Plasma is the liquid component of blood in horses, consisting primarily of water, electrolytes, proteins, and waste products. It serves as a transport medium for nutrients, hormones, and waste products throughout the body. Plasma also plays a role in maintaining blood pressure and volume, as well as serving as a reservoir for critical proteins involved in clotting and immune responses. Research on equine plasma often focuses on its composition, functions, and applications in veterinary medicine, such as transfusions and diagnostic testing. This page compiles peer-reviewed research studies and scholarly articles that explore the properties, functions, and clinical applications of plasma in equine health.
Silva ESM, Ignácio FS, Fritsch SC, Zanoni DS, Pantoja JCF, Oliveira-Filho JP, Meira C.To test the hypothesis that the administration of 2.5 mg of estradiol benzoate (EB) followed by 1500 mg of long acting progesterone (LA P4) causes similar uterine changes and molecular dynamics in anovulatory mares to those observed in cyclic ones, we evaluated the changes of estrogen (ERα and ERβ) and progesterone receptors (PR) in anestrous, transitional and cyclic mares by RT-qPCR and immunohistochemistry. In addition, we evaluated uterine edema, tonus and estrogens and progesterone plasma profile. Endometrial biopsies were taken from anestrous and transitional mares immediately before ...
Liu Y, Uboh CE, Li X, Guan F, You Y, Maylin GA, Zhu F, Soma LR.A rapid and sensitive method for simultaneous screening, quantification and confirmation of 17 barbiturates in horse plasma using liquid chromatography-tandem mass spectrometry is described. Analytes were recovered from plasma by liquid-liquid extraction using methyl tert-butyl ether, separated on a C18 column, and analyzed in negative electrospray ionization mode. Multiple-reaction monitoring was employed for screening and quantification. Confirmation for the presence of the analytes was achieved by comparing ion intensity ratio. The ranges for limits of detection, quantification and confirma...
Fragkaki AG, Kioukia-Fougia N, Kiousi P, Kioussi M, Tsivou M.The artificial increase of the physical capability of horses using drugs is well known in racing and other equine sports. Both illicit and therapeutic substances are regarded as prohibited substances in competition in most countries. Some countries make distinctions for a few, specific drugs which are, however, allowed for use in other countries. The primary objective in the case of doping control is the detection of any trace of drug exposure, either parent drug or any of its metabolites, using the most powerful analytical methods which are generally based on chromatographic/mass spectrometri...
Baskerville CL, Bamford NJ, Harris PA, Bailey SR.Insulin-like growth factor-1 (IGF-1) plays several important physiological roles, and IGF-related pathways have been implicated in developmental osteochondral disease and endocrinopathic laminitis. This factor is also a downstream marker of growth hormone activity and its peptide mimetics. Unfortunately, previously used assays for measuring equine IGF-1 (radioimmunoassays and ELISAs) are no longer commercially available, and many of the kits on the market give poor results when used on horse samples. The aim of the present study was to compare three different ELISA assays (two human and one ho...
Niimura Del Barrio MC, Bennett RC, Hughes JML.Influence of detomidine or romifidine constant rate infusion (CRI) on plasma lactate concentration and isoflurane requirements in horses undergoing elective surgery. Methods: Prospective, randomised, blinded, clinical trial. Methods: A total of 24 adult healthy horses. Methods: All horses were administered intramuscular acepromazine (0.02 mg kg) and either intravenous detomidine (0.02 mg kg) (group D), romifidine (0.08 mg kg) (group R) or xylazine (1.0 mg kg) (group C) prior to anaesthesia. Group D was administered detomidine CRI (10 μg kg hour) in lactated Ringer's solution (LRS), group...
Barnett SE, Sellon DC, Hines MT, Seino KK, Knych HK.OBJECTIVE To determine the plasma pharmacokinetics and safety of 1% diclofenac sodium cream applied topically to neonatal foals every 12 hours for 7 days. ANIMALS Twelve 2- to 14-day old healthy Arabian and Arabian-pony cross neonatal foals. PROCEDURES A 1.27-cm strip of cream containing 7.3 mg of diclofenac sodium (n = 6 foals) or an equivalent amount of placebo cream (6 foals) was applied topically to a 5-cm square of shaved skin over the anterolateral aspect of the left tarsometatarsal region every 12 hours for 7 days. Physical examination, CBC, serum biochemistry, urinalysis, gastric endos...
