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.
Tharasanit T, Colleoni S, Galli C, Colenbrander B, Stout TA.Vitrifying oocytes is a potentially valuable means of preserving the female germ line, but significantly compromises oocyte developmental competence. This study examined the hypothesis that the cumulus complex protects the oocyte during vitrification. Vitrified-warmed immature cumulus oocyte complexes (COCs) were labelled with a plasma membrane impermeant DNA marker (ethidium homodimer-1) to examine the percentage and location of dead cumulus cells, and to investigate the effect of the proportion of dead cells (+1,+2 or +3) on the success of in vitro maturation (IVM). Further, oocytes were lab...
Lode A, Bernhardt A, Kroonen K, Springer M, Briest A, Gelinsky M.The application of bone graft substitutes with osteoinductive properties is of high importance for the repair of large bone defects. COLLOSS E, a protein lyophilizate extracted from equine long bones, exhibits an osteoinductive potential which has been proven in several studies. In this work, a mechanically stable, but biodegradable support for COLLOSS E has been developed aiming at a bone graft substitute that retains shape and size when coming in contact with body fluids. Mineralization of collagen type I, isolated from horse tendon, resulted in a stable collagen hydroxyapatite nanocomposite...
Sasaki N, Minami T, Yamada K, Yamada H, Inoue Y, Kobayashi M, Tabata Y.To evaluate the effect of intra-articular injection of gelatin hydrogel microspheres containing basic fibroblast growth factor (bFGF) on experimentally induced defects in third metacarpal bones (MC3s) of horses, in vivo. Methods: 6 healthy adult Thoroughbreds. Methods: Horses were anesthetized, and a hole (diameter, 4.5 mm) was drilled into the medial condyle of both MC3s of each horse. One milliliter (100 microg) of a solution of gelatin hydrogel microspheres (2 mg) containing bFGF was injected into the joint capsule of the right metacarpophalangeal joint of each horse (bFGF joint). One milli...
Whishaw IQ, Sacrey LA, Gorny B.An animal that has stepped over an obstacle with its forelimbs uses a memory of the obstacle to guide the hind limbs so that they also clear the obstacle, even in situations in which long pauses are introduced between forelimb and hind limb stepping. To further clarify the features of hind limb obstacle clearance memory, the present study examined hind limb obstacle clearance in the horse. A rider guided horses over obstacles and paused the horse over obstacles in tests that examined the relationship between forelimb and hind limb stepping, with the following results. First, the horses display...
Brøkner C, Nørgaard P, Hansen HH.The ingestive and post-digestion effect of a blend of special essential oil compounds (EO) on eating, chewing and faecal parameters were measured in horses. Ingestive effects appear after no adaptation. Post-digestion effects appear after adaptation. Six Icelandic horses were assigned to two groups in a Latin Square subplot design with EO treatments to four different roughage types and four different concentrates. The horses were fed four different roughage meals and two different concentrate meals on each of the four sampling days. Eating time and saliva were observed during meals. Jaw moveme...
Bailey SR, Adair HS, Reinemeyer CR, Morgan SJ, Brooks AC, Longhofer SL, Elliott J.The link between the fermentation of carbohydrate in the equine large intestine and the development of acute laminitis is poorly understood. Absorption of endotoxin (lipopolysaccharide; LPS) into the plasma has been observed in one experimental model of laminitis, but does not cause laminitis when administered alone. Thus, the potential role of endotoxin is unclear. Platelet activation has previously been demonstrated in the developmental stage of laminitis. Equine platelets are more sensitive than leukocytes to activation by endotoxin, and can be activated directly by LPS in the low pg/ml ran...
Witonsky SG, Ellison S, Yang J, Gogal RM, Lawler H, Suzuki Y, Sriranganathan N, Andrews F, Ward D, Lindsay DS.Equine protozoal myeloencephalitis (EPM) due to Sarcocystis neurona infection is 1 of the most common neurologic diseases in horses in the United States. The mechanisms by which most horses resist disease, as well as the possible mechanisms by which the immune system may be suppressed in horses that develop EPM, are not known. Therefore, the objectives of this study were to determine whether horses experimentally infected with S. neurona developed suppressed immune responses. Thirteen horses that were negative for S. neurona antibodies in serum and cerebrospinal fluid (CSF) were randomly assig...
