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.
Van Eenoo P, Delbeke FT, Deprez P.Clenbuterol, a beta-adrenergic agonist, is used in the treatment of recurrent airway obstruction in horses. It is prohibited by horse racing authorities, because of its stimulating and growth-promoting properties. However, information on detection times of clenbuterol after administration by nebulization is lacking. In this study, a fast, sensitive quantitative GC-MS(2) method for the detection of clenbuterol in urine was developed. Alkaline liquid-liquid extraction was followed by derivatization to a cyclic methyl boronate derivative and analysis on a Finnigan MAT GCQ instrument. Method valid...
Veenman JN, Dujardint CL, Hoek A, Grootendorst A, Klein WR, Rutten VP.Equine acute abdominal disease is often associated with shock. Important aspects in the onset of this complication include hypovolaemia, the translocation of endotoxins from the gut and the subsequent activation of the cytokine network. The clinical efficacy of high volume continuous venovenous haemofiltration (HV-CVVH) and the clearance of cytokines were therefore investigated in an equine endotoxaemic model. Ten male Shetland ponies received a slow infusion of LPS (2 microg/kg bwt) under general anaesthesia. The treatment group (n = 5) received HV-CVVH (2 ml/kg bwt/min) using a 75 kD polymet...
Hubbell JA, Hinchcliff KW, Grosenbaugh DA, Beard WL, Beard LA.Frusemide reduces pulmonary vascular pressures in resting horses and attenuates exercise-induced increases in these pressures in exercising horses. The mechanism underlying these effects of frusemide is unclear. We tested the hypothesis that the haemodynamic effects of frusemide are dependent on diuresis by examining the effect of frusemide in anaesthetised horses in which diuresis was prevented by ligation of ureters. Twenty four horses were assigned randomly to one of 4 treatments: 1) frusemide (1 mg/kg bwt i.v.) and intact ureters; 2) frusemide and ligated ureters; 3) saline placebo and lig...
van Dixhoorn ID, Meershoek LS, Huiskes R, Schamhardt HC.Motion of the navicular bone might play a role in the development of navicular disease in horses but is difficult to asses. In the present study, 3-dimensional motion of this bone was determined using roentgen stereophotogrammetric analysis. Tantalum pellets were inserted, in vitro, in the bones of 6 forelimbs of mature Shetland ponies and kinematics were measured during vertical loading up to 2 kN. The motions of the navicular bone and coffin joint were limited to flexion/extension, there were no substantial out-of-plane motions. There was only little flexion between the navicular bone and th...
Demoruelle K, Guo B, Kao S, McDonald HM, Nikic DB, Holman SC, Wilson WW.The Haas - Drenth - Wilson (HDW) (Haas et al., 1999) theoretical model was used to correlate osmotic second virial coefficient (B) values with solubility (S) values for equine serum albumin (ESA) and ovalbumin for corresponding solution conditions. The best fit from the theoretical model was compared to experimental S versus B data. B values were experimentally measured using static light scattering. Solubilities of ESA were estimated using a sitting drop method. When the experimental data for S versus B were plotted, an excellent fit for ESA was obtained according to the HDW model. The result...
Faleiros RR, Macoris DG, Alessi AC, Saquetti CH, Rasera L.To determine the effect of experimental intraluminal distention on microvascular perfusion of the small colon in horses. Methods: 6 mixed-breed healthy horses (mean age [+/- SDI, 9.1 +/- 2 years). Methods: Under general anesthesia, the small colon was exposed by celiotomy and 3 segments were demarcated. In 1 of these segments, intraluminal obstruction was created by placement of a latex balloon inflated to a pressure of 40 mm Hg (obstructed segment). The other segments were the sham-operated segment and the control segment. Microvascular perfusion was evaluated in the mucosal, submucosal, musc...
Van Eenoo P, Deventer K, Delbeke FT.A sensitive, accurate and precise liquid chromatography/tandem mass spectrometry (LC/MS(2)) method was developed for the quantification of salmeterol in the urine of horses. The method consists of a liquid-liquid extraction with tert-butylmethyl ether and isopropanol at pH 12 after enzymatic hydrolysis. The extracts are analysed using an LC/MS system equipped with an electrospray ionisation (ESI) probe. Method validation showed excellent linearity, specificity, accuracy, precision and intra-laboratory repeatability and reproducibility. The limit of quantitative detection was 0.25 ng/mL and the...
Kim HY, Mott J, Zhi N, Tajima T, Rikihisa Y.Human granulocytic ehrlichiosis (HGE), a tick-borne zoonosis, is caused by an obligatory intragranulocytic bacterium, the HGE agent, a strain of Anaplasma phagocytophila. The equine model of HGE is considered valuable in understanding pathogenic and immune mechanisms of HGE. In the present study, cytokine mRNA expression by peripheral blood leukocytes (PBLs) in horses was examined during the course of infection by intravenous inoculation of A. phagocytophila or by allowing feeding by infected ticks. The p44 genes encoding the major outer membrane protein P44s of A. phagocytophila were detected...
