Sedation in horses involves the administration of pharmacological agents to induce a state of calmness, relaxation, or sleepiness. This practice is commonly employed to facilitate veterinary procedures, diagnostic imaging, or transportation by reducing stress and movement in the animal. The primary sedatives used in equine medicine include alpha-2 adrenergic agonists, such as xylazine and detomidine, and opioids, like butorphanol. These agents act on the central nervous system to achieve the desired sedative effects. The choice of sedative and its dosage depend on various factors, including the horse's age, weight, health status, and the procedure's nature. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacology, efficacy, and safety considerations of sedation in equine practice.
Curtis RA, Hahn CN, Evans DL, Williams T, Begg L.Electrolaryngeography was used to study the latencies of the thoracolaryngeal adductor reflex in Thoroughbred horses with and without recurrent laryngeal neuropathy (RLN). Latencies were compared in horses with grades 1 and 2 RLN, diagnosed by endoscopy in resting horses. The reliability of the measurements, effect of sedation and correlations of latencies with age of the horse were also studied. There was no effect of sedation on reflex latency periods. The latency of the reflex period measured to a convolved peak of the electromyographic response was significantly different in horses with gr...
Dixon PM, Dacre I, Dacre K, Tremaine WH, McCann J, Barakzai S.Extraction of cheek teeth (CT) by the conventional repulsion technique requires general anaesthesia and carries a high rate of post operative complications. Consequently, an alternative method of extraction, i.e. orally in standing horses, was evaluated. Objective: The need for and risks of general anaesthesia could be avoided and post extraction sequelae reduced by performing extractions orally in standing horses. Methods: One hundred mainly younger horses (median age 8, range 2-18 years) with firmly attached CT that required extraction because of apical infections, displacements, diastemata,...
Marntell S, Nyman G, Funkquist P, Hedenstierna G.To study pulmonary gas exchange and cardiovascular responses to sedation achieved with romifidine and butorphanol (RB) alone, or combined with acepromazine, and during subsequent tiletamine-zolazepam anaesthesia in horses. Methods: Six (four males and two females) healthy Standardbred trotters aged 3-12 years; mass 423-520 kg. Methods: Randomized, cross-over, experimental study. Methods: Horses were anaesthetized on two occasions (with a minimum interval of 1 week) with intravenous (IV) tiletamine-zolazepam (Z; 1.4 mg kg(-1)) after pre-anaesthetic medication with IV romifidine (R; 0.1 mg kg(-1...
Price J, Eager RA, Welsh EM, Waran NK.This study aimed to characterise current practice relating to equine castration in the UK. A questionnaire was posted to all 655 veterinary practices specified to provide veterinary care for horses, or classified as specialist equine practices. Respondents were asked to cite the number of equine castrations performed annually by the practice, describe techniques used for castration, outline anaesthetic/sedative/analgesic drug protocols used and provide details of post-operative medication. There was a 43% response rate to the questionnaire. Considerable variation in techniques and analgesia pr...
Corletto F, Raisis AA, Brearley JC.The aim of this study was to compare two different alpha2 agonist-opioid combinations in ponies undergoing field castration. Methods: Prospective double-blind randomized clinical trial. Methods: Fifty-four ponies undergoing field castration. Methods: The ponies were randomly allocated to receive one of three different pre-anaesthetic medications [intravenous (IV) romifidine 100 microg kg(-1) and butorphanol 50 micro kg(-1); romifidine 100 microg kg(-1) and morphine 0.1 mg kg(-1) IV, or romifidine 100 microg kg(-1) and saline IV] before induction of anaesthesia with ketamine 2.2 mg kg(-1) IV. F...
Greene SK.The reintroduction and development of safe motorized instruments, the increased availability of continuing education, and the understanding and implementation of appropriate procedures allow practitioners to provide better dental care. Veterinarians realize that sedation, analgesia, a full-mouth speculum, and proper instrumentation are necessary to provide these services. Continued instrument design, future research, and new treatment and prophylactic protocols should have a positive impact on the future of equine dental health. New and rediscovered procedures for equilibrating equine occlusio...
Bettschart-Wolfensberger R, Freeman SL, Bowen IM, Aliabadi FS, Weller R, Huhtinen M, Clarke KW.Currently available sedatives depress cardiopulmonary function considerably; therefore, it is important to search for new, less depressive sedatives. The study was performed to assess duration and intensity of cardiopulmonary side effects of a new sedative, dexmedetomidine (DEX), in horses. Objective: To study pharmacokinetics and cardiopulmonary effects of i.v. DEX. Methods: Pharmacokinetics of 3.5 microg/kg bwt i.v. DEX were studied in a group of 8 mature (mean age 4.4 years) and 6 old ponies (mean age 20 years). Cardiopulmonary data were recorded in mature ponies before and 5, 10, 20, 30, 4...
