Pharmacology in horses involves the study and application of drugs and medications to diagnose, treat, and prevent diseases and conditions in equine species. This field encompasses the understanding of pharmacokinetics and pharmacodynamics specific to horses, including how drugs are absorbed, distributed, metabolized, and excreted by the equine body. Commonly studied pharmacological agents in horses include non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, sedatives, and anthelmintics. Research in equine pharmacology focuses on determining appropriate dosages, understanding drug interactions, and minimizing adverse effects. This page compiles peer-reviewed research studies and scholarly articles that investigate the efficacy, safety, and regulatory aspects of pharmacological interventions in equine veterinary practice.
de Albuquerque PPLF, Santos LHS, Antunes D, Caffarena ER, Figueiredo AS.Infections produced by hepaciviruses have been associated with liver disease in horses. Currently, at least three viruses belonging to the Flaviviridae family are capable of producing a chronic infection in equines: non-primate hepacivirus (NPHV), Theiler's disease-associated virus (TDAV), and equine pegivirus (EPgV). The RNA-dependent RNA polymerases of viruses (RdRp) (NS5 protein), from the flavivirus family, use de novo RNA synthesis to initiate synthesis. The two antiviral drugs currently used to treat hepatitis C (HCV), sofosbuvir and dasabuvir, act on the viral NS5B polymerase as nucleos...
Bond SL, Greco-Otto P, MacLeod J, Galezowski A, Bayly W, Léguillette R.Mild asthma in horses decreases racing performance and impairs gas exchange. The efficacy of treatment on performance is unknown. Objective: Treatment targeting lung inflammation improves V ˙ O2 peak in horses with mild asthma. Methods: Thoroughbred polo horses (n = 12) with smoke-induced mild asthma. Horses were exposed to increased ambient particulate matter (35.51 μg/m3 [PM2.5 ]; day mean, centrally measured) from day -33 to 0, from bushfire smoke (natural model). Methods: Prospective, randomized, placebo-controlled, double-blinded clinical trial. All horses completed 3 V ˙ O2 peak t...
Muntwyler N, Dubois MS, Weese JS.To describe perioperative antimicrobial use in horses undergoing elective arthroscopy. Methods: Retrospective study. Methods: Horses that underwent elective arthroscopy at one institution between July 2016 and May 2018, excluding those with a suspected infectious orthopedic disease or with a comorbidity that may have impacted prophylactic antimicrobial use decisions. Methods: Medical records were reviewed to evaluate preoperative, intraoperative, and postoperative antimicrobial drug selection, dose, and timing. Associations between body weight and underdosing were evaluated by using analysis o...
Maciel JF, Gressler LT, da Silveira BP, Dotto E, Balzan C, Matter LB, Siqueira FM, de Vargas APC.Data about phylogenetic classification of Escherichia coli colonizing calves, lambs and foals are routinely neglected and restricted to outdated methodologies, even in the context of antimicrobial susceptibility (AS) testing. Thus, the aim of this study was to determine the phylogenetic diversity and the AS profile of E. coli colony-forming units (CFUs) from faecal samples of healthy animals. Five CFUs of E. coli were randomly selected from each faecal culture of calves (n = 13), foals (n = 13) and lambs (n = 13), totalizing 195 CFUs phylo-typed by quadruplex PCR. The AS profile of five ...
Gough S, Hallowell G, Rendle D.Equine squamous gastric disease (ESGD) is a highly prevalent disease in horses, particularly in elite athletes. Some horses respond slowly, or fail to respond, to the licensed treatment, oral omeprazole (ORLO). To compare rates of ESGD healing and improvement between ORLO and a long-acting injectable omeprazole preparation (LAIO). Retrospective clinical study. The case records and gastroscopy images of horses presenting to Rainbow Equine Hospital over a 12-month period were reviewed, with images being reviewed blind by one of the authors (David Rendle). Treatment responses were compared betwe...
Gilbertie JM, Schaer TP, Schubert AG, Jacob ME, Menegatti S, Ashton Lavoie R, Schnabel LV.Infectious arthritis is difficult to treat in both human and veterinary clinical practice. Recent literature reports Staphylococcus aureus as well as other gram-positive and gram-negative isolates forming free-floating biofilms in both human and equine synovial fluid that are tolerant to traditional antimicrobial therapy. Using an in vitro equine model, we investigated the ability of platelet-rich plasma (PRP) formulations to combat synovial fluid biofilm aggregates. Synovial fluid was infected, and biofilm aggregates allowed to form over a 2-hour period. PRP was collected and processed into d...