Vannella KM, Moore BB.Idiopathic pulmonary fibrosis (IPF) remains exactly that. The disease originates from an unknown cause, and little is known about the mechanisms of pathogenesis. While the disease is likely multi-factorial, evidence is accumulating to implicate viruses as co-factors (either as initiating or exacerbating agents) of fibrotic lung disease. This review summarizes the available clinical and experimental observations that form the basis for the hypothesis that viral infections may augment fibrotic responses. We review the data suggesting a link between hepatitis C virus, adenovirus, human cytomegalo...
Lemos KR, Marques LC, Aquino LP, Alessi AC, Zacarias RZ.This study aimed to characterize astrocytic and microglial response in the central nervous system (CNS) of equines experimentally infected with T. evansi. The experimental group comprised males and females with various degrees of crossbreeding, ages between four and seven years. The animals were inoculated intravenously with 10(6) trypomastigotes of T. evansi originally isolated from a naturally infected dog. All equines inoculated with T. evansi were observed until they presented symptoms of CNS disturbance, characterized by motor incoordination of the pelvic limbs, which occurred 67 days aft...
Garré B, Gryspeerdt A, Croubels S, De Backer P, Nauwynck H.The purpose of the current study was to investigate the therapeutic efficacy of valacyclovir against EHV1 in a controlled study. Eight naïve Shetland ponies were inoculated with 10(6.5) TCID(50) of the neuropathogenic strain 03P37. Four ponies were treated with valacyclovir at a dosage of 40mg/kg bodyweight, 3 times daily, for 5 (n=2) or 7 (n=2) consecutive days, while the other four ponies served as untreated controls. The treatment regimen started 1h before inoculation. Ponies were monitored daily for clinical signs. At 0, 1, 2, 3, 4, 5, 7, 9, 11, 14, 17 and 21 days post inoculation (d pi),...
MacKay RJ.The aim of the current study was to quantify sweating responses to intradermal terbutaline in normal horses. Seven Thoroughbred horses were used. Terbutaline (10-fold dilutions from 1000-0.001 mg/l) and a saline control were injected intradermally (0.1 ml/site) and sweat collected for 30 min into absorbent pads taped over each injection site. Tests were performed monthly for 11 successive months and temperature, relative humidity and dewpoint were measured at the time of testing. There was no significant effect (P<or=0.05) of environmental variables or time of year on sweat responses at any...
Muhonen S, Connysson M, Lindberg JE, Julliand V, Bertilsson J, Jansson A.The objective of this study was to investigate the effect of CP intake from 2 grass silage-only diets, differing in CP concentration, fed at similar DMI on the equine colon ecosystem after an abrupt feed change between the diets. Four adult right ventral colon-fistulated geldings were fed one silage-only diet high in CP (HP, 873 g of CP/d) and one diet providing recommended intakes (RP, 615 g of CP/d). An adaptation period of 15 d on either the HP or the RP diet was followed by 2 experimental periods when the diets were fed for 22 d each in a crossover design. Colon samples were taken before a...
Pollock S, Stover SM, Hull ML, Galuppo LD.The first objective of this study was to experimentally determine surface bone strain magnitudes and directions at the donor site for bone grafts, the site predisposed to stress fracture, the medial and cranial aspects of the transverse cross section corresponding to the stress fracture site, and the middle of the diaphysis of the humerus of a simplified in vitro laboratory preparation. The second objective was to determine whether computing strains solely in the direction of the longitudinal axis of the humerus in the mathematical model was inherently limited by comparing the strains measured...
Huang L, Zhu W, Saunders CP, Macleod JN, Zhou M, Stromberg AJ, Bathke AC.Identification of biomarkers among thousands of genes arrayed for disease classification has been the subject of considerable research in recent years. These studies have focused on disease classification, comparing experimental groups of effected to normal patients. Related experiments can be done to identify tissue-restricted biomarkers, genes with a high level of expression in one tissue compared to other tissue types in the body. Results: In this study, cartilage was compared with ten other body tissues using a two color array experimental design. Thirty-seven probe sets were identified as...
Shibeshi W, Abraham G, Kneuer C, Ellenberger C, Seeger J, Schoon HA, Ungemach FR.Culture of airway epithelial cells is a useful model to investigate physiology of airway epithelia and airway disease mechanisms. In vitro models of airway epithelial cells are established for various species. However, earlier published method for isolation and culture of equine tracheal epithelial cells requires significant improvements. In this report, the development of a procedure for efficient isolation, characterization, culture, and passage of primary equine tracheal epithelial cells are described. Epithelial cells were isolated from adult equine trachea by exposing and stripping the mu...
