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.
Lindinger MI, Waller AP.The present study determined the independent contributions of temperature, strong ion difference ([SID]), total weak acid concentration ([Atot]) and PCO2 to changes in arterial and mixed venous [H+] and total carbon dioxide concentration ([TCO2]) during 37 min of moderate intensity exercise (~50% of heart rate max) and the first 60 min of recovery. Six horses were fitted with indwelling carotid and pulmonary artery (PA) catheters, had PA temperature measured, and had blood samples withdrawn for immediate analysis of plasma ion and gas concentrations. The increase in core temperature during exe...
Schnuelle ML, Hopster K, Toribio RE, Hurcombe SD.To compare the effects of 7.2% hypertonic and 0.9% isotonic saline (sodium chloride) solutions on cardiovascular parameters and plasma arginine vasopressin (AVP) concentrations in healthy, isoflurane-anesthetized horses. Methods: 8 healthy horses. Methods: In a prospective, randomized, crossover study, horses were anesthetized with isoflurane twice with a 14-day washout period between anesthetic episodes. While anesthetized, horses received a bolus (4 mL/kg) of 7.2% hypertonic saline solution (HS) or 0.9% isotonic saline solution (IS). Heart rate; systolic, mean, and diastolic arterial blood p...
Turner SE, Knych HK, Adams AA.To determine the pharmacokinetics, bioavailability, and pharmacological effects of cannabidiol (CBD) in senior horses. Methods: 8 university-owned senior horses. Methods: In this randomized, crossover study, horses were assigned to receive either a single oral dose of 2 mg/kg CBD in oil or a single IV dose of 0.1 mg/kg CBD in DMSO between August 10 and September 4, 2020. Blood samples were collected before and then 0.5, 1, 4, 8, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, and 264 hours after CBD administration. Serum biochemical analyses and CBCs were performed. Plasma concentrations of CBD ...
Migliorisi A, Hart K, Vaughn S, Austin S, Aldridge B, Wilkins P.To describe ascorbic acid (AA) concentrations, plasma antioxidant capacity (PAC) and markers of oxidative stress, as measured by derivatives of reactive oxygen metabolites (dROMs), in healthy foals at birth and during the first month of life. Methods: Venous blood samples were collected from healthy Standardbred (n = 13) and Quarter Horse (n = 10) foals. Plasma AA, PAC, and dROMs were assessed at 3 to 12 hours, 3 days, and 1, 2, and 4 weeks of age. Methods: AA was measured via high-performance liquid chromatography. PAC and dROMs were measured with a free radical analytical system. Comparisons...
Christmann U, Page AE, Horohov DW, Adams AA, Chapman SE, Hancock CL, Emery AL, Poovey JR, Hagg C, Ortega Morales SM, Duncan AR, Morgan J, Couetil LL....To perform lipidomic analysis of surfactant and plasma from asthmatic and healthy horses. Methods: 30 horses with clinical signs of asthma and 30 age-matched control horses. Methods: Detailed history, physical examination, CBC, and bronchoalveolar lavage fluid (BALF) cytologies were obtained. Asthmatic horses were grouped based on their BALF inflammatory profile: severe equine asthma (SEA), mild equine asthma with neutrophilic airway inflammation (MEA-N), or mild equine asthma with eosinophilic airway inflammation (MEA-E). Each asthma group was assigned its own age-matched control group. Lipid...
Hunyadi L, Chigerwe M, Sundman E.SAA is a commonly used biomarker for measuring acute inflammation in equine practice, and the administration of prophylactic plasma to foals is a routine practice in large breeding farms. Despite this, limited information is available on the values of SAA in healthy or sick neonatal foals following this common procedure. A prospective study was conducted with 31 foals from a veterinary hospital in Texas in one year. Enrolled foals were part of a foaling program, where a prophylactic hyperimmunized plasma was administered 12Â h after birth. Blood was collected for SAA measurements at birth and ...
Colombo I, Podico G, Rudolf-Vegas A, Bauersachs S, Canisso IF.Progesterone is pivotal to maintain pregnancy in the first trimester and low concentration ( .05). Multiple ovulations were associated with greater progesterone concentration and luteal tissue area (P = .0001). There was a moderate positive association between the number of ovulations and luteal tissue area (r = 0.54; P = .0001). The lack of change in the progesterone concentration and luteal tissue area between bred and non-bred mares suggests that horse seminal plasma does not affect luteal function in mares. As all mares had progesterone above 4 ng/mL after 5-days post-ovulation; it i...