Kwok WH, Choi TLS, Leung GNW, Wong ASY, Yue SK, Wan TSM, Ho ENM.The insulin-like peptide relaxin (RLX), an endogenous peptide hormone produced in human for pregnancy and reproduction, is also known to exert a range of physiological and pathological effects. Its use is banned in human sports, horseracing, and equestrian competitions due to its potential performance enhancing effect through vasodilation resulting in the increase of blood and oxygen supplies to muscles. Little is known about the biotransformation and elimination of RLX in horses. This paper describes an administration study of rhRLX-2 and its elimination in horses, and the development of sens...
Brunner TJ, Lescun TB, Moore GE, Grady SE, Davern AJ, Taylor SD.The mechanism by which nonsteroidal anti-inflammatory drugs mitigate pain caused by a heart bar shoe (HBS) model of lameness is unknown. The purpose of this study was to determine if this HBS model of lameness induces inflammation in horses. Five healthy adult horses from a university teaching herd were enrolled. A custom HBS was applied to the left front foot of each horse, followed by induction of the American Association of Equine Practitioners Lameness Score of 4. Inflammatory markers including serum amyloid A (SAA) concentration, local venous tumor necrosis factor alpha and prostaglandin ...
Karakka Kal AK, Nalakath J, Kunhamu Karatt T, Perwad Z, Mathew B, Subhahar M.The detection and separation of medetomidine enantiomers from the complex biological matrices poses a great analytical challenge, especially in the field of forensic toxicology and pharmacology. Couple of researchers reported resolution of medetomidine using protein-based chiral columns, but the reported method is quiet challenging and tedious to be employed for routine analysis. This research paper reported a method that enables the enantio-separation of medetomidine by using polysaccharide cellulose chiral column. The use of chiralcel OJ-3R column was found to have the highest potential for ...
Reginato GM, Xavier NV, Alonso BB, Lima DP, Pereira Sirqueira TC, Carregaro AB.The study evaluated the effect of a 1/10 dose of flunixin meglumine administered into the governing vessel 1 (GV1) acupoint in horses that underwent castration. Twenty animals received 0.02 mg/kg detomidine intravenously, followed by 2.2 mg/kg ketamine and 0.1 mg/kg diazepam by the same route, and also a local anesthesia with 30 mL lidocaine. As postoperative analgesia, the animals received 1.1 mg/kg flunixin meglumine IV (FIV) or 0.11 mg/kg flunixin meglumine into the GV1 acupoint (FGV). Behavioral parameters were assessed 12 hours before the procedure (baseline) and at 4, 6, 12, and 2...
Zielinski K, Sekula B, Bujacz A, Szymczak I.Serum albumin, the most abundant transport protein of mammalian blood, interacts with various nonsteroidal anti-inflammatory drugs (NSAIDs) affecting their disposition, metabolism, and excretion. A big group of chiral NSAIDs transported by albumin, profens, is created by derivatives of 2-arylpropionic acid. The chiral center in the structures of profens is adjacent to the carboxylate moiety and often determines different pharmacological properties of profen enantiomers. This study describes crystal structures of two albumins, isolated from equine and leporine serum, in complexes with three pro...
Carregaro AB, Ueda GI, Censoni JB, Bisetto SP, Alonso BB, Reginato GM.The aim of this study was to compare the effects of methadone combined with detomidine or acepromazine on the quality of sedation and its influence over dissociative anesthesia in healthy horses. In a crossover design, seven horses were administered with 0.1 mg/kg methadone and 0.02 mg/kg detomidine intravenously (group MD) or 0.1 mg/kg methadone and 0.05 mg/kg acepromazine intravenously (group MA). Subsequently, anesthesia was induced with a combination of 2.2 mg/kg ketamine and 0.1 mg/kg midazolam intravenously. Descriptive scales and footages were used to evaluate the quality of sedat...
Davkharbayar B, Davaasuren B, Narantsatsral S, Battur B, Punsantsogvoo M, Battsetseg B, Mizushima D, Inoue N, Suganuma K.Dourine is a lethal protozoan disease of equids, and it is caused by Trypanosoma equiperdum infection via coitus. To date, treatment strategies against the dourine are not recommended because of the frequent relapses; therefore, the World Organisation for Animal Health recommends the stamping-out policy for the control of dourine. Our previous studies have revealed a number of horses with dourine in Mongolia that is the fifth largest horse-breeding country. It is difficult to apply the stamping-out policy for cases of dourine in Mongolia because of an inadequate livestock guarantee system. The...
Boone LH, DeGraves FJ, Klein CE, Cole RC, Schumacher J.To assess onset of analgesia for 3% chloroprocaine hydrochloride and 2% mepivacaine hydrochloride when used for median and ulnar nerve blocks in lame horses. Methods: 6 naturally lame horses. Methods: A crossover experiment was conducted. Horses were assigned to 1 of 2 treatment groups (3% chloroprocaine or 2% mepivacaine first). Median and ulnar nerve blocks were performed in the lame limb with the assigned treatment. Lameness was objectively evaluated before treatment administration and at various points for 120 minutes after treatment with a wireless inertial sensor-based motion analysis sy...