Sanchez LC, Merritt AM.Most current models of visceral sensitivity testing in the horse have required visceral cannulation. Colorectal distention (CRD) is a widely used, noninvasive method for testing in other species and could be adapted for use in horses. Objective: To develop a protocol of controlled CRD in the conscious horse and to evaluate the effect of i.v. xylazine or intrarectal lidocaine on CRD threshold and rectal compliance. Methods: Eight horses were used for baseline studies (3 trials each) and 6 horses to evaluate treatments (4 trials, 2 per treatment). A 45 cm diameter polyvinyl balloon attached to p...
McKnight AL, Manduca A, Felmlee JP, Rossman PJ, McGee KP, Ehman RL.Magnetic resonance imaging (MRI) of the distal extremities of the standing, sedated horse would be desirable if diagnostic quality images could be obtained. With the availability of extremity and special purpose magnet designs on the market, a system to safely accommodate the standing horse may gain increasing popularity. This paper considers the issue of motion that will need to be addressed to achieve successful, diagnostic quality images. The motion of the carpus and tarsus of five standing, sedated horses was quantified. The obtained motion records were then used to induce motion in cadave...
Lehner AF, Hughes CG, Karpiesiuk W, Harkins JD, Dirikolu L, Bosken J, Camargo F, Boyles J, Troppmann A, Woods WE, Tobin T.Amitraz (N'-(2,4-dimethylphenyl)-N-[[(2,4-dimethylphenyl)imino]methyl]-N-methyl-methanimidamide) is an alpha-2 adrenergic agonist used in veterinary medicine primarily as a scabicide- or acaricide-type insecticide. As an alpha-2 adrenergic agonist, it also has sedative/tranquilizing properties and is, therefore, listed as an Association of Racing Commissioners International Class 3 Foreign Substance, indicating its potential to influence the outcome of horse races. We identified the principal equine metabolite of amitraz as N-2,4-dimethylphenyl-N'-methylformamidine by electrospray ionization(+...
Carastro SM.This article is intended to provide the practitioner with a succinct but complete source regarding equine orbital and ocular anatomy,instrumentation available for ophthalmic examination, a methodical examination technique, sedation and regional nerve blocks, and diagnostic procedures involving the eye. Such knowledge of orbital and ocular anatomy is essential to allow recognition of normal,normal variations, or an abnormality of the equine eye and orbit.
Robertson SA.Several ocular procedures, including examination, removal of corneal foreign bodies, nictitans surgery, eyelid repair, and tumor excision,can be successfully performed in the appropriately restrained and sedated standing horse. Sedation is best achieved with xylazine,with or without the addition of acepromazine. Additional analgesia can be provided with appropriate local anesthetic blocks. Surgical conditions are greatly improved by using an auriculopalpebral and supraorbital block and topical anesthetics. More elaborate standing sedation involving continuous rate infusions of lidocaine or det...
Ganidagli S, Cetin H, Biricik HS, Cimtay I.Two groups of six mares aged from eight to 18 years were anaesthetised by caudal epidural injections of ropivacaine (0.5 per cent, 0.1 mg/kg) or a combination of ripovacaine (0.08 mg/kg) and fentanyl (100 microg) in a randomised study. The onset of anaesthesia was significantly more rapid (P<0.001) and it lasted significantly longer (P<0.001) in the group anaesthetised with the combination of drugs. The surgical comfort scores of the group anaesthetised with the combination were higher than those of the group anaesthetised with ropivacaine alone (P<0.001), and the quality of intraoper...
Gehlen H, Kroker K, Deegen E, Stadler P.30 warmblood horses were examined before and after sedation with 20 micrograms/kg BW detomidine, to determine changes of cardiac function parameters, using B-mode, M-mode and Doppler echocardiography. 15 horses showed a heart murmur, but no clinical signs of cardiac heart failure, 15 horses had neither a heart murmur nor other signs of cardiac disease. After sedation with detomidine we could recognise a significant increase of end-diastolic left atrium diameter, an increase of end-systolic left ventricular diameter and aortic root diameter. The end-systolic thickness of papillary muscle and in...
Natalini CC, Alves SD, Guedes AG, Polydoro AS, Brondani JT, Bopp S.To evaluate the analgesic, physiologic, and behavioral effects of the epidural administration of tiletamine/zolazepam in horses. Methods: Prospective, double-blind, randomized experimental study. Methods: Five adult, healthy horses aged 10-16 years and weighing (mean +/- SD) 400 +/- 98 kg. Methods: The horses were sedated with 1.0 mg kg(-1) intravenous (IV) xylazine, and an epidural catheter was placed into the first intercoccygeal intervertebral space. After a 48-hour resting period, epidural tiletamine/zolazepam, 0.5 mg kg(-1) (treatment I) or 1.0 mg kg(-1) (treatment II), diluted up to 5 mL...