Stefánsdóttir GJ, Gunnarsson V, Roepstorff L, Ragnarsson S, Jansson A.This study examined the effect of increasing BW ratio (BWR) between rider and horse, in the BWR range common for Icelandic horses (20% to 35%), on heart rate (HR), plasma lactate concentration (Lac), BWR at Lac 4 mmol/l (W4), breathing frequency (BF), rectal temperature (RT) and hematocrit (Hct) in Icelandic horses. In total, eight experienced school-horses were used in an incremental exercise test performed outdoors on an oval riding track and one rider rode all horses. The exercise test consisted of five phases (each 642 m) in tölt, a four-beat symmetrical gait, at a speed of 5.4±0.1 m/s (...
Macpherson ML, Giguère S, Pozor MA, Runcan E, Vickroy TW, Benson SA, Troedsson MHT, Hatzel JN, Larson J, Vanden Berg E, Kelleman AA, Sanchez LC....Eleven pregnant pony mares (D270-326) were administered ceftiofur sodium intramuscularly at 2.2 mg/kg (n = 6) or 4.4 mg/kg (n = 5), once daily. Plasma was obtained prior to ceftiofur administration and at 0.5, 1, 2, 4, 8, 12, and 24 hr after administration. Eight pony mares were re-enrolled in the study at least 3 days from expected foaling to ensure steady-state concentrations of drug at the time of foaling. Mares were administered ceftiofur sodium (4.4 mg/kg, IM) daily until foaling. Parturition was induced using oxytocin 1 hr after ceftiofur sodium administration. Allantoic and am...
Berlin S, Randow T, Scheuch E, Grube M, Venner M, Siegmund W.The long-acting azalide antibiotic gamithromycin is marketed for intramuscular treatment of bovine and swine infections. Off-label use in foals leads to severe local lesions likely caused by hyperosmolality of the injected solution. We provide evidence from a pharmacokinetic study in 10 warm-blooded healthy foals for intravenous bolus injection of gamithromycin diluted in distilled water to be a safe and well tolerated alternative. By intravenous dosing, markedly higher plasma exposure and better penetration into bronchoalveolar lavage cells but lower distribution into epithelial lining fluid ...
Knych HK, Stanley SD, Harrison LM, Mckemie DS.The use of corticosteroids, such as betamethasone, in performance horses is tightly regulated. The objective of the current study was to describe the plasma pharmacokinetics of betamethasone as well as time-related urine and synovial fluid concentrations following intra-articular administration to horses. Twelve racing-fit adult Thoroughbred horses received a single intra-articular administration (9Â mg) of a betamethasone sodium phosphate and betamethasone acetate injectable suspension into the right antebrachiocarpal joint. Blood, urine, and synovial fluid samples were collected prior to and...
Choi TLS, Wong JKY, Ho ENM, Kwok WH, Leung GNW, Curl P, Wan TSM.Lithium salts are commonly prescribed to treat bipolar disorder in humans. They are effective for the treatment of acute mania and the prophylaxis of manic relapses through long-term use. Although there is no reported legitimate therapeutic use of lithium in horses, its potential mood-stabilizing effect, low cost, and ready availability make lithium salt a potential agent of abuse in equine sports, especially for equestrian competition horses. Lithium can be found in soil, plants, and water, as such it is naturally present in the equine body, thus a threshold is necessary to control its misuse...
Jacobson GA, Raidal S, Robson K, Narkowicz CK, Nichols DS, Haydn Walters E.Salbutamol is usually administered as a racemic mixture but little is known about the enantioselectivity of salbutamol pharmacokinetics in the lung. This study was designed to investigate enantiomer concentrations in lung tissue after inhaled dosing. Horses (n = 12) received racemic salbutamol 1000 μg via inhalation. Enantioselective ultra performance liquid chromatography-tandem mass spectrometry was used to determine salbutamol concentrations in pulmonary epithelial lining fluid (PELF) sampled 2, 5, 10 and 15 min after administration, in central lung (endoscopic bronchial biopsy) and per...
The goal of the current study was to evaluate the comparative efficacy of ivermectin (IVM) against small strongyles (cyathostomins) following its oral and intramuscular (IM) administration, in naturally parasitized horses. The parasitological data were complemented with the assessment of the plasma disposition kinetics of IVM. The trial included two different experiments. In experiment I, 40 horses naturally infected with small strongyles were randomly allocated into four experimental groups (n=10) and treated with IVM (0.2mg/kg) as follows: IVM oral paste, animals were orally treated with Eqv...
Elzinga SE, Rohleder B, Schanbacher B, McQuerry K, Barker VD, Adams AA.Extracts derived from the leaves of the stevia plant (stevioside) are commonly used as sweeteners for humans and horses. Stevioside appears to be safe for human consumption, including for individuals with insulin dysregulation. In the horse, the safety or metabolic effects of stevioside on normal animals or on those with metabolic dysfunction are unknown. Furthermore, the inflammatory response to a glycemic challenge or to stevioside in horses is not well defined. Therefore, the objective of this study was to measure the effects of stevioside and a glycemic challenge on insulin, glucose, and i...
