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.
Kravets ID, Garin NS, Krutovskikh AV, Volkovoĭ KI, Fedorov VL.The authors present the results of studies on obtaining and comparative assessment of experimental anthrax diagnostic sera in experiments on various animals. Donkeys, sheep, horses, rabbits and monkeys (Papio hamadryas) were immunized with the STI-I vaccine by a single scheme. The activity of the obtained sera was tested in the diffuse precipitation reaction by the amount of the detected antibodies and the titre. The most active sera were obtained from donkeys and sheep: their titre was 5.5 and 4 times greater and amount of the detected antibodies 2.6--2 times greater than in the sera of horse...
Krook L, Whalen JP, Lesser GV, Berens DL.Nutritional secondary hyperparathyroidism (NSH) defines a spontaneous and experimental disease in most domesticated and in some wild animals, caused by dietary calcium deficiency and/or phosphorus excess. Calcium deficiency results directly in hypocalcemia, and phosphorus excess induces hyperphosphatemia which causes hypocalcemia. Secondary hyperparathyroidism thus results and the plasma parameters return to normal and are maintained but only at the expense of progressive bone loss. The bone loss is generalized but the bones are not uniformly affected. The hierarchy of bone loss is, in decreas...
Douglas RH, Ginther OJ.Nine groups of pony mares (3/group) were used in a 3 times 3 factorial experiment. The factors were dose of PGF-2 alpha (0, 0.25 of 1.25 mg and route of administration (im, iu or il). Mares were laparotomized and treated on day 7 postovulation. Jugular blood was collected for progesterone RIA at 0 (pretreatment) and 1,6,12,24,48, and 72 hr posttreatment. In mares given either 0.25 mg or 1.25 mg PGF-2alpha, progesterone concentrations were not significantly different among the three routes at any of the posttreatment times studied except at 6 hr posttreatment. In mares given 0.25 mg, progestero...
Augustinsson KB, Bartfai T, Mannervik B.The steady-state kinetics of the butyrylcholinesterase-catalysed hydrolysis of butyrylthiocholine and thiophenyl acetate were shown to deviate from Michaelis-Menten kinetics. The ;best' empirical rate law was selected by fitting different rate equations to the experimental data by non-linear regression methods. The results were analysed in view of two alternative interpretations: (1) the reaction is catalysed by a mixture of enzymes, or (2) the activity is due to a single enzyme displaying deviations from Michaelis-Menten kinetics. It was concluded that the second alternative applies, and this...
Williams MR.Rats were injected intradermally with rabbit anti-ovalbumin serum and 3 hours later were challenged intravenously with ovalbumin and Evans Blue dye. Inflammatory lesions were produced within 20 minutes and their size was markedly dose-dependent. Attempts were made to interfere with this passive cutaneous anaphylaxis (PCA) by admixture of normal IgG with the rabbit anti-ovalbumin to measure the relative tissue binding affinities of IgG from various species. It was found that normal IgG from any of the species tested had an enhancing effect on PCA in rats. These immunoglobulins serially arranged...
Hoy TG, Harrison PM, Shabbir M, Macara IG.The rate of release of iron to 1,10-phenanthroline from ferritin fractions of different iron contents has been studied. The experimental results could be interpreted by a simple hypothetical model of the shape of the hydrous ferric oxide micelle at different iron contents, and reasonable correlation obtained between the rate of release and the calculated micelle surface areas. Initial rates of release did not correlate significantly with protein concentration.
Thoburn R, Hurvitz AI, Kunkel HG.Various mammalian species contain an anionic serum protein that reacts specifically with native DNA. It is considerably less reactive with single-strand DNA and does not react with monodeoxyribonucleotides, homopolyribonucleotides, or duplexes of homopolyribonucleotides. Synthetic dA.dT was an effective inhibitor of the reaction with native DNA, while Micrococcus luteus DNA and dG.dC were not inhibitory. This protein was encountered in the course of studies on DNA antibodies. Although it reacted with red cells coated with DNA and gave agar precipitation bands, it was clearly distinct from DNA ...
Carrier SP, Bannister GL, Boulanger P.Twenty-nine lots of acetone-ether extracted liquid antigen were prepared from the pulp of 11 spleens collected from horses at the acute phase of experimental infection. The lots prepared from the highly reactive pulp resulted in general in a liquid antigen of greater activity than those extracted from weakly reactive pulps. Some variations in activity between lots of antigen prepared from the same spleen were also observed. No matter what the results, given a wide enough variation, all results were reproducible. The procedure permitted production of a greater number of antigen test doses from ...