Ginther OJ, Meira C, Beg MA, Bergfelt DR.Deviation during a follicular wave in mares begins when the largest follicle (F1) reaches a mean diameter of 22.5 mm and is characterized by continued growth of F1 to become the dominant follicle and regression of F2 to become the largest subordinate follicle. In the present study, F1 was ablated at the expected beginning of deviation (Hour 0) to provide a reference point for characterizing the intrafollicular changes preceding experimental deviation between F2 and F3. Diameters and concentrations of follicular fluid factors in F2 and F3 were determined in F1-ablated mares at Hours 0, 12, 24, ...
Read EK, Read MR, Townsend HG, Clark CR, Pharr JW, Wilson DG.To evaluate the effect of hemi-circumferential periosteal transection and elevation (HCPTE) in foals with, experimentally induced angular limb deformities. Methods: Prospective study. Methods: 10 healthy foals. Methods: When foals were 30 days old, transphyseal bridge implants were placed on the lateral aspects of both distal radial physes. At 90 days of age (or when 15 degrees of angulation had developed), implants were removed, and HCPTE was performed on 1 limb. Foals were confined in small pens after surgery; the front feet of the foals were rasped weekly to maintain medial-to-lateral hoof ...
Scoggin CF, Meira C, McCue PM, Carnevale EM, Nett TM, Squires EL.Equine pituitary extract (EPE) has been reported to induce heightened follicular development in mares, but the response is inconsistent and lower than results obtained in ruminants undergoing standard superovulatory protocols. Three separate experiments were conducted to improve the ovarian response to EPE by evaluating: (1) effect of increasing the frequency or dose of EPE treatment; (2) use of a potent gonadotropin-releasing hormone agonist (GnRH-a) prior to EPE stimulation; (3) administration of EPE twice daily in successively decreasing doses. In the first experiment, 50 mares were randoml...
Long MT, Mines MT, Knowles DP, Tanhauser SM, Dame JB, Cutler TJ, MacKay RJ, Sellon DC.Sarcocystis neurona was isolated from the blood of a 5-month-old Arabian foal with severe combined immunodeficiency. The foal had been inoculated approximately 3 weeks previously with 5 x 10(5) sporocysts that were isolated from the intestines of an opossum and identified by restriction enzyme analysis of PCR products as S. neurona. The isolate obtained from the blood of this foal was characterized by genetic, serologic, and morphologic methods and identified as S. neurona (WSU1). This represents the first time that S. neurona has been isolated from any tissue after experimental infection of a...
Wagner IP, Hood DM.To evaluate the effect of prolonged water exposure on tissue mass and solutes of outer and inner layers of the stratum medium, sole, frog, and the stratum medium (SMZA) zona alba layer of horses' hooves. SPECIMEN POPULATION: 10 hooves from 10 horses without foot abnormalities. Methods: Hoof wall tissue specimens were obtained and immersed for 10 days in distilled deionized water. Serial changes in mass were recorded during the immersion period. Subsequently, osmolarity and Na+, K, Cl-, and protein concentrations of the immersion solution were quantified. Results: Fully cornified outer hoof wal...
Cornelissen BP, Rijkenhuizen AB, Buma P, Barneveld A.In this study the potential role of circulatory disturbances in the pathogenesis of sesamoiditis was investigated by studying the clinical and histological effects of experimental occlusion of the sesamoidean artery, which is the main nutrient artery of the proximal sesamoid bone (PSB). For this purpose, five adult Dutch Warmblood horses were used in which the sesamoidean artery was occluded with polyvinyl alcohol foam particles. Bone labelling was carried out with oxytetracycline and calcein. All animal were checked clinically three times a week and radiographically at days 14, 21, 28 and 35....
Merritt AM, Xie H, Lester GD, Burrow JA, Lorenzo-Figueras M, Mahfoud Z.To evaluate the reliability of a method for inducing colic via small intestinal distention in horses and to examine the analgesic potential of bilateral electroacupuncture (EAP) at the Guan-yuan-shu (similar to BL21) acupoint. Methods: 5 healthy adult horses, each with a gastric cannula. Methods: A polyester balloon connected to an electronic barostat was introduced into the duodenum via the gastric cannula. At 2 specified intervals (before and after commencement of EAP), the balloon was inflated to a barostat-controlled pressure that induced signs of moderate colic. Each inflation was maintai...