Barton AK, Heinemann H, Schenk I, Machnik M, Gehlen H.OBJECTIVE To evaluate the influence of respiratory tract disease (ie, recurrent airway obstruction [RAO]) and mode of inhalation on detectability of inhaled budesonide in equine plasma and urine samples. ANIMALS 16 horses (8 healthy control horses and 8 horses affected by RAO, as determined by results of clinical examination, blood gas analysis, bronchoscopy, and cytologic examination of bronchoalveolar lavage fluid). PROCEDURES 4 horses of each group inhaled budesonide (3 μg/kg) twice daily for 10 days while at rest, and the remaining 4 horses of each group inhaled budesonide during lunging ...
Buntenkötter K, Osmers M, Schenk I, Schänzer W, Machnik M, Düe M, Kietzmann M.Although acetylsalicylic acid (ASA) is not frequently used as a therapeutic agent in horses, its metabolite SA is of special interest in equestrianism since it is a natural component of many plants used as horse feed. This led to the establishment of thresholds by horse sport organizations for SA in urine and plasma. The aim of this study was to investigate plasma and urine concentrations of salicylic acid (SA) after oral administration of three different single dosages (12.5 mg/kg, 25 mg/kg and 50 mg/kg) of acetylsalicylic acid (ASA) to eight horses in a cross-over designed study. Results:...
Crosignani N, Luna SP, Dalla Costa T, Pimenta EL, Detoni CB, Guterres SS, Puoli Filho JN, Pantoja JC, Pigatto MC.We investigated the thermal, electrical and mechanical antinociceptive and physiological effects (heart rate, respiratory rate, arterial blood pressure, head height and abdominal auscultation score), and pharmacokinetics, of 0.5Â mg/kg of the injectable formulation (ORAL) or nanoparticulated methadone (NANO) given orally, in six adult mares, using a crossover, blind and prospective design. Repeated-measure models were used to compare parametric data between and within treatments, followed by Tukey's test. Nonparametric data were analysed with Wilcoxon signed-rank, adjusted by Bonferroni tests....
Heffron B, Bash J, Larsen AK.The use of alkinizing agents by trainers to counteract the accumulation of lactic acid in racehorses has been well documented. A by-product of this administration is elevated total carbon dioxide (tCO2) concentrations. Most regulatory authorities have set the threshold for tCO2 in plasma at 37 mM. The quantification of tCO2 often presents a challenge to laboratories due to the instrumentation required, which can be expensive to use and maintain. The Beckman DxC 600 (Brea, CA) is currently used in our laboratory for tCO2 quantification. The goal of this research was to determine if another anal...
Edwards SH, Khalfan SA, Jacobson GA, Pirie AD, Raidal SL.OBJECTIVE To determine plasma drug concentrations after IV administration of a bolus followed by continuous rate infusion (CRI) of sodium benzylpenicillin and ceftiofur sodium to healthy adult horses. ANIMALS 6 Thoroughbred mares (3 to 9 years old; mean ± SD body weight, 544 ± 55 kg) with no history of recent antimicrobial treatment. PROCEDURES Horses were used in 2 experiments conducted 14 days apart. For each experiment, horses were housed individually in stables, and catheters were placed bilaterally in both jugular veins for drug administration by CRI (left catheter) and for intermittent...
Bonelli F, Meucci V, Divers TJ, Wagner B, Intorre L, Sgorbini M.Endotoxemia represents a significant clinical and economic problem for the equine industry. This study assesses the kinetics of soluble CD14 (sCD14), chemokine (CC motif) ligand 2 (CCL2), interleukin 10 (IL-10) and plasma procalcitonin (PCT) in healthy horses after the intravenous infusion of lipopolysaccharide (LPS). The aim was to contribute to the basic understanding of the equine species-specific kinetics of these molecules in response to LPS exposure, which could support further findings in clinical studies and identify valuable inflammatory biomarkers for equine practice. Eleven healthy ...
Nagel C, Trenk L, Wulf M, Ille N, Aurich J, Aurich C.In mares, foaling is associated with changes in hematology, plasma electrolytes, blood pressure and heart rate and it has been hypothesized that these are induced by oxytocin. To test this hypothesis, mares (n = 8-14/group) were treated with oxytocin (OT; 20 I.U.) or saline (CON) at 1 h (test A) and 12 h after foaling (test B) and during first postpartum diestrus (test C). Heart rate, heart rate variability (HRV), atrioventricular blocks, salivary cortisol concentration, blood pressure, plasma electrolytes and blood count were determined. Heart rate decreased from test A to C (P < 0.001)...
