plasma Thr concentration was constant until 0.41%, and then increased rapidly with increasing dietary Thr levels. The Thr requirement was estimated to be 67% of lysine with plasma Thr concentration at four Thr levels.
Changes in Synovial Fluid Biomarkers after Experimental Equine Osteoarthritis. The study aimed to clarify the changes in the concentration of inflammatory mediators, proteases, and cartilage degradation biomarkers in the synovial fluid of joints in an equine osteoarthritis model. Methods: Osteoarthritis was induced in eight Mongolian horses by a sterile intra-articular injection of amphotericin B, which was injected into the left carpal joint in a dose of 2 mL (25 mg/mL). The control group comprised five horses which were injected with an equal dose of sterile physiological saline into the left carpal joint. Synovial fluid was obtained at baseline and every week after in...
Culture of somatic cells isolated from frozen-thawed equine semen using fluorescence-assisted cell sorting. Nuclear transfer using somatic cells from frozen semen (FzSC) would allow cloning of animals for which no other genetic material is available. Horses are one of the few species for which cloning is commercially feasible; despite this, there is no information available on the culture of equine FzSC. After preliminary trials on equine FzSC, recovered by density-gradient centrifugation, resulted in no growth, we hypothesized that sperm in the culture system negatively affected cell proliferation. Therefore, we evaluated culture of FzSC isolated using fluorescence-assisted cell sorting. In Exp. 1,...
Cryopreservation of donkey sperm using non-permeable cryoprotectants. The aim of this study was to evaluate the effect of different concentrations of sucrose combined with bovine serum albumin (BSA), as non-permeable cryoprotectants, on donkey sperm parameters after cryopreservation, in comparison to a control extender containing glycerol. Semen from five Andalusian donkeys (n = 12) were centrifuged and resuspended with a commercial extender for equine sperm (Gent A, Minitube) adding 1% BSA and different concentrations (M, mol/l) of water-diluted sucrose: 0.05, 0.1, 0.25, 0.35 and 0.45. Thereafter, semen (n = 24) were diluted in the same base extender co...
Passive protection against anthrax in mice with plasma derived from horses hyper-immunized against Bacillus anthracis Sterne strain. In this study, equine source polyclonal anti-Bacillus anthracis immunoglobulins were generated and utilized to demonstrate passive protection of mice in a lethal challenge assay. Four horses were hyper-immunized with B. anthracis Sterne strain for approximately one year. The geometric mean anti-PA titer in the horses at maximal response following immunization was 1:77,936 (Log2 mean titer 16.25, SEM ± 0.25 95% CI [15.5 -17.0]). The geometric mean neutralizing titer at maximal response was 1:128 (Log2 mean titer 7, SEM ± 0.0, 95% CI 7). Treatment with hyper-immune plasma or purified immun...
Effects of priming with cytokines on intracellular survival and replication of Rhodococcus equi in equine macrophages. Rhodococcus equi is a common cause of pneumonia in foals and an opportunistic pathogen in immunosuppressed people. The ability of R. equi to survive and replicate in macrophages is the basis of its pathogenicity. Limited knowledge about the role of cytokines in host defense against R. equi comes from studies in mice and the role of cytokines in intracellular survival of R. equi in equine macrophages is unknown. The objectives of this study were to determine the effect of priming with interferon (IFN)-γ, interleukin (IL)-1β, IL-4, IL-6, IL-10, or tumor necrosis factor (TNF)-α at various conc...
A scoping review of the evidence for efficacy of acupuncture in companion animals. Acupuncture has become increasingly popular in veterinary medicine. Within the scientific literature there is debate regarding its efficacy. Due to the complex nature of acupuncture, a scoping review was undertaken to identify and categorize the evidence related to acupuncture in companion animals (dogs, cats, and horses). Our search identified 843 relevant citations. Narrative reviews represented the largest proportion of studies (43%). We identified 179 experimental studies and 175 case reports/case series that examined the efficacy of acupuncture. Dogs were the most common subjects in the e...
Numerical time-domain modelling of hoof-ground interaction during the stance phase. Hoof-ground interaction impacts on the health and performance characteristics of horses. Due to complex interactions between hoof and ground during the stance phase, previous experimentally dominated studies concentrated on subproblems of the phenomena observed. A multidisciplinary methodology with mathematical modelling, material testing and in vivo experimental measurements seems promising. Objective: With the help of a mathematical approach, this contribution aims to explain from a biomechanical point of view the phenomena observed during experimental investigations (hoof acceleration, inte...
Major histocompatibility complex-linked social signalling affects female fertility. Genes of the major histocompatibility complex (MHC) have been shown to influence social signalling and mate preferences in many species, including humans. First observations suggest that MHC signalling may also affect female fertility. To test this hypothesis, we exposed 191 female horses () to either an MHC-similar or an MHC-dissimilar stimulus male around the time of ovulation and conception. A within-subject experimental design controlled for non-MHC-linked male characteristics, and instrumental insemination with semen of other males ( = 106) controlled for potential confounding effects of ...