Rossi M, Gonzalez-Castro R, Falomo ME.Different additives have been tested in cooled stallion sperm, in order to maintain sperm quality and to ameliorate the decrease in sperm fertility potential. In several species, caffeine and pentoxifylline promote sperm motility by increasing energy production. We evaluate the effects of caffeine and pentoxifylline when added to stallion sperm before or after cooling. Three ejaculates from five stallions each were processed and resuspended in skim milk extender. Caffeine (5 mM), pentoxifylline (3.5 mM), or both additives combined were included to sperm before or after cooling (4°C for 24 ...
Kornicka-Garbowska K, Pędziwiatr R, Woźniak P, Kucharczyk K, Marycz K.In athlete horses, suspensory ligament (SL) injuries are the most common cause of lameness. Healing of SL injury is still problematic, and even proper rehabilitation and pharmacological therapy do not guarantee returning to the initial performance level. In our previous studies, we have shown that a combination of 5-azacytidine (AZA) and resveratrol (RES) exerts beneficial, rejuvenating effects on metabolic syndrome derived adipose-derived stem cells (ASCs). Thus, in the presented research, we investigate whether not only rejuvenated ASC but also microvesicles (MVsAZA/RES) secreted by them pos...
Bauquier JR, Tennent-Brown BS, Tudor E, Bailey SR.Doramapimod (BIRB-796-BS), is an anti-inflammatory compound, acting through p38 MAPK inhibition, but its anti-inflammatory effects have not previously been studied in the horse. Whole blood aliquots from healthy horses diluted 1:1 with cell culture medium were incubated for 21 h with 1 μg/ml of lipopolysaccharide (LPS), lipoteichoic acid (LTA) or peptidoglycan (PGN) in the presence of increasing concentrations of doramapimod (3 × 10 M to 10 M). Cell bioassays were used to measure TNF-α and IL-1β activity. Doramapimod significantly and potently inhibited TNF-α and IL-1β activity induced b...
Turkan F, Harbi Calimli M, Akgun A, Gulbagca F, Sen F.Benzimidazoles are antiparasitic drugs having an extensive application field like agriculture, medicine, and especially in veterinary medicine. In this study, we report the effect of some benzimidazole drugs such as ricobendazole (RBZ), thiabendazole (TBZ), albendazole (ALBA) and oxfendazole (OFZ) on glutathione s-transferase (GST) enzyme activity. The kinetics studies, IC and Ki values of the tested drugs on GSTs enzyme activity were investigated. The obtained ranking of IC values were found to be approximately RBZ (53.31 μM, r 0.9778) < OFZ (57.75 μM, r 0.9630) < ALBA (63.00 μM, r 0...
Scare JA, Leathwick DM, Sauermann CW, Lyons ET, Steuer AE, Jones BA, Clark M, Nielsen MK.An alternative control regimen for drug-resistant parasites is combination deworming, where two drugs with different modes of action are administered simultaneously to target the same parasite. Few studies have investigated this in equine cyathostomins. We previously reported that an oxibendazole (OBZ) and pyrantel pamoate (PYR) combination was not sustainable against a cyathostomin population with high levels of OBZ and PYR resistance. This study consisted of a field study and two computer simulations to evaluate the efficacy of a moxidectin-oxibendazole (MOX-OBZ) combination against the same...
Leng J, Walton G, Swann J, Darby A, La Ragione R, Proudman C.The intestinal microbiota of the horse, an animal of huge economic and social importance worldwide, is essential to the health of the animal. Understanding the intestinal ecosystem and its dynamic interaction with diet and dietary supplements currently requires the use of experimental animals, with consequent welfare and financial constraints. Here, we describe the development and assessment, using multiple analytical platforms, of a three-vessel, continuous-flow, model of the equine hindgut. After inoculation of the model with fresh horse feces, the bacterial communities established in each ...
Sánchez-Aparicio P, Florán B, Rodríguez Velázquez D, Ibancovichi JA, Varela Guerrero JA, Recillas S.Osteoarticular equine disease is a common cause of malady; in general, its therapy is supported on steroids and nonsteroidal anti-inflammatories. Nevertheless, many side effects may develop when these drugs are administered. Nowadays, the use of new alternatives for this pathology attention is demanded; in that sense, cannabinoid CB2 agonists may represent a novel alternative. Cannabinoid belongs to a group of molecules known by their psychoactive properties; they are synthetized by the Cannabis sativa plant, better known as marijuana. The aim of this study was to contribute to understand the ...