Cruz AM, Kerr CL, Bouré LP, Sears WC.To determine the cardiovascular effects of 60 minutes of abdominal insufflation with CO2 to an intra-abdominal pressure of 15 mm Hg in standing horses receiving a constant rate infusion of detomidine. Methods: 5 horses. Methods: Horses were randomly allocated into treatment or control groups. A washout period of a minimum of 7 days separated the 2 experimental periods of the crossover study. Catheters were placed into the right atrium, pulmonary artery, jugular vein, and right transverse facial artery after lidocaine infiltration. All horses were sedated with detomidine (8.54 microg/kg/h, i.v....
DeRossi R, Sampaio BF, Varela JV, Junqueira AL.Epidural administration of bupivacaine and meperidine produces analgesia in several animal species and in humans. A prospective randomized study was conducted in 18 healthy horses to compare the effect of these 2 drugs administered by the epidural route. Animals were divided into 3 treatment groups of 6 animals each. All drugs were injected by the epidural route in all animals between the 1st and 2nd coccygeal vertebrae. Treatment 1 (BUP)--0.06 mg/kg of body weight of 0.5% hyperbaric bupivacaine; treatment 2 (MEP)--0.6 mg/kg of body weight of 5% meperidine; treatment 3 (SS)--0.9% saline soluti...
Mazan MR, Deveney EF, DeWitt S, Bedenice D, Hoffman A.This study was conducted to determine whether horses with naturally occurring, severe chronic recurrent airway obstruction (RAO) 1). have a greater resting energy expenditure (REE) than control horses, 2). suffer body mass depletion, and 3). have significantly decreased REE after bronchodilation and, therefore, also 4). whether increased work of breathing contributes to the cachexia seen in some horses with RAO. Six RAO horses and six control horses underwent indirect calorimetric measures of REE and pulmonary function testing using the esophageal balloon-pneumotachograph method before and aft...
Moens Y, Lanz F, Doherr MG, Schatzmann U.To study the analgesic potency of the alpha2-agonist romifidine in the horse using both an electrical current and a mechanical pressure model for nociceptive threshold testing. In addition, a comparison was made with doses of detomidine and xylazine that produce equivalent degrees of sedation. Methods: Randomized, placebo-controlled, blinded cross-over study. Methods: Six adult Swiss warmblood horses, one mare and five geldings, weighing from 530 to 650 kg and aged 6-15 years. Methods: Nociceptive thresholds were measured using an electrical stimulus applied to the coronary band and using a pn...
Skarda RT, Muir WW.To determine the analgesic, behavioral, hemodynamic and respiratory effects of midsacral subarachnoid administration of ropivacaine hydrochloride solution in mares. Methods: Randomized, blinded study. Methods: Ten healthy mares, weighing from 470 to 560 kg. Methods: Intravascular and subarachnoid catheters were placed after infiltration of the skin and subcutaneous tissues with 2% lidocaine. Ropivacaine (0.2%, 5 mL) or 0.9% NaCl was then administered subarachnoidally at the midsacral (S2-S3) vertebrae. Analgesia was determined by lack of sensory perception to electrical stimulation (>40 mA)...
Olbrich VH, Mosing M.To evaluate and compare the effects of caudal epidural administration of methadone (METH) and lidocaine (LIDO) on tolerance to thermal stimulation over the dermatomes of the perineal, sacral, lumbar and thoracic regions in the horse. Methods: A blinded, randomized, prospective, experimental cross-over study. Methods: Seven healthy horses, 15.7 +/- 4.9 years (mean +/- SD) of age, weighing 536 +/- 37 kg. Methods: The horses were randomly assigned to receive two treatments (group M: METH, 0.1 mg kg-1 or group L: LIDO, 0.35 mg kg-1) at intervals of at least 28 days. An 18-gauge 80-mm Tuohy epidura...
Bienert A, Bartmann CP, von Oppen T, Poppe C, Schiemann V, Deegen E.Isofluorane is a modern, only slightly depressive inhalation anaesthetic with excellent pharmacologic characteristics in use in equine medicine. In contrast to halothane, isofluorane is hardly broken down in the liver, but is eliminated by the lung. It low solubility in blood permits excellent control of anaesthesia. However, due to its swift elimination from the organism there is heightened risk of premature recovery from isofluorane anaesthesia. In this study the recovery phases of 96 horses were monitored for its duration and the animals' physical coordination. The horses were divided into ...