Durham AE, Potier JF, Huber L.Use of plasma adrenocorticotropic hormone (ACTH) concentrations for the diagnosis of PPID in equids requires awareness of other factors that might influence ACTH concentrations, including breed and time of year. This study was designed to investigate effects of breed on plasma ACTH concentrations and potential interactions between breed and time of year. Ten breeds were selected from a laboratory database containing data on plasma ACTH concentrations. Breeds represented were Arabians, Cobs, Connemara ponies, donkeys, Irish Sports horses, New Forest ponies, Shetland ponies, Thoroughbreds, Warmb...
Mercer MA, McKenzie HC, Byron CR, Pleasant RS, Bogers SH, Council-Troche RM, Werre SR, Burns T, Davis JL.Acetaminophen has been used clinically in horses alone or combined with traditional non-steroidal anti-inflammatory drugs for treatment of musculoskeletal pain in horses. Objective: To determine the pharmacokinetics and efficacy of acetaminophen at two doses in horses with mechanically induced lameness compared with phenylbutazone or placebo control. Methods: In vivo experiment. Methods: Nine healthy mares with mechanical lameness induced via a reversible sole pressure horseshoe model were treated with acetaminophen (20 mg/kg PO; A20), acetaminophen (30 mg/kg PO; A30), phenylbutazone (2.2â...
Contreras MJ, Arias ME, Silva M, Cabrera P, Felmer R.Cryopreservation of stallion semen is less efficient than other species such as bovine. This is mainly because of the greater susceptibility of stallion sperm to the freezing damage that generates oxidative stress and plasma membrane injury, resulting in DNA fragmentation and cell death. These data suggest the need to develop new strategies of sperm cryopreservation that can improve the efficiency of this technique in stallions by reducing or preventing membrane damage and cell death. The present study aimed to evaluate the effect of adding membrane stabilizers to the freezing medium and asses...
Cheung HW, Wong KS, Lin VYC, Farrington AF, Bond AJ, Wan TSM, Ho ENM.The concern about gene doping has remained high in horseracing and other equestrian competitions. Our laboratory has previously developed a duplex quantitative polymerase chain reaction (qPCR) assay capable of detecting in equine blood the human erythropoietin (hEPO) transgene and equine tubulin α 4a (TUBA4A) gene as an internal control the latter providing quality control over DNA extraction and qPCR. This study aimed to optimize the method for routine testing of regulatory samples. The use of an automated DNA extraction system has increased the sample throughput, consistency of DNA extracti...
Reed R, Trenholme N, Skrzypczak H, Chang K, Ishikawa Y, Barletta M, Quandt J, Knych H, Sakai D.To compare the effects of hydromorphone and butorphanol in horses undergoing arthroscopy and describe the pharmacokinetics of hydromorphone in anesthetized horses. Methods: Randomized controlled clinical trial. Methods: A total of 40 adult horses admitted for elective arthroscopy. Methods: Horses were randomly assigned to be administered intravenous hydromorphone (0.04 mg kg-1; group TxH; n = 19) or butorphanol (0.02 mg kg-1; group TxB; n = 21) prior to surgery as part of a standardized anesthetic protocol. Pain was scored by two observers unaware of group assignment using the Equine Utrecht...
Hoffmann SL, Seminoff K, McKemie DS, Kass PH, Knych HK.Grapiprant is a prostaglandin E2 receptor antagonist that has been found to be an effective anti-inflammatory in dogs and that is devoid of some of the adverse effects associated with traditional NSAIDs that elicit their effects through inhibition of PGE2 production. Previously published reports have described the pharmacokinetics of this drug in horses when administered at 2 mg/kg; however, pharmacodynamic effects in this species have yet to be described. The objective of the current study was to describe the pharmacokinetics and pharmacodynamics of grapiprant at a higher dose. Eight horses...
Loos CMM, Urschel KL, Vanzant ES, Oberhaus EL, Bohannan AD, Klotz JL, McLeod KR.The objectives of the study were to study the effects of the synthetic ergot alkaloid (EA), bromocriptine, on glucose and lipid metabolism in insulin dysregulated (ID, n = 7) and non-ID (n = 8) mares. Horses were individually housed and fed timothy grass hay and two daily concentrate meals so that the total diet provided 120% of daily DE requirements for maintenance. All horses were given intramuscular bromocriptine injections (0.1 mg/kg BW) every 3 days for 14 days. Before and after 14 days of treatment horses underwent a combined glucose-insulin tolerance test (CGIT) to assess insulin sensit...