Heleski C, Bauson L, Bello N.Horse training often relies upon negative reinforcement (NR). This study tested the hypothesis that adding positive reinforcement (PR) to NR would enhance learning in horses (n = 34) being taught to walk over a tarp (novel/typically frightening task). Subjects were Arabians, and the same person handled all of them. This person handled half "traditionally" (NR only)--that is, halter/lead were pulled; when horse stepped forward, pressure was released; process repeated until criterion met (horse crossed the tarp with little/no obvious anxiety). The same person handled the other half traditionally...
Waite JA, Love CC, Brinsko SP, Teague SR, Salazar JL, Mancill SS, Varner DD.Two experiments were conducted to investigate modifications in cushioned centrifugation of stallion semen. Specifically, the effects of tube type, centrifugation medium, cushion type, and centrifugation force on post-centrifugation sperm recovery rate and quality were evaluated. In Experiment 1, sperm recovery rate was higher (P<0.05) in conventional plastic conical-bottom tubes (103%) than in newly developed glass nipple-bottom tubes (96%) following cushioned centrifugation; however, several measures of semen quality (i.e., % total motility [MOT], % progressive motility [PMOT], curvilinear...
Vinardell T, David F, Morisset S.To describe a direct arthroscopic approach to the suprapatellar pouch (SPP), its intra-articular anatomy, and report our clinical experience with SPP arthroscopy. Methods: (1) Experimental study and (2) retrospective clinical study. Methods: (1) Cadaveric equine hind limbs (n=24; 14 horses) and (2) 5 horses. Methods: Four femoropatellar joints (FPJ) were dissected or injected with latex to document surface landmarks and topographic anatomy. (1) Arthroscopic exploration of 20 SPP (10 equine cadavers) was performed and described, followed by dissection. (2) Medical records of horses that had FPJ...
Clayton HM, White AD, Kaiser LJ, Nauwelaerts S, Lavagnino M, Stubbs NC.A lightweight bracelet that provides tactile stimulation to the horse's pastern and coronet induces a higher flight arc of the hoof. This study addresses the pattern of habituation to these devices. Objective: To evaluate short-term habituation to tactile stimulation of the pastern and coronet in trotting horses. Methods: Tactile stimulation was provided by a lightweight (55 g) device consisting of a strap with seven chains that was attached loosely around the pastern. Reflective markers were fixed to the dorsal hoof wall, the forehead and over the tenth thoracic vertebra of eight sound horses...
Vandekerckhove A, Glorieux S, Broeck WV, Gryspeerdt A, van der Meulen KM, Nauwynck HJ.An in vitro model of the upper respiratory tract of the horse was developed to investigate mechanisms of respiratory diseases. Four tissues of the upper respiratory tract of three horses were collected. Explants were maintained in culture at an air-liquid interface for 96h. At 0, 24, 48, 72 and 96h of cultivation, a morphometric analysis was performed using light microscopy, scanning electron microscopy and transmission electron microscopy. The explants were judged on morphometric changes of epithelium, basement membrane and connective tissue. Viability was evaluated using a fluorescent Termin...
Araújo JA, Curcio B, Alda J, Medeiros RM, Riet-Correa F.Two outbreaks of Hypochaeris radicata-induced Australian stringhalt involving two farms and seven horses from southern Brazil are reported here. Subsequently, the disease was experimentally reproduced in a feeding trial with one colt fed H. radicata from the suspect paddocks. Fresh H. radicata was fed to the experimental animal for 50 days at an average daily dosage of 9.8 kg. Initially, the plant was collected from the paddock where the clinical disease occurred and was fed for 19 consecutive days producing mild clinical signs. However, on days 20-23 fresh plant was collected from a neighbori...
Cheetham J, Witte TH, Rawlinson JJ, Soderholm LV, Mohammed HO, Ducharme NG.The success of laryngoplasty is limited by abduction loss in the early post operative period. Objective: To determine the efficacy of polymethylmethacrylate (PMMA) in stabilising the cricoarytenoid joint (CAJ) and reducing the force on the laryngoplasty suture. Objective: Injection into the cricoarytenoid joint resists the forces produced by physiological laryngeal air flows and pressures thereby reducing the force experienced by the laryngoplasty suture. Methods: Ten cadaver larynges were collected at necropsy and PMMA was injected into one CAJ at selected random. Each larynx was subjected to...