Effect of flecainide on atrial fibrillatory rate in a large animal model with induced atrial fibrillation. Atrial fibrillatory cycle length has been considered one of the indices of atrial electrical remodelling during atrial fibrillation (AF), which can be assessed from surface ECG by computer-assisted calculation of atrial fibrillatory rate (AFR). Horses have been suggested as a bona fide model for AF studies since horses too, develop lone AF, however data on AF characteristics in horses are extremely sparse and non-invasive characterization of AF complexity using surface ECG processing has not been reported. Objective: The aim was to study characteristics of induced AF and its modification by fl...
Equine in vivo-derived metabolites of the SARM LGD-4033 and comparison with human and fungal metabolites. LGD-4033 has been found in human doping control samples and has the potential for illicit use in racehorses as well. It belongs to the pharmacological class of selective androgen receptor modulators (SARMs) and can stimulate muscle growth, much like anabolic steroids. However, SARMs have shown superior side effect profiles compared to anabolic steroids, which arguably makes them attractive for use by individuals seeking an unfair advantage over their competitors. The purpose of this study was to investigate the metabolites formed from LGD-4033 in the horse in order to find suitable analytical ...
Matrix-Induced Autologous Chondrocyte Implantation (MACI) Using a Cell-Seeded Collagen Membrane Improves Cartilage Healing in the Equine Model. Autologous chondrocyte implantation (ACI) using a collagen scaffold (matrix-induced ACI; MACI) is a next-generation approach to traditional ACI that provides the benefit of autologous cells and guided tissue regeneration using a biocompatible collagen scaffold. The MACI implant also has inherent advantages including surgical implantation via arthroscopy or miniarthrotomy, the elimination of periosteal harvest, and the use of tissue adhesive in lieu of sutures. This study evaluated the efficacy of the MACI implant in an equine full-thickness cartilage defect model at 1 year. Methods: Autologous...
Effects of transdermal lidocaine or lidocaine with prilocaine or tetracaine on mechanical superficial sensation and nociceptive thermal thresholds in horses. To evaluate the transdermal local anaesthetic effect of lidocaine or lidocaine combined with prilocaine or tetracaine in horses. Methods: Experimental, randomized study. Methods: A total of five healthy adult warmblood horses. Methods: Horses were clipped bilaterally at the withers, cranial saddle area and caudal saddle area. Baseline measurements for mechanical superficial sensation via von Frey filaments and nociceptive thermal thresholds were performed. A 5% lidocaine patch (12 hour exposure, treatment L), a lidocaine/prilocaine cream (each 2.5%, treatment LP) and a lidocaine/tetracaine cre...
Effects of controlled hypoxemia or hypovolemia on global and intestinal oxygenation and perfusion in isoflurane anesthetized horses receiving an alpha-2-agonist infusion. Aim of this prospective experimental study was to assess effects of systemic hypoxemia and hypovolemia on global and gastrointestinal oxygenation and perfusion in anesthetized horses. Therefore, we anesthetized twelve systemically healthy warmblood horses using either xylazine or dexmedetomidine for premedication and midazolam and ketamine for induction. Anesthesia was maintained using isoflurane in oxygen with either xylazine or dexmedetomidine and horses were ventilated to normocapnia. During part A arterial oxygen saturation (SaO) was reduced by reducing inspiratory oxygen fraction in steps...
The possible role of Stomoxys calcitrans in equine sarcoid transmission. The association between bovine papillomavirus (BPV) and equine sarcoids is well established, but it is unclear how the virus spreads. Although evidence in support of viral spread through direct animal contact exists, this does not explain sarcoid development in isolated equids. BPV DNA has been detected in flies, which could indicate that these insects serve as a vector. This study aimed to investigate whether BPV-negative stable flies (Stomoxys calcitrans) become positive for BPV DNA after exposure to equine sarcoid or bovine papilloma tissue under experimental conditions and, if so, for how ...
A conditioned reinforcer did not help to maintain an operant conditioning in the absence of a primary reinforcer in horses. The use of conditioned reinforcers is increasingly promoted in animal training. Surprisingly, the efficiency of their use remains to be demonstrated in horses. This study aimed to determine whether an auditory signal which had previously been associated with a food reward 288 times could be used as a conditioned reinforcer to replace the primary reinforcer in an unrelated operant conditioning procedure. Fourteen horses were divided into two groups of 7: No Reinforcement (NR) and Conditioned Reinforcement (CR). All horses underwent nine sessions of Pavlovian conditioning during which the word "...
