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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.
Epithelial strips: an alternative technique for examining arachidonate metabolism in equine tracheal epithelium. We have developed an alternative method for examining equine tracheal epithelial arachidonic acid (AA) metabolism that utilizes strips of pseudostratified columnar epithelium attached to a layer of elastic tissue 80 to 130 microns thick. We compared the responses of this preparation with those of enzymatically dispersed suspensions of tracheal epithelium obtained from the same animal. Strips incubated with [3H]AA incorporated 40.8 +/- 3.6% of added radioactivity and released 2.55 +/- 0.23% of incorporated radioactivity when stimulated with 5 microM A23187. Values for the cell suspension were 5...
Preliminary findings for an inactivated African horsesickness vaccine using binary ethyleneimine. Investigation studies on inactivated African horsesickness vaccine using binary ethyleneimine were conducted. The inactivation process of virulent type-9 strain using the above inactivant revealed complete virus inactivation at 18, 48 and 84 h post-treatment with inactivant concentrations of 0.004, 0.003 and 0.002M, respectively, without detection of residual virus. An inactivant concentration of 0.003M is recommended and no changes in viral antigenic properties were noticed in complement fixation test. The physical parameters in oil-emulsion vaccine using the incomplete Freund's adjuvant, wer...
Establishing an acceptability threshold for equine influenza vaccines. Shortcomings in the original methods (based on haemagglutination of erythrocytes) used to measure potency of equine influenza vaccines and antibody responses stimulated by vaccines, coupled with the lack of a reliable challenge system in the target species, has hindered progress in identifying the antigenic content required to provide protection. Reliable methods are now available for measuring the haemagglutinin (HA) content of vaccines and the antibody responses they elicit. The development of challenge systems in the target species has allowed antibody levels consistent with protection to b...
Exercise-induced pulmonary hemorrhage in horses with experimentally induced allergic lung disease. The lungs of sensitized horses were exposed to aerosolized ovalbumin. Some horses (n = 4) were given ovalbumin in 1 lung only, whereas in others (n = 7), ovalbumin or vehicle were inoculated in the cranial, ventral, and caudal regions of the caudal lung lobe. Horses were exercised 5 hours after ovalbumin exposure. Immediately before exercise, endoscopy failed to reveal any abnormality. After exercise, endoscopic examination of horses subjected to unilateral ovalbumin exposure revealed extensive blood in airways leading to the exposed lung in all horses. Blood was not observed in the airways le...
[Teratogenic effect of the Venezuelan equine encephalitis virus: a review of the problem]. Clinical findings on Venezuelan Equine Encephalitis virus infection and the teratogenic effects of several Togaviruses are described. Similarities between the intrauterine alterations induced by Venezuelan Equine Encephalitis virus and rubella virus are pointed out. Findings described by Wenger in 1967 were those of massive cerebral necrosis in fetuses of women presumably suffering of encephalitis and they are commented along with the development of an animal experimental model at the end of 1970-1980. Pathogenesis of the intrauterine infection seemed to be related to changes in the placental ...
Thirst and salt appetite in horses treated with furosemide. When a preliminary experiment in sodium-replete ponies revealed an increase, but not a significant increase, in salt consumption after furosemide treatment, the experiment was repeated using sodium-deficient horses in which aldosterone levels might be expected to be elevated to test the hypothesis that a background of aldosterone is necessary for salt appetite. Ten Standardbred mares were injected intravenously with furosemide or an equivalent volume of 0.9% sodium chloride as a control to test the effect of furosemide on their salt appetite and blood constituents. Sodium intake and sodium los...
Comparison of high-performance liquid chromatography with a radiometric assay for determination of the effect of intra-articular administration of corticosteroid and saline solution on synovial fluid hyaluronate concentration in horses. Two recently developed direct methods, radioassay-125I-labeled hyaluronic acid binding protein (125I-HABP)- and high-performance liquid chromatography (HPLC), were used to assess and compare the concentration of hyaluronate (HA) in synovial fluid of horses. Also determined were changes in the HA concentration in an experimental treatment model involving physiologic saline solution (PSS)-irrigated or methylprednisolone acetate-injected tarsocrural joints of clinically normal horses. Serum HA concentration was determined simultaneously, using the 125I-HABP assay. Synovial fluid HA concentration ...
Effects of superoxide dismutase on injury induced by anoxia and reoxygenation in equine small intestine in vitro. Sheets of mucosa from the jejunum of healthy horses were mounted in incubation chambers and bathed with Krebs-Ringer bicarbonate solution. Changes in tissue function and histologic appearance were compared after the following conditions: (1) control conditions for 30 minutes with 95% O2/5% CO2 in the gas phase; (2) same conditions as control, except incubation with superoxide dismutase (300 U/ml) during the last 18 minutes; (3) anoxia for 15 minutes with 95% N2/5% CO2, followed by reoxygenation for 15 minutes; (4) same conditions as 3, except incubation with superoxide dismutase during reoxyge...