Kondampati KD, Saini SPS, Sidhu PK, Anand A, Kumar D, Beesam S, Bedi JS, Kaur R, Bhardwaj R.The pharmacokinetics of ampicillin-cloxacillin, given as single intravenously dose of 10 mg.kg-1 (5 mg.kg-1 of ampicillin plus 5 mg.kg-1 of cloxacillin) was examined in clinically presented Indian thoroughbred horses (n = 6) in order to design appropriate dosing strategies. Drug concentrations in plasma were determined by high performance liquid chromatography (HPLC) and pharmacokinetic parameters were derived by non-compartmental analysis using WinNonlin software. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ampicillin-cloxacillin against qualit...
Kwak YB, Yu J, Yoo HH.SR9009 and SR9011 are metabolic modulators pharmacologically targeting REV-ERB receptors as synthetic agonists. A liquid chromatography-tandem mass spectrometry method for the detection of SR9009 and SR9011 in equine plasma was developed and validated. Plasma samples were pretreated by protein precipitation with methanol and were loaded onto an ACQUITY ultra performance liquid chromatography high-strength silica C18 column (2.1 × 150 mm, 1.8 μm) for chromatographic separation. The mobile phase consisted of 5-mM ammonium formate (pH 3.0) in distilled water and 0.1% formic acid in ac...
Bianchi CP, Bruno S, Videla Dorna I, RodrÃguez E, Aba MA.In study I, plasma progesterone concentrations were evaluated in anoestrous mares that received an intravaginal progesterone release device (IPRD) for 10 days. Mares were divided into 3 groups based on the dosage of progesterone (0 g, n=3; 1.38 g, n=5; and 1.9 g, n=5). No statistical differences were found in plasma progesterone concentrations between the two doses tested. In study II, the effects of a protocol based on a short program of artificial light combined with an IPRD containing 1.38 g of progesterone on oestrous behaviour and onset of ovulation were evaluated. IPRDs were inserted int...
Haughan JE, Missanelli JR, You Y, Stefanovski D, Soma LR, Robinson MA.Glaucine, an aporphine alkaloid with anti-tussive, anti-inflammatory, and anti-nociceptive properties, has been identified in post-race samples from racehorses. To investigate pharmacokinetics of glaucine in horses, a three-way crossover study of intravenous and oral glaucine (0.1 mg/kg) and orally administered tulip poplar shavings (50 g shavings = 0.001 mg/kg glaucine) was performed in six horses. A two-compartment model best described IV administration with alpha ( ) and beta ( ) half-life lives of 0.3 (0.1-0.7) and 3.1 (2.4-7.8) h, respectively. The area under the curve ( ) was ...
Journal of proteomicsMarch 26, 2022
Volume 261 104571 doi: 10.1016/j.jprot.2022.104571
Koziy RV, Bracamonte JL, Yoshimura S, Chumala P, Simko E, Katselis GS.Septic arthritis (SA) is a life-threatening condition in horses, and identifying eradication of infection in equine SA is challenging. This study explored the discovery of putative biomarkers for the eradication of joint infection in horses. We performed proteomics analysis of synovial fluid (SF) and plasma from horses with experimental SA, non-septic lipopolysaccharide-induced arthritis, and controls. The point of eradication of infection in horses with SA was determined previously. We compared spectral intensities between groups as well as before and after the eradication of infection. Twent...
Cutler C, Viljanto M, Taylor P, Habershon-Butcher J, Van Eenoo P.Ibutamoren mesylate, or MK-0677, is an orally active, nonpeptide growth hormone secretagogue that has been developed to stimulate excretion of endogenous growth hormone. It has been evaluated for the treatment of a range of clinical conditions but is not available therapeutically. Nonetheless, MK-0677 is widely available to purchase online, sold as 'supplement' products. The mode of action and relative ease of purchase make MK-0677 a potential threat with regard to sports doping. The aim of this study was to investigate the metabolism of MK0677 in the horse following in vitro incubation and or...
Ott EC, Cavinder CA, Wang S, Smith T, Lemley CO, Dinh TTN.Oxidative stress caused by routine physical stressors may negatively impact the performance of equine athletes; thus, the present study identifies oxidative biomarkers in the blood plasma of exercising horses. Stock-type horses were subject to a standardized moderate-intensity exercise protocol 3 times per week for 8Â wk. Exercise protocol followed NRC guidelines consisting of 30% walk, 55% trot, and 15% canter, with a target heart rate (HR) of 90 BPM. Blood plasma was collected in wk 1, 2, 7, and 8 immediately before and 0, 30, 60, and 90Â min after exercise and analyzed for total antioxidant...
Ishii H, Leung GN, Yamashita S, Nagata SI, Kushiro A, Sakai S, Toju K, Okada J, Kawasaki K, Kusano K, Kijima-Suda I.The use of nicotine stimulants in horses is generally banned in horse racing and equestrian sports-accidental consumption of tobacco products is one of the possible causes of nicotine exposure in horses. The authors recently reported a comprehensive metabolic study of nicotine in equines, differentiating between nicotine exposure and sample contamination by means of a nicotine biomarker trans-3'-hydroxycotinine. To identify potential biomarkers for the differentiation of genuine nicotine administration and consumption of tobacco products, tobacco leaves (equivalent to 250 mg of nicotine) wer...