Pirie RS, McLachlan G, McGorum BC.Currently, heaves is investigated by exposing susceptible horses to dusty hay. Consequently, the response will be dependent on the organic dust content and composition of the hay. It was hypothesised that the use of a hay dust suspension (HDS) would reduce the variability of the challenge and therefore standardise experimental protocols. Furthermore, analysis of HDS would also permit further investigation of the organic dust components responsible for the response. Three hay dust suspensions (HDS-1, 2 and 3) were prepared for use in the diagnosis and investigation of heaves. HDS were produced ...
Cristoni S, Bernardi LR, Biunno I, Guidugli F.A new approach, based on the use of atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-ITMS), but without a corona discharge, was investigated for application to creating and monitoring protein ions. It must be emphasized that APCI is not usually used in protein analysis. In order to verify the applicability of the proposed method to the analysis of proteins, two standard proteins (horse cytochrome c and horse myoglobin) were analyzed. A mixture of the two proteins was also analyzed showing that this novel approach, based on the use of APCI, can be used in the analysis o...
Birnbaum MH, Wakcher SV.JavaScript programs can be used to control Web experiments. This technique is illustrated by an experiment that tested the effects of advice on performance in the classic probability-learning paradigm. Previous research reported that people tested via the Web or in the lab tended to match the probabilities of their responses to the probabilities that those responses would be reinforced. The optimal strategy, however, is to consistently choose the more frequent event; probability matching produces suboptimal performance. We investigated manipulations we reasoned should improve performance. A ho...
Dowling BA, Dart AJ, Hodgson DR, Rose RJ, Walsh WR.To evaluate the effect of recombinant equine growth hormone (rEGH) on the in vitro biomechanical properties of healing superficial digital flexor tendon (SDFT) in horses. Methods: Completely randomized design. Methods: Twelve Standardbred horses, 3 to 7 years of age, with ultrasonographically normal forelimb SDFT. Methods: One week after induction of collagenase (2,000 U) induced superficial flexor tendonitis, horses were randomly divided into groups of 6. One group was administered intramuscular rEGH (10 microg/kg/day for 1 week, then 20 microg/kg/day for 5 weeks), whereas the other group (co...
Dart AJ, Cries L, Jeffcott LB, Hodgson DR, Rose RJ.To evaluate the effect of a commercially available 25% propylene glycol hydrogel preparation (Solugel; Johnson and Johnson Medical, North Ryde, Australia) on healing of full-thickness skin wounds on the distal aspect of the limb in horses. Methods: Experimental. Methods: Eight Standardbred horses. Methods: Standardized (2.5 x 2.5 cm) full-thickness skin wounds were created over the mid-dorsomedial aspect of both metacarpi in 8 horses. One wound in each horse was dressed with saline solution (0.9% NaCl) soaked gauze, and one was treated with Solugel under dry regular gauze; wounds were then ban...
Dart AJ, Cries L, Jeffcott LB, Hodgson DR, Rose RJ.To evaluate the effect of intramuscular administration of recombinant equine growth hormone on healing of full thickness skin wounds on equine limbs. Methods: Experimental. Methods: Nine Standardbred horses. Methods: In study 1, standardized full thickness skin wounds (2.5 x 2.5 cm) were made over the dorsomedial aspect of the mid-cannon bone of 1 forelimb and 1 hindlimb in 9 horses. Wounds were bandaged without treatment (control subjects) and videorecorded twice weekly until healed. Then, in study 2, similar wounds were created on the opposite limbs; 6 horses were administered intramuscular ...
Dowling BA, Dart AJ, Hodgson DR, Rose RJ, Walsh WR.To evaluate the effect of recombinant equine growth hormone (rEGH) on the in vitro biomechanical properties of normal adult equine superficial digital flexor tendon (SDFT). Methods: Completely randomized design. Methods: Nine Standardbred horses, 6 to 9 years of age with ultrasonographically normal forelimb SDFT. Methods: Six horses were administered intramuscular (IM) rEGH at 10 microg/kg/day for 1 week, and then 20 microg/kg/day for another 5 weeks; 3 horses (control subjects) were administered an equivalent daily volume of sterile water IM. Horses were killed at the end of the 6-week treatm...
Bowles KS, Beadle RE, Mouch S, Pourciau SS, Littlefield-Chabaud MA, Le Blanc C, Mistric L, Fermaglich D, Horohov DW.Equine recurrent airway obstruction (RAO; a term combining both chronic obstructive pulmonary disease (COPD) and summer pasture associated obstructive pulmonary disease (SPAOPD)) is one of the most common equine respiratory diseases with up to 50% of horses affected worldwide. The etiopathogenesis of RAO is unknown although pulmonary hypersensitivity to inhaled mold antigens may be involved. Recent work in our laboratory demonstrating elevated levels of IL-4 and IL-13 mRNA in the airways and peripheral blood of horses with RAO is consistent with an atopic component to RAO. Little is known rega...