Ibrahim HMM, Abouelnasr KS, Hamed MA, Eltayesh RA, El-Khodery SA.The aim of the present study was to assess and compare the changes of the echocardiographic dimensions and cardiac function indices after epidural injection of xylazine or dexmedetomidine in clinically healthy donkeys. In an experimental prospective randomized cross-over study, 10 healthy adult donkeys were injected with saline solution, xylazine (0.20 mg kg), and dexmedetomidine (0.005 mg kg) into the epidural space between the second and third coccygeal vertebrae. Echocardiographic dimensions as well as cardiac function indices were assessed using a 2-3.9 MHz sector transducer, at the l...
Blohm KO, Tichy A, Nell B.To determine efficacy of contrast-enhanced ultrasonography (CEUS) using different sulfur hexafluoride (SF6) doses to assess blood flow and perfusion in equine eyes and to evaluate safety of SF6 in horses. Methods: Ocular B-mode and contrast-enhanced ultrasonography were performed bilaterally in nine sedated university-owned horses. Intravenous SonoVue® bolus injections of 5, 10, 15, 20, 25, and 30 mL were administered for 2/18, 5/18, 6/18, 3/18, 1/18, and 1/18 eyes, respectively. Doses were increased based on ascending bodyweight. Each eye within one horse was examined utilizing a different ...
Young JM, Schoonover MJ, Kembel SL, Taylor JD, Bauck AG, Gilliam LL.To evaluate the analgesic effects of orally administered gabapentin on horses with chronic thoracic limb lameness. Methods: Randomized, crossover design. Methods: A total of 14 adult horses with chronic thoracic limb lameness. Methods: Following baseline measurement of lameness, horses were administered each of four treatments orally in grain: treatment G, gabapentin (20 mg kg) twice daily for 13 doses; treatment F, firocoxib (171 mg once, then 57 mg once daily for six doses); treatment GF, gabapentin and firocoxib at previously stated doses and frequencies; or treatment C, grain only as a con...
Kerrigan LE, Thompson DL, Chapman AM, Oberhaus EL.Sympathoadrenal stimulation may perturb results of endocrine tests performed on fractious horses. Sedation may be beneficial; however, perturbation of results may preclude useful information. Four experiments were designed to 1) determine the effects of epinephrine on insulin response to glucose (IR2G), 2) assess the effects of detomidine (DET), alone or combined with butorphanol (DET/BUT), on IR2G and glucose response to insulin (GR2I), and 3) assess the effects of BUT alone on IR2G. In Experiment 1, mares were administered saline or epinephrine (5 μg/kg BW) immediately before infusion of gl...
Patan-Zugaj B, Egerbacher M, Licka TF.Angiogenesis and sepsis-related equine laminitis have several features in common. Both events can be induced by endotoxin (lipopolysaccharide- LPS) and both are associated with increased expression of the enzyme cyclooxygenase (COX), of which two isoforms (COX-1 and COX-2) exist. To examine the causal relationship between LPS exposure and COX expression and to investigate the tissue distribution of COX in the LPS-exposed tissue, the technique of extracorporeal haemoperfusion of isolated equine forelimbs was utilized. Perfusion was performed for 10 hr under physiological conditions (control-pe...
Snowden RT, Schumacher J, Blackford JT, Cypher EE, Cox SK, Sun X, Whitlock BK.To determine whether therapeutic concentrations (> 0.5 to 1.0 μg/mL) of polymyxin B (PB) were achieved in the tarsocrural joint of horses when the drug was administered by IV regional limb perfusion (IV-RLP) via a saphenous vein at doses of 25, 50, and 300 mg and to describe any adverse systemic or local effects associated with such administration. Methods: 9 healthy adult horses. Methods: In the first of 2 experiments, 6 horses each received 25 and 50 mg of PB by IV-RLP via a saphenous vein with at least 2 weeks between treatments. For each treatment, a tourniquet was placed at the midmetata...
Markell R, Saviola G, Barker EA, Conway JD, Dujardin C.There has recently been some controversy over the use of bisphosphonates in horses and some confusion regarding the different classes of bisphosphonates and the differences between the mechanism of actions and effects of each class. This review article explores the different bisphosphonate classes and their different effects and mechanisms of action based on research from both the human and equine veterinary fields. This collaborative review between veterinary surgeons and medical doctors describes the latest use of bisphosphonates in humans and horses, including safety aspects, and allows com...
Viljanto M, Kicman AT, Walker CJ, Wolff K, Muir T, Hincks P, Biddle S, Scarth J.Boldenone (1-dehydrotestosterone) is an exogenous anabolic-androgenic steroid (AAS) but is also known to be endogenous in the entire male horse and potentially formed by microbes in voided urine, the gastrointestinal tract, or feed resulting in its detection in urine samples. In this study, equine fecal and urine samples were incubated in the presence of selected stable isotope labeled AAS precursors to investigate whether microbial activity could result in 1-dehydrogenation, in particular the formation of boldenone. Fecal matter was initially selected for investigation because of its high mic...
