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.
Effects of pretreatment with ketoprofen and phenylbutazone on experimentally induced synovitis in horses. To compare the analgesic and anti-inflammatory effects of the nonsteroidal anti-inflammatory drugs (NSAID), ketoprofen (2.20 and 3.63 mg/kg of body weight) and phenylbutazone (4.40 mg/kg), in an acute equine synovitis model. Methods: 4 groups of 6 horses received NSAID or saline solution in a randomized design. Methods: 24 clinically normal mares and geldings. Methods: Left intercarpal joints were injected with sterile carrageenan to induce synovitis at the same time as IV administration of NSAID or saline solution. Clinical assessments were made and synovial fluid was withdrawn at 0, 1, 3, 6,...
Biochemical and biomechanical alterations in equine articular cartilage following an experimentally-induced synovitis. The effects of inflammation on the biochemical and biomechanical properties of articular cartilage at two sites (dorsal and palmar) from the radial facet of the equine third carpal bone were examined in response to a synovitis induced with Escherichia coli lipopolysaccharide (LPS). Four groups were studied. In group 1 synovitis was induced at time zero and evaluated at week 6. Group 2 was the sham-treated control for group 1. In group 3 synovitis was induced at time zero and evaluated at week 2. Group 4 was the sham-treated control for group 3. There was a significant increase (P palmar). The...
Genomic quasispecies associated with the initiation of infection and disease in ponies experimentally infected with equine infectious anemia virus. Equine infectious anemia virus (EIAV) provides a uniquely dynamic system in which to study the mechanism and role of genomic variation in lentiviral persistence and pathogenesis. We have used a Shetland pony model of infection to investigate the association of specific long terminal repeat (LTR) and env gene genomic sequences with the initiation of infection and the onset of disease. We analyzed viral RNA isolated from a pathogenic stock of virus (EIAV PV) and from plasma taken during the first disease episode from two ponies infected with EIAV PV. Overall sequence variation within gp90 was lo...
Influence of methylprednisolone acetate on osteochondral healing in exercised tarsocrural joints of horses. To evaluate joint function and healing of surgically created full-thickness articular cartilage defects in exercised horses after intra-articular administration of methylprednisolone acetate (MPA; 120 mg) and sterile saline solution in the contralateral limb. Methods: Experimental investigation. Methods: 12 healthy, sound, radiographically normal horses with induced full-thickness osteochondral lesions on the medial and lateral trochlear ridges of the tali. Methods: Two 8.4-mm-diameter full-thickness articular cartilage lesions were created in each tarsocrural joint (12 horses [24 tarsocrural ...
In vitro maturation and transmission electron microscopic observation of horse oocytes after vitrification. The study was designed to examine the suitability of immature horse oocytes for vitrification. Immature oocytes derived from slaughtered horse ovaries were transferred to a vitrification solution (EFS; 40% ethylene glycol, 18% Ficoll, and 0.3 M sucrose in modified phosphate-buffered saline) directly (Groups 1 and 4) or were first exposed to 20% ethylene glycol solution for 10 min (Groups 2 and 5) or 20 min (Groups 3 and 6). Oocytes were handled at 20 degrees C (Groups 1, 2, and 3) or 30 degrees C (Groups 4, 5, and 6). After vitrification and warming, their viability was assessed by maturation ...
Effects of administration of N-methyl-D,L-aspartate (NMA) on gonadotropin secretion in untreated and steroid-treated ovariectomized mares during the breeding season and in intact and ovariectomized mares during anestrus. The purpose of this experiment was to investigate whether N-methyl-D,L-aspartate stimulated gonadotropin secretion in mares and to determine the response in two experimental paradigms where gonadotropin secretion is low or elevated. In Experiment 1, conducted during the breeding season (summer), eight long-term ovariectomized mares were treated daily for 21 d with progesterone plus estradiol (n = 4) or oil vehicle. Beginning on Day 14, each mare received, in a randomized design on alternate days, an intravenous injection of either 0, 0.5, 1.0, or 5.0 mg/kg NMA. Treatment with NMA was not accom...
