Veterinary medicine for horses encompasses the study and application of medical practices to diagnose, treat, and prevent diseases in equine species. This field involves a comprehensive understanding of equine anatomy, physiology, pathology, and pharmacology. Veterinary practitioners employ a range of diagnostic tools and therapeutic interventions to address health issues in horses, including lameness, gastrointestinal disorders, respiratory conditions, and infectious diseases. Preventative care, such as vaccination and deworming programs, is also a significant aspect of equine veterinary medicine. This page gathers peer-reviewed research studies and scholarly articles that explore various aspects of veterinary medicine as it pertains to horses, including advancements in diagnostic techniques, treatment protocols, and preventive health strategies.
Bosch G, Moleman M, Barneveld A, van Weeren PR, van Schie HT.The repair process of tendon injuries, which are common in both human and equine athletes, is slow and the quality of the repair tissue is often inferior to the original tendon tissue, which frequently leads to re-injury. The relatively poor vascularization of tendons is considered to be one of the reasons for their limited healing potential. Recently, platelet-rich plasma (PRP), an autologous concentrate of platelets, rich in growth factors, has been shown to enhance the repair process of injured tendons. This effect has been ascribed to the high levels of growth factors in PRP, several of wh...
Tatarniuk DM, Carmalt JL, Allen AL.To report intraoperative complications during needle penetration and suture placement through the cricoid cartilage during a prosthetic laryngoplasty procedure. Methods: Case report. Methods: An 11-year-old American Paint gelding with grade IV left laryngeal hemiplegia underwent a terminal prosthetic laryngoplasty for teaching purposes. Passage of the needle through the cricoid cartilage was difficult and resulted in needle breakage before eventual success using a new needle. The larynx was examined postmortem. Results: Palpation of the larynx revealed hardening of the cricoid cartilage. Radio...
Current HIV researchMarch 10, 2010
Volume 8, Issue 1 87-93 doi: 10.2174/157016210790416424
Carpenter S, Dobbs D.Equine infectious anemia virus (EIAV) is one of the most divergent members of the lentivirus subfamily of retroviruses and is considered a useful comparative model for molecular studies of lentivirus replication. The Rev protein of EIAV is functionally homologous with other lentiviral Revs and facilitates export of incompletely spliced viral mRNAs through a Crm1-dependent pathway. The trans- and cis-acting elements that mediate EIAV Rev function are similar to, but distinct from, the well-characterized elements in human immunodeficiency virus (HIV-1), the prototypical Rev protein. In addition,...
Sod GA, Riggs LM, Mitchell CF, Hubert JD, Martin GS.To compare in vitro monotonic biomechanical properties of an axial 3-hole, 4.5 mm narrow dynamic compression plate (DCP) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion (DCP-TLS) with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion (3-TLS) for the equine proximal interphalangeal (PIP) joint arthrodesis. Methods: Paired in vitro biomechanical testing of 2 methods of stabilizing cadaveric adult equine forelimb PIP joints. Methods: Cadaveric adult equine forelimbs (n=15 pairs). Methods: For each fore...
Grossi B, Canals M.We analyzed the morphology and the walk-trot and trot-gallop transition velocities of nine juvenile horses and compared them with their mothers. We also compared the relative stride length and the duty factor of the juveniles with respect to adults at three equivalent trotting speeds (Froude numbers 0.5, 0.75, and 1.0), to determine dynamic similarity. Juveniles had a negative allometry in their leg bones, mainly because of little size changes of the distal portions. The negative allometry of extremities allows juveniles to increase stride length without increasing step frequency, which can be...
Current HIV researchMarch 10, 2010
Volume 8, Issue 1 66-72 doi: 10.2174/157016210790416352
Payne SL, Fuller FJ.Equine infectious anemia virus (EIAV) is a macrophage-tropic lentivirus that rapidly Induces disease in experimentally infected horses. Because EIAV infection and replication is centered on the monocyte/macrophage and has a pronounced acute disease stage, it is a useful model system for understanding the contribution of monocyte/macrophages to other lentivirus-induced diseases. Genetic mapping studies utilizing chimeric proviruses in which parental viruses are acutely virulent or avirulent have allowed the identification of important regions that influence acute virulence. U3 regions in the vi...