Electromagnetic stimulation of bone repair: a histomorphometric study. The effect of pulsing electromagnetic fields (PEMFs) on bone repair was studied in principal metacarpal bones of eight adult male horses: Six horses were treated with PEMFs, and two horses were untreated. In treated horses, Helmholtz coils were applied during a 60-day period to the left metacarpal bones, bored with eight holes of equal diameter and depth, from the middiaphysis toward the distal metaphysis. Eight equal holes bored in the right metacarpal, surrounded by unactivated Helmholtz coils, were taken as controls. The two untreated horses were taken as additional control. The results of ...
Co-culture of day-5 to day-7 equine embryos in medium with oviductal tissue. Oviductal and uterine embryos were collected from mares at 5 to 7 days following ovulation 1) to evaluate the effects of oviductal tissue explants on in vitro growth and development of equine embryos and 2) to study the morphologic development of equine embryos in culture. Embryos were incubated for 5 days in a medium (control group) or in medium supplemented with oviductal tissue explants (co-culture group). Embryos were evaluated and the media changed daily. Following 5 days in culture, 10 10 (100%) control embryos and 27 29 (93%) co-cultured embryos had doubled in diameter. All embryos that...
Xanthine oxidase formation during experimental ischemia of the equine small intestine. We hypothesized that xanthine oxidase plays a role in the postischemic reperfusion injury in the equine small intestine. Under anesthesia, four horses and two ponies underwent ischemic strangulating obstructions of segments of the proximal jejunum, mid-jejunum and ileum. Prior to vascular occlusion, and at 1 h and 2 h of ischemia, full-thickness intestinal biopsies were collected for histopathological evaluation and for determination of combined xanthine dehydrogenase (XDH) plus xanthine oxidase (XO) activity, and XO activity alone. The level of XO activity was expressed in percentage accordin...
Influence of polysulfated glycosaminoglycan on equine articular cartilage in explant culture. Articular cartilage explants from 3 horses were maintained in tissue culture to test the effects of a polysulfated glycosaminoglycan on proteoglycan biosynthesis. Cultures were exposed to concentrations of 0, 50, or 200 micrograms of the drug/ml for either 2 days or 6 days, and labeled with 35S, before measuring the content of sulfated proteoglycan in the culture media and in extracts of cartilage. In a second experiment, the explants were incubated with the isotope and subsequently exposed to the same concentrations of the polysulfated glycosaminoglycan for 4 days. Subsequently, the amount of...
Effect of viral inoculum size on appearance of clinical signs in equine Getah virus infection. A study was performed to examine the effect of viral inoculum size on the appearance of clinical signs in equine Getah virus (GV) infection by intramuscular inoculation with 10(1.3) to 10(6.3) TCID50 of the MI-110 strain in 6 experimental horses. When inoculated with more than 10(3.3) TCID50 of the virus, every horse developed pyrexia, edema in the hind legs, serous nasal discharge, lymphopenia and viremia in the relatively early stage of disease. On the other hand, enlargement of the submandibular lymph node was observed only in horses inoculated with 10(5.3) and 10(6.3) TCID50 of the virus, ...
Clenbuterol plasma concentrations after repeated oral administration and its effects on cardio-respiratory and blood lactate responses to exercise in healthy Standardbred horses. To evaluate the effects of clenbuterol on cardio-respiratory parameters and blood lactate relation to exercise tolerance, experimental horses performed standardized exercise tests on a high-speed treadmill before and after administration of the drug. Clenbuterol was administered in feed to six healthy Standardbreds at a dose rate of 0.8 micrograms/kg b.wt twice daily for 5.5 days. Each horse was tested twice, without and with a respiratory mask, during two consecutive days. One week elapsed between the baseline tests without drug and the tests with clenbuterol treatment (each horse served as i...
Clinical signs and humoral immune response in horses following equine herpesvirus type-1 infection and their susceptibility to equine herpesvirus type-4 challenge. A group of three horses was experimentally infected with equine herpesvirus type 1 (EHV-1) and showed clinical signs characterised by a biphasic febrile response, leucopenia and cell associated viraemia accompanied by virus shedding from the nasopharynx. A second exposure to the virus 18 days later resulted in the isolation of virus from the nasopharynx of one horse. This and a further group of three EHV-1 seropositive horses were subsequently infected with equine herpesvirus type 4 (EHV-4) 147 days after the initial EHV-1 infection and virus was shed from the nasopharynx in the absence of cli...