Regulation of glycosaminoglycan metabolism by bone morphogenetic protein-2 in equine cartilage explant cultures. To investigate whether recombinant human bone morphogenetic protein-2 (rhBMP-2) regulates glycosaminoglycan (GAG) synthesis and release from equine articular cartilage explant cultures. Methods: Equine articular cartilage explants were maintained in vitro for 7 days in the presence of 0 (control), 1, 10, or 100 ng of rhBMP-2/ml. Synthesis and release of GAG were assessed as measures of production and degradation of the extracellular matrix, respectively. Methods: 6 horses (age range, 2 to 25 years old) without clinically detectable musculoskeletal abnormalities. Methods: Rate of synthesis of G...
Histopathological and immunofluorescent studies on transplacental infection in experimentally induced abortion by equine arteritis virus. Five pregnant mares, at between 6 and 8 months gestation, were experimentally infected with the Bucyrus strain of equine arteritis virus (EAV). Of the five mares, four aborted and one died. The pathogenesis of the abortions was studied, using histopathologic techniques, tissue immunofluorescence and virus isolation. Common microscopic lesions in the maternal reproductive organs indicated myometritis with a degeneration of the myocytes and an infiltration of the mononuclear cells. Epithelial cells of the endometrial gland showed sporadic degeneration. Lesions in the fetal tissue included an atr...
Fine specificity of equine infectious anaemia virus gp90-specific antibodies associated with protective and enhancing immune responses in experimentally infected and immunized ponies. Equine infectious anaemia virus (EIAV) provides a model for examining the natural immunological control of a persistent lentivirus infection and for evaluating the efficacy of various vaccine strategies. As an initial characterization of antibody responses associated with protective or enhancing immune responses elicited by experimental infections or vaccinations, we have utilized synthetic peptide ELISA to characterize the fine specificity of antibodies to linear determinants of the EIAV surface glycoprotein, gp90. The data indicated that serum antibodies associated with protective or enhanci...
Effects of sodium bicarbonate and sodium chloride on the elimination of etorphine in equine urine. The combination of large doses of sodium bicarbonate and the potent narcotic, etorphine, has reportedly been given to racehorses in attempts to improve their performance and also to "mask" the presence of etorphine in urine samples. The increased urinary output and pH associated with sodium bicarbonate (approximately 500 g) administration may reduce the urinary concentration of etorphine, making it more difficult to detect. Our experiment was designed to examine the effects of this combination. Six Thoroughbred horses were used in a latin-square design with three horse pairs and three treatmen...
The effects of irradiation dose on the stiffness of cartilage grafts. Various centers report irradiated cartilage graft absorption rates that differ quite widely. We postulated that a major factor governing this phenomenon might be irradiation dose. Irradiation produces collagen cross-binding and increased resistance to absorption of such material when implanted. Since cross-binding produces stiffening of collagen, cartilage grafts were exposed to increasing doses of irradiation and their elastic modulus was measured. The postulate was that increasing radiation doses will produce grafts of increasing stiffness. Sternal cartilage, harvested from horses, was cut i...
13-cis-Retinoic acid affect sheath-shaft interaction of equine hair follicles in vitro. A major challenge to the study of hair follicle growth is an appropriate assay system. Because equine mane follicles are large and noncurved, enabling easy dissection; are readily accessible from a single defined source; and possess a long anagen growth phase, we initiated a study of them in culture. As in our previous studies of human and sheep follicles (Dev Biol 165:469, 1994), we found in this system that transection level dictates the pattern of follicle growth in vitro: follicles transected below the sebaceous gland show a type 1 growth pattern (the shaft grows out with an adherent sheat...
Evaluation of five common induction protocols by comparison of hemodynamic responses to surgical manipulation in halothane-anesthetized horses. To determine whether hemodynamic responses of halothane-anesthetized horses undergoing surgical procedures depended on anesthetic induction protocols used, and to determine whether hemodynamic responses to surgical manipulation could be detected. Methods: Prospective experimental study without controls. Methods: 36 clinically normal horses. Methods: Horses were allotted to 5 groups according to anesthetic induction protocol: acepromazine/guaifenesin/thiamylal, acepromazine/guaifenesin/ketamine, xylazine/guaifenesin/thiamylal, xylazine/guaifenesin/ketamine, and xylazine/diazepam/ketamine. Anest...
Horses are sensitive to pictorial depth cues. In an attempt to demonstrate whether horses could make use of pictorial cues to depth, two were trained initially to make a relative-line-length discrimination between two lines placed one above the other. Psychophysical measurement of their discrimination thresholds showed that from a viewing distance of approximately 160 cm they could reliably distinguish a lower line of 10 cm from an upper one of 14 cm. In the second phase of the experiment, two lines of equal length were superimposed on a photograph of a set of railway tracks with many pictorial cues to depth, or a photograph of a pastoral...