Tou K, Cawley A, Bowen C, Sornalingam K, Fu S.The conventional detection of exogenous drugs in equine doping samples has been used for confirmation and subsequent prosecution of participants responsible. In recent years, alternative methods using indirect detection have been investigated due to the expanding number of pharmaceutical agents available with the potential of misuse. The monitoring of endogenous biomarkers such as hydrocortisone (HC) has been studied in equine urine with an international threshold of 1 μg/ml established; however, there is no current threshold for equine plasma. The aim of this research was to investigate pl...
Júnior ÂMCA, da Silva AH, Bastos FL, Seidner JT, Filho LAJM, Faleiros RR, Gobesso AAO.This study evaluated the incidence of gastritis in foals subjected to different weaning management methods. Sixteen crossbreed foals [230 ± 35 kg], were enrolled in an experiment with a randomized block design. After weaning, foals were housed in either individual pens or a group pen. Gastritis in the foals was evaluated through gastroscopy. Data were submitted to analysis of variance by the non-parametric Friedman test at 0.05 significance level. Before weaning, gastritis was observed in 87.5% of the foals, and the scores for the number of gastric lesions were 2.10 and 1.56 for foals housed ...
Davis JG, GarcÃa-López JM.To report the findings and long-term outcome of 76 sport horses with meniscal injury. Methods: Retrospective case series. Methods: Seventy-six horses with 93 meniscal injuries in 85 stifles. Methods: Medical records of sport horses diagnosed with meniscal injury during arthroscopy were reviewed. Owner follow up was obtained via telephone interview ≥1.5 years postoperatively. Preoperative and intraoperative findings, and postoperative treatments, were analyzed for potential association with return to athletic performance. Results: The medial meniscus was involved in 82.8% of cases, with gra...
Bayless RL, Cooper BL, Sheats MK.Plasma cell-free DNA (cfDNA) is a biomarker of ischemia, systemic inflammation, and mortality in humans with gastrointestinal disease. Cell-free DNA has not been investigated as a biomarker for equine colic, to our knowledge. We hypothesized that cfDNA could be measured accurately in neat equine plasma using a benchtop fluorometer and that plasma cfDNA would be elevated in emergency patients compared to healthy horses. Plasma was obtained from blood collected in Roche DNA stabilizing tubes. We used the Qubit 4 fluorometer and 1× dsDNA HS assay kit to measure cfDNA concentration in neat patien...
Rivolta AA, Pittman DC, Kappes AJ, Stancil RK, Kogan C, Sanz MG.The efficacy of Rhodococcus equi-specific hyperimmune plasma (HIP) is usually evaluated in vitro. Anticoagulants (AC) used for plasma collection can negatively impact bacterial replication but their effect on R. equi growth has not been evaluated. The aim of this study was to establish the effect that AC routinely used in veterinary medicine (ACD, KEDTA, Li Heparin, and Na Citrate) have on in vitro R. equi growth. To assess this, in vitro assays commonly used to test HIP efficacy (direct effect on microorganism and macrophage infection), were performed using each AC and non-treated bacteria. R...
Gold JR, Grubb TL, Cox S, Malavasi L, Villarino NL.The repeated administration of high doses of gabapentin may provide better analgesia in horses than current clinical protocols. Objective: Administration of gabapentin at 40 and 120 mg/kg PO q 12 h for 14 days will not alter serum biochemistry findings or cause adverse effects. Our objectives were to evaluate the effect of gabapentin on serum biochemistry, physical examination, and plasma pharmacokinetics of gabapentin. Methods: Six healthy adult mares. Methods: Horses received 40 and 120 mg/kg of gabapentin orally q 12 h for 14 days. Horses were examined and scored for ataxia and ...
Hunyadi L, Datta P, Rewers-Felkins K, Sundman E, Hale T, Fajt V, Wagner S.The objective of this study was to determine the pharmacokinetic parameters of oclacitinib maleate as a top dress given to adult horses. Six adult horses with a mean weight of 528Â kg were administered a single dose of 0.5Â mg/kg oclacitinib maleate. Blood was collected prior to drug administration and at 15Â min, 30Â min, 45Â min, 1, 2, 4, 6, 8, 12, 24, 48, and 72Â h after treatment. Oclacitinib maleate plasma concentrations were measured by liquid chromatography/mass spectrometry. Pharmacokinetic parameters were found best to fit a one-compartment model. Mean C was 486Â ng/ml (range 423-549Â...