Barton AK, Pelli A, Rieger M, Gehlen H.Procalcitonin (PCT), a precursor protein of the hormone calcitonin, is a sensitive inflammatory marker in human medicine, which is primarily used for diagnosis of bacterial sepsis, but is also useful in diagnosis of exacerbation of asthma and COPD. In this study, PCT was evaluated as a potential biomarker for different chronic pneumopathies in the horse using an equine specific ELISA in comparison to established clinical markers and different interleukins. Sixty-four horses were classified as free of respiratory disease, recurrent airway obstruction (RAO), inflammatory airway disease (IAD) or ...
Arroyo LG, Costa MC, Guest BB, Plattner BL, Lillie BN, Weese JS.Duodenitis-proximal jejunitis (DPJ) is an acute sporadic gastrointestinal disorder of horses of unknown cause. Objective: We hypothesize that Clostridium difficile toxins are involved in the pathogenesis of DPJ in horses. The objective of this study was to determine whether experimentally delivered C. difficile toxins cause clinical signs and histologic lesions similar to those of naturally occurring DPJ. Methods: Six healthy mature mixed breed horses. Methods: Experimental study: animal model of animal disease. Fasted horses were administered crude C. difficile toxins via gastroscopy and moni...
Younkin TJ, Davis EG, Kukanich B.The primary study objective was to compare the pharmacokinetics of p.o. terbinafine alone to p.o. terbinafine administered with p.o. cimetidine in healthy adult horses. The second objective was to assess the pharmacokinetics of terbinafine when administered per rectum in two different suspensions at 30Â mg/kg to adult horses. Six healthy adult horses were included in this crossover study. Plasma terbinafine concentrations were quantified with liquid chromatography and mass spectrometry. The half-life (geometric mean) was 8.38 and 10.76Â h, for p.o. alone and p.o. with cimetidine, respectively....
Wong KS, Chan GHM, Ho ENM, Wan TSM.Growth hormone (GH), or somatotropin, is a protein that may enhance physical performance and facilitate growth and wound healing. For this reason, growth hormones and their recombinant analogues are prohibited in human sports by the World Anti-Doping Agency (WADA) and in horseracing under Article 6 of the International Agreement on Breeding, Racing and Wagering published by the International Federation of Horse Racing Authorities (IFHA). Identifying the illicit use of GHs in both human athletes and racehorses is challenging, especially when differentiating between endogenous and exogenous GHs,...
Johnson CB, Bloomfield M, Taylor PM.To characterise the effects of thiopentone on the equine electroencephalogram during halothane anaesthesia. Methods: Prospective controlled study. Methods: Eight healthy Welsh mountain pony geldings between 5 and 9 years old and weighing between 270 and 330 kg (mean 301 kg). Methods: Anaesthesia was induced with thiopentone and maintained using halothane in oxygen. End tidal halothane was maintained above 0.75 and below 0.85%. EEG was recorded continuously and a binaural broad band click stimulus was provided throughout the experiment at 6.1224 Hz. An infusion of 500 mg thiopentone was given o...
Taylor PM, Luna S, Dye A.To determine the effects of surgery, hypoxia, hypercapnia and flunixin administration on plasma β-endorphin immunoreactivity (BEI) in anaesthetized horses. Methods: Prospective crossover study. Methods: Six healthy adult Welsh Mountain ponies and seven healthy adult Thoroughbreds. Methods: Ponies were anaesthetized with thiopentone and halothane or with pentobarbitone and the horses with guaiphenesin, thiopentone and halothane. Ponies were anaesthetized for 2 hours and on separate occasions underwent a period of hypoxia, hypercapnia, anaesthesia only, or were given flunixin at induction. The ...
Taylor PM, White KL, Fowden AL, Giussani DA, Bloomfield M, Sear JW.To characterize propofol anaesthesia in pregnant ponies. Methods: Fourteen pony mares, at 256 ± 49 days gestation, undergoing abdominal surgery to implant fetal and maternal vascular catheters. Methods: Pre-anaesthetic medication with intravenous (IV) acepromazine (20 µg kg), butorphanol (20 µg kg) and detomidine (10 µg kg) was given 30 minutes before induction of anaesthesia with detomidine (10 µg kg) and ketamine (2 mg kg) IV Maternal arterial blood pressure was recorded (facial artery) throughout anaesthesia. Arterial blood gas values and plasma concentrations of glucose, lactate, cort...