Transient suppression of equine immune responses by equine infectious anemia virus (EIAV). Suppression of the immune system is a common aspect of the disease pathogenesis associated with retroviral infections in both man and animals. We have measured transient suppression of the equine immune system as a loss or decrease in antigen-specific and polyclonal lymphocyte proliferation following experimental infection of ponies with three variants of equine infectious anemia virus (EIAV) with difference virulence characteristics. The transient suppression of proliferative responses was temporally associated with recurrent febrile episodes, which are the hallmark symptom of EIAV-induced di...
Stimulus generalization, discrimination learning, and peak shift in horses. Using horses, we investigated three aspects of the stimulus control of lever-pressing behavior: stimulus generalization, discrimination learning, and peak shift. Nine solid black circles, ranging in size from 0.5 in. to 4.5 in. (1.3 cm to 11.4 cm) served as stimuli. Each horse was shaped, using successive approximations, to press a rat lever with its lip in the presence of a positive stimulus, the 2.5-in. (6.4-cm) circle. Shaping proceeded quickly and was comparable to that of other laboratory organisms. After responding was maintained on a variable-interval 30-s schedule, stimulus generalizat...
Responses of cortisol and prolactin to sexual excitement and stress in stallions and geldings. Sexual stimulation induces rapid secretion of cortisol and prolactin (PRL) in stallions. Experiment 1 was designated to determine whether stallions associated location and(or) procedure with previous sexual stimulation in that location. After a control period on d 1, four stallions were exposed to an estrous mare for 5 min on d 2. On d 3, 4, 5, and 6, the same procedure was followed with no mare present. Concentrations of PRL and cortisol increased (P less than .05) after mare exposure on d 2 but did not vary (P greater than .05) on d 1, 3, 4, 5, or 6. In Exp. 2, six stallions were used to det...
Effects of steroid administration on pituitary luteinizing hormone and follicle-stimulating hormone in ovariectomized pony mares in the early spring: pituitary responsiveness to gonadotropin-releasing hormone and pituitary gonadotropin content. These experiments tested the hypothesis that administration of steroid hormones to ovariectomized (OVX) mares during the vernal transition to the breeding season would influence LH and FSH secretion. Circulating gonadotropin concentrations, response to exogenous GnRH, and pituitary gonadotropin content were monitored. Experiments 1 and 2 were conducted, beginning 10 March, and 3 February, respectively, utilizing a total of 30 long-term OVX pony mares. In experiment 1, mares were administered vehicle (n = 5) or estradiol-17 beta (E2, n = 5, 5 mg/3 ml sesame oil), twice daily for 16 days. Blood ...
[The effectiveness of therapeutic horseback-riding in the treatment of chronic schizophrenic patients. Experimental results and clinical experiences]. After describing horse-riding as a facility in managing mentally ill patients, a program for chronic schizophrenic in-patients is presented. Clinical experience with this program and also results of a controlled study are reported. The therapeutic value and slope for horse-riding are discussed in relation to different diagnoses.
Assessment of histamine, bradykinin, prostaglandins E1 and E2 and carrageenin as vascular permeability agents in the horse. The vascular leakage induced by histamine, bradykinin, serotonin and prostaglandin E1 and E2 was assessed. The test agents were injected intradermally into the shaved thoracic skin of horses and the vascular leakage estimated either semi-quantitatively by recording the diameter of the lesions or by measuring the actual volume of extravasated plasma in microliters using iodine-125-labelled human serum albumin (125I-HSA) as a marker in the blood plasma. Using the latter method, the vascular leakage induced by carrageenin and the effect of coadministered prostaglandins E1 and E2 upon the vascular...
Pharmacodynamics and pharmacokinetics of miloxicam in the horse. The novel non-steroidal anti-inflammatory drug (NSAID) miloxicam was administered intravenously to six New Forest ponies at a dosage rate of 0.6 mg/kg in a two-part cross-over study. In each part, three horses received miloxicam and three were given a placebo preparation. The actions of miloxicam, compared to placebo, were assessed in a carrageenan-sponge model of acute inflammation. The rise in skin temperature over the site of the acute inflammatory reaction was less in treated ponies, but differences were not statistically significant. Concentrations of the enzymes acid phosphatase (AP) and...
Modification of the cutting thread technique for intestinal anastomoses using diathermy. The author has modified a surgical technique, which was originally developed at the turn of the century, for the aseptic establishment of an intestinal anastomosis. The principle of this technique, known as the "cutting thread" principle, was that a loop of thread was introduced into the lumen of each of two approximated loops of intestine. After suturing the two loops of intestine together around the intraluminal parts of the thread, the latter was used as a "wire-saw" to create a stoma between the two intestinal loops. The author modified the method in such a way that the cutting could be pe...