MacÃas GarcÃa B, González Fernández L, Ortega Ferrusola C, Morillo RodrÃguez A, Gallardo Bolaños JM, RodrÃguez Martinez H, Tapia JA....Fatty acids and plasmalogens were extracted from the phospholipids of the plasma membrane of stallion spermatozoa, to determine their relation with sperm quality after freezing and thawing. Sperm quality was rated using a quality index that combined the results of the analysis of sperm motility and velocity (CASA analysis), membrane status and mitochondrial membrane potential (flow cytometry) post thaw. Receiving operating system (ROC) curves were used to evaluate the value of specific lipid components of the sperm membrane herein studied as forecast of potential freezeability. From all parame...
Dawson DR, Nydam DV, Price CT, Graham JE, Cynamon MH, Divers TJ, Felippe MJ.To investigate the effect of opsonization of Rhodococcus equi with R. equi-specific antibodies in plasma on bacterial viability and phagocyte activation in a cell culture model of infection. Methods: Neutrophils and monocyte-derived macrophages from 6 healthy 1-week-old foals and 1 adult horse. Methods: Foal and adult horse phagocytes were incubated with either opsonized or nonopsonized bacteria. Opsonization was achieved by use of plasma containing high or low concentrations of R. equi-specific antibodies. Phagocyte oxidative burst activity was measured by use of flow cytometry, and macrophag...
Crawford C, Sepulveda MF, Elliott J, Harris PA, Bailey SR.Pasture-induced laminitis in the horse is associated with the overconsumption of fermentable carbohydrate, in the form of simple sugars, fructans, or starch. The fermentation of carbohydrate in the cecum and large intestine results in the production of lactic acid and other toxins or "laminitis trigger factors." Vasoactive amines have been suggested as possible initiating factors. The aim of this study was to feed a commercially available form of fructan carbohydrate (inulin, 3 g/kg of BW per day) to normal ponies and to ponies predisposed to laminitis, to mimic a change from a basal hay diet ...
Schramme AR, Pinto CR, Davis J, Whisnant CS, Whitacre MD.Current therapy protocols to treat persistent post mating endometritis and retained fetal membranes in mares typically include the administration of ecbolic drugs. Evaluation of the pharmacokinetics and tolerability of carbetocin, a long-acting oxytocin analogue, after i.v. administration is required. Objective: To determine the pharmacokinetic parameters (principally half-life) of carbetocin in horses. Methods: Five mature mares and one gelding received 0.175 mg carbetocin i.v. All animals were monitored periodically throughout the study for elevation in rectal temperature, heart rate, respir...
The Journal of physiologyMarch 24, 2005
Volume 565, Issue Pt 3 1019-1030 doi: 10.1113/jphysiol.2004.078469
Giussani DA, Forhead AJ, Fowden AL.In mammals, the mechanisms regulating an increase in fetal arterial blood pressure with advancing gestational age remain unidentified. In all species studied to date, the prepartum increase in fetal plasma cortisol has an important role in the maturation of physiological systems essential for neonatal survival. In the horse, the prepartum elevation in fetal cortisol and arterial blood pressure are delayed relative to other species. Hence, the mechanisms governing the ontogenic increase in arterial blood pressure in the horse fetus may mature much closer to term than in other fetal animals. In ...
Folmar CN, Cywes-Bentley C, Bordin AI, Rocha JN, Bray JM, Kahn SK, Schuckert AE, Pier GB, Cohen ND.The bacterium Rhodococcus equi can cause severe pneumonia in foals. The absence of a licensed vaccine and limited effectiveness of commercial R. equi hyperimmune plasma (RE-HIP) create a great need for improved prevention of this disease. Objective: Plasma hyperimmune to the capsular polysaccharide poly-N-acetyl glucosamine (PNAG) would be significantly more effective than RE-HIP at mediating complement deposition and opsonophagocytic killing (OPK) of R. equi. Methods: Venipuncture was performed on 9 Quarter Horses. Methods: The ability of the following plasma sources to mediate complement com...
Auer DE, Ng JC, Thompson HL, Inglis S, Seawright AA.An acute phase reaction was elicited in four horses to which Freund's adjuvant was administered intramuscularly. The localised inflammation was accompanied by changes in the plasma concentrations of copper, iron and zinc. The plasma copper concentration, the plasma ceruloplasmin copper concentration and the ceruloplasmin oxidase activity in the plasma steadily increased to a maximum 24 days after the administration of the adjuvant. At this time, the plasma copper concentration was 2.2 micrograms/ml, a 90 per cent increase over the baseline concentration. The ratio of the concentration of plasm...