Sod GA, Mitchell CF, Hubert JD, Martin GS, Gill MS.To compare monotonic biomechanical properties and fatigue life of a 5.5 mm broad limited-contact dynamic compression plate (5.5-LC-DCP) fixation with a 4.5 mm broad LC-DCP (4.5-LC-DCP) fixation to repair osteotomized equine third metacarpal (MC3) bones. Methods: In vitro biomechanical testing of paired cadaveric equine MC3 with a mid-diaphyseal osteotomy, stabilized by 1 of 2 methods for fracture fixation. Methods: Adult equine cadaveric MC3 bones (n=18 pair). Methods: MC3 were divided into 3 test groups (6 pairs each) for: (1) 4-point bending single cycle to failure testing; (2) 4-point bendi...
Lemos KR, Marques LC, Deaquino LP, Alessi AC, Machado RZ.An histochemical and immunohistochemical study was carried out to evaluate the mechanisms of immune response of horses experimentally infected by Trypanosoma evansi. For this purpose the HE histochemical stain and the avidin biotin peroxidase method were used. To determine the presence and immunoreactivity of immune cells we used anti-major histocompatibility complex II antibodies. Cellular infiltration phenotype was characterized with the aid of anti-CD3 antibody for T lymphocytes and by anti-BLA 36 antibodies for B lymphocytes. Macrophages were marked with an antibody against myeloid/histyoc...
Polyak MM, Morton AJ, Grosche A, Matyjaszek S, Freeman DE.Several therapeutic agents have been tested in models of ischaemia and reperfusion injury (IRI) in equine jejunum, with mixed results. This study was based on the use of an organ perfusion solution (OPS) designed to protect human allografts from IRI. Objective: A modified OPS can preserve the integrity of equine large colon during 12 h of isolated pulsatile perfusion, in the absence of oxygen and blood. Methods: Segments of large colon were removed from anaesthetised horses, the contents removed and the mucosa rinsed with 0.9% saline. Experimental segments were perfused for 12 h with one litre...
Assis RA, Kuchler IL, Miekeley N, Tozzi MB.Capillary electrophoresis coupled to inductively coupled plasma mass spectrometry was used in a speciation study on disodium monomethylarsonate (DS-MMA(V)) and its metabolites in horses, to which the drug was administered by intramuscular injection on five consecutive days at a single arsenic dosage of 270 mg day(-1). Samples of urine, whole blood, plasma, and mane hair were analyzed before, during, and after drug administration. The data show that blood clearing and urinary excretion of MMA is a fast process following first-order kinetics with biological half-lives of about 38 h and 44 h for ...
Heskett KA, Mackay RJ.To investigate the use of a specific antibody index (AI) that relates Sarcocystis neurona-specific IgG quotient (Q(SN)) to total IgG quotient (Q(IgG)) for the detection of the anti-S neurona antibody fraction of CNS origin in CSF samples obtained from horses after intragastric administration of S neurona sporocysts. Methods: 18 adult horses. Methods: 14 horses underwent intragastric inoculation (day 0) with S neurona sporocysts, and 4 horses remained unchallenged; blood and CSF samples were collected on days - 1 and 84. For purposes of another study, some challenged horses received intermitten...
Mackay RJ, Tanhauser ST, Gillis KD, Mayhew IG, Kennedy TJ.To evaluate the effect of intermittent oral administration of ponazuril on immunoconversion against Sarcocystis neurona in horses inoculated intragastrically with S neurona sporocysts. Methods: 20 healthy horses that were seronegative for S neurona-specific IgG. Methods: 5 control horses were neither inoculated with sporocysts nor treated. Other horses (5 horses/group) each received 612,500 S neurona sporocysts via nasogastric tube (day 0) and were not treated or were administered ponazuril (20 mg/kg, PO) every 7 days (beginning on day 5) or every 14 days (beginning on day 12) for 12 weeks. Bl...
Karasiewicz J, Andrzej-Modlinski J.Our Department of Experimental Embryology originated from The Laboratory of Embryo Biotechnology, which was organized and directed by Dr. Maria Czlonkowska until her premature death in 1991. Proving successful international transfer of frozen equine embryos and generation of an embryonic sheep-goat chimaera surviving ten years were outstanding achievements of her term. In the 1990s, we produced advanced fetuses of mice after reconstructing enucleated oocytes with embryonic stem (ES) cells, as well as mice originating entirely from ES cells by substitution of the inner cell mass with ES cells. ...