Fritz D.Positive PCR results for piroplasms were obtained on EDTA blood samples from 166 dogs and 111 horses between March 2006 and March 2008. The organisms were initially identified using common primers, followed by restriction enzyme profiles to determine the species and types of Babesia/Theileria. In 27 dogs and eight horses with positive results, the size of the specimen was insufficient to separate species/types. We identified Babesia canis canis in 105 of the 166 dogs (63%) and Theileria equi in 89 of the 111 horses (80%). Babesia caballi was also present, but rare, in only two Babesia/Theileri...
Aytekin I, Onmaz AC, Aypak SU, Gunes V, Kucuk O.The aim of this study was to compare hematological, some biochemical parameters, and serum trace element concentrations in horses with or without pica. Fifteen horses with pica (group I) and another 15 healthy horses without pica (group II) were used. The hematological parameters were not changed between the two groups. In group I, hemoglobin values were lower than those of group II. However, the difference in hemoglobin values between the two groups was not significant (P > 0.05). Serum iron and copper concentrations and the copper/zinc ratio were lower in group I than those of group I...
Knowles EJ, Mair TS, Butcher N, Waller AS, Wood JL.Thirty horses with no external signs of strangles were tested for exposure to Streptococcus equi subspecies equi (S equi) using a new, commercially available serological test. The horses were also tested for persistent carriage of S equi by endoscopy of the guttural pouches and PCR analysis of lavage samples. The owners were questioned about the recent medical history of the horses. Serology suggested that four horses had been recently exposed to S equi. None of the horses had a known history of strangles but three of the four seropositive horses had recently shown non-specific signs of respir...
Becher AM, Mahling M, Nielsen MK, Pfister K.For 9 consecutive months (March-November 2008), faecal samples were collected monthly from 129 horses residing within 40 km of Salzburg, Austria. Samples were analysed quantitatively using a modified McMaster egg counting technique. Whenever a faecal egg count (FEC) result exceeded 250 eggs per gram (EPG), the horse was treated with pyrantel, ivermectin or moxidectin. In 52 of 129 horses (40.3%), no strongyle eggs were ever detected over the course of 9 months. In 39 horses (30.2%), strongyle eggs were detected in at least 1 sample, but the egg count never exceeded 250 EPG. The remaining 38 (2...
Mosher CM, Court MH.Pharmacogenomics is the study of the impact of genetic variation on drug effects, with the ultimate goal of achieving "personalised medicine". Since the completion of the Human Genome Project, great strides have been made towards the goal of personalised dosing of drugs in people, as exemplified by the development of gene-guided dosing of the anticoagulant drug, warfarin. Although the pharmacogenomics of domestic animals is still at an early stage of development, there is great potential for advances in the coming years as the direct result of complete genome sequences currently being derived ...
Sharma S, Davies Morel MC, Dhaliwal GS.Decreased reproductive performance due to summer stress is a well known phenomenon in farm livestock. Whether this occurs in the mare and specifically how this might affect postpartum reproductive activity and performance, especially at Foal Heat (FH), is unknown. This study, therefore, aims to investigate this and the factors that might affect postpartum reproductive activity. Reproductive records of 228 Thoroughbred mares (694 mare years) bred in subtropical north-western India were retrospectively analysed. Overt oestrous activity occurred within 21 d postpartum in 92.94% (645/694) of mares...
Toutain PL.In racing and other equine sports, it is possible to increase artificially both the physical capability and the presence of a competitive instinct, using drugs, such as anabolic steroids and agents stimulating the central nervous system. The word doping describes this illegitimate use of drugs and the primary motivation of an equine anti-doping policy is to prevent the use of these substances. However, an anti-doping policy must not impede the use of legitimate veterinary medications and most regulatory bodies in the world now distinguish the control of illicit substances (doping control) from...