Keoughan CG, Rodgerson DH, Brown MP.To describe a hand-assisted, laparoscopic technique to remove the left kidney in standing horses. Methods: Prospective evaluation. Methods: Eight horses. Methods: Food was withheld for a minimum of 12 hours. Horses were sedated with detomidine hydrochloride (0.01-0.02 mg/kg, intravenously) and restrained in standing stocks. The left paralumbar fossa was prepared for surgery, and the surgical site was infiltrated with 2% mepivacaine. Hand-assisted, laparoscopic removal of the left kidney was performed through an incision in the center of the paralumbar fossa; the surgeon's hand was used to isol...
Bettschart-Wolfensberger R, Bowen IM, Freeman SL, Weller R, Clarke KW.To search for long-term total i.v. anaesthesia techniques as a potential alternative to inhalation anaesthesia. Objective: To determine cardiopulmonary effects and anaesthesia quality of medetomidine-ketamine anaesthesia induction followed by 4 h of medetomidine-propofol anaesthesia in 6 ponies. Methods: Sedation consisted of 7 microg/kg bwt medetomidine i.v. followed after 10 min by 2 mg/kg bwt i.v. ketamine. Anaesthesia was maintained for 4 h with 3.5 microg/kg bwt/h medetomidine and propofol at minimum infusion dose rates determined by application of supramaximal electrical pain stimuli. Ve...
Latimer FG, Eades SC, Pettifer G, Tetens J, Hosgood G, Moore RM.Abdominal insufflation is performed routinely during laparoscopy in horses to improve visualisation and facilitate instrument and visceral manipulations during surgery. It has been shown that high-pressure pneumoperitoneum with carbon dioxide (CO2) has deleterious cardiopulmonary effects in dorsally recumbent, mechanically ventilated, halothane-anaesthetised horses. There is no information on the effects of CO2 pneumoperitoneum on cardiopulmonary function and haematology, plasma chemistry and peritoneal fluid (PF) variables in standing sedated horses during laparoscopic surgery. Objective: To ...
Nollet H, Van Ham L, Gasthuys F, Dewulf J, Vanderstraeten G, Deprez P.Horses need to be sedated before they are investigated by transcranial magnetic stimulation because of the mild discomfort induced by the evoked muscle contraction and the noise of stimulation. This paper describes the influence of a combination of detomidine (10 microg/kg bodyweight) and a low dose of buprenorphine (2.4 microg/kg) on the onset latency and peak-to-peak amplitude of magnetic motor-evoked potentials in normal horses. There were no significant differences between measurements of these parameters made before the horses were sedated and measurements made 10 and 30 minutes after the...
Komáromy AM, Andrew SE, Sapp HL, Brooks DE, Dawson WW.The goal of our study was the evaluation of a practical method for the recording of flash electroretinograms (ERGs) in sedated, standing horses with the DTL microfiber electrode. Methods: The horses were sedated intravenously with detomidine hydrochloride (0.015 mg/kg). The pupil was dilated and the auriculopalpebral nerve was blocked. The ERGs were recorded with the active electrode on the cornea (DTL), the reference electrode near the lateral canthus, and the ground electrode over the occipital bone. The light intensities of the white strobe light were 0.03 cd x s/m2 (scotopic) and 3 cd x s/...
Santos M, Fuente M, Garcia-Iturralde R, Herran R, Lopez-Sanroman J, Tendillo FJ.Recovery from inhalant anaesthesia in the horse is a critical and difficult period to manage; however, several factors could help to obtain a calm recovery period including choice of anaesthetic and analgesic procedure used and the conditions under which anaesthetic maintenance and recovery occur. Objective: The objective of this study was to evaluate and compare the quality of recovery in horses administered saline, xylazine, detomidine or romifidine during recovery from isoflurane anaesthesia. Methods: Six mature and healthy horses were premedicated with i.v. xylazine and butorphanol, and an...
Mazan MR, Hoffman AM, Kuehn H, Deveney EF.To evaluate effects of sedation on stability of resistance of the respiratory system (RRS) and measures of resting energy expenditure (REE) by use of open-flow indirect calorimetry (IC) and treatment with aerosolized albuterol on REE in horses with recurrent airway obstruction (RAO). Methods: 9 clinically normal horses and 8 horses with RAO. Methods: In phase 1, RRS was measured by using forced oscillometry (FOT) in 5 clinically normal horses before and after sedation with xylazine. In phase 2, REE was measured in 4 clinically normal horses between 20 and 25 minutes and again 35 to 40 minutes ...
Yamashita K, Muir WW, Tsubakishita S, Abrahamsen E, Lerch P, Hubbell JA, Bednarski RM, Skarda RT, Izumisawa Y, Kotani T.To compare the analgesic and cardiopulmonary effects of medetomidine and xylazine when used for premedication of horses undergoing general anesthesia. Methods: Randomized clinical trial. Methods: 40 horses. Methods: Twenty horses were premedicated with medetomidine (10 microg/kg [4.5 microg/lb], i.m.) and the other 20 were premedicated with xylazine (2 mg/kg [0.9 mg/kg], i.m.). Horses were then anesthetized with a combination of guaifenesin and ketamine; anesthesia was maintained with halothane. Additional doses of medetomidine or xylazine were given if horses were not sufficiently sedated at ...