Seo JP, Yamaga T, Tsuzuki N, Yamada K, Haneda S, Furuoka H, Sasaki N.To compare the biomechanical properties of a 5-hole 4.5 mm narrow locking compression plate (LCP) and 5-hole 4.5 mm narrow dynamic compression plate (DCP) for equine proximal interphalangeal (PIP) joint arthrodesis. Methods: Experimental mechanical study. Methods: Cadaveric adult equine forelimbs (n = 6 pair). Methods: For each forelimb pair, 1 PIP joint was stabilized with LCP and the contralateral PIP joint with DCP. The 6 construct pairs were tested using a single-cycle, 3-point dorsopalmar bending system. PIP joints were evaluated with pre- and post-test radiography. Results: The L...
Page P, Ganswindt A, Schoeman J, Venter G, Guthrie A.African horse sickness (AHS) is of importance to health and international trade in horses worldwide. During export from and transit through AHS endemic countries or zones, physical and chemical measures to protect horses from the vectors of AHS virus (AHSV) are recommended by the World Organization for Animal Health. Protection of containerized air transport systems for horses (jet stalls) with alphacypermethrin insecticide-treated high density polyethylene mesh is effective in reducing the Culicoides midge vector attack rate. In order to determine the effect of this mesh on jet stall ventilat...
Burrows GE.Phenylbutazone (PBZ), a classic anti-inflammatory and prostaglandin-synthesis inhibitor drug, was used to determine the role of prostaglandins and other mediators on the development and perpetuation of the response to intraperitoneal Escherichia coli endotoxin administration. The PBZ (15 mg/kg of body weight) was administered IV 30 minutes after endotoxin administration and was repeated later at 6 and 12 hours at a dose of 10 mg/kg. A variety of evaluation measurements (hematologic, blood glucose, pyruvate, lactate and fibrinogen, serum beta-glucuronidase, prothrombin time, blood gases, hepati...
Tadros EM, Frank N, Newkirk KM, Donnell RL, Horohov DW.The role of endotoxemia in the development of laminitis remains unclear. Although systemic inflammation is a risk factor for laminitis in hospitalized horses, experimental endotoxin administration fails to induce the disease. While not sufficient to cause laminitis by itself, endotoxemia might predispose laminar tissue to damage from other mediators during systemic inflammation. In "two-hit" models of organ damage, sequential exposure to inflammatory stimuli primes the immune system and causes exaggerated inflammatory responses during sepsis. Acute laminitis shares many characteristics with se...
García-Tamayo J.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 ...
Murray JA, Longland AC, Moore-Colyer MJ, Dunnett C.A series of experiments was conducted to determine the effects of a fibrolytic enzyme preparation (enzyme 1; E1) on the in vitro fermentation of lucerne incubated with equine faecal inocula. In experiment 1, high-temperature-dried (HT) lucerne was treated with five levels of E1 (0 to 2.4 ml/g DM) and incubated at 50 degrees C for 20 h. Samples then received a simulated foregut digestion (SFD) treatment before DM and NSP analysis. In experiment 2, HT lucerne was treated with the same enzyme levels used in experiment 1. Samples were then split into two groups; plus or minus an SFD treatment befo...
Mumford EL, Squires EL, Jasko DJ, Nett TM.A lack of pituitary LH stores has been implicated as the cause of seasonal anestrus and failure to ovulate during the spring transition period in mares. In this experiment, 40 mares were used to study the effects of GnRH, estrogen, and an estrogen-GnRH combination on increasing releasable pituitary LH. Mares were stratified based on their ability to secrete LH in response to a 950-micrograms challenge of GnRH (n = 10 per group) and then assigned to one of four treatment groups: 1) controls, given no treatment; 2) 1 mg of estradiol-17 beta in oil i.m. daily for 8 d; 3) 200 micrograms of GnRH an...