Merwyn S, Kumar S, Agarwal GS, Rai GP.Glanders is highly contagious disease of equines, caused by Burkholderia mallei. The disease though rare, can be transmitted to humans. Here, we report a strategy for rapid detection of B. mallei from environmental samples. Different bacteriological media were evaluated and brain heart infusion broth medium with selective supplements (BHIB-SS) of penicillin (200 U/ml) and crystal violet (1:10,00000) was found to support the maximum growth of B. mallei even in the presence of other bacteria like Escherichia coli and Staphylococcus aureus. A polymerase chain reaction (PCR) and a DNA hybridizatio...
Jacobson CC, Choi YH, Hayden SS, Hinrichs K.Oocytes may be collected from live mares from either the stimulated preovulatory follicle or from all visible immature follicles. We evaluated the yield of mature oocytes, and of blastocysts after intracytoplasmic sperm injection (ICSI), for both follicle types. In Experiment 1, mares were assigned to Progesterone (1.2g biorelease progesterone weekly) or Control treatments. Transvaginal aspiration of all follicles was performed every 14 d. Overall, 596 follicles were aspirated, with a 54% oocyte recovery rate. There was no difference between treatments in number of follicles punctured (9.0 to ...
Reinemeyer CR, Prado JC, Nichols EC, Marchiondo AA.The expanding prevalence of Parascaris equorum populations that are resistant to macrocyclic lactone (ML) anthelmintics makes it desirable to identify dewormers which remain effective. The objective was to evaluate the efficacy of pyrantel pamoate in 14 suckling foals that had been infected orally with approximately 600 larvated eggs of a P. equorum isolate selected for ML resistance (ML-R). Seventy days after inoculation, foals were weaned, housed individually, and fecal samples were examined frequently to detect the onset of patency. Between 73 and 80 days post-inoculation, all 14 foals deve...
Reinemeyer CR, Prado JC, Nichols EC, Marchiondo AA.In recent years, numerous veterinary practitioners have reported anecdotal episodes in which anthelmintic treatment did not appear to deliver the expected efficacy against equine pinworms (Oxyuris equi). Anthelmintic resistance has not been demonstrated formally in equine pinworms, so a clinical study was designed to evaluate the efficacy of paste formulations of pyrantel pamoate or ivermectin against naturally acquired infections with O. equi. Twenty-one horses (>4 months to 15 years of age) with patent, naturally acquired pinworm infections were blocked by source of origin and allocated rand...
Preziuso S, Laus F, Tejeda AR, Valente C, Cuteri V.Streptococcus (S.) dysgalactiae subsp. equisimilis is responsible for severe diseases in humans, including primary bacteraemia, pneumonia, endocarditis, and toxic shock syndrome. Infection in some animal species can also occur, although a few studies have looked into cross-species infectivity. In horses, S. equisimilis is generally considered infrequent or opportunistic, but has recently been isolated from cases of strangles-like disease. Rapid and sensitive diagnostic techniques could enable epidemiological studies and effective investigation of outbreaks involving these bacteria. In this stu...
Zhang J, Stein DA, Timoney PJ, Balasuriya UB.A significant consequence of equine arteritis virus (EAV) infection of horses is persistence of the virus in a variable percentage of infected stallions. We recently established an in vitro model of EAV persistence in cell culture for the purpose of furthering our understanding of EAV biology in general and viral persistence in the stallion in particular. In this study we investigated whether persistently infected HeLa cells could be cured of EAV infection by treatment with an antisense peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) designed to target the 5'-terminal region o...
Ma G, Lu C, Osterrieder N.A single amino acid variation in the equine herpesvirus type 1 (EHV-1) DNA polymerase (Pol) (D752/N752) determines its neuropathogenic potential. Here, an EHV-1 strain RacL11 mutant with a deletion of Pol residue 752 was constructed. The deletion virus was then repaired to encode D752 or N752, respectively. The Delta752 mutant virus replicated with kinetics indistinguishable from those of D752 and N752 viruses. In addition, we could demonstrate that the deletion mutant was significantly more resistant to aphidicolin, a drug targeting Pol, compared with the N752 but not the D752 variant. In equ...