Hallebeek JM, Beynen AC.In a Latin square design, six horses were fed hay and concentrates with isoenergetic amounts of either starch, cellulose or medium chain triacylglycerols (MCT). The dietary variables provided on average 22% of total dietary net energy. Plasma triacylglycerols and other variables of lipid metabolism were determined. The experimental periods lasted 21 days. Blood samples were taken just before the morning meal and three and six hours later. The diet rich in MCT significantly raised the plasma level of triacylglycerols when compared to either the starch- or cellulose-rich diet. The plasma concent...
Love CC, Love LB, Varner DD, Hinrichs K.The relationship of holding time in media at room temperature (approximately 22 degrees C) to initial chromatin configuration and rate of in vitro maturation (IVM) of equine oocytes was determined. Only oocytes having a complete, compact cumulus were used in this study. Oocytes were removed from ovaries 3.5-8 h after slaughter and were put into one of four treatment groups: (1) immediate/fix (IF) = immediate fixation following removal from the ovary; (2) delay/fix (DF) = fixation after oocytes were held 1-4 h in medium at room temperature; (3) immediate/mature (IM) = immediate placement into m...
Visser EK, van Reenen CG, van der Werf JT, Schilder MB, Knaap JH, Barneveld A, Blokhuis HJ.Forty-one Dutch Warmblood immature horses were used in a study to quantify temperamental traits on the basis of heart rate (HR) and heart rate variability (HRV) measures. Half of the horses received additional training from the age of 5 months onwards; the other half did not. Horses were tested at 9, 10, 21 and 22 months of age in a novel object and a handling test. During the tests, mean HR and two heart variability indices, e.g. standard deviation of beat-to-beat intervals (SDRR) and root mean square of successive beat-to-beat differences (rMSSD), were calculated and expressed as response va...
Dougherty DM, Lewis P.Using three horses we imvestigated responding on several concurrent variable-interval schedules. Each horse was first trained, using the method of successive approximations, to press a response lever with its upper lip. Following successful acquisition of the lip-press response, horses spent several days on pretraining schedules. These included a continuous reinforcement schedule and three variable-interval concurrent schedules: VI 15-sec VI 15-sec, VI 30-sec VI 30-sec, and VI 45-sec VI 45-sec. Horses were then exposed to the experimental sessions; sessions were conducted daily in the horse's ...
Davidson TR, Chamberlain CS, Bridges TS, Spicer LJ.Little is known regarding the hormonal regulation of granulosa cell steroidogenesis and the ovarian insulin-like growth factor (IGF) system in the mare. The objectives of this study were to determine, first, if estradiol, insulin, and/or FSH affect steroid production by equine granulosa cells (experiment 1) and, second, if the components of the IGF system are produced by equine granulosa cells in culture as well as whether estradiol, insulin, and/or FSH affects IGF and/or IGF-binding protein (IGFBP) production by equine granulosa cells (experiment 2). Granulosa cells from small (6-15 mm), medi...
Theoret CL, Barber SM, Moyana TN, Gordon JR.To determine whether transforming growth factor (TGF)-beta1 and -beta3 expression differs between equine limb wounds healing normally and those healing with experimentally induced exuberant granulation tissue (EGT). Methods: Six wounds were created on the lateral aspect of both metacarpi of each horse; one forelimb was untreated, and the other was bandaged to stimulate the development of EGT. Sequential wound biopsies allowed comparison of growth factor expression between the two types of wound. Methods: Four horses (2 to 4 years of age; 350 to 420 kg). Methods: Wounds were assessed grossly, h...
Andrea CR, Stover SM, Galuppo LD, Taylor KT, Rakestraw PC.To compare screw insertion characteristics and pullout mechanical properties between self-tapping (ST) and non-self-tapping (NST) AO 4.5-mm cortical bone screws in adult equine third metacarpal bone (MC3). Methods: In vitro biomechanical experiment. Methods: Seven pairs of adult equine MC3. Methods: Bicortical holes were drilled transversely in proximal metaphyseal, diaphyseal, and distal metaphyseal locations of paired MC3. NST screws were inserted in pre-tapped holes in 3 sites of one bone pair, and ST screws were inserted in non-tapped holes of contralateral MC3. Tapping and screw insertion...
Gibb Z, Grupen CG, Maxwell WM, Morris LH.The fertility of sex-sorted, cryopreserved stallion sperm must be improved for the sex-sorting technology to be applied commercially. Objective: To optimise the conditions used to liquid store stallion sperm prior to sex-sorting and assess the fertility of sperm following sex-sorting and cryopreservation. Methods: Both in vitro experiment and randomised controlled trial in healthy, client-owned mares. Methods: Stallion ejaculates (n = 9) were diluted in either a skimmed milk (KMT) or BSA (I-BSA) based media to 25 × 106 sperm/ml directly (+SP25) or washed to remove seminal plasma and diluted t...