Kitzman JV, Wilson RC, Booth NH, Hendricks HL, Bush PB.The pharmacokinetics of 4-aminopyridine (4-AP), a drug capable of antagonizing nondepolarizing neuromuscular blocking drugs, as well as several classes of injectable sedative and anesthetic agents, were studied in 6 intact, awake horses. Plasma samples were assayed for 4-AP over a frequent sampling schedule for 8 hours after IV administration. The plasma 4-AP vs time data best fit a 2-compartment pharmacokinetic model. Distribution half-life was 7.4 minutes, elimination half-life was 259 minutes, volume of the central compartment was 0.89 L/kg, volume of distribution (area) was 1.98 L/kg, volu...
Beazley SG, Focken A, Fernandez-Parra R, Thomas KL, Adler A, Duke-Novakovski T.To determine changes in distribution of lung ventilation with increasing intra-abdominal pressure (IAP) from carbon dioxide (CO) insufflation in standing sedated horses. Methods: Prospective experimental study. Methods: A group of six healthy adult horses. Methods: Each horse was sedated with acepromazine, detomidine and butorphanol and sedation maintained with a detomidine infusion. The horse was restrained in a stocks system and a 32 electrode electrical impedance tomography (EIT) belt was wrapped around the thorax at the fifth-sixth intercostal space. EIT images and arterial blood samples f...
Cock G, Blakeney Z, Hernandez JA, DeNotta S.Atlantoaxial (AA) cerebrospinal fluid (CSF) collection in standing horses utilizes the controlled narcotic morphine, thereby limiting feasibility in field practice settings. Objective: To compare AA CSF collection time and reaction scores in horses sedated with morphine-containing and opioid-free sedation protocols: detomidine + morphine (DM), detomidine + xylazine (DX), detomidine + detomidine (DD), detomidine alone (D0); To develop a novel method for assessing sedation in standing horses using open-source motion-tracking software. Methods: Six healthy adult horses. Methods: Randomi...
Schiesser E, Geyer H, Kummer M, Jackson M.The interest in equine dentistry has significantly increased in the last 15 years. On the part of the veterinarians as well as of the horse owners there is a strong attention to the topic. The aim of the questionnaire was to investigate amongst horse owners what their level of information and preferences about dental treatment are and how they are implemented. The questionnaire was translated into the three national languages and included 20 questions about level and sources of information, frequency of treatments and the horse owner's stance over sedation of the animals. With a return rate of...
LeBlanc PH, Eberhart SW, Robinson NE.In horses with noninduced, reversible airway obstruction (heaves), pulmonary function is improved after sedation with the alpha 2-adrenergic agonist xylazine. The mechanism of this effect is undetermined. Because the predominant excitatory innervation of equine airways is cholinergic, the influence of alpha 2-adrenergic receptor stimulation on the response of isolated distal airways to cholinergic stimulation was determined. Distal bronchial segments from 22 healthy horses were suspended in isolated organ baths where their mechanical responses to various stimuli could be studied. Each tissue w...
Gray SM, Gutierrez-Nibeyro SD, Secor EJ.To report our experience with partial arytenoidectomy in sedated standing horses. Methods: Retrospective study. Methods: Fourteen client-owned adult horses. Methods: The medical records (2013-2017) of horses treated with unilateral partial arytenoidectomy while standing and sedated were reviewed. Demographics, endoscopic findings, previous treatments, and outcome after surgery were investigated and recorded. Results: Thirteen horses had unilateral left-sided recurrent laryngeal neuropathy (RLN) and 1 horse had bilateral RLN. Five horses had a previous failed prosthetic laryngoplasty. Left-side...
Perotta JH, Canola PA, Lopes MC, Evora PM, Martinez PE, Escobar A, Valadão CA.To evaluate the effects of intravenous (IV) or intramuscular (IM) hyoscine premedication on physiologic variables following IV administration of medetomidine in horses. Methods: Randomized, crossover experimental study. Methods: Eight healthy crossbred horses weighing 330 ± 39 kg and aged 7 ± 4 years. Methods: Baseline measurements of heart rate (HR), cardiac index (CI), respiratory rate, systemic vascular resistance (SVR), percentage of patients with second degree atrioventricular (2(o) AV) block, mean arterial pressure (MAP), pH, and arterial partial pressures of carbon dioxide (PaCO2 ) an...