Krakowski L, Krawczyk CH, Wrona Z, Dabrowski R, Jarosz Ł.The objective of the present study was to analyse the immune status of mares in the early stages of pregnancy and mares which experienced early embryonic death (EED). Forty-eight fertile purebred Arabian mares were used for the study. The mares were divided into two groups. Group I was the control group composed of 32 mares in the early stages of a normal pregnancy. Group II was composed of 12 mares which had experienced EED. In both groups, subpopulations of T lymphocytes containing CD2(+), CD4(+) and CD8(+) were characterized using flow cytometry. The percentages of CD3(+) lymphocytes (addin...
Pearson W.Standardbred trainers from 1 racetrack and 7 off-track training facilities were surveyed to determine the most common drugs, and prevalence of concurrent herb administration. Furosemide (on-track) and anti-inflammatory drugs (off-track) were the most common drugs administered. Among horses on-track, 9.8% received herbs compared with 13.8% off-track horses; 67% and 58% of these horses, respectively, received concurrent drugs. Les soigneurs de Standardbreds de 1 piste de course et de 7 installations d’entraînement hors piste ont été interrogés afin de déterminer les médicaments les plus...
Carter RA, McCutcheon LJ, Valle E, Meilahn EN, Geor RJ.To determine effects of exercise training without dietary restriction on adiposity, basal hormone and lipid concentrations and glucose and insulin dynamics in overweight or obese, insulin-resistant horses. Methods: 12 overweight or obese (body condition score > or = 7), insulin-resistant (insulin sensitivity < or = 1.2 x 10(-4) L/min/mU) geldings. Methods: 4 horses remained sedentary, and 8 horses were exercised for 4 weeks at low intensity and 4 weeks at higher intensity, followed by 2 weeks of detraining. Prior to and after each training period, frequently sampled IV glucose tolerance ...
Castro JR, Adair HS, Radecki SV, Kiefer VR, Elliot SB, Longhofer SL.To determine effects of domperidone and acepromazine maleate on microvascular blood flow in digital laminae of clinically normal adult horses. Methods: 8 clinically normal adult horses (4 mares and 4 geldings). Methods: In a 4-period crossover study, domperidone was administered PO at 1.1 mg/ kg and 5.5 mg/kg and IV at 0.2 mg/kg; acepromazine was administered IV at 0.04 mg/kg. The washout period between treatments was 1 week. A 3-minute measurement of laminar microvascular blood flow (LMBF) was obtained with laser Doppler flowmetry. Baseline measurements were obtained at -2, -1, and 0 hours pr...
Monreal L, Navarro M, Armengou L, José-Cunilleras E, Cesarini C, Segura D.To assess the effect of enteral fluid therapy (EFT) in horses with colic, 78 adult horses with colon impactions and 30 with left dorsal colon displacements received an isotonic electrolyte solution via a nasogastric tube at a rate of 8 to 10 l every two hours until resolution of clinical signs. Clinical progression was monitored closely, and plasma biochemistry was evaluated before, during and after treatment. Volume of fluids, time to resolution, and outcome were also recorded. EFT was well tolerated by 102 of 108 horses and was an effective method to resolve 99 per cent of colon impactions a...
Jarrett M, Hibbert DB, Osborne R, Young EB.The analysis of total carbon dioxide (TCO(2)) in equine plasma is conventionally done in Australia and elsewhere using Beckman Synchron EL-ISE(R) analysers. This instrument is no longer being manufactured and has not been supported by the supplier since December 2008. For testing for TCO(2) to continue, it is necessary to evaluate and commission alternative instrumentation. In this paper, we compare the Beckman Synchron EL-ISE, the Beckman Synchron CX5, the Beckman UniCel DxC 600 and the Randox Daytona instruments. Results indicate that all four instruments perform in accordance with the manuf...