Total replacement of the metatarsophalangeal joint in the horse. A single pilot study. In this paper the successful replacement of an equine metatarsophalangeal joint by a human total condylar knee prosthesis is reported. In the period of observation following implantation of the endoprosthesis the experimental animal showed almost no lameness when exercised at walk, bearing weight on the operated limb. Flexion and extension of the joint were markedly reduced. The clinical and histological observations clearly support further investigation into the equine metatarsophalangeal joint replacement by an endoprosthesis.
Factors affecting motion characteristics of frozen-thawed stallion spermatozoa. Five experiments were conducted to evaluate damage incurred in each processing step for cryopreservation of stallion spermatozoa. In Experiment 1, semen was centrifuged for 9 centrifugation times and the percentage of spermatozoa recovered after each treatment was calculated and spermatozoal motion characteristics analysed. Recovery of spermatozoa was > or = 80% when spermatozoa were centrifuged for > or = 10 min. Experiment 2 evaluated spermatozoa cryopreserved at 5 different concentrations in each of 2 extenders (skim milk-egg yolk-glycerol, SM-EYG; and lactose-EDTA, LAC). In SM-EYG, T...
Effects of tendon grip technique (frozen versus unfrozen) on in vitro surface strain measurements of the equine deep digital flexor tendon. To determine effects of tendon grip technique on in vitro surface strain measurements of equine deep digital flexor tendon (DDFT) when loaded in tension. Methods: 12 hind limb DDFT from 8 adult horses (mean age, 9.8 years [range, 4.5 to 17 years]; mean body weight, 472 kg [range, 450 to 509 kg]), with no clinical evidence of hind limb lameness. Methods: After calibration, liquid mercury strain gauges were sutured to plantar surfaces of the tendons at distal (position 1), middle (position 2), and proximal (position 3) metatarsal regions. Each tendon was affixed to a materials testing machine (d...
The vasomotor effects of 5-hydroxytryptamine on equine basilar arteries in vitro. The vasomotor effects of 5-hydroxytryptamine (5-HT) on isolated equine basilar arteries were studied. 5-HT induced contractions of equine basilar arteries in a concentration-dependent manner, with a pEC50 value (with 95% confidence limits) of 7.35 (7.08-7.62). Similar results were obtained with endothelium-denuded basilar arteries. Contractions were not competitively inhibited by the 5-HT2 receptor antagonist ketanserin at low concentrations of 5-HT. Conversely, at high concentrations of 5-HT, contractions were inhibited by ketanserin in a concentration-dependent manner, with a pA2 value of 8....
An in vitro biomechanical study of a multiplanar circular external fixator applied to equine third metacarpal bones. The biomechanical characteristics of a 4-ring circular multiplanar fixator applied to equine third metacarpal bones with a 5 mm mid-diaphyseal osteotomy gap were studied. Smooth Steinmann pins, either 1/8 inch, 3/16 inch, or 1/4 inch, were driven through pilot holes in the bone in a crossed configuration and full pin fashion and fastened to the fixator rings using cannulated fixation bolts. The third metacarpal bone fixator constructs were tested in three different modes (cranial-caudal four-point bending, axial compression, and torsion). Loads of 2,000 N were applied in bending and axial comp...
Neutron anatomy. The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content-the crystals of the hexagonal hydroxyapatite- and this...
Evaluation of a porous bovine collagen membrane bandage for management of wounds in horses. To evaluate the effect of a porous bovine-derived collagen membrane (PBCM) on the rates of wound healing, cellular events, presence of granulation tissue, and appearance at termination of the study in surgically created full-thickness cutaneous wounds of the distal portion of the extremities of horses. Methods: Treated wounds (n = 12) received a PBCM dressing and control wounds were covered with a nonadherent dressing. Forelimbs and hind limbs were cross paired; the right forelimb and left hind limb always received the same dressing application, as did the left forelimb and right hind limb. Li...