In vitro development of day-2 equine embryos co-cultured with oviductal explants or trophoblastic vesicles. This study compared the in vitro development of Day-2 equine embryos co-cultured with either trophoblastic vesicles or oviductal explants. Embryos were collected surgically from the oviducts of pony mares 2 d after ovulation and assessed for stage of development. Culture medium was Ham's F12 and Dulbecco's Modified Eagle's Medium (50:50 v/v) in a humidified atmosphere of 5% CO(2) in air at 38.5 degrees C with either trophoblastic vesicles or oviductal explants. The quality score of embryos was assessed daily. After 4 d in culture, embryos were stained (Hoechst 33342) and evaluated with epifluo...
[Year-round antibody profile of groups of horses of a herd kept in isolation after differently terminating use of an experimental viral combination vaccine]. The commercial vaccine "Resequin F Konz." devised against viral respiratory infections of horses contains the abortigenic Equine Herpesvirus-1 (EHV-1). Therefore we had used it in our protection project of the Austrian Lipizzaners+ primarily to prevent abortions. Taking into account the recent perception that for young horses the respiratory-pathogenic EHV-4 type is essential Behringwerke Marburg added this particular virus to their market product to produce a multicomponent experimental vaccine. We examined this vaccine for its antibody induction as well as their persistence against each of i...
Role of antibody to extracellular proteins of Rhodococcus equi in protection against R. equi pneumonia in foals. Rhodococcus equi produces two exoenzymes (REE), a cholesterol oxidase in large amounts and a phospholipase C, which cause lysis of sheep red blood cells (SRBC) sensitized with Staphylococcus aureus beta toxin. Two immunization studies were done in foals to determine the role of antibody to REE in protection against R. equi pneumonia. In the first study, three foals (mean age 10 days) were vaccinated four times at 2-week intervals with over 1 million units of partially purified exoenzymes (PREE). In the second study, three foals (mean age 19 days) were administered plasma from an adult horse va...
Effects of hydroxyflutamide on rats treated with a superovulatory dose of pregnant mare serum gonadotropin. Immature female rats treated with superovulatory doses of pregnant mare serum gonadotropin (PMSG) were used to study the effects of the antiandrogen hydroxyflutamide on steroid production, particularly the biologically active androgens, in two experiments. In the first experiment, animals were given either 5 mg hydroxyflutamide or vehicle alone at 30 and 36 h following 40 IU PMSG. Compared with the vehicle group, hydroxyflutamide treatment significantly reduced the percentage of degenerate oocytes recovered from oviducts (p less than 0.05). Serum levels of testosterone and androstenedione, and...
Evaluation of progesterone deficiency as a cause of fetal death in mares with experimentally induced endotoxemia. The role of decreased luteal activity in embryonic loss after induced endotoxemia was studied in mares 21 to 35 days pregnant. Fourteen pregnant mares were treated daily with 44 mg of altrenogest to compensate for the loss of endogenous progesterone secretion caused by prostaglandin F2 alpha (PGF2 alpha) synthesis and release following intravenous administration of Salmonella typhimurium endotoxin. Altrenogest was administered daily from the day of endotoxin injection until day 40 of gestation (group 1; n = 7), until day 70 (group 2; n = 5), or until day 50 (group 3; n = 2). In all mares, secr...
Biochemical study of repair of induced osteochondral defects of the distal portion of the radial carpal bone in horses by use of periosteal autografts. Periosteal autografts were used for repair of large osteochondral defects in 10 horses aged 2 to 3 years old. In each horse, osteochondral defects measuring 1.0 x 1.0 cm2 were induced bilaterally on the distal articular surface of each radial carpal bone. Control and experimental defects were drilled. Periosteum was harvested from the proximal portion of the tibia and was glued into the principal defects, using a fibrin adhesive. Control defects were glued, but were not grafted. Sixteen weeks after the grafting procedure, the quality of the repair tissue of control and grafted defects was asse...
Pulsed radio frequency therapy of experimentally induced arthritis in ponies. The effect of pulsed radio frequency therapy (PRFT) was evaluated on seven ponies with no arthritis and in 28 ponies in which arthritis was created using intra-articular amphotericin B to induce synovitis in the right middle carpal joint. The ponies were divided into five treatment and two control groups. Two levels of arthritis were created and two dosage levels of PRFT were evaluated. The effect of PRFT on arthritic and nonarthritic joints was measured by comparing synovial fluid parameters, the degree and duration of lameness, the range of carpal motion, and carpus circumference, for treate...