Fleurance G, Duncan P, Fritz H, Gordon IJ, Grenier-Loustalot MF.The spatial heterogeneity of grasslands determines the abundance and quality of food resources for grazing animals. As plants mature, they increase in mass, which allows greater instantaneous intake rates, but the cell wall concentrations increase too, reducing diet quality. In ruminants, daily intake rates are often constrained by the time needed for the ingesta to pass through the rumen, which is influenced by the rate of digestion. It has been suggested that the digestive constraint should have much less effect on hindgut fermenters such as equids. Horses play an increasing role in the mana...
Chaucheyras-Durand F, Durand H.The use of probiotics for farm animals has increased considerably over the last 15 years. Probiotics are defined as live microorganisms which can confer a health benefit for the host when administered in appropriate and regular quantities. Once ingested, the probiotic microorganisms can modulate the balance and activities of the gastrointestinal microbiota, whose role is fundamental to gut homeostasis. It has been demonstrated that numerous factors, such as dietary and management constraints, can strongly affect the structure and activities of the gut microbial communities, leading to impaired...
Martin GS, McIlwraith CW, Turner AS, Nixon AJ, Stashak TS.A retrospective study was made of 21 horses in which proximal interphalangeal arthrodesis had been performed. The right hindlimb was the most often affected (52%). Acute trauma was the most common reason for performing the surgery (62%). Follow-up data were obtained from the owners regarding return to serviceability . When available, follow-up radiographs and clinical examinations were reviewed. Of the 20 horses on which follow-up information was available, 16 were serviceable . Of the horses in which a hindlimb was arthrodesed , 86% were serviceable , whereas 67% of the horses affected in the...
Langston VC, Fontenot RL, Byers JA, Andrews CM, Mochal-King CA.The objective of this study was to determine the pharmacokinetics of meropenem in horses after intravenous (IV) administration. A single IV dose of meropenem was administered to six adult horses at 10 mg/kg. Plasma and synovial fluid samples were collected for 6 hr following administration. Meropenem concentrations were determined by bioassay. Plasma and synovial fluid data were analyzed by compartmental and noncompartmental pharmacokinetic methods. Mean ± SD values for elimination half-life, volume of distribution at steady-state, and clearance after IV administration for plasma samples ...
Knickelbein KE, Scherrer NM, Lassaline M.To compare corneal sensitivity and tear production in horses with keratitis to horses with other ocular disease. Methods: Retrospective medical record review was used to identify equine patients presented during a 1-year period for an ocular complaint who had Schirmer Tear Test (STT) or Corneal Touch Threshold (CTT) measured. Variables studied included patient age and sex; affected eye; category of presenting ocular complaint (keratitis vs. other ocular complaint); STT; and CTT. Patients with a complaint of ulcerative keratitis, immune-mediated keratitis, and stromal abscess were categorized i...
Hanche-Olsen S, Matiasek K, Molín J, Rosati M, Hahn C, Hultin Jäderlund K, Gröndahl G.Acquired equine polyneuropathy (AEP), formerly also known as Scandinavian knuckling syndrome, is one of the most prevalent polyneuropathies in equids in Norway and Sweden, with more than 400 cases registered since first observations in 1995. Despite geographical clustering and an association to forage feeding, its aetiology remains unknown. Clinically AEP is characterized by knuckling due to dysfunction of metatarsophalangeal extensor muscles. This neuropathological study aimed to gain further insights in the pathobiology of AEP and its underlying aetiopathogenesis. We thereby confirmed that a...
West JB, Mathieu-Costello O.Exercise induced pulmonary haemorrhage (EIPH) is a serious problem in the Thoroughbred industry. The condition apparently occurs essentially in all Thoroughbreds in training but the mechanism has proved elusive. There is now strong evidence that the condition is caused by mechanical failure of the walls of the pulmonary capillaries when the pressure inside them rises to very high levels. It is well known that pulmonary capillaries have extremely thin walls to allow rapid exchange of respiratory gases across them. Recently we have shown that the wall stresses are very large when the capillary t...