Di Salvo A, Della Rocca G, Bazzica C, Giontella A, Cagnardi P, Nannarone S.The study aims to evaluate whether the analgesic effect of intra-articular (IA) route of xylazine administered to horses following arthroscopic surgery is due to a local or a systemic action. Two connected studies were performed. In the first, 1 mg/kg b.w. of xylazine was injected IA, and blood samples were taken to assess drug systemic absorption. In addition, systemic effects of the drug (sedation, ataxia or reduction of respiratory and cardiac rate) were registered. Control horses injected with saline IA were included in the study to exclude the influence of anaesthesia in the occurrence o...
Sanchez LC, Merritt AM.Most current models of visceral sensitivity testing in the horse have required visceral cannulation. Colorectal distention (CRD) is a widely used, noninvasive method for testing in other species and could be adapted for use in horses. Objective: To develop a protocol of controlled CRD in the conscious horse and to evaluate the effect of i.v. xylazine or intrarectal lidocaine on CRD threshold and rectal compliance. Methods: Eight horses were used for baseline studies (3 trials each) and 6 horses to evaluate treatments (4 trials, 2 per treatment). A 45 cm diameter polyvinyl balloon attached to p...
Hagedorn HW, Zuck S, Schulz R.The azaphenothiazine neuroleptic prothipendyl (Dominal) is suspected to be administered illegally at low doses to race-horses to improve their performance. Since for this species pharmacokinetic data of the drug are missing we studied its elimination from blood and urine in a standard-bred mare. At a low (subtherapeutic) dose (i.v., 0.24 mg/kg) the horse is described to be less excited while locomotor activity and attention remain unaffected. In contrast, sedation and ataxia are brought about at 1 mg/kg (therapeutic dose). Identification of prothipendyl given i.v. at subtherapeutic doses was a...
van de Pol C, Sloet van Oldruitenborgh-Oosterbaan MM.Measuring the height at the withers of a pony is one of the requirements of the Fédération Equestre Internationale (FEI), before competitors can participate in an official pony event. A pony has to be measured each year until it is eight years old. With and without shoes the height at the withers must be below 149.0cm and 148.0cm, respectively. When a pony exceeds the regulated height, it is excluded from participating in FEI pony competitions. Besides being excluded from competing, the selling price of the pony decreases dramatically, because the animal is then classified as a horse. For th...
Gaughan EM, Hackett RP, Ducharme NG, Rakestraw PC.Sensory innervation of the larynx was examined by tactile stimulation with a blunt biopsy forceps passed through a flexible videoendoscope. Twenty horses with no evidence of laryngeal motor deficit were stimulated on 10 sites by touch with the forceps. Unilateral neurectomies of the internal branch of the left cranial laryngeal nerve were performed on 5 other horses. These horses were stimulated by touch on the same sites preoperatively and up to 1 week postoperatively. In all 25 horses the motor response of the larynx was recorded on videotape and evaluated by 2 observers blind as to treatmen...
Freeman SL, England GC.To compare sedative effects of romifidine following IV, IM, or sublingual (SL) administration in horses. Methods: 30 horses that required sedation for routine tooth rasping. Methods: Horses (n = 10/group) were given romifidine (120 microg/kg) IV, IM, or SL. Heart rate, respiratory rate, head height, distance between the ear tips, thickness of the upper lip, response to auditory stimulation, response to tactile stimulation, and degree of ataxia were recorded every 15 minutes for 180 minutes. Tooth rasping was performed 60 minutes after administration of romifidine, and overall adequacy of sedat...
Cruz AM, Kerr CL, Bouré LP, Sears WC.To determine the cardiovascular effects of 60 minutes of abdominal insufflation with CO2 to an intra-abdominal pressure of 15 mm Hg in standing horses receiving a constant rate infusion of detomidine. Methods: 5 horses. Methods: Horses were randomly allocated into treatment or control groups. A washout period of a minimum of 7 days separated the 2 experimental periods of the crossover study. Catheters were placed into the right atrium, pulmonary artery, jugular vein, and right transverse facial artery after lidocaine infiltration. All horses were sedated with detomidine (8.54 microg/kg/h, i.v....
Racine J, O'Brien T, Bladon BM, Cruz AM, Stoffel MH, Haenssgen K, Rodgerson DH, Livesey MA, Koch C.To investigate the feasibility and complications associated with ceratohyoidectomy (CHE) in standing sedated horses unaffected (experimental horses) and standing sedated horses affected (clinical cases) with temporohyoid osteoarthropathy (THO). Methods: Case series. Methods: Six experimental horses and four clinical cases. Methods: Standing CHE was performed in six experimental horses euthanized 30 minutes (n = 3) and 7 days (n = 3) postoperatively. The four clinical cases were presented because of central facial nerve paralysis (n = 3), vestibular ataxia (n = 3), auricular hemorrhage (n =...