Sp N, Kang DY, Kim DH, Lee HG, Park YM, Kim IH, Lee HK, Cho BW, Jang KJ, Yang YM.Cortisol is a hormone involved in stress during exercise. The application of natural compounds is a new potential approach for controlling cortisol-induced stress. Tumour suppressor protein p53 is activated during cellular stress. Succinate dehydrogenase complex subunit A () and hypoxanthine phosphoribosyl transferase 1 () are considered to be two of the most stable reference genes when measuring stress during exercise in horses. In the present study cells were considered to be in a 'stressed state' if the levels of these stable genes and the highly stress responsive gene p53 were altered. It ...
Pettengill MA, Lam VW, Ollawa I, Marques-da-Silva C, Ojcius DM.Ivermectin is currently approved for treatment of both clinical and veterinary infections by nematodes, including Onchocerca cervicalis in horses and Onchocerca volvulus in humans. However, ivermectin has never been shown to be effective against bacterial pathogens. Here we show that ivermectin also inhibits infection of epithelial cells by the bacterial pathogen, Chlamydia trachomatis, at doses that could be envisioned clinically for sexually-transmitted or ocular infections by Chlamydia.
Stout TA, Colenbrander B.There are a number of situations in which it is desirable to suppress part or all of the reproductive endocrine system in a horse, notably the competing animal whose tractability during training, or performance during competition, is compromised by the expression of sexual or aggressive behavior. The current therapeutic approaches to reproductive endocrine suppression include gonadectomy and progestagen administration, where the former carries surgical risks and entails irreversible loss of breeding potential, and effective progestagen therapy requires frequent administration for extended peri...
Figueiredo MD, Moore JN, Vandenplas ML, Sun WC, Murray TF.To evaluate proinflammatory effects of the second-generation synthetic lipid A analogue E5564 on equine whole blood and isolated monocytes and to determine the ability of E5564 to prevent LPS (lipopolysaccharide)-induced procoagulant activity (PCA); tumor necrosis factor (TNF)-alpha production; and mRNA expression of TNF-alpha, interleukin (IL)-1beta, IL-6, and IL-10 by equine monocytes. Methods: Venous blood samples obtained from 19 healthy horses. Methods: Whole blood and monocytes were incubated with Escherichia coli O111:B4 LPS, E5564, or E5564 plus E coli O111:B4 LPS. Whole blood and cell...
Hagen SJ, Carswell CW, Sjolander EM.We have measured the effect of temperature and denaturant concentration on the rate of intrachain diffusion in an unfolded protein. After photodissociating a ligand from the heme iron of unfolded horse cytochrome c, we use transient optical absorption spectroscopy to measure the time scale of the diffusive motions that bring the heme, located at His18, into contact with its native ligand, Met80. Measuring the rate at which this 62 residue intrachain loop forms under both folding and unfolding conditions, we find a significant effect of denaturant on the chain dynamics. The diffusion of the cha...
Mosing M, Auer U, MacFarlane P, Bardell D, Schramel JP, Böhm SH, Bettschart-Wolfensberger R, Waldmann AD.The aim of this study was to evaluate the effect of continuous positive airway pressure (CPAP) on regional distribution of ventilation and dead space in anaesthetized horses. Methods: Randomized, experimental, crossover study. Methods: A total of eight healthy adult horses. Methods: Horses were anaesthetized twice with isoflurane in 50% oxygen and medetomidine as continuous infusion in dorsal recumbency, and administered in random order either CPAP (8 cmHO) or NO CPAP for 3 hours. Electrical impedance tomography (and volumetric capnography (VCap) measurements were performed every 30 minutes. L...
Love EJ, Taylor PM, Clark C, Whay HR, Murrell J.In the UK butorphanol has a marketing authorisation for administration to horses for sedation in combination with detomidine, and at a higher dose (0.1 mg/kg bwt), for the alleviation of pain. There is only a limited number of clinical studies designed to examine the analgesic effects of butorphanol administration following surgery. Objective: To investigate the effect of premedication with butorphanol on post operative pain following castration under general anaesthesia in ponies. Objective: Ponies receiving butorphanol would experience less pain after castration than ponies that did not rece...
Ohmura H, Nukada T, Mizuno Y, Yamaya Y, Nakayama T, Amada A.To determine a safe and efficacious dose of flecainide acetate for treating equine atrial fibrillation (Af), the safe dosage level was determined by injecting 1, 2, or 3 mg/kg i.v. of 1% flecainide acetate solution at a rate of 0.2 mg/kg/min to five clinically healthy horses. Clinical signs and the ECG were monitored (HR, PR, QRS, and QT intervals) and blood was taken to measure the plasma flecainide concentration pre- and post-administration. No abnormal signs were observed in the 1- or 2-mg/kg groups, while agitation was observed in three of five horses in the 3-mg/kg group. The QRS, and QT ...