Tranquilli WJ, Thurmon JC, Neff-Davis CA, Davis LE, Benson GJ, Hoffman W, Lock TF.Plasma glucose and serum insulin concentrations in Thoroughbreds administered xylazine hydrochloride (1.1 mg/kg; IV) and ketamine hydrochloride (2.2 mg/kg; IV) at dosages sufficient to induce short periods of recumbency and anesthesia were measured. Samples of blood were collected from 6 adult horses before, during, and after the anesthetic period. Plasma glucose (mg/dl) was significantly increased above control (-30 minute concentration) from 15 to 150 minutes after xylazine administration with the peak value occurring at 30 minutes. Serum insulin (microU/ml) was significantly decreased from ...
van Duijkeren E, Ensink JM, Meijer LA.The distribution of trimethoprim (TMP) and sulfadiazine (SDZ) into subcutaneously implanted noninfected tissue chambers was studied in healthy adult ponies. Six ponies were given an oral TMP/SDZ paste formulation at a dose of 5 mg/kg TMP and 25 mg/kg SDZ at 12 h intervals for 2 days in order to reach steady-state concentrations. Plasma concentrations and tissue chamber fluid (TCF) concentrations of both drugs were measured at regular intervals during a period commencing 24 h after the last oral administration. The peak concentration of TMP (mean +/- SD) was 2.92 +/- 0.86 microg/mL for plasma a...
Scheuch E, Spieker J, Venner M, Siegmund W.The long-acting antibiotic tulathromycin is on the marked for treatment of pulmonary infection of cattle, swine and horses. To measure disposition and distribution of tulathromycin in foals, a high throughput method was developed for horse plasma (calibration range: 0.006-0.8 microg/mL) and broncho-alveolar cells (calibration range: 0.1-4.0 microg/10(9)cells) using tandem mass spectrometry. Tulathromycin was extracted from plasma and broncho-alveolar fluid using cation exchange cartridges with acetonitrile/ammonia (95:5, v/v). The chromatography was performed isocratically with a mobile phase ...
Forro M, Cieslar S, Ecker GL, Walzak A, Hahn J, Lindinger MI.The purposes of this study were 1) to determine the compartmentation of body water in horses by using indicator dilution techniques and 2) to simultaneously measure bioelectrical impedance to current flow at impulse current frequencies of 5 and 200 kHz to formulate predictive equations that could be used to estimate total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV). Eight horses and ponies weighing from 214 to 636 kg had catheters placed into the left and right jugular veins. Deuterium oxide, sodium thiocyanate, and Evans blue were infused for the...
Hackl S, van den Hoven R, Zickl M, Spona J, Zentek J.Few data are available on post-prandial changes of plasma amino acids (AAs) in horses and on the repeatability and the individual variance on different sampling days. The objective of the present study was to measure pre- and post-prandial concentrations of plasma AA in 10 yearling horses. Blood samples were taken on days 1 and 40 of the study before feeding of hay, oats and soya meal and over an 8 h post-prandial period in 2-h intervals. The plasma AAs were measured by high-pressure liquid chromatography after ortho-phthalaldehyde derivatization. Mean fasting concentrations of the AAs were no...
Gehlen H, Twickel S, Stöckle S, Weber C, Bartmann CP.Pituitary pars intermedia dysfunction is the most prevalent endocrine disease in horses. Although donkeys and mules may also be affected, only a few data have been published. Reference values for diagnostic parameters, such as adrenocorticotropic hormone (ACTH), are especially scarce or even lacking. Therefore, in the present study, available data from the literature have been verified and completed to facilitate a reliable diagnosis. Clinical inspections and haematological and biochemical examinations were carried out four times in a three-month interval (February to November) in 44 donkeys a...
Lavoie JP, Thompson D, Hamilton E, Debrue M, David F, Hickey G.It has been suggested that many of the beneficial effects of corticosteroids are mediated through mitogen-activated protein kinase (MAPK) p38 inhibition. Objective: To investigate the efficacy of the MAPK p38 inhibitor compound MRL-EQ1 to either prevent (Phase 1) or treat (Phase 2) recurrent airway obstruction (RAO) in horses. Methods: MRL-EQ1 was administered i.v. at a dosage of 0.75-1.5 mg/kg bwt q. 12 h. In Phase 1, susceptible horses in clinical remission were divided into 2 groups (n = 5/group), based on historical values of respiratory mechanics. All horses were entered in the study in p...