Kim A, Sasaki N, Lee I, Seo JP.The purpose of this study was to assess the cardiorespiratory and behavioral responses to the combination of medetomidine and tramadol (M-T) or butorphanol (M-B) in standing laparoscopic ovariectomy in horses. One ovary was removed under M-T and the contralateral ovary was removed under M-B with at least 4 weeks between operations at random. Horses were sedated using intravenous medetomidine (5 µg/kg) followed by tramadol (1 mg/kg) or butorphanol (10 µg/kg) after 5 min. Sedation was maintained through the repeated injection of medetomidine (1 µg/kg) and tramadol (0.4 mg/kg) or medetomidine ...
Easley JT, McGilvray KC, Hendrickson DA, Bruemmer J, Hackett ES.To determine the temperature of a vessel sealer and divider device during unilateral paralumbar laparoscopic ovariectomy in standing, sedated mares. Methods: Prospective study. Methods: Fifteen healthy research mares. Methods: Healthy mares with normal ovarian palpation and ultrasonographic appearance were enrolled. Horses were restrained in standing stocks and sedated. A right or left paralumbar ovariectomy was performed with a laparoscopic portal and 2 instrument portals. Ovaries were excised with traumatic forceps and a blunt tip vessel sealer and divider. Temperatures of the vessel sealer ...
Caffey SR, Lund CM, Farnsworth KD, Fransson BA, Ragle CA.The effects of head position on internal carotid artery (ICA) and external carotid artery (ECA) pressures in standing sedated horses were evaluated in this study. The common carotid artery (CCA) was catheterized in 6 horses using an ultrasound-guided technique to facilitate placement of a pressure transducer within the ICA and ECA at the level of the guttural pouch. Transducer position was confirmed by endoscopic visualization. Mean arterial pressure (MAP) was measured with horses in both a head-up and head-down position. The dorsal metatarsal artery was catheterized as a control. Maintaining ...
Birmingham SSW, Mason RM.Serum amyloid A (SAA) is one of the major acute phase proteins in horses. It serves as a marker for systemic inflammation and infection, as the concentration can increase 100- to even 1000-fold during systemic disease processes. The objective of this study was to evaluate the effect of sedation, oral examination, and odontoplasty on systemic inflammation as measured by SAA in the adult performance horse. This study included 32 clinically healthy adult performance horses. Blood samples were collected immediately prior to sedation, oral examination, and odontoplasty and 48 and 72 hours afterward...
Nóbrega Neto PI, Luna SP, Queiroz-Williams P, Mama KR, Steffey EP, Carregaro AB.This study investigated the antinociceptive effects of a constant rate infusion (CRI) of lidocaine during xylazine and ketamine anesthesia in horses and aimed to correlate these effects with cardiorespiratory variables, bispectral index (BIS) and plasma lidocaine concentrations. Six adult crossbred mares weighing 320-400 kg were anesthetized on three different occasions. Sedation was performed with xylazine (0.75 mg/kg IV) and anesthetic induction with guaifenesin (75 mg/kg IV) and ketamine (2 mg/kg IV). Anesthesia was maintained with 37.5 μg/kg/min of xylazine and 87.5 μg/kg/min of ketamine...
Giuliano EA, Maggs DJ, Moore CP, Boland LA, Champagne ES, Galle LE.The objective of this study was to describe method of placement, and frequency and severity of complications associated with a subpalpebral lavage system placed in the medial aspect of the equine inferior eyelid. The inferomedial subpalpebral lavage (ISPL) tube is positioned deep in the medial aspect of the inferior conjunctival fornix so that the footplate lies flat between the lower eyelid and the anterior surface of the nictitans. Retrospective data from the placement of 92 ISPL systems placed in 86 horses during a 31-month period were examined. Tube placement was performed using sedation a...
Vakkuri O, Salonen JS, Leppäluoto J, Anttila M, Karjalainen A, Järvensivu P.A sensitive and specific radioimmunoassay was developed for detomidine, 4(5)-(2,3-dimethylbenzyl)imidazole. The antibodies were raised in rabbits against a conjugate of detomidine and bovine thyroglobulin prepared by diazo reaction. Detomidine was iodinated with chloramine-T and immunoreactive tracer was purified in cation exchange chromatography. The sensitivity of the RIA was 1.6 fmol/tube allowing direct detomidine measurements from minute serum and urine samples (0.1-0.2 microliter) as well as tissue homogenates (10 microliters). For concentrations below 16 pmol/ml chloroform extraction wa...