Gough S, Hallowell G, Rendle D.Equine squamous gastric disease (ESGD) is a highly prevalent disease in horses, particularly in elite athletes. Some horses respond slowly, or fail to respond, to the licensed treatment, oral omeprazole (ORLO). To compare rates of ESGD healing and improvement between ORLO and a long-acting injectable omeprazole preparation (LAIO). Retrospective clinical study. The case records and gastroscopy images of horses presenting to Rainbow Equine Hospital over a 12-month period were reviewed, with images being reviewed blind by one of the authors (David Rendle). Treatment responses were compared betwe...
Powis G, Snow DH.There are now several examples showing that experimentally induced changes in hepatic blood flow can have a marked effect upon the elimination of certain high clearance drugs. Changes in hepatic blood flow produced by exercise might therefore be expected to influence the clearance of these drugs. There was an increase of up to 100%, compound to control values, in the plasma levels of propranolol in horses given either d- or dl-propranolol, 0.2 mg/kg b.wt., and then subjected to sustained exercise for 30 minutes. There was, however, no similar increase with exercise in the plasma levels of anti...
Adamson PJ, Wilson WD, Hirsh DC, Baggot JD, Martin LD.In vitro antimicrobic susceptibility patterns of commonly isolated aerobic gram-positive and gram-negative bacterial pathogens of equine origin were determined, using the agar-plate dilution method. All organisms were recent clinical isolates and included Corynebacterium (Rhodococcus) equi, Corynebacterium pseudotuberculosis, (coagulase positive) Staphylococcus sp, Streptococcus equi, Streptococcus zooepidemicus, Actinobacillus sp, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella. In vitro susceptibility levels were outlined for 14 antimicro...
Vishwanath K, McClure SR, Bonassar LJ.Intra-articular injections of hyaluronic acid have been a mainstay of osteoarthritis treatment for decades. However, controversy surrounds the mechanism of action and efficacy of this therapy. As such, there has been recent interest in developing synthetic lubricants that lubricate cartilage. Recently, a synthetic 4 wt% polyacrylamide (pAAm) hydrogel was shown to effectively decrease lameness in horses. However, its mechanism of action and ability to lubricate cartilage is unknown. The goal of this study was to characterize the lubricating ability of this hydrogel and determine its efficacy ...
Harlow BE, Lawrence LM, Kagan IA, Flythe MD.The goals of this study were to determine if β-acid from hops (Humulus lupulus L.) could be used to control fructan fermentation by equine hindgut micro-organisms, and to verify the antimicrobial mode of action on Streptococcus bovis, which has been implicated in fructan fermentation, hindgut acidosis and pasture-associated laminitis (PAL) in the horse. Results: Suspensions of uncultivated equine faecal micro-organisms produced fermentation acids when inulin (model fructan) was the substrate, but β-acid (i.e. lupulone) concentrations ≥9 ppm inhibited lactate production and mitigated the d...
Stout TA, Lamming GE, Allen WR.Recent evidence indicates that, in mares, as in the domestic ruminants, oxytocin and its endometrial receptor play important roles in stimulating the pulsatile releases of prostaglandin F2 alpha from the endometrium that effect luteolysis. In the present experiment, continuous administration of oxytocin by subcutaneous minipump to five mares during days 8-20 after ovulation abolished luteolysis in four of them, while all four of the control mares infused similarly with saline underwent luteolysis at the expected time. When oxytocin administration began on day 10, instead of on day 8, after ovu...
Eysker M, Boersema JH, Kooyman FN.A controlled and critical test on the efficacy of ivermectin against larval and adult stages of the cyathostomes was carried out in six yearling castrated male Shetland ponies. The ponies grazed together as one group from 3 May to 4 October 1990, after which they were housed. Three ponies were treated with ivermectin on 29 October while the others served as controls. The shedding of helminths in the faeces was followed in all ponies until necropsy on 14 November. Comparison of worm counts of both groups before and after necropsy showed no evidence for an effect of ivermectin against inhibited ...
Weidolf LO, Lee ED, Henion JD.Sulfoconjugated anabolic steroids were separated by micro-bore high-performance liquid chromatography. The eluent was introduced into the atmospheric pressure ion source of the triple-quadrupole mass spectrometer via an ion spray liquid chromatograph/mass spectrometer interface operated in the negative ion mode. The limit of detection was 10 pg on-column by selected ion monitoring of the molecular ion and the response increased linearly over a concentration range of 2.4 orders of magnitude. Following work-up by a liquid-solid extraction procedure of equine urine samples, full-scan daughter ion...