Goff AK, Pontbriand D, Sirois J.In Exp. 1, 4 mares were given oxytocin intravenously (10 i.u./500 kg body wt) daily between Days 9 and 14 (Day 0 = day of ovulation) when pregnant and on Days 9-14, 16, 18, 20 when non-pregnant (not inseminated). In the non-pregnant mares the increase in plasma PGFM response to oxytocin was greater at Day 13 (235 +/- 54 pg/ml) than at Day 11 (113 +/- 38 pg/ml; P less than 0.05) and was maximum at Day 16. However, these animals did not return to oestrus and plasma progesterone did not fall below 4 ng/ml. There was no significant increase in response to oxytocin between Days 9 and 14 in the preg...
Silver M, Fowden AL, Knox J, Ousey JC, Franco R, Rossdale PD.The effects of insulin-induced hypoglycaemia on plasma catecholamines, cortisol and metabolites have been examined in newborn and 7-14-day-old foals. The fall in plasma glucose elicited by the highest dose of insulin (1.0 i.u./kg) given to the neonates was slower in onset and less severe in effect than 0.5 i.u./kg in the older foals. There was a significant inverse correlation between the concentrations of glucose and adrenaline (but not noradrenaline) in plasma once the glucose level had fallen below 2 mmol/l; the adrenergic response to hypoglycaemia was greater in the 7-14-day-old foals than...
Calamari L, Ferrari A, Bertin G.This study was conducted to determine the effects of either dietary Se source or dose on the Se status of horses. Twenty-five mature horses were blocked by BW and randomly allocated to 1 of 5 dietary treatments that comprised the same basal diet that differed only in Se source or dose. Treatments were as follows: negative control (0.085 mg of Se/kg of DM), 3 different dietary concentrations of supplemental organic Se (Se yeast; 0.2, 0.3, and 0.4 mg of total Se/kg of DM), and positive control (0.3 mg of total Se/kg of DM) supplemented with Na selenite. Horses initially received the control diet...
Sprouse RF, Garner HE, Green EM.Thirteen (65 per cent) of 20 horses subjected to carbohydrate overload developed Obel Grade 3 lameness within 56 h. Increases in plasma endotoxin from control levels of less than 0.1 ng/litre to values ranging from 2.4 to 81.53 ng/litre were measured in 11 (85 per cent) of 13 horses during the onset of Obel Grade 3 lameness. Obel Grade 3 lameness was associated with rises in plasma Gram-negative endotoxin levels in 11 (92 per cent) of 12 horses. Two peak increases separated by 16 h were verified in five (45 per cent) of 11 horses that exhibited both endotoxaemia and Obel Grade 3 lameness. The ...
De la Rúa-Domènech R, Mohammed HO, Cummings JF, Divers TJ, De Lahunta A, Summers BA.Equine motor neuron disease (EMND) is a neurodegenerative disorder of the somatic lower motor neurons that results in a syndrome of diffuse neuromuscular disease in the adult horse. The aetiology of this disorder is unknown, although prior studies have suggested that a deficiency in the lipid antioxidant vitamin E (alpha-tocopherol) contributes to the development of EMND. This paper describes a case-control study designed to investigate the association between plasma vitamin E levels and the risk of EMND for horses. Signalment, plasma vitamin E levels at the time of referral, and information r...
Trim CM, Hanson RR.The intravenous administration of xylazine (1.1 mg/kg bodyweight) in six ponies resulted in a significant increase in urine output over two hours, with maximum flow occurring between 30 and 60 minutes after injection. Urine specific gravity, osmolality and glucose concentration decreased. Renal clearance of endogenous creatinine was unchanged. Significant increases in the excretion of potassium and chloride occurred. Plasma glucose concentration was increased 30 minutes after the administration of xylazine by a mean value of 37 per cent. Serum osmolality and sodium, potassium and chloride conc...
Sykes BW, Underwood C, McGowan CM, Mills PC.The objectives were to document the pharmacokinetics of intravenous, enteric-coated oral and plain oral omeprazole in fasted horses and to investigate the impact of feeding on the bioavailability of an enteric-coated omeprazole. Twelve horses received four treatments: intravenous omeprazole (0.5Â mg/kg) in the fasted state (IV-Fasted), enteric-coated omeprazole (4Â mg/kg) orally in the fasted state (ECO-Fasted), enteric-coated omeprazole (4Â mg/kg) orally in the fed state (ECO-Fed) and plain omeprazole (4Â mg/kg) orally in the fasted state (PL-Fasted). Plasma omeprazole concentrations were det...