Rose RJ, Allen JR, Hodgson DR, Stewart JH, Chan W.Four standardbred horses with subcutaneously relocated carotid arteries were given a seven week training programme of treadmill exercise at a gradient of 19 per cent in order to assess if there were any effects of exercise and training on haematology, arterial blood gas and acid base measurements, plasma biochemistry and heart rate. The exercise consisted of one minute walking at 110 metres/minute followed by five minutes trotting at 200 metres/minute, twice daily in the first week. The period of trotting exercise was increased by one minute per week so that by the seventh week the horses were...
Baker B, Gaffin SL, Wells M, Wessels BC, Brock-Utne JG.Endotoxins (lipopolysaccharides-LPS) and anti-endotoxin IgG antibodies were measured in racehorses before and after races of 1,000, 2,000 and 2,800 m. Results show that the mean plasma concentration of endotoxin increased significantly (p less than 0.02) while the anti-LPS IgG concentration decreased significantly (p less than 0.005) in all horses following the races. Pre-race and post-race anti-LPS IgG levels in racing-fit racehorses were significantly higher than in untrained horses (p less than 0.05). The possibility therefore exists that training-induced stress leads to leakage of LPS into...
Vukojević V, Bowen AM, Wilhelm K, Ming Y, Ce Z, Schleucher J, Hore PJ, Terenius L, Morozova-Roche LA.Recent evidence supports the idea that early aggregates, protein, and lipoprotein oligomers but not large aggregates like fibrils that are formed at late stages of the aggregation process are responsible for cytotoxicity. Oligomers can interact with the cellular plasma membrane affecting its structure and/or dynamics or may be taken up by the cells. In either case, disparate cascades of molecular interactions are activated in the attempt to counteract the disturbance induced by the oligomers. If unsuccessful, cell death follows. Here, we study the molecular and cellular mechanisms underlying P...
Grimsrud KN, Mama KR, Thomasy SM, Stanley SD.Detomidine is commonly used i.v. for sedation and analgesia in horses, but the pharmacokinetics and metabolism of this drug have not been well described. Objective: To describe the pharmacokinetics of detomidine and its metabolites, 3-hydroxy-detomidine (OH-detomidine) and detomidine 3-carboxylic acid (COOH-detomidine), after i.v. and i.m. administration of a single dose to horses. Methods: Eight horses were used in a balanced crossover design study. In Phase 1, 4 horses received a single dose of i.v. detomidine, administered 30 microg/kg bwt and 4 a single dose i.m. 30 microg/kg bwt. In Phase...
Chiavaccini L, Claude AK, Lee JH, Ross MK, Meyer RE, Langston VC.The study objective was to compare butorphanol pharmacokinetics and physiologic effects following intravenous and subcutaneous administration in horses. Ten adult horses received 0.1 mg/kg butorphanol by either intravenous or subcutaneous injections, in a randomized crossover design. Plasma concentrations of butorphanol were measured at predetermined time points using highly sensitive liquid chromatography-tandem mass spectrometry assay (LC-MS/MS). Demeanor and physiologic variables were recorded. Data were analyzed with multivariate mixed-effect model on ranks (P ≤ 0.05). For subcutaneous i...
Lejeune JP, Sandersen C, Votion D, Caudron I, Vander Heyden L, Franck T, Ceusters J, Mouithys-Mickalad A, Niesten A, De La Rebière de Pouyade G....Intensive exercise induces a systemic inflammatory response characterised by an increase of blood neutrophil count and myeloperoxidase (MPO) release. Neutrophil elastase (NE) could also contribute to tissues lesions by its proteinase activities. Objective: To compare plasmatic NE concentrations before and after different forms of intensive exercise. Methods: EDTA blood samples were taken from 51 eventing horses (EvH) and 32 endurance horses (EndH) were sampled before the race (T0). Blood sampling was performed 2 h (T1) after completing either phase D of a one or 2 star eventing competition (n ...
McGorum BC, Mayhew IG, Amory H, Deprez P, Gillies L, Green K, Mair TS, Nollet H, Wijnberg ID, Hahn CN.Equine motor neuron disease (EMND) was diagnosed in 3 horses maintained on lush, grass-based pasture. This contrasted with North American studies which identified limited or no access to green herbage as an important risk factor for EMND. Objective: Grazing horses that have an apparently adequate intake of pasture herbage to meet normal equine vitamin E requirements can develop EMND. Methods: Owners of 32 European horses diagnosed with EMND completed a questionnaire regarding intrinsic, managemental, nutritional and environmental factors that could potentially be risk factors for EMND, and als...