Muir WW, Skarda RT, Sheehan W.A combination of intramuscular xylazine plus intravenous guaifenesin and ketamine hydrochloride was evaluated as a method for chemical restraint and casting of the adult horse. This drug combination provided safe and rapid induction of the horse and uneventful recovery from lateral recumbency. Cardiopulmonary function remained within base-line values for the adult horse, although cardiac output, arterial blood pressure, and arterial partial pressure of oxygen were decreased from base-line values. Xylazine, guaifenesin, and ketamine hydrochloride provided safe induction to general anesthesia wi...
Wettstein D, Moens Y, Jaeggin-Schmucker N, Böhm SH, Rothen HU, Mosing M, Kästner SB, Schatzmann U.To evaluate pulmonary and cardiovascular effects of a recruitment maneuver (RM) combined with positive end-expiratory pressure (PEEP) during total intravenous anesthesia in ponies. Methods: 6 healthy adult Shetland ponies. Methods: After premedication with detomidine (10 microg/kg, IV), anesthesia was induced with climazolam (0.06 mg/kg, IV) and ketamine (2.2 mg/kg, IV) and maintained with a constant rate infusion of detomidine (0.024 mg/kg/h), climazolam (0.036 mg/kg/h), and ketamine (2.4 mg/kg/h). The RM was preceded by an incremental PEEP titration and followed by a decremental PEEP titrati...
Hardefeldt LY, Gilkerson JR, Billman-Jacobe H, Stevenson MA, Thursky K, Browning GF, Bailey KE.Antimicrobial resistance is a public health emergency, placing veterinary antimicrobial use under growing scrutiny. Antimicrobial stewardship, through appropriate use of antimicrobials, is a response to this threat. The need for antimicrobial stewardship in Australian veterinary practices has had limited investigation. A 2016 survey undertaken to investigate antimicrobial usage patterns by Australian veterinarians found that antimicrobial dose rates were varied and often inappropriate. Doses of procaine penicillin in horses and cattle were often low, with 68% and 90% of respondents, respective...
Luna SP, Lopes C, Rosa AC, Oliveira FA, Crosignani N, Taylor PM, Pantoja JC.To validate a model for investigating the effects of analgesic drugs on mechanical, thermal and electrical stimulation testing. Objective: To investigate repeatability, sensitivity and specificity of nociceptive tests. Methods: Randomised experiment with 2 observers in 2 phases. Methods: Mechanical (M), thermal (TL) and electrical (E) stimuli were applied to the dorsal metacarpus (M-left and TL-right) and coronary band of the left thoracic limb (E) and a thoracic thermal stimulus (TT) was applied caudal to the withers in 8 horses (405 ± 43 kg). Stimuli intensities were increased until a clear...
Olave C, Morales N, Uberti B, Henriquez C, Sarmiento J, Ortloff A, Folch H, Moran G.Macrophages and neutrophils are important cellular components in the process of acute inflammation and its subsequent resolution, and evidence increasingly suggests that they play important functions during the resolution of chronic, adaptive inflammatory processes. Exacerbated neutrophil activity can be harmful to surrounding tissues; this is important in a range of diseases, including allergic asthma and chronic obstructive pulmonary disease in humans, and equine asthma (also known as recurrent airway obstruction (RAO). Tamoxifen (TX) is a non-steroidal estrogen receptor modulator with effec...
Dauvillier J, Felippe MJ, Lunn DP, Lavoie-Lamoureux A, Leclère M, Beauchamp G, Lavoie JP.Corticosteroids currently are the most effective pharmacological treatment available to control heaves in horses. Systemically administered corticosteroids have been shown to alter immune response in horses, humans, and other species. Aerosolized administration theoretically minimizes systemic adverse effects, but the effect of inhaled corticosteroids on immune function has not been evaluated in horses. Objective: To evaluate the effects of prolonged administration of inhaled fluticasone on the immune system of heaves-affected horses. Methods: Heaves-affected horses were treated with inhaled f...
Couetil L, Hammer J, Miskovic Feutz M, Nogradi N, Perez-Moreno C, Ivester K.Equine recurrent airway obstruction (RAO) is characterized by airway inflammation, bronchoconstriction, and increased mucus production in the airways. Anticholinergic drugs like atropine induce bronchodilatation and rapid improvement in lung function. N-butylscopolammonium bromide (NBB) is an anticholinergic drug used to relieve spasmodic colic in horses, but its effect on airway smooth muscle is unknown. Objective: To evaluate the effect of NBB on clinical signs and lung function of RAO-affected horses. Methods: Nine horses diagnosed with RAO. Methods: Double-blind, placebo-controlled, random...