Karatt TK, Sathiq MA, Laya S, Karakka Kal AK, Subhahar MB, M P MA, Philip M, Graiban FM, Caveney MR.Since 2010, there has been an increasing number of adverse analytical findings related to selective androgen receptor modulators (SARMs) in competitive sports. It emphasizes the importance of comprehensive doping control analytical procedures that are capable of detecting SARM misuse. Methods: In this study, it is described how LY2452473, a SARM, was metabolized in thoroughbred horses after a single-dose oral administration and in vitro with equine liver microsome preparations. An investigation of the metabolism of LY2452473 in horses' urine, plasma, and hair matrices was carried out during th...
Zerpa H, Vega F, Vasquez J, Ascanio E, Campos G, Sogbe E, Romero E, Ascanio M, García H.Endotoxaemia is a syndrome linked to the development of equine laminitis; however, the relationship between them is uncertain. The aim of this experiment was to evaluate the effect of an experimental acute sublethal endotoxaemia model on in vitro equine palmar digital vascular reactivity. Rings of arteries and veins of each forelimb were obtained from 11 clinically healthy horses submitted to two surgical procedures, 3 weeks apart. Before the second surgery, 0.25 microg/kg of lipopolysaccharide from Escherichia coli O55:B5 in saline, was administered i.v. in 30 min. After 3 h, the vessels were...
Reardon R, Bailey R, Walmsley J, Heller J, Lischer C.The mechanical properties of equine cervical vertebrae joined by implants have not yet been reported. Locking compression plates (LCP) may provide a useful alternative system to the commonly used stainless steel kerf-cut cylinders (KCC) currently used for fixation of cervical vertebrae in horses. Objective: The objectives of this study were to establish a method for biomechanical testing of equine C4-C5 articulations and to compare the biomechanical properties of cadaveric spines stabilised with KCC and LCP. Methods: Twenty-four equine cadaveric cervical spines were size measured from radiogra...
Rutledge JJ, Paegelow J, Ritchey J, Singh A, Rizzi T, Murray C, Gilliam L, Crisman E, Williams NJ, Holbrook TC.The objective of this study was to determine the extent that nebulized glycosylated caffeic acid phenylether ester-4-O-alpha-D-glucopyranoside (G-CAPE) attenuates particulate-induced airway inflammation in healthy horses. Our hypothesis was that nebulization with G-CAPE would result in improved respiratory scores, higher arterial oxygen partial pressure, and less inflammatory airway infiltrates in horses with induced airway inflammation, compared with untreated controls. Five healthy adult horses were housed inside a climate controlled, closed barn on straw bedding and fed moldy grass hay for...
Lindsay DS, Dykstra CC, Williams A, Spencer JA, Lenz SD, Palma K, Dubey JP, Blagburn BL.Equine protozoal myeloencephalitis (EPM) is a neurologic syndrome in horses from the Americas and is usually caused by infection with the apicomplexan parasite, Sarcocystis neurona. A horse model of EPM is needed to test the efficacy of chemotherapeutic agents and potential vaccines. Five horses that were negative for antibodies to S. neurona in their serum and cerebrospinal fluid (CSF) were injected in the subarachnoid space with living merozoites of the SN2 isolate of S. neurona. None of the horses developed clinical disease or died over a 132-day observation period. All five horses develope...
Cambridge H, Reynoldson JA, Dunsmore JD.Plasma thromboxane B2 (TXB2) the stable inactive metabolite of thromboxane A2 (TXA2), was measured daily by specific radioimmunoassay in three groups of animals before and after experimental infection with Strongylus vulgaris. Infection of four 'parasite naive' foals produced a typical acute syndrome with intermittent but statistically insignificant rises in TXB2 levels. Interpretation of results was complicated by the presence of a non-septic peritonitis associated with implantation of the foals with electrodes for recording myoelectrical activity. In two foals of similar age, with some natur...
Hopster K, Hurcombe SDA.Bioreactance is the continuous analysis of transthoracic voltage variation in response to an applied high frequency transthoracic current and was recently introduced for non-invasive cardiac output measurement (NICOM). We evaluated NICOM compared to thermodilution (TD) in adult horses. Six healthy horses were used for this prospective, blinded, experimental study. Cardiac output (CO) measurements were performed simultaneously using TD and the bioreactance method. Different cardiac output scenarios were established using xylazine (0.5 mg/kg IV) and dobutamine (1.5-3 mcg/kg/min). Statistical ana...