Slusarewicz M, Slusarewicz P, Nielsen MK.Fecal egg counts are the primary diagnostic tools of equine parasitology and use of the McMaster test and its variants in clinical practice is widely recommended. Manual counting is, however, prone to various sources of human error. For example, in real-world situations analysts can be under significant pressure to process high numbers of samples in a limited time. This practice could affect test result quality, but yet no studies have determined whether this is the case. This study's purpose was to assess the effect of shortened counting duration (from either restricting counting time or coun...
David F, Cadby J, Bosch G, Brama P, van Weeren R, van Schie H.Larger superficial digital flexor tendon (SDFT) injuries have a poorer prognosis than smaller lesions. During the inflammatory phase enlargement of the initial lesion is frequently noted, with biomechanical loading being recently proposed to play an important role. Objective: To evaluate the effect of lower limb cast immobilisation on tendon lesion propagation in an equine model of surgically induced SDFT injury. Methods: Core lesions were surgically induced in both front SDFTs of 6 young mature horses. At the end of surgery, one leg was randomly placed in a lower limb cast and the other leg (...
Matsuda M, Miyazawa T, Ishida Y, Moore JE.The genomic DNA of eight strains of Taylorella equigenitalis, isolated from seven Norwegian Trotters and a Norwegian pony with contagious equine metritis in Norway, was examined by pulsed-field gel electrophoresis after separate digestions with two restriction enzymes, namely, ApaI and NotI. The respective electrophoretic profiles of the fragments were essentially identical but differed from those of T. equigenitalis NCTC11184T and Kentucky 188. They also exhibited slight differences from profiles obtained from Japanese isolates. These results may possibly suggest a common genotype and a commo...
Pospischil A, Lieb A, Corboz L.In Switzerland during the foaling season 1988 and 1989 the cause of abortion in 60 foals was investigated. Special attention was paid to infections with equine herpesvirus 1 (EHV 1). Diagnosis were based on post-mortem, histopathological, bacteriological and immunofluorescence investigation. The results confirm data from other countries, that EHV 1 is the most prevalent viral (20%) cause of abortion, followed by various bacterial agents (12%). Other causes were umbilical torsion, twin pregnancy and malformations. In 18% of the cases the investigation of fetuses did not give any results as to t...
Ma Y, Wen X, Hoshino Y, Yuan L.Group A equine rotavirus (ERV) is the main cause of diarrhea in foals and causes severe economic loss due to morbidity and mortality on stud farming worldwide. Molecular evolution of equine rotaviruses remains understudies. In this study, whole-genomic analysis of 2 group A ERV, FI-14 (G3P[12]), H-2 (G3P[12]) isolated from American, and FI23 (G14P[12]) from British was carried out and genotype constellations were determined as G3-P[12]-I6-R2-C2-M3-A10-N2-T3-E2-H7 for FI-14; G14-P[12]-I2-R2-C2-M3-A10-N2-T3-E2-H7 for FI23; and G3-P[12]-I6-R2-C2-M3-A10-N2-T3-E2-H7 for H-2, respectively. With the ...
Mair TS, Wills JM.Nasal and conjunctival swabs were obtained from 300 horses and Chlamydia psittaci was isolated from 15 of them (5 per cent). Eleven nasal swabs and six conjunctival swabs were positive on culture, but there was no association between the isolation of the organism and the presence of clinical ocular or respiratory disease. Six ponies were challenged with an equine isolate of C psittaci into the eye, nasal cavity or bronchial tree. The organism could be isolated from nasal and conjunctival swabs taken from the ponies for up to 17 days after challenge, but there was no clinical evidence of diseas...
Hunter BG, Schlipf JW, Cebra C.The transverse facial venous sinus (TFVS) can be used for blood collection in horses, but information on the validity of blood values from this site is limited. Objective: To determine if packed cell volume (PCV), total solids (TS) and blood lactate concentrations in blood drawn simultaneously from a TFVS and jugular vein of critically ill horses are correlated and determine the effect of serial TFVS sampling on the same parameters in healthy horses. Methods: Prospective observational study. Methods: Critically ill horses had simultaneous blood samples drawn from a TFVS and jugular vein. Blood...