Johnson JA, Prescott JF, Markham RJ.The intragastric inoculation of a suspension of Corynebacterium equi on five consecutive days induced severe ulcerative colitis, typhlitis, and lymphadenitis of colonic and cecal nodes in two ponies necropsied three weeks after infection. No gross lesions were observed in two ponies necropsied ten days after infection. A single inoculum of equivalent size failed to induce gross lesions in four ponies killed at ten or 20 days after infection. Microscopic lesions consistent with early C. equi infection of Peyer's patches were seen in two of the ponies killed ten days after infection. Only one sm...
Dinger JE, Noiles EE.Eight sexually inexperienced, 2-yr-old Morgan stallions were used in a consecutive two-phase design with two groups of four stallions each. Each phase lasted 16 wk, with semen collections every 14 d. Libido scores were assigned to stallions during each semen collection. Scores ranged from zero to four, with zero indicating minimum and four representing maximum libido. In Phase 1, four stallions received daily forced exercise for 16 wk, and the remaining four stallions were confined to box stalls. In Phase 2, the previously exercised stallions were confined to box stalls, and the non-exercised ...
Jacobi S, Townsend WM, Bolin CA.To evaluate whether equine serum administered via a simulated subpalpebral lavage system (SPL) supports proliferation of Streptococcus zooepidemicus or Pseudomonas aeruginosa within the tubing. Methods: A sterile i.v. catheter with injection cap was inserted into sterilized silicone tubing (Mila). To mimic an SPL within the dorsal conjunctival fornix, the tubing was secured to an elevated platform. The tip of the tubing extended from the platform into a vial containing culture medium just inoculated with approximately 1.5 x 10(8) CFU/mL P. aeruginosa or S. zooepidemicus. To mimic administratio...
Easter JL, Hague BA, Brumbaugh GW, Nguyen J, Chaffin MK, Honnas CM, Kemper DL.To evaluate the effect of peritoneal lavage on pharmacokinetics of gentamicin sulfate in healthy horses after experimental celiotomy. Methods: 13 clinically normal horses. Methods: Horses were randomly assigned to control or experimental groups. All horses received gentamicin (6.6 mg/kg of body weight, IV, q 24 h) before surgery, underwent experimental abdominal surgery, and had abdominal drains placed percutaneously. Horses of the experimental group received postoperative peritoneal lavage; horses of the control group did not receive peritoneal lavage. The day after surgery, 24 hours after th...
Lyons VN, Townsend WM, Moore GE, Liang S.Amniotic membrane extract enhances the rate of epithelialisation after corneal ulceration in several species but has not been studied in the equine cornea. Objective: To evaluate the effect of amniotic membrane extract on re-epithelialisation of equine corneal ulcers compared with ulcers treated with antibiotic, antifungal and mydriatic medical therapy alone, and to evaluate equine corneal healing after experimentally induced superficial ulceration. Methods: Masked, randomised, controlled experimental trial. Methods: Superficial, 8 mm corneal ulcers were created bilaterally in each horse. One...
Palmer JE, Benson CE, Lotz GW.Ten healthy, mature ponies were orally infected with Ehrlichia risticii using Ehrlichia-infected P388D1 mouse monocyte tissue culture cells. Seven developed signs of equine ehrlichial colitis including fever, depression, anorexia, reduced borborygmi, increased abdominal hyperresonance, and diarrhoea. Three remained clinically normal apart from early fever in one. Indirect fluorescent antibody titres were detected in the clinically affected ponies by Days 12 to 17 post infection and increased rapidly to high levels (1:640 to 1:5120) which were maintained until the end of the observation period ...
Russell MA, Rodiek AV, Lawrence LM.The effects of meal frequency and fasting on selected plasma free amino acids (PFAA) was studied in horses. Six 22-mo-old Quarter Horses were used in a replicated 3 X 3 Latin-square design in which each horse received one meal per day (1M), two meals per day (2M) or six meals per day (6M) for 2 wk. A complete pelleted ration was fed at a rate of 1.75% of body weight daily. The consumption of a meal by the horses fed 1M and 2M daily was followed by an increase (P less than .05) in plasma methionine. The highest levels were observed at 5 h and 3 h in the 1M and 2M treatments, respectively. The h...
Wehrenberg WB, Fowler S, Kurhajec J, Hutz RJ.Forty-four female ranch mink, maintained out-of-doors under standard conditions, were exposed to natural photoperiod supplemented with a period of artificial light from approximately 2300 hr to 0300 hr from early January to mid February. Breeding was initiated on March 1. After repeated attempts to breed the animals, it was determined that the likelihood of their breeding was very low, presumably due to the artificial and asynchronous long-day photoperiod. In an attempt to induce breeding, the mink were randomly assigned to one of four treatment groups: saline, 25 International Units (IU) PMSG...