Brock AK, Chamoun-Emanuelli AM, Howard EA, Huntzinger KD, Lawhon SD, Bryan LK, Cosgriff-Hernandez EM, Cohen ND, Whitfield-Cargile CM.To compare: (1) the load and diversity of cultivatable bacterial species isolated from tissue biopsies with cultures from surface swabs, and (2) the ability of each technique to detect methicillin-resistant Staphylococcus aureus (MRSA) in a model of MRSA-infected equine wounds. Methods: Experimental in vivo study. Methods: Three light-breed adult horses. Methods: Four 2.5 × 2.5 cm full-thickness skin wounds were created on the dorsolateral aspect of each forelimb. Five days later, each wound was inoculated with a pure culture of MRSA (ATCC 43300). One hundred microlitres of 0, 5 × 1...
Coignoul FL, Bertram TA, Cheville NF.Neutrophils isolated from venous blood of adult and foal ponies inoculated with equine herpesvirus-1 were evaluated by in vitro function tests and by electron microscopy. Foals had fever and severe neutropenia 24 hours after inoculation; increased neutrophil random migration under agarose and decreased antibody-dependent cell-mediated cytotoxicity were significant at 24 hours, but values had returned to preinoculation levels by 72 hours. Mares had fever and leukopenia of less severity, increases in neutrophil migration, and longer persistence of primary granule release than were seen in foals....
Roessner HA, Hurcombe SD, Klein CE, Hopster K, Engiles JB.To compare end-to-end jejunal anastomoses with a one-layer (Utrecht) and two-layer (simple continuous/Cushing) patterns. Methods: Experimental study. Methods: Eight healthy adult horses. Methods: Jejunal end-to-end anastomoses were performed in randomly assigned one-layer or two-layer patterns. Horses were recovered from surgery and monitored for complications. At 14 days, the opposite pattern was performed (cross-over design) prior to euthanasia. Duration of closures was compared between patterns. Serosal width was measured before harvesting anastomotic sites from the first procedure. Lumin...
Munsterman AS, Gillen AM, Coleridge MOD, Hanson RR.To evaluate the effect of changes in intra-abdominal pressure (IAP) on medial saphenous venous pressure (MSVP) and hemodynamics in normal horses. Methods: Experimental, in-vivo study. Methods: University Teaching Hospital. Methods: Convenience sample of 7 mixed breed horses; 5 geldings, and 2 mares. Methods: Pneumoperitoneum was induced in horses under standing sedation with carbon dioxide gas using a laparoscopic insufflator for a total of 60 minutes to simulate clinical elevation in IAP. Pressure was increased stepwise to 20 mm Hg over 30 minutes, and maintained at that pressure for 30 minu...
Nieto JE, Morales B, Yamout SZ, Stanley SD, Harmon FA, Snyder JR.To determine the response to neostigmine of the contractile activity of the jejunum and pelvic flexure and the effects of a continuous rate infusion (CRI) of neostigmine in horses. Methods: 7 adult horses and tissue from 12 adult horses. Methods: A CRI of neostigmine (0.008 mg/kg/h) or placebo was administered to 6 horses in a crossover study design. Gastric emptying was evaluated by the acetaminophen test. The frequency of defecation and urination and the consistency and weight of feces were recorded throughout the experiment. The effect of neostigmine on smooth muscle contractile activity wa...
Burrows GE, MacAllister CG, Ewing P, Stair E, Tripp PW.The effects of time and method of administration of rifampin with respect to feeding were evaluated in five mature horses. There was a significant (P less than or equal to 0.05) delay in time of maximum serum concentration and an apparent but not significant decrease in oral absorption when rifampin was given as a top dressing on grain as compared with administration in corn syrup 2 h before or 2 h after feeding. Although there were no differences between administration before or after feeding, administration 2 h prior to feeding was selected as the method of choice for future experiments. The...
Watson ED, Stokes CR, Bourne FJ.Prostaglandins (PGs) F and E2 were measured in lavage fluid from the uterus of ovariectomised mares after experimental induction of uterine inflammation. Treatment with progesterone alone, or progesterone followed by oestradiol, significantly increased the concentrations of these PGs in the lavage compared with mares treated with oestradiol or control mares. Ovarian steroids, therefore, influenced uterine PG synthesis in response to an inflammatory stimulus. To determine whether the uterine lavage procedure might contribute to the concentrations of prostaglandins in the lavage, the procedure w...