Zamos DT, Schumacher J, Loy JK.Nasopharyngeal conidiobolomycosis caused by Conidiobolus coronatus was diagnosed in a horse after endoscopic and histopathologic examinations of a biopsy specimen. The fungal lesions in the nasopharynx were substantially reduced in size after intralesional injection of amphotericin B through the biopsy channel of a videoendoscope in combination with i.v. administration of sodium iodide and oral administration of potassium iodide during a 2-month period. Endoscopy performed 15 months after initial examination revealed regression of the granulomatous masses in the nasopharynx and complete disapp...
Bailey SR, Menzies-Gow NJ, Marr CM, Elliott J.Disturbances of digital blood flow are thought to be fundamental to the pathophysiology of acute laminitis. However, factors linking the initiating events in the equine hindgut with these disturbances in the foot remain to be determined. Objective: Amine compounds, formed by bacteria in the equine hindgut, have digital vasoconstrictor effects in vivo. Methods: Tryptamine (1.6 microg/kg/min) and phenylethylamine (2.13 microg/kg/min) were infused i.v. into standing nonsedated horses. Digital blood flow was measured by Doppler ultrasound and foot surface temperature was monitored. Plasma 5-hydrox...
Pozor MA, Macpherson ML, McDonnell SM, Nollin M, Roser JF, Love C, Runyon S, Thomas BF, Troedsson MH.The objective of this study was to determine whether an indenopyridine derivative RTI-4587-073(l) was a good candidate for male contraception in horses. We hypothesized that a single administration of RTI-4587-073(l) causes significant suppression of testicular function in stallions without affecting sexual behavior. Three Miniature horse stallions received a single dose of 12.5 mg/kg RTI-4587-073(l) orally (group "treated"), whereas three other Miniature horse stallions received placebo only (group "control"). Semen was collected and evaluated from all stallions twice a week for three baselin...
De Ridder T, Ruppin M, Wheeless M, Williams S, Reddell P.Tigilanol tiglate is a novel small molecule approved as a veterinary pharmaceutical in Europe for intratumoural treatment of non-metastatic, non-resectable canine mast cell tumors. The drug has a "tumor agnostic" mode of action associated with induction of an acute inflammatory response at the treatment site, immune cell recruitment, and disruption of tumor vasculature. Consequently, tigilanol tiglate has potential in treating a range of tumor types in humans and companion animals. However, it is likely that species-specific dosing and concomitant medication protocols will be required, especia...
Daurio CP, Holste JE, Andrews FM, Merritt AM, Blackford JT, Dolz F, Thompson DR.In a multicentre trial, 13 cannulated horses were treated orally once daily with a paste that delivered omeprazole at a dose of 4 and 5 mg/kg bwt in a 2-period crossover design to evaluate steady state gastric acid suppression. In each period, basal (unstimulated) and pentagastrin-stimulated gastric output were evaluated at 5-8 h after 5 doses, at 13-16 h after 10 doses, and at 21-24 h after 15 doses. Baseline data for gastric acid secretion were collected once for each horse in the month prior to initiation of omeprazole treatment. The inhibition of gastric acid secretion relative to baseline...
van der Harst MR, Bull S, Laffont CM, Klein WR.The aminoglycoside gentamicin is often used in equine practice. Despite its clinical use, concerns remain regarding the potential toxic side-effects, such as nephrotoxicity, in equine patients, particularly after repeated dosing. The aim of the study was to investigate first in vitro the mechanisms contributing to the renal toxicity of gentamicin and to identify sensitive biomarkers indicating proximal tubule damage. To this end, the kidney-derived cell lines LLC-PKI and MDCK were treated with gentamicin at different concentrations. Toxicity was assessed by measuring the release of gamma-gluta...
Aleman M, Williams DC, Guedes A, Madigan JE.An overdose of pentobarbital sodium administered i.v. is the most commonly used method of euthanasia in veterinary medicine. Determining death after the infusion relies on the observation of physical variables. However, it is unknown when cortical electrical activity and brainstem function are lost in a sequence of events before death. Objective: To examine changes in the electrical activity of the cerebral cortex and brainstem during an overdose of pentobarbital sodium solution for euthanasia. Our testing hypothesis is that isoelectric pattern of the brain in support of brain death occurs bef...
Johnson PJ, Slight SH, Ganjam VK, Kreeger JM.The administration of exogenously administered GCs and syndromes associated with GC excess are both attended by increased risk for the development of laminitis in adult horses. However, there exists substantial controversy as to whether excess GCs cause laminitis de novo. If true, the pathogenesis of laminitis arising from the effects of GC excess is probably different from that associated with diseases of the gastrointestinal tract and endotoxemia. Although a satisfactory explanation for the development of laminitis as a consequence of GC action is currently lacking, numerous possible and pla...