Jacobson GA, Raidal S, Robson K, Narkowicz CK, Nichols DS, Haydn Walters E.Salbutamol is usually administered as a racemic mixture but little is known about the enantioselectivity of salbutamol pharmacokinetics in the lung. This study was designed to investigate enantiomer concentrations in lung tissue after inhaled dosing. Horses (n = 12) received racemic salbutamol 1000 μg via inhalation. Enantioselective ultra performance liquid chromatography-tandem mass spectrometry was used to determine salbutamol concentrations in pulmonary epithelial lining fluid (PELF) sampled 2, 5, 10 and 15 min after administration, in central lung (endoscopic bronchial biopsy) and per...
Schumacher SA, Yardley J, Bertone AL.Magnesium sulfate (MgSO ) was administered to calm competition horses. We evaluated the impact of regulatory requirements for the handling of blood samples on plasma ionized magnesium (iMg), ionized calcium (iCa), the iMg to iCa ratio, and pH. We hypothesized that iCa, iMg. and iMg/iCa would be similar among storage and collection methods. Four blood samples were collected from each of 50 horses on the same day: Group 1 - collection in a heparinized syringe and processed within hours in a clinical laboratory; Group 2 - collection into a plasma separator tube (PST) centrifuged just prior to ana...
Goodale L, Frank N, Hermida P, D'Oench S.To determine whether plasma ACTH concentrations vary following administration of a thyrotropin-releasing hormone (TRH) solution prepared for research purposes and stored at -20°C (rTRH) or prepared by a compounding pharmacy and stored at room temperature (approx 22°C; cTRH). Methods: 34 adult horses. Methods: The study consisted of 2 experiments. In experiment 1, each horse underwent 2 TRH stimulation tests separated by 24 hours; 10 horses were administered cTRH for the first test and rTRH for the second test (group 1), 10 horses were administered rTRH for the first test and cTRH for the sec...
Rossdale PD, Ousey JC, McGladdery AJ, Prandi S, Holdstock N, Grainger L, Houghton E.Plasma progestagen concentrations were measured daily by radioimmunoassay (RIA) in 35 sick foals for the duration of their illness. The foals were divided into three groups on the basis of time to stand after birth. Foals were given intensive care treatment according to the severity of their illness. Plasma and urine concentrations of pregnenolone (P5) and pregnenediol (P5 beta beta) were measured by gas chromatography--mass spectrometry; plasma cortisol concentrations were measured by RIA and the foals' renal and respiratory status were assessed by creatinine clearance ratios and arterial oxy...
Kahn SK, Cohen ND, Bordin AI, Coleman MC, Heird JC, Welsh TH.The bacterium Rhodococcus equi causes pneumonia in foals that is prevalent at breeding farms worldwide. In the absence of an effective vaccine, transfusion of commercial plasma from donor horses hyperimmunised against R. equi is used by many farms to reduce the incidence of pneumonia among foals at farms where the disease is endemic. The effectiveness of hyperimmune plasma for controlling R. equi pneumonia in foals has varied considerably among reports. The purposes of this narrative review are: (1) to review early studies that provided a foundational basis for the practice of transfusion of h...
Harris PA, Marlin DJ, Gray J.In order to investigate the effect of age, sex and month on the response of plasma aspartate aminotransferase (AST) and creatine kinase (CK) to exercise, blood samples were collected once a month between March and September from a group of 40 2- and 3-year-old (2yo and 3yo) thoroughbred racehorses (kept under the same managemental regimen) at rest before exercise (PRE) and at 2 (2H) and 24 h (24H) post-exercise. The absolute change in activities between the 2H and PRE samples (2H delta) and the 24H and PRE samples (24H delta) was also calculated. Age had a significant effect on all measured an...
De Moffarts B, Portier K, Kirschvink N, Coudert J, Fellmann N, van Erck E, Letellier C, Motta C, Pincemail J, Art T, Lekeux P.The aim of this study was to investigate in a placebo-controlled field study the effect of a (n-3)-vitamin supplementation on erythrocyte membrane fluidity (EMF), oxidant/antioxidant markers and plasmatic omega3/omega6 fatty acid ratio (FAR) in 12 eventing horses. Venous blood was sampled at rest before (PRE) and after (POST) a three week treatment period with either the supplement (group S, n=6) or a placebo (group P, n=6) as well as after 15min (POST E15') and 24h (POST E24h) after a standardised exercise test. The following markers were analysed: EMF, plasma antioxidant capacity of water an...
Uney K, Altan F, Altan S, Erol H, Arican M, Elmas M.The plasma and synovial fluid pharmacokinetics and safety of cefquinome, a 2-amino-5-thiazolyl cephalosporin, were determined after multiple intravenous administrations in sixteen healthy horses. Cefquinome was administered to each horse through a slow i.v. injection over 20 min at 1, 2, 4, and 6 mg/kg (n = 4 horses per dose) every 12 h for 7 days (a total of 13 injections). Serial blood and synovial fluid samples were collected during the 12 h after the administration of the first and last doses and were analyzed by a high-performance liquid chromatography assay. The data were evaluate...