Schulze N, Werpy N, Gernhardt J, Fritsch G, Hildebrandt T, Vanderperren K, Klopfleisch R, Ben Romdhane R, Lischer C, Ehrle A.Dynamic computed tomography (CT) imaging has been introduced in human orthopaedics and is continuing to gain popularity. With dynamic CT, video sequences of anatomical structures can be evaluated in motion. Objective: To investigate the feasibility of dynamic CT for diagnostic imaging of the equine cervical articular process joints (APJs) and to give a detailed description of the APJ movement pattern. Methods: Descriptive cadaver imaging. Methods: Cervical specimens of twelve Warmblood horses were included. A custom-made motorised testing device was used to position and manipulate the neck spe...
Collier MA, Brighton CT, Norrdin R, Twardock AR, Rendano VT.The effect of a 20-microA direct-current implantable bone growth stimulator (BGS) on bone production with a "gap healing" model in the horse was evaluated. The right and left 4th metatarsal bones (Mt-4) were used in 7 adult horses to create the "gap healing" model. A 4-mm section of the Mt-4 bone was resected bilaterally in each horse. The BGS was surgically placed into the 7 left Mt-4 defects. The 7 right Mt-4 defects served as controls. Six horses survived the 16-week experimental period. Signs of pain, decreased range of limb motion, or lameness was not observed in any animal during the 16 ...
Hyland JH, Wright PJ, Clarke IJ, Carson RS, Langsford DA, Jeffcott LB.In Exp. 1, 30 Standardbred mares in deep seasonal anoestrus were divided into 3 equal groups and treated with 0, 50 (G50) or 100 (G100) ng GnRH kg-1h-1 for 28 days via osmotic minipumps. Ovulation occurred in 0/10, 3/10 and 7/10 mares respectively (P less than 0.05). Plasma GnRH profiles (Days -6, 0, 2, 6, 12, 20, 28 and 34 relative to pump insertion) were dose-dependent (P less than 0.01) and peaked on Day 12 of infusion. Mean daily plasma LH concentrations were biphasic in treated mares that ovulated, with LH peaks occurring around Day 6 and Days 16-20. By contrast, in treated mares that did...
Smith RL, Murphy DJ, Day RE, Lester GD.To test single cycle to failure tensile strength characteristics of 6 suture material-pattern combinations in equine superficial digital flexor (SDF) tenorrhaphy, specifically to compare a 10-strand modification of the Savage core suture technique with the 3-loop pulley technique. Methods: Ex vivo mechanical experiment comparing 3 different suture patterns with 2 different materials. Methods: Forelimb and hindlimb SDF tendons (n=48) harvested from adult Thoroughbred and Standardbred horses of mixed age and gender. Methods: Six suture material-pattern combinations were evaluated: (1) 10-strand ...
Brosnahan MM, Silvela EJ, Crumb J, Miller DC, Erb HN, Antczak DF.Invasive trophoblast from Day 34 horse conceptuses survives in extrauterine sites in allogeneic recipients that are immunologically naive to donor major histocompatibility complex class I antigens. The ectopic trophoblast retains its in utero characteristics, including similar lifespan, physiologic effect of its secreted product (equine chorionic gonadotropin) upon the recipient's ovaries, and induction of host immune responses. Immunologic memory has not been considered previously in this experimental system. We hypothesized that primary exposure to ectopic trophoblast would affect the recipi...
Carmalt JL, Delaney L, Wilson DG.To compare the biomechanical cyclic fatigue properties of 2 and 3 parallel transarticular 5.5 mm cortical screws used in arthrodesis of the proximal interphalangeal (PIP) joint. Methods: Randomized block design, for horse, fixation method (2 versus three 5.5 mm cortical screws), side (right, left) and end (front, hind) in cadaveric equine limbs. Methods: Cadaveric adult equine fore- and hindlimbs (n=5 pairs each). Methods: Two parallel 5.5 mm cortical screws were inserted in lag fashion, transarticularly through the PIP joint in 1 limb of a pair, and in the contralateral limb, three 5.5 mm cor...
Allen WR, Sanderson MW, Greenwood RE, Ellis DR, Crowhurst JS, Simpson DJ, Rossdale PD.A total of 18 experimental pony and 136 commercial maiden, barren and foaling Thoroughbred mares in seasonal or lactation-related anoestrus were injected subcutaneously with 1 or 2 slow-release D,L-lactide-glycolide co-polymer implants impregnated with 0.9 or 1.8 mg of the potent GnRH analogue, ICI 118 630, to give a daily release of, respectively, 30 or 60 micrograms analogue for 28 days; 32 of the Thoroughbred mares were also given a daily oral dose of 27.5 mg allyl trenbolone for 5 days after injection of the implant. Thirteen pony (76%) and 120 Thoroughbred (88%) mares ovulated 3-18 days a...