Beelitz P, Göbel E, Gothe R.In this epidemiological study of endoparasites 37 donkeys and 23 horses were included, which were examined coproscopically in regular intervals over a 15 month period. The animals derived from ten farms, in which regular prophylactic treatments with anthelmintics had been practiced at least for two years before this investigation. This study revealed the presence of at least twelve parasite species in donkeys, Eimeria leuckarti, Gasterophilus intestinalis, Fasciola hepatica, Anoplocephala perfoliata, Strongyloides westeri, Parascaris equorum, Dictyocaulus arnfieldi, Trichostrongylus axei and s...
Allen KJ, Fitzharris LE, McConnell AK.Inspiratory muscle training applies a training stimulus directly to the inspiratory muscles and is distinct from whole-body training. The potential benefits of inspiratory muscle training have yet to be explored in horses. Objective: The objectives were as follows: (a) to develop an equine-specific method of testing and training inspiratory muscles; (b) to assess tolerance and feasibility in a pilot study in a commercial Thoroughbred training establishment. Methods: Field study. Methods: A mask was used to interface commercial human inspiratory muscle training equipment. Ten horses undertook i...
Dimaio Knych HK, Steffey EP, Deuel JL, Shepard RA, Stanley SD.Yohimbine is an alpha 2 adrenergic receptor antagonist used most commonly in veterinary medicine to reverse the effects of the alpha 2 receptor agonists, xylazine and detomidine. Most notably, yohimbine has been shown to counteract the CNS depressant effects of alpha 2 receptor agonists in a number of species. The recent identification of a yohimbine positive urine sample collected from a horse racing in California has led to the investigation of the pharmacokinetics of this compound. Eight healthy adult horses received a single intravenous dose of 0.12 mg/kg yohimbine. Blood samples were co...
Uchida-Fujii E, Niwa H, Kinoshita Y, Nukada T.Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is used for identification of bacterial species isolated from horses. However, because of insufficiencies in the reference database, some bacterial species isolated from horses are difficult to identify with MALDI-TOF MS, and enriching the databases is expected to enhance the accuracy of MALDI-TOF MS identification. Here we created an in-house database including 271 bacterial isolates from horses. Furthermore, we used an enhanced database (our in-house database plus a commercially provided database) to ...
Evans AG, Paradis MR, O'Callaghan M.Six horses with chronic obstructive pulmonary disease (COPD) and 8 horses with recurrent urticaria were skin tested with 67 extracts from 58 allergens, including pollens, epidermals, cultivated farm plants, dusts, molds, and insects. Reactions were evaluated 3 times over a 24-hour period immediately after the injections. Results were compared with those obtained from 11 clinically normal horses. All horses had positive skin test reactions. Significant differences was evident between horses with COPD and clinically normal horses for only 3.0% of the possible extract reactions, and between horse...
Lynch TM, Caron JP, Arnoczky SP, Lloyd JW, Stick JA, Render JA.To evaluate the influence of exogenous hyaluronan (HA) on in vitro synthesis of HA and collagenase by equine synoviocytes from normal and inflamed joints. Methods: 9 adult horses. Methods: Synoviocytes for culture were taken from the middle carpal joint of 3 horses with normal joints (control) and 6 horses with osteochondral fractures (principal). Synoviocytes were propagated in monolayer cultures and were incubated with 3 commercial HA products at concentrations of 0, 200, 400, and 1,500 micrograms/ml. Newly synthesized HA was radiolabeled with [3H]glucosamine and quantified by cetylpyridiniu...
Crispin SM.Tear-deficient dry eye (keratoconjunctivitis sicca), and evaporative dry eye, with some overlap between these two categories, are two major categories of dry eye recognized in the horse. Careful examination of the eyelid margins, the inner and outer surfaces of the upper and lower eyelids, assessment of blink and third eyelid movement, specific testing of tear production, assessment of corneal sensitivity, and slit-lamp examination of the ocular surface before and after fluorescein dye application is recommended to detect dry eye problems. Rose Bengal dye application is also recommended in man...