Soma LR, Uboh CE, Luo Y, Guan F, Moate PJ, Boston RC.To determine the pharmacokinetics of methylprednisolone (MP) and develop a pharmacokinetic-pharmacodynamic model of the related changes in plasma concentrations of endogenous hydrocortisone (HYD) and cortisone (COR) following intra-articular administration of methylprednisolone acetate (MPA) in horses. Methods: 6 Thoroughbreds. Methods: In each horse, 200 mg of MPA was injected intrasynovially into a carpal joint, and plasma MP, HYD, and COR concentrations were determined via liquid chromatography-mass spectrometry. Results: A 5-compartment pharmacokinetic-pharmacodynamic model was used to des...
Jensen RB, Rockhold LL, Tauson AH.The main objectives of this study were to evaluate the accuracy of different body weight formulas for estimating body weight of Icelandic and Warmblood horses, as well as to assess the associations between the variables cresty neck score, body condition score, and plasma concentrations of leptin, insulin and cortisol. A total of 81 adult (≥ 4 years of age) horses (43 Icelandic and 38 Warmblood horses) was included in this study. The following morphological measurements were collected by two examiners simultaneously; body weight; height at withers; neck length; 0.5 neck length; neck circum...
Wilson WD, Spensley MS, Baggot JD, Hietala SK.The pharmacokinetics and estimated bioavailability of amoxicillin were determined after IV, intragastric, and IM administration to healthy mares. After IV administration of sodium amoxicillin (10 mg/kg of body weight), the disposition of the drug was best described by a 2-compartment open model. A rapid distribution phase was followed by a rapid elimination phase, with a mean +/- SD half-life of 39.4 +/- 3.57 minutes. The mean volume of distribution was 325 +/- 68.2 ml/kg, and the mean body clearance was 5.68 +/- 0.80 ml/min.kg. It was concluded that frequent IV administration of sodium amoxic...
Ho EN, Wan TS, Wong AS, Lam KK, Stewart BD.Insulin administration can increase muscle glycogen by utilising hyperinsulinaemic clamps prior to sports events or during the recovery phases, and increase muscle size by its chalonic action to inhibit protein breakdown. In order to control insulin abuse in equine sports, a method to detect effectively the use of insulins in horses would be required. Besides the readily available human insulin and its synthetic analogues, structurally similar insulins from other species can also be used as doping agents. This study describes a method for the simultaneous detection of bovine, porcine and human...
Salazar-Ortiz J, Monget P, Guillaume D.Feed intake affects the GH-IGF system and may be a key factor in determining the ovarian follicular growth rate. In fat mares, the plasma IGF-1 concentration is high with low GH and a quick follicular growth rate, in contrast to values observed in thin mares. Nothing is known regarding the long-term effects of differential feed intake on the IGF system. The objective of this experiment was to quantify IGFs, IGFBPs, GH, glucose, insulin, gonadotropin and progesterone (P4) in blood and in preovulatory follicular fluid (FF) in relation to feeding levels in mares. Methods: Three years prior to the...
Sticker LS, Thompson DL, Bunting LD, Fernandez JM, DePew CL.Sixteen light horse mares (8 to 9 yr of age; 457 to 579 kg BW) were fed Bermudagrass hay and a corn/cottonseed hull-based supplement formulated to contain either 100% (control) or 50% (restricted) of the protein and(or) energy requirements for maintenance in a 2 x 2 factorial arrangement of treatments. Daily measurements of intake, BW, and plasma hormones and metabolites were made for 33 d. Plasma glucose, insulin, NEFA, and urea N were measured in hourly samples drawn on d 27, and parallel with an i.v. glucose tolerance test (IVGTT) and epinephrine challenge on d 29. Energy restriction increa...
Giannetto C, Carcangiu V, Luridiana S, Parmeggiani A, Piccione G.Photoperiodic treatments have been of practical interest in controlling seasonal reproduction in sheep, goats and horses. Melatonin is the principal mediator of the environmental photoperiodic message. To investigate the intra- and inter-subject variability of melatonin 24 h rhythm, ten female Italian Saddle horses (8-10 yrs old, mean body weight 525 ± 30 kg), ten female Sarda breed sheep (2-3 yrs old, mean body weight 40.5 ± 2.8 kg) and ten female Sarda breed goats (3-4 yrs old, mean body weight 38.9 ± 4.1 kg), housed individually in a 4 × 4 m soundproof box equipped with 50 Ã...