The biomechanical construction of the horse’s body and activity patterns of three important muscles of the trunk in the walk, trot and canter. The activity patterns of trunk muscles are commonly neglected, in spite of their importance for maintaining body shape. Analysis of the biomechanics of the trunk under static conditions has led to predictions of the activity patterns. These hypotheses are tested experimentally by surface electromyography (EMG). Five horses, with and without a rider, were examined in the walk, trot and canter. Footfall was synchronised with EMG by an accelerometer. Averages of ten consecutive cycles were calculated and compared by statistical methods. The start and stop times of the muscle activities of 5-10 un...
Spontaneous attention-capture by auditory distractors as predictor of distractibility: a study of domestic horses (Equus caballus). Distractibility (i.e. individual distraction from his ongoing activity) is thoughts to affect daily life. The present study develops an easy way to assess inter-individual variations of distractibility of an animal model, the domestic horse. We developed the 'distractibility test' (DT), based on auditory stimuli, a major source of distraction in daily life. We hypothesized that the broadcast of unusual sounds would provide a reliable source of distraction and that the responses to these unusual sounds would yield a good estimation of a horse's level of distractibility. Validity of the DT was a...
Placental alterations in structure and function in intra-uterine growth-retarded horses. Following embryo transfer (ET), the size and breed of the recipient mare can affect fetal development and subsequent post natal growth rate and insulin sensitivity in foals. Objective: To investigate placental adaptation in pregnancies where increased or restricted fetal growth was induced through ET between Pony, Saddlebred and Draught horses. Methods: In vivo experiment. Methods: Control Pony (P, n = 21) and Saddlebred (S, n = 28) pregnancies were obtained by artificial insemination. Increased pregnancies were obtained by transferring Pony (P-D, n = 6) and Saddlebred (S-D, n = 8) emb...
Hemodynamics of the corpus luteum in mares during experimentally impaired luteogenesis and partial luteolysis. The aim of the current project was to characterize the luteal vascularity and the plasma concentrations of progesterone (P4), prolactin (PRL) and 13,14-dihydro-15-keto-PGF (PGFM) in mares with luteal disturbances during early and mid-diestrus. In Experiment 1, twenty-one mares were treated with 2 mL of 0.9% NaCl, or 1 mg Dinoprost, or 10 mg Dinoprost on day two after ovulation (Control-D2, 1/10PGF-D2 and PGF-D2 groups, respectively; n = 7 mares/group). In Experiment 2, similar treatments were performed eight days post-ovulation using a different cohort of 21 mares (Control-D8, 1/10PGF-D8 ...
Equine Endometrial Explants Undergo Significant Degenerative Changes in Culture. This study evaluated equine endometrial explants following 12, 24, and 48 hr in culture. Measurement of an indicator of cell death in explant supernatant, light microscopy, and gene expression of biomarkers of endometrial function and cellular stress were used to compare the effect of six different media on explant viability and morphology. Viability of explants was assessed indirectly through measuring LDH activity in the culture supernatant. Regardless of culture medium composition, a significant increase in LDH activity was observed within 12 hr of culture, indicating occurrence of cell dam...
Quantification of the effect of instrumentation error in objective gait assessment in the horse on hindlimb symmetry parameters. Objective gait analysis is becoming more popular as a tool assisting veterinarians during the clinical lameness exam. At present, there is only limited information on the effect of misplacement of markers/motion-sensors. Objective: To investigate and describe the effect of marker misplacement on commonly calculated pelvic symmetry parameters. Methods: Experimental study. Methods: Each horse was equipped with custom-made devices consisting of several reflective markers arranged in a predefined manner with a reference marker correctly positioned regarding the anatomical landmark and several misp...
Assessment of a novel equine tarsocrural experimental joint disease model using recombinant interleukin-1β and arthroscopic articular sampling of the medial malleolus of the tibia on the standing sedated horse. Joint disease and osteoarthritis are common problems in the horse and numerous experimental studies have been developed to determine the safety and efficacy of new therapies. Synovitis, a critical component of joint disease, has been experimentally induced using recombinant interleukin-1 beta (reIL-1β) to investigate new joint therapies in a controlled environment, although the use of reIL-1β has not been reported in the equine tarsocrural joint. A common consequence of performing controlled experiments is that articular tissue collection typically requires general anesthesia or euthanasia. ...
Venom and Antivenom of the Redback Spider (Latrodectus hasseltii) in Japan. Part II. Experimental Production of Equine Antivenom against the Redback Spider. This is the first report on large-scale experimental production of an equine antivenom against the redback spider (Latrodectus hasseltii) lived in Japan. We captured 10,000 redback spiders in Japan and prepared the toxoids of crude venom extract, mixed the toxoids with a mineral oil adjuvant, and immunized healthy horses repeatedly over a period of several weeks. Thereafter, we separated the horse plasma, purified the γ-globulin fraction, and stocked it as a purified antivenom concentrate. Consequently, we manufactured approximately 6,500 vials of a single-dose freeze-dried test lot from a po...