Kindahl H, Daels P, Odensvik K, Daunt D, Fredricksson G, Stabenfeldt G, Hughes JP.Three different routes of administering Salmonella typhimurium endotoxin to mimic naturally occurring endotoxaemia were tried in the mare. Bolus injection, repeated bolus injections and continuous low-dose infusion were compared with prostaglandin F2 alpha release, leucocyte count and clinical response. A biphasic prostaglandin release and a pronounced leucopenia of almost identical patterns were seen in all models. Repeated bolus injections showed that the second injection initiated only a small prostaglandin release indicating the development of refractoriness to the treatment. A similar ref...
Dobler D, Gerber M, Schmidts TM, Runkel F, Schlupp P.Human nail diseases, mostly caused by fungal infections, are common and difficult to treat. The development and testing of new drugs and drug delivery systems for the treatment of nail diseases is often limited by the lack of human nail material for permeation studies. Animal material is frequently used, but there are only few comparative data on the human nail plate, and there is neither a standardized test design nor a nail bed analogue to study drug uptake into the nail. In this study, a new permeation device was developed for permeation studies, and the permeation behavior of three model s...
Roberts MC, Seawright AA.Colic was induced in horses and ponies following topical or intravenous (iv) administration of amitraz, a formamidine acaricide. The condition was characterised by rapid cessation of intestinal sounds, stasis, extensive impaction and tympany throughout the large colon. Three animals that were necropsied had a faecalith obstructing the proximal small colon aboral to marked colonic impaction. A reproducible and reversible impaction colic syndrome could be induced by an iv injection of 1 mg amitraz/kg body weight in solvent. There were immediate central nervous system and intestinal signs. Large ...
Pye JL, Garcia TC, Kapatkin AS, Samol MA, Stover S.To compare (1) performance of compact versus standard flute drill bits, (2) screw insertion properties and (3) pullout variables between interlocking thread (ITS) and buttress thread (BTS) self-tapping screws in third metacarpi. Methods: In vitro experimental study. Methods: Paired third metacarpi from 11 Thoroughbreds aged 2-4 years. Methods: Screws were inserted into the lateral condylar fossae following bone preparation using the respective drill bit for each screw type. Screw pullout was achieved using a mechanical testing system. Density and porosity of bone surrounding screw holes was ...
Schmall LM, Muir WW, Robertson JT.A comparison of the haemodynamic benefits of small volume hypertonic saline (2,400 mOsm/litre) versus isotonic saline (300 mOsm/litre) was conducted in 12 adult horses using a haemorrhagic shock model. The horses were anaesthetised and intravascular catheters placed for the measurement of haemodynamic data. Mean systemic arterial pressure was then reduced to 50 to 60 mmHg by controlled haemorrhage and maintained at that level for 40 mins. Cardiac output, stroke volume, mean systemic arterial pressure, plasma volume and urine production decreased significantly following blood loss. Hypertonic o...
Lees MJ, Fretz PB, Bowen CV, Leach DH.Equine limb wounds often heal slowly by epithelialization, and large scars are a frequent end result. In some ways, they resemble the wound associated with human tibial injuries. The literature indicates that previous investigators have failed to transfer free skin flaps successfully in the horse. In this paper, we review our experimental work with the deep circumflex iliac flap in the horse. Dissections of 20 cadavers confirmed the anatomical consistency of the flap. Four flaps survived well when elevated as island flaps, but five orthotopic and nine heterotopic free flap transfers all failed...
Scott WM, Fowler JD, Matte G, Allen AL, Wilkinson AA, Bailey JV, Fretz PB.To investigate neutrophil accumulation after ischemia and reperfusion (IR) in microvascular tissue flaps in horses. Methods: Randomized controlled experiment. Methods: A total of 8 horses between 1 and 10 years of age, 4 of each sex. Methods: Control and experimental myocutaneous island flaps based on the superficial branch of the deep circumflex iliac vessels were dissected on each horse. Atraumatic vascular clamps were applied to the pedicle of the experimental flap for 90 minutes and then removed to allow reperfusion. Based on the assumption that rapid infiltration of neutrophils into affec...