Iniesta J, Cooper HJ, Marshall AG, Heptinstall J, Walton DJ, Peterson IR.The iodination of proteins remains a useful tool in biochemistry for radiolabelling. However, chemical or enzymatic iodination is difficult to control and can give deleterious polyiodination. Previously, we have shown that electrooxidation with nitrite is a rapid method for the selective nitration of tyrosine residues in proteins. In principle, it should be possible to substitute a number of electrooxidisable anions into the tyrosine phenol ring. Electrochemical iodination is more difficult to control than nitration because the rapid anodic oxidation of I(-) leads to persistent formation of th...
Lavin TE, Nielsen BD, Zingsheim JN, O'Connor-Robison CI, Link JE, Hill GM, Shelton J.An experiment was conducted to study P digestibility in mature horses because of the growing environmental concerns regarding P runoff and previous equine research focused mostly on young and growing animals or used ponies as a model. Phytase supplementation of swine and poultry diets can result in greater phytate-P digestibility, leading to a decreased need for inorganic P supplementation and a decrease in P excreted to the environment; this, however, has not been demonstrated in the horse. Six mature Arabian geldings were fed 6 diets consisting of pelleted concentrate and alfalfa hay. The co...
Seiler GS, Campbell N, Nixon B, Tsuruta JK, Dayton PA, Jennings S, Redding WR, Lustgarten M.Vascular alterations play important roles in many orthopedic diseases such as osteoarthritis, tendonitis, and synovitis in both human and equine athletes. Understanding these alterations could enhance diagnosis, prognosis, and treatment. Contrast-enhanced ultrasound (CEUS) could be a valuable method for evaluation of blood flow and perfusion of these processes in the equine distal limb, however no reports were found describing feasibility or safety of the technique. The goal of this prospective, experimental study was to describe the feasibility and safety of distal limb CEUS in a sample of si...
Gabor V, Gerken M.Numerical competence is one of the aspects of animal cognition with a long history of research interest, but few results are available for the horse. In the present study, we investigated the ability of three Shetland ponies to discriminate between different quantities of geometric symbols presented on a computer screen in a matching-to-sample arrangement. In Experiment 1, the ponies had to relate two similar quantities to another, paired in contrasts (1 vs. 2, 3 vs. 4 and 4 vs. 5) of the same stimulus (dot). Specific pairs of quantities (all differing by one) of up to five different geometric...
Miyamoto A, Obi T, Nishio A.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....
Kappel S, Ramirez Montes De Oca MA, Collins S, Herborn K, Mendl M, Fureix C.The use of 2-dimensional representations (e.g. photographs or digital images) of real-life physical objects has been an important tool in studies of animal cognition. Horses are reported to recognise objects and individuals (conspecifics and humans) from printed photographs, but it is unclear whether image recognition is also true for digital images, e.g. computer projections. We expected that horses trained to discriminate between two real-life objects would show the same learnt response to digital images of these objects indicating that the images were perceived as objects, or representation...
Canisso IF, Loux S, Scoggin KE, Squires EL, Troedsson MH, Ball BA.Characterisation of fetal fluids in healthy and disease states of pregnant mares can help to unravel the pathophysiology and to identify putative markers of disease. Thus, this study aimed to compare the protein composition of: (1) amniotic and allantoic fluids of healthy mares obtained immediately after euthanasia and (2) allantoic fluid harvested via centesis before and after experimental induction of placentitis via transcervical inoculation of Streptococcus equi ssp zooepidemicus in healthy mares. Fetal fluids were analysed with a high-throughput proteomic technique after in-gel digestion....
Read EK, Chandler D, Wilson DG.To compare the biomechanical characteristics and mode of failure of 2 techniques using parallel 5.5 mm screws for pastern joint arthrodesis in horses. Methods: Randomized block design, for horse (1-5), method of fixation (two 5.5 mm screws versus three 5.5 mm screws), side (right, left), and end (front, hind). Constructs were tested to failure in 3-point bending. Methods: Twenty limbs (5 cadavers). Methods: A combined aiming device was used to facilitate screw placement. Two parallel 5.5 mm screws were inserted in lag fashion in 1 limb of a pair, and three 5.5 mm screws were inserted in the co...
Wohlsein P, Pohlenz JF, Davidson FL, Salt JS, Hamblin C.The distribution of viral antigen was studied in various tissues of three ponies, aged 3-4 years, infected experimentally with a virulent strain of African horse sickness virus (AHSV) serotype 4. Tissues were collected from the animals in the terminal stage of the peracute form of the disease and from one noninfected horse, included as a control. A polyclonal antibody with specificity for AHSV, plus the nonstructural protein NS2, was used in a sensitive avidin-biotin-peroxidase-complex (ABC) method performed on formalin-fixed, paraffin-embedded tissue sections. AHSV antigen was located primari...