Shilo Y, Britzi M, Eytan B, Lifschitz T, Soback S, Steinman A.Tramadol is a centrally acting analgesic drug that has been used clinically for the last two decades to treat moderate to moderately severe pain in humans. The present study investigated tramadol administration in horses by intravenous, intramuscular, oral as immediate-release and oral as sustained-release dosage-form routes. Seven horses were used in a four-way crossover study design in which racemic tramadol was administered at 2 mg/kg by each route of administration. Altogether, 23 blood samples were collected between 0 and 2880 min. The concentration of tramadol and its M1 metabolite were ...
Silver M, Fowden AL.The present study was carried out on 19 chronically catheterized mares and fetuses in late gestation (term > 320 days). In six animals which were monitored up to the time of delivery of a live foal, plasma and amniotic fluid cortisol concentrations remained low until 4-5 days before parturition when there was a rapid, significant rise (P < 0.05) which was not accompanied by any corresponding changes in maternal plasma cortisol. Circulating fetal ACTH concentrations became more variable close to delivery and ANOVA revealed no significant increases during this critical period, although a n...
Ho EN, Leung DK, Leung GN, Wan TS, Wong AS, Wong CH, Soma LR, Rudy JA, Uboh C, Sams R.Administration studies of levamisole in horses were carried out using two different levamisole preparations, namely, levamisole hydrochloride oral bolus and levamisole phosphate injectable solution. These preparations were analysed in detail for the presence of aminorex-like impurities. Both levamisole preparations were found to contain 1-(2-mercaptoethyl)-4-phenyl-2-imidazolidinone (I) and 4-phenyl-2-imidazolidinone (II) as degradation impurities, but neither aminorex nor rexamino was detected in these preparations. After the administration of these preparations to horses, aminorex, rexamino,...
Becú T, Polledo G, Gaskin JM.An immunoprophylaxis program for R. equi infection of foals has been established on a number of thoroughbred breeding farms in Argentina over the past 4 years. Nearly 800 mares annually were immunized subcutaneously during the last 2 months of pregnancy with 2-3 doses of a vaccine containing soluble antigens of R. equi, including the virulence associated protein (VapA) and 'equi factors' exoenzymes. The mortality from R. equi pneumonia in the foals from vaccinated dams dropped from an average of 3% in the 5 years before the vaccination program was initiated to an average of 1.2% in the 4 years...
Liu Y, Siard M, Adams A, Keowen ML, Miller TK, Garza F, Andrews FM, Seeram NP.The human health benefits attributed to turmeric/curcumin spice has resulted in its wide utilization as a dietary supplement for companion pets and other animals including horses. While the quantification of free curcuminoids (curcumin, demethoxycurcumin, bisdemethoxycurcumin) and their phase-2 metabolites (curcumin-O-sulfate, curcumin-O-glucuronide) have been extensively investigated in human and rodent biological samples (primarily plasma and serum), there is lack of similar data for horses. Herein, we report a validated LC-ESI-MS/MS method for the simultaneous quantification of the aforemen...
Tinworth KD, Edwards S, Noble GK, Harris PA, Sillence MN, Hackett LP.To determine pharmacokinetics and plasma steady-state kinetics of metformin after oral or nasogastric administration in insulin-resistant (IR) ponies. Methods: 8 IR ponies. Methods: Metformin (30 mg/kg) was administered to 8 ponies via nasogastric tube Blood samples were collected at intervals for 24 hours. Plasma concentrations of metformin were measured via liquid chromatography-electrospray tandem mass spectroscopy Pharmacokinetic variables were determined via noncompartmental analysis. Metformin (15 mg/kg, PO, twice daily [8 am and 5 pm]) was administered to 4 ponies for an additional 20 d...
Rendle DI, Litchfield E, Heller J, Hughes KJ.There is little published information on whether measurement of plasma ACTH concentration at a single timepoint is a repeatable indicator of pituitary pars intermedia dysfunction (PPID). Objective: To determine whether ultradian or circadian fluctuations in ACTH production influence plasma ACTH concentration in normal horses and horses with PPID. Methods: Prospective observational study. Methods: Plasma ACTH concentration in 8 non-PPID horses and 8 horses with PPID was measured at 08.00, 11.00, 14.00 and 17.00 h on 5 nonconsecutive days within a 3 week period. In addition, at 08.30 h on one da...
Gordon ME, McKeever KH, Betros CL, Manso Filho HC.Six Standardbred (STB) mares (11+/-2 years, 521+/-77 kg; means+/-SD) performed an exercise trial (EX) where they underwent an incremental exercise test (GXT) as well as a parallel control trial (CON) to test the hypothesis that short-term, high intensity exercise would alter plasma concentrations of glucose, leptin, adiponectin, ghrelin, insulin and cortisol. Plasma samples were taken before (0 min), during (last 10s at 6, 8m/s, and the velocity eliciting VO(2max)), and after exercise (2, 10, 30, 60 min; 12 and 24h post-GXT). A second set of blood samples was collected before and after an afte...