The dose-related effects of phenylbutazone and a methylprednisolone acetate formulation (Depo-Medrol) on cultured explants of equine carpal articular cartilage. The dose-related effects of phenylbutazone and Depo-Medrol on chondrocyte viability and chondrocyte-mediated synthesis and depletion of proteoglycans were investigated using cultured explants of equine middle carpal joint articular cartilage. Explants from 12 horses (941 x 3 mm diameter) were cultured for a total of 5 days, which included 3 days' exposure to either phenylbutazone (0, 2, 20, 200 or 2000 micrograms/mL) or Depo-Medrol (0, 20, 200 or 2000 micrograms/mL). For each explant, amino sugar content was used as a measure of proteoglycan content, 35S incorporation as a measure of the rate ...
Evidence for endothelium-derived relaxing factor/nitric oxide in equine digital arteries. To test the hypothesis that endothelium-derived nitric oxide modulates vasomotor reactivity in equine digital arteries. Methods: Digital arteries were isolated from adult horses, and their vasodilator properties were examined in an in vitro controlled environment. Methods: Five adult horses (1 gelding, 4 mares) without evidence of hoof or vascular disease were studied. Methods: Arterial rings with or without endothelium were exposed to endothelium-dependent vasodilator drugs in the presence or absence of a pharmacologic inhibitor of the enzyme nitric oxide synthase. Results: Vasodilator effect...
Fatigue behavior of the equine third metacarpus: mechanical property analysis. This is the first in a series of experiments to study the fatigue properties of equine cannon (third metacarpal) bone specimens from Thoroughbred racehorses. Monotonic and fatigue tests to failure were performed in four-point bending on diaphyseal specimens in a 37 degrees C saline bath to answer three initial questions. (a) Will a linear variable differential transducer yield the same elastic modulus as strain gauges? (b) Will fatigue results depend on whether the periosteal or endosteal side of the beam is in tension? (c) Are there regional variations in the monotonic and fatigue properties ...
Dose titration of moxidectin oral gel against migrating Strongylus vulgaris and Parascaris equorum larvae in pony foals. Moxidectin was tested for efficacy in ponies against experimental infections of 56 day Strongylus vulgaris larvae and 11 day Parascaris equorum larvae. Three dosages of moxidectin were tested: 300 micrograms per kg live body weight, 400 micrograms per kg, and 500 micrograms per kg, and the vehicle served as control. Ponies were first infected with 600 S. vulgaris third-stage larvae (L3) on Experiment Day 0 and then with 3000 embryonated P. equorum eggs on Day 45. Moxidectin treatments were administered on Day 56 and necropsy examinations were performed on Day 91. Strongylus vulgaris fourth-sta...
Effect of hepatic isoferritins from iron overloaded rats on lymphocyte proliferative response: role of ferritin iron content. Iron and ferritin impair a variety of immunological functions. To evaluate the effect of ferritin iron content on rat lymphocyte proliferative response, isoferritins that differ in their iron content and isoelectric point (pI) were isolated from iron overload rat livers by ultracentrifugation (isoferritins with high iron content and low pI) or crystallization (isoferritins with low iron content and high pI) methods. Additionally, commercial horse splenic ferritin (with a lower pI and higher iron content than rat isoferritins) was also tested. Proliferative response to Con A was decreased in a ...
Evaluation of fetal infection and abortion in pregnant ponies experimentally infected with Ehrlichia risticii. Fetal infectivity of Ehrlichia risticii was investigated in 19 ponies that were E risticii negative on the basis of results of an indirect fluorescent antibody (IFA) test. Thirteen pregnant ponies were infected by IV administration of E risticii between 90 and 180 days of gestation. Six pregnant ponies served as noninfected controls. Each infected pony had clinical signs of equine monocytic ehrlichiosis, was confirmed to be ehrlichemic, and developed an IFA titer to E risticii. Two infected ponies became recumbent, were unresponsive to supportive care, and were euthanatized. After recovery fro...
Equine pelvic flexure myoelectric activity during fed and fasted states. The pelvic flexure is the midpoint of the equine large colon that marks the junction of dorsal and ventral components. Previous studies of intraluminal pressure in this region indicate that it could be an important motility control center. The present study was undertaken to expand our knowledge of normal myoelectric activity around the pelvic flexure region. Eight bipolar silver wire electrodes were surgically fixed at 5-cm intervals to the colonic serosa of five adult horses, starting 30 cm oral to the pelvic flexure on the left ventral colon and ending 15 cm aboral to the pelvic flexure on ...