Gross S, Wilms D, Krause J, Brezesinski G, Andrä J.Equine sarcoid is a topically accessible model for the evaluation of anticancer peptides acting by physical membrane disruption avoiding the complexity of a systemic application. We aim at evaluating and improving natural peptides for host defence as lead structures, where we focus on the cationic and amphipathic peptide NK-2. Cytotoxicity tests, fluorescence microscopy and a chip-based biosensor, which enabled real-time monitoring of cell metabolism, were applied. Cancer cell killing was dynamic with an initial phase of increased cellular respiration, followed by membrane destruction. NK-2 wa...
MacMillan AP, Baskerville A, Hambleton P, Corbel MJ.Five mares, one stallion and a colt foal were inoculated intraconjunctivally with Brucella abortus strain 544. No clinical signs of disease developed except mild pyrexia. Intermittent bacteraemia was detected in the mares but not in the stallion or foal. Antibodies to B abortus became detectable from the second week after inoculation. Titres in the serum agglutination and complement fixation tests declined substantially after six to eight weeks but reactions to the Coombs antiglobulin, 2-mercaptoethanol and immunodiffusion tests were maintained. No consistent changes in biochemical or haematol...
Souza SS, Aguiar FLN, Alves BG, Alves KA, Brandão FAS, Brito DCC, Raposo RDS, Gastal MO, Rodrigues APR, Figueiredo JR, Teixeira DÍA, Gastal EL.Ovarian tissue transplantation methods using cooled and cryopreserved samples have been attractive options for fertility preservation in animal models and humans. The aim of this study was to evaluate the impact of previous exposure to cooling, cryopreservation, and VEGF on the overall efficiency of equine ovarian tissue after heterotopic xenotransplantation in mice. The end points evaluated were follicular morphology and development, follicular and stromal cell densities, angiogenesis (i.e. the density of new and mature blood vessels), collagen types I and III fiber densities, and total fibro...
Cleaver BD, Grubaugh WR, Davis SD, Sheerin PC, Franklin KJ, Sharp DC.Melatonin is thought to play a role in relaying photic information to the central nervous system as part of the seasonal reproductive cycle of the mare. However, the mechanisms by which melatonin may act are unknown. Therefore, this study was designed to determine whether exposure to constant light would, by reducing circulating melatonin concentrations, have any effect on hypothalamic gonadotrophin-releasing hormone (GnRH) content and circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Blood samples were collected for 12 h at 15-min intervals from 8 ovariect...
Grubb T, Edner A, Frendin JH, Funkquist P, Rydén A, Nyman G.To assess oxygenation, ventilation-perfusion (V/Q) matching and plasma endothelin (ET-1) concentrations in healthy horses recovering from isoflurane anaesthesia administered with or without pulse-delivered inhaled nitric oxide (iNO). Methods: Prospective experimental trial. Methods: Healthy adult Standardbred horses. Methods: Horses were anaesthetized with isoflurane in oxygen and placed in lateral recumbency. Six control (C group) horses were anaesthetized without iNO delivery and six horses received pulse-delivered iNO (NO group). After 2.5 hours of anaesthesia isoflurane and iNO were abrupt...
Clayton HM, White AD, Kaiser LJ, Nauwelaerts S, Lavagnino M, Stubbs NC.A lightweight bracelet that provides tactile stimulation to the horse's pastern and coronet induces a higher flight arc of the hoof. This study addresses the pattern of habituation to these devices. Objective: To evaluate short-term habituation to tactile stimulation of the pastern and coronet in trotting horses. Methods: Tactile stimulation was provided by a lightweight (55 g) device consisting of a strap with seven chains that was attached loosely around the pastern. Reflective markers were fixed to the dorsal hoof wall, the forehead and over the tenth thoracic vertebra of eight sound horses...
Lucas Castillo JA, Gozalo-Marcilla M, Werneck Fonseca M, Possebon FS, da Rosa AC, de Araujo Aguiar AJ.Information on appropriate protocols for sedation of Nordestino donkeys is scarce. Objective: To evaluate the sedative and cardiorespiratory effects of low doses of intravenous (i.v.) xylazine with and without acepromazine in 'Nordestino' donkeys. Methods: Seven healthy female Nordestino donkeys (150 ± 18 kg) were included in this blinded, randomised, crossover experiment. Methods: Four treatments were administered, consisting of two i.v. injections, at baseline (T0, 1st injection) and 15 min later (T15, 2nd injection). Treatments included acepromazine 0.05 mg/kg bwt + saline (AS), saline + x...