Wilcke JR, Crisman MV, Sams RA, Gerken DF.Single doses (2.2 mg/kg of body weight) of phenylbutazone (PBZ) were administered IV to 6 neonatal horses (5 to 17 hours old at time of dosing). Plasma concentrations of PBZ and its metabolite oxyphenbutazone were monitored serially for 120 hours after drug administration. Pharmacokinetic variables were calculated, using 1- and 2-compartment open models. Descriptive equations from the best model for each foal were then used to derive model-independent variables describing PBZ disposition. Median volume of distribution at steady-state was 0.274 L/kg (range, 0.190 to 0.401 L/kg). Median terminal...
Kaps S, Richter M, Spiess BM.To determine corneal sensitivity in healthy adult horses in order to establish reference values. Methods: One hundred eyes of 50 healthy adult horses. Methods: Corneal sensitivity was determined by evaluating the corneal touch threshold (CTT) in five different corneal regions using a Cochet-Bonnet esthesiometer. Results: Comparing CTT values (in mm filament length) of the five prescribed corneal regions revealed regional variations in corneal sensitivity, with the central region (21.15 +/- 6.23 mm) being the most sensitive, followed by the nasal (20.75 +/- 5.14 mm), temporal (20.70 +/- 5.37 mm...
Kuroda T, Minamijima Y, Nomura M, Yamashita S, Yamada M, Nagata S, Mita H, Tamura N, Fukuda K, Kuwano A, Kusano K, Toutain PL, Sato F.For medication control in several jurisdictions, withdrawal time is the period of refrain from racing after drug administration. It is set by adding a safety period to an experimental detection time. However, there are no reports of statistical analyses of detection time for the determination of withdrawal time in flunixin meglumine-treated horses. Objective: To analyse the population pharmacokinetics of flunixin in horses through the generation of a dataset for detection time statistical analysis and predictions via Monte Carlo simulation. Methods: Experimental study. Methods: Drug plasma and...
Töneke K.The density and subtype pattern of beta-adrenoceptors in equine tracheal epithelium, tracheal smooth muscle and heart from 6-9 horses were investigated by radioligand binding studies using the nonselective beta-adrenoceptor antagonist 125I-cyanopindolol (ICYP). The specific binding of ICYP was 341 +/- 162 fmol/mg protein (mean +/- SD) for epithelium, 42 +/- 13 fmol/mg for smooth muscle and 124 +/- 39 and 101+/- 19 fmol/mg for the cardiac atrium and ventricle, respectively. The Kd value of ICYP was 6.7 10.2 pmol/L. In competition studies, different concentrations of either the beta2-selective d...
Ryu SH, Kim BS, Lee CW, Yoon J, Lee YL.A 3-year-old Thoroughbred filly was referred to the Equine Hospital, Korea Racing Association for evaluation of hematuria, inappetite, weight loss and depression. From 25 days prior to admission, the horse was treated for right carpal lameness with 20 mg intramuscular administration of triamcinolone acetonide per day for consecutive 10 days by a local veterinarian. Clinical and laboratory findings included vaginal hyperemia, flare in bladder wall, neutrophilia, lymphopenia, polyuria, polydipsia and laminitis in the end. High activities of aspartate transaminase and gamma glutamyltransferase an...
Holyoak GR, Giles RC, McCollum WH, Little TV, Timoney PJ.The nature and extent of changes associated with equine arteritis virus (EAV) infection of the reproductive tract was documented in 21 prepubertal and 15 peripubertal colts. This study was part of an investigation into the relationship between stage of reproductive tract maturity and susceptibility to the experimental establishment of persistent infection with EAV. After intranasal challenge with a field isolate of EAV, all colts developed clinical signs of equine viral arteritis (EVA) from which they recovered rapidly. Clinical signs during the acute phase consisted of fever, serous to mucopu...