Jonsdottir S, Hamza E, Janda J, Rhyner C, Meinke A, Marti E, Svansson V, Torsteinsdottir S.Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by bites of midges (Culicoides spp.). IgE-mediated reactions are often involved in the pathogenesis of this disease. IBH does not occur in Iceland due to the absence of Culicoides, but it occurs with a high frequency in Icelandic horses exported to mainland Europe, where Culicoides are present. We hypothesize that immunization with the Culicoides allergens before export could reduce the incidence of IBH in exported Icelandic horses. The aim of the present study was therefore to compare intradermal and intralymphatic ...
Tshewang U, Dowsett KF, Knott LM, Trigg TE.To investigate the effects of two doses (200 and 400 mg) of a water-soluble gonadotrophin-releasing hormone vaccine on the ovarian activity of 2-year-old fillies. Methods: A controlled vaccination dose rate experiment. Methods: Six 2-year-old Australian Stock Horse fillies were randomly allocated to three treatment groups; unvaccinated controls, those receiving 200 mg of the vaccine and those receiving 400 mg of the vaccine. Results: Ovarian activity of the treated fillies was suppressed at the peak of breeding season while that of untreated controls continued normally. The control fillies dis...
Wada R, Fukunaga Y, Kanemaru T, Kondo T.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...
Hilbert BJ, Rowley G, Antonas KN, McGill CA, Reynoldson JA, Hawkins CD.Sodium hyaluronate was injected into normal horse joints and joints that had undergone an arthrotomy and experimental cartilage damage. The elimination half-life for hyaluronic acid in normal joints was found to be approximately 96 h. The injection caused a non-significant increase (42%) in synovial fluid protein concentration and a fall in the intrinsic viscosity of the fluid. In the arthrotomy group the synovial fluid hyaluronic acid concentration fell after surgery but it was unaffected by the injection of sodium hyaluronate. An initial rise in the intrinsic viscosity of the synovial fluid ...
Johnson AL.A study was conducted to evaluate the effectiveness of gonadotropin-releasing hormone (GnRH) pulse infusion to stimulate follicular development and induce ovulation in seasonally anestrous standardbred mares. Seventeen mares were selected for use in this experiment, on the basis of a previous normal reproductive history, and were housed under a photoperiod of 8L:16D beginning one week prior to the start of the experiment (second week in January). Mares were infused with 20 micrograms (n = 7) or 2 micrograms (n = 6) GnRH/h, or were subjected to photoperiod treatment only (controls, n = 4). Seru...
Darien BJ, Stone WC, Dubielzig RR, Clayton MK.The morphologic changes following ascending colon volvulus result from the interaction of inflammatory and coagulation mediators. The objective of this study was to establish a quantifiable histopathologic scoring system to evaluate the serial pathomorphologic changes during ischemia and reperfusion. Such a scoring system could then be applied to subsequent studies designed to attenuate bowel lesions by regulating activity of individual mediators. Ten normal, healthy adult ponies were randomly divided into two equal groups. Following anesthesia and a 30-minute stabilization period, the colon o...
Quam VG, Altmann NN, Brokken MT, Durgam SS.Intrasynovial deep digital flexor tendon (DDFT) injuries occur frequently and are often implicated in cases of navicular disease with poor outcomes and reinjuries. Cell-based approaches to tendon healing are gaining traction in veterinary medicine and ultimately may contribute to improved DDFT healing in horses. However, a better understanding of the innate cellular characteristics of equine DDFT is necessary for developing improved therapeutic strategies. Additionally, fibrocartilaginous, intrasynovial tendons like the DDFT are common sites of injury and share a poor prognosis across species,...
Ball MA, Rebhun WC, Trepanier L, Gaarder J, Schwark WS.The objectives of this study were to determine the concentration of itraconazole achieved in corneal tissue and aqueous humour after topical application of a 1% itraconazole ointment: to determine the effect of including dimethyl sulphoxide (DMSO) in the ointment on achievable ocular tissue itraconazole concentrations; and to assess if any gross or histopathologic ocular toxicity results from the topical application of 1% itraconazole with or without the addition of DMSO. The experimental trial consisted of 6 horses considered to have normal eyes. Each horse had one eye treated with 0.3 mL of ...