Baumwart CA, Doherty TJ, Schumacher J, Willis RS, Adair HS, Rohrbach BW.To determine the effectiveness of preinduction hyperbaric oxygen treatment (HBOT) in ameliorating signs of experimentally induced endotoxemia in horses. Methods: 18 healthy adult horses. Methods: Horses were randomly assigned to 1 of 3 equal-sized treatment groups to receive normobaric ambient air and lipopolysaccharide (LPS), HBOT and LPS, or HBOT and physiologic saline (0.9% NaCl) solution. Horses were physically examined, and blood was obtained for a CBC and to determine concentration or activity of plasma tissue necrosis factor-α, blood lactate, and blood glucose before the horses were tr...
Reilly JD, Hopegood L, Gould L, Devismes L.The lipid chemistry of the normal equine hoof, together with the effect of oral supplementation with an evening primrose oil mixture (EPOM) on its growth, growth rate and lipid content was assessed in a controlled and blinded feeding trial at the Defence Animal Centre. Twelve horses were paired as closely as possible according to sex, age, weight, height and colour and then one from each pair was randomly allocated to treatment or control groups. The treatment group received 30 ml of oral EPOM/day, otherwise the nutrition and management regimes were the same for all horses. No significant diff...
Cribb NC, Bouré LP, Hanna WJ, Akens MK, Mattson SE, Monteith GJ, Weese JS.To assess the antimicrobial elution characteristics, toxicity, and antimicrobial activity of amikacin-impregnated ferric-hyaluronate implants (AI-FeHAI) for amikacin delivery to the tarsocrural joint of horses. Methods: Experimental study. Methods: AI-FeHAI implants, equine cartilage, and synovium, and horses (n=6). Methods: In vitro study: Five AI-FeHAI were placed in saline solution with daily replacement until implant degradation. Eluent was tested for amikacin concentration and bioactivity. Synovial and cartilage explants were incubated in the presence or absence of AI-FeHAI for 72 hours a...
Valenchon M, Deneubourg JL, Nesterova AP, Petit O.In collective movements, specific individuals may emerge as leaders. In this study on the domestic horse (Equus ferus caballus), we conducted experiments to establish if an individual is successfully followed due to its social status (including hierarchical rank and centrality). We first informed one horse about a hidden food location and recorded by how many it was followed when going back to this location. In this context, all horses lead their groupmates successfully. In a second step, we tested whether group members would trust some leaders more than others by removing the food before the ...
Umair M, Beitsma M, de Ruijter-Villani M, Deelen C, Herrera C, Stout TAE, Claes A.The cryotolerance of equine blastocysts larger than 300 μm can be improved by aspirating blastocoele fluid prior to vitrification; however, it is not known whether blastocoele aspiration also enables successful slow-freezing. The aim of this study was therefore to determine whether slow-freezing of expanded equine embryos following blastocoele collapse was more or less damaging than vitrification. Grade 1 blastocysts recovered on day 7 or 8 after ovulation were measured (>300-550 μm, n = 14 and > 550 μm, n = 19) and blastocoele fluid was aspirated prior to slow-freezing in 10...
Fouad KE, Elzomor S, Farghali HAM, Emam IA.There are varieties of surgical approaches reported for equine splenectomy and all of them were dealing with the most reachable situation of splenic hilus and easy handling of the spleen. The aim of this work was to establish the normal ultrasound parameters of spleen in donkeys (normal echogenicity, hilus situation, topographic location and correlation with neighboring organs) as a guide to select the best approach for total splenectomy in donkeys. Splenic ultrasound was carried out on six normal donkeys before experimental total splenectomy in the standing position. The splenic topographic l...
Pablo LS, Purohit RC, Teer PA, Newton JC, Hammond LS.Total strangulation obstruction of the caudal part of the jejunum was induced in 3 groups (each of 3 ponies) for 2, 4, and 6 hours. Coagulation tests which included blood platelet counts, prothrombin time, activated partial thromboplastin time, activated coagulation time, plasma fibrinogen level, and fibrin/fibrinogen degradation products assay were performed at specified time intervals for 1 week or until death of the experimental ponies. Another 3 ponies (sham-operated) were similarly treated, except that intestinal strangulation obstruction (ISO) was not induced. Necropsy was done on ponies...
Haughan JE, Missanelli JR, You Y, Stefanovski D, Soma LR, Robinson MA.Glaucine, an aporphine alkaloid with anti-tussive, anti-inflammatory, and anti-nociceptive properties, has been identified in post-race samples from racehorses. To investigate pharmacokinetics of glaucine in horses, a three-way crossover study of intravenous and oral glaucine (0.1 mg/kg) and orally administered tulip poplar shavings (50 g shavings = 0.001 mg/kg glaucine) was performed in six horses. A two-compartment model best described IV administration with alpha ( ) and beta ( ) half-life lives of 0.3 (0.1-0.7) and 3.1 (2.4-7.8) h, respectively. The area under the curve ( ) was ...