Daniel AJ, Leise BS, Burgess BA, Morley PS, Cloninger M, Hassel DM.To compare the perioperative response of serum amyloid A (SAA) to fibrinogen in horses requiring exploratory celiotomy for colic and to determine if SAA could be used to predict complications and outcome. Methods: Prospective observational clinical study. Methods: University teaching hospital. Methods: Eighteen horses undergoing exploratory celiotomy for colic. Inclusion criteria for the study included survival and anesthetic recovery from exploratory celiotomy, no history of surgery within the past year. Methods: Blood was obtained via jugular venipuncture before surgery (time 0) and at 24, 4...
Barton MH, Morris DD, Norton N, Prasse KW.Thirteen coagulation tests evaluating hemostatic and fibrinolytic indices and serum cytokine and plasma endotoxin concentrations were obtained in 34 foals with a positive sepsis score (septic group) and 46 age-matched healthy foals. Compared to healthy foals, the prothrombin, activated partial thromboplastin, and whole blood recalcification times were significantly longer in septic foals. The fibrinogen and fibrin degradation products concentrations, percent plasminogen, alpha-2 antiplasmin, and plasminogen activator inhibitor activities, and tumor necrosis factor and interleukin-6 activities ...
Lankveld DP, Driessen B, Soma LR, Moate PJ, Rudy J, Uboh CE, van Dijk P, Hellebrekers LJ.Ketamine (KET) possesses analgesic and anti-inflammatory activity at sub-anesthetic doses, suggesting a benefit of long-term KET treatment in horses suffering from pain, inflammatory tissue injury and/or endotoxemia. However, data describing the pharmacodynamic effects and safety of constant rate infusion (CRI) of KET and its pharmacokinetic profile in nonpremedicated horses are missing. Therefore, we administered to six healthy horses a CRI of 1.5 mg/kg/h KET over 320 min following initial drug loading. Cardiopulmonary parameters, arterial blood gases, glucose, lactate, cortisol, insulin, non...
Grady JA, Davis EG, Kukanich B, Sherck AB.To assess pharmacokinetic and pharmacodynamic properties of dexamethasone administered PO as a solution or powder, compared with properties of dexamethasone solution administered IV, in apparently healthy horses. Methods: 6 adult horses. Methods: Serum cortisol concentration for each horse was determined before each treatment (baseline values). Dexamethasone (0.05 mg/kg) was administered PO (in solution or powdered form) or IV (solution) to horses from which feed had or had not been withheld (unfed and fed horses, respectively). Each horse received all 6 treatments in random order at 2-week in...
Kim J, Park Y, Kim EJ, Jung H, Yoon M.Oxytocin (OXT) and serotonin (5-HT) are essential neurotransmitters associated with the behavior of animals. Recently, we found that the plasma concentration of OXT is positively correlated with horse docility and friendliness toward humans. However, the relationships between the neurotransmitters and other temperaments such as fearfulness, dominance, and trainability are unknown. This study aimed to identify whether the plasma concentration of OXT or 5-HT is correlated with fearfulness, dominance, and trainability of horses. Blood samples of 34 horses were collected at the Horse Industry Comp...
Haughan J, Jiang Z, Stefanovski D, Moss KL, Ortved KF, Robinson MA.Gene therapy promotes the expression of missing or defective genes and can be curative following administration of a single dose. Gene therapy is prohibited in equine athletes by regulatory bodies due to the high potential for abuse and novel analytical methods are needed for detection. The goal of this study was to detect the administration of an experimental gene therapy: a recombinant adeno-associated viral vector (rAAV) carrying a transgene for the anti-inflammatory cytokine IL-10 (rAAV-IL10). Twelve horses were randomly assigned to receive an intra-articular injection of rAAV-IL10 or phos...
Aguilera-Tejero E, Estepa JC, López I, Bas S, Mayer-Valor R, RodrÃguez M.The acid-base status of venous blood was studied in 17 show jumpers before and after exercise using both a traditional and a quantitative approach. Partial pressure of carbon dioxide (PCO(2)), pH, haemoglobin, and plasma concentrations of sodium (Na(+)), chloride (Cl(-)), potasium (K(+)), ionized calcium (Ca(2+)), total proteins, albumin, lactate and phosphorus were measured in jugular venous blood samples obtained before and immediately after finishing a show jumping competition. Bicarbonate, anion gap and globulin concentration were calculated from the measured parameters. 'Quantitative anal...