Fultz L, Giguère S, Berghaus LJ, Davis JL.Current labelling for the use of ceftiofur crystalline free acid (CCFA) in horses states that 2 i.m. doses must be administered 4 days apart to provide 10 days of therapeutic coverage. A 10 day treatment regimen is not sufficient for the long-term treatment of horses with severe lung consolidation or pleuropneumonia. There are currently no data to guide an appropriate dosing interval when a longer treatment regimen is warranted. Objective: To determine steady-state plasma and pulmonary epithelial lining fluid (PELF) concentrations of desfuroylceftiofur acetamide (DCA) after weekly i.m. adminis...
Maninchedda U, Lepage OM, Gangl M, Benredouane K.To (1) describe ultrasound-guided percutaneous introduction of a transarterial angiographic catheter into the common carotid artery (CCA); (2) investigate the feasibility of using angiography of the carotid arteries in the guttural pouch region and assess transarterial coil (TAC) placement into the internal carotid artery (ICA). Methods: Experimental study. Methods: Healthy Standardbred horses (n = 6), aged 5-8 years. Methods: Six horses had ultrasound-guided percutaneous CCA catheterization and angiography under general anesthesia. Catheterization sites were ultrasonographically evaluated pos...
Francl AT, Amann RP, Squires EL, Pickett BW.The effects of extender and storage at 20 degrees C on equine spermatozoa were evaluated in two experiments using embryo recovery as the end point. In both experiments, inseminations were every other day, starting on Day 2 or 3 of estrus or after a 35-mm follicle was detected, with 250 x 10(6) progressively motile cells (based on initial evaluation). In Experiment 1, semen from two stallions was used to compare the motility and fertility of spermatozoa maintained in a) heated skim milk extender at 37 degrees C with insemination in <1 h; b) E-Z Mixin extender at 37 degrees C with inseminatio...
Troya-Portillo L, López-Sanromán J, Villalba-Orero M, Santiago-Llorente I.Standing surgery under sedation reduces anesthetic-related mortality in horses. Medetomidine, alone and combined with morphine in a constant rate infusion (CRI), has been described for standing surgery but their cardiorespiratory, sedative and antinociceptive effects have never been compared. The addition of ketamine could improve analgesia in these procedures with minimal cardiorespiratory consequences. The objectives were to compare the cardiorespiratory effects, quality of sedation, antinociception and ataxia produced by administration of a medetomidine-based CRI with morphine, ketamine or ...
Brinsko SP, Van Wagner GS, Graham JK, Squires EL.The aim of the present study was to determine whether there are characteristics of fresh, cooled and frozen-thawed semen samples that can be used to predict the suitability of stallion semen for preservation by cooling or freezing. Each of three ejaculates obtained from 12 stallions was divided into aliquots to be analysed for sperm motility, morphology and membrane integrity as fresh, cooled and frozen-thawed samples. The percentage of morphologically normal spermatozoa was similar in fresh and cooled samples and both were greater than in the frozen samples. There were no strong linear relati...
Ambrisko TD, Lammer V, Schramel JP, Moens YP.A spirometry device equipped with mainstream CO2 flow sensor is not available for large animal anaesthesia. Objective: To measure the resistance of a new large animal spirometry device and assess its agreement with reference methods for volume measurements. Methods: In vitro experiment and crossover study using anaesthetised horses. Methods: A flow partitioning device (FPD) equipped with 4 human CO2 flow sensors was tested. Pressure differences were measured across the whole FPD and across each sensor separately using air flows (range: 90-720 l/min). One sensor was connected to a spirometry ...
Lohmann KL, Bahr A, Cohen ND, Boothe DM, Roussel AJ.To evaluate the correlation between the half-time of liquid-phase gastric emptying (T50) determined by use of nuclear scintigraphy, using technetiumTc 99m pentetate, and absorption variables of orally administered acetaminophen in horses with experimentally delayed gastric emptying. Methods: 6 mature horses. Methods: Delayed gastric emptying was induced by IV injection of atropine sulfate. Twenty minutes later, acetaminophen and technetium Tc 99m pentetate were administered simultaneously via nasogastric tube. Serial lateral images of the stomach region were obtained, using a gamma camera. Pow...