Wong DM, Davis JL, Alcott CJ, Hepworth-Warren KL, Galow-Kersh NL, Rice S, Coetzee JF.The objective of this study was to evaluate the pharmacokinetic properties and physiologic effects of a single oral dose of alprazolam in horses. Seven adult female horses received an oral administration of alprazolam at a dosage of 0.04 mg/kg body weight. Blood samples were collected at various time points and assayed for alprazolam and its metabolite, α-hydroxyalprazolam, using liquid chromatography/mass spectrometry. Pharmacokinetic disposition of alprazolam was analyzed by a one-compartmental approach. Mean plasma pharmacokinetic parameters (±SD) following single-dose administration of ...
Kaegi B.25 horses which entered the clinic for minor surgery, received ketamine (2.2 mg/kg i.v.) for induction of anesthesia after previous sedation with xylazine (1.1 mg/kg i.v.). As soon as the horses were in the lateral recumbency, the benzodiazepine derivate climazolam was administered at a dose of 0.1 mg/kg i.v. (10 horses) or 0.2 mg/kg i.v. (15 horses). The anesthesia was maintained with repeated injections of ketamine (1.1 mg/kg i.v. every 9-12 minutes). At the end of the surgery, 20 minutes after the last ketamine injection, Ro 15-3505, a benzodiazepine antagonist, was injected at a dose of 0....
Guinnefollau L, Gee EK, Norman EJ, Rogers CW, Bolwell CF.Horses are used in practical teaching classes in many equine and veterinary science degree programmes to develop and refine the handling and clinical skills of students. In this study, the activities of 24 teaching horses grouped in three herds were investigated over an entire calendar year. Although also used for research and general husbandry, teaching-related activities were the predominant use of the horses. Herd B was used for a greater number of teaching sessions (median = 28, IQR = 27-29.5 per year) than herds M (median = 21, IQR = 20-21 per year) and T (median = 19.5, IQR = 13.75-25.5 ...
Knych HK, Kanarr K, Fang Y, McKemie DS, Kass PH.To describe the pharmacokinetics, behavioral and physiologic effects and effects on thermal thresholds of morphine, morphine 6-glucuronide (M6G) and morphine 3-glucuronide (M3G) following administration to horses. Methods: Randomized balanced crossover study. Methods: A total of seven University-owned horses, five mares and two geldings, aged 3-6 years. Methods: Horses were treated with a single intravenous dosage of saline, morphine (0.2 mg kg), M6G (0.01 mg kg) and M3G (0.03 mg kg). Blood was collected prior to (baseline) and at several times post administration. Drug and metabolite concentr...
Honnas CM, Wheat JD.Transnasal, axial division of the aryepiglottic fold was performed to correct entrapment of the epiglottis in 20 sedated, standing horses, using a hooked bistoury and topical anesthesia. Presenting complaints included decreased exercise tolerance or loss of racing performance, abnormal respiratory noise, and coughing. The surgical procedure was technically easy to perform with a minimum of instrumentation. The horses were rested an average of 18 days before race training or riding was resumed. Evaluation of racing records or contact with owners indicated that most affected horses competed succ...
Ganidagli S, Cetin H, Biricik HS, Cimtay I.Two groups of six mares aged from eight to 18 years were anaesthetised by caudal epidural injections of ropivacaine (0.5 per cent, 0.1 mg/kg) or a combination of ripovacaine (0.08 mg/kg) and fentanyl (100 microg) in a randomised study. The onset of anaesthesia was significantly more rapid (P<0.001) and it lasted significantly longer (P<0.001) in the group anaesthetised with the combination of drugs. The surgical comfort scores of the group anaesthetised with the combination were higher than those of the group anaesthetised with ropivacaine alone (P<0.001), and the quality of intraoper...
Waldern NM, Weishaupt MA, Imboden I, Wiestner T, Lischer CJ.To evaluate the effects of shock wave treatment on cutaneous nerve function, compared with the effects of local nerve block and sedation. Methods: 18 clinically sound Swiss Warmbloods. Methods: Horses were randomly allocated to 3 groups and received different amounts and types of shock waves (extracorporeal shock wave treatment [ESWT] or radial pressure wave treatment [RPWT]). Horses were sedated with xylazine and levomethadone. Shock waves were applied to the lateral palmar digital nerve at the level of the proximal sesamoid bones on 1 forelimb. Skin sensitivity was evaluated by means of an e...
Miller PJ, Martin IC, Kohnke JR, Rose RJ.The effects of acepromazine maleate (ACP), given orally in a paste form, were examined in six standard-bred geldings over a 12 hour period. Three dose rates, zero (placebo paste), 0.13 mg kg-1 and 0.26 mg kg-1, given before or after feeding, were investigated. The data were divided into two sampling periods for analysis, one from zero to 120 minutes and the other from four to 12 hours. Sedation was assessed by a score (TS score) based on general appearance, anal sphincter relaxation and penile protrusion. This TS score was significantly elevated 40 minutes after dosing with ACP, irrespective o...