Arcaro I, Fischer BL, Lascola KM, Clark-Price SC.To investigate the effects of intravenous (IV) administration of terbutaline on PaO, PaCO, pH, heart rate (HR) and arterial pressures in healthy, laterally recumbent horses breathing ambient air under total intravenous anesthesia (TIVA). Methods: Prospective experimental study. Methods: Eight healthy adult horses were enrolled. Six horses, four mares and two geldings weighing 433-624 kg, completed the study. Methods: Horses were sedated with xylazine (1.0 mg kg) IV for placement of arterial and venous catheters. Anesthesia was induced with midazolam (0.1 mg kg) and ketamine (2.2 mg kg) IV and ...
Leise BS, Fugler LA, Stokes AM, Eades SC, Moore RM.To determine the magnitude and duration of effects of acepromazine administered intramuscularly (IM) on digital and systemic hemodynamic variables in clinically healthy horses. Methods: Experimental study. Methods: Healthy adult horses (n=12). Methods- An ultrasonic Doppler flow probe was surgically implanted around the medial palmar digital artery before the study. Catheters were inserted in the transverse facial artery, lateral palmar digital artery, and jugular vein. A treatment group (n=6) was administered 0.04 mg/kg body weight of acepromazine IM; control horses (n=6) were administered an...
MacNicol JL, Pearson W. organ culture can provide insight into isolated mucosal responses to particular environmental stimuli. The objective of the present study was to investigate the impact of a prolonged culturing time as well as the addition of acidic gastric fluid into the environment of cultured gastric antral tissue to evaluate how altering the commonly used neutral environment impacted tissue. Furthermore, we aimed to investigate the impact of G's Formula, a dietary supplement for horses, on the secretion of gastrin, interleukin1-beta (IL-1β), and nitric oxide (NO). These biomarkers are of interest due to ...
Harkins JD, Queiroz-Neto A, Mundy GD, West D, Tobin T.This report describes the development of a behaviour chamber and the validation of the chamber of measure locomotor activity of a horse. Locomotor activity was detected by four Mini-beam sensors and recorded on a data logger every 5 min for 22 h. Horses were more active during daytime than in the evening, which was at least partially related to human activity in their surroundings. To validate the ability of the chambers to detect changes in activity, fentanyl citrate and xylazine HCl, agents well-characterized as a stimulant and a depressant, respectively, were administered to five horses. Fe...
Bubeck KA, García-López J, Maranda LS.To compare heat generation and time to finish between a new step drill and sequential drilling in order to create a 6.2 mm pilot hole for insertion of a positive profile transfixation pin into the equine third metacarpal bone. Methods: Nine pairs of equine third metacarpal bones from cadavers of adult horses were used. Maximum temperature rise of the bone was measured continuously at the cis- and trans-cortices 1, 2 and 3 mm from the final pilot hole during creation of a 6.2 mm hole using a step drill and sequential drilling with 4.5, 5.5 and 6.2 mm drill bits. Five holes were drilled into the...
Wentink GH.The locomotor pattern of the hind limb of seven horses has been studied in intact animals and after transection of the following structures: the peroneus tertius tendon, the cranial tibial muscle, both cranial tibial muscle and peroneus tertius tendon, and the superficial digital flexor tendon. The investigation was carried out by high speed cinematography and electromyography. It is concluded that (1) the muscles and tendons over the cranial aspect of the tibia play an important role during the support phase; (2) the movements of the hind limb may be performed without the action of the crania...
Cho SN, Collins MT, Reif JS, McChesney AE.Attempts to infect horses with Legionella pneumophila were undertaken to determine pathogenicity and to evaluate the possibility that horses serve as a reservoir for the organism. A previous study showed that the prevalence of antibodies to L pneumophila in the equine population exceeded 30% of over 600 sera examined. Horses were infected experimentally with the Philadelphia 1 or Bloomington 2 strain of L pneumophila IV or by aerosolization. Signs of clinical illness were restricted to a transient febrile response. A transient decrease in circulating lymphocytes occurred 2 days after inoculati...
Sanz MG, Viljoen A, Saulez MN, Olorunju S, Andrews FM.The objective of this study was to evaluate the effect of a commercial feed supplement containing pectin-lecithin on squamous mucosa ulceration in horses exposed to an experimental ulceration model. Five mares were treated while five mares were controls for this crossover, blinded study. The mares were fed concentrates and hay and were stabled with a two-hour turn out per day for a period of four weeks. The pectin-lecithin complex was fed for the duration of the study on the treated group. At the end of a four-week period, all mares underwent a seven-day alternating feed deprivation (week 5). ...
