Urine analysis in horses involves the examination of urine to assess the health and physiological status of the animal. This diagnostic tool provides insights into the renal function, hydration status, and potential presence of systemic diseases. Key parameters evaluated in equine urine analysis include pH, specific gravity, protein levels, glucose, ketones, and the presence of blood or sediment. Variations in these parameters can indicate metabolic disorders, infections, or other health issues. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and clinical implications of urine analysis in equine veterinary practice.
Babel I, Stella RC, Prado ES.Previous experiments indicated that horse urinary kallikrein (UK) hydrolyzes salminei- e and polyarginine, a but not polylysine. This paper reports the action of UK on bradykinyl-serine, methionyllysyl-bradykinin and lysyllysyl-bradykinin.
Karawya MS, El-Keiy MA, Wahba SK, Kozman AR.A chromatographic separation of amphetamine, methylamphetamine and ephedrine from horse urine is possible on alkaline Silica Gel G plates developed with acetone-methanol (1:3). After elution, the bases are determined colorimetrically. The intensity of the violet colour resulting from the nitration of amphetamine is measured in a Unicam SP1300 colorimeter using filter No. 1 (sensitivity 50–250 μg). The colour produced by the interaction of methylamphetamine, sodium nitro-prusside, acetaldehyde and triethanolamine is measured at 590 mμ (sensitivity 200–2,000 μg). Ephedrine was determined ...
Visutakul P, Bell ET, Loraine JA, Fisher RB.Human chorionic gonadotrophin (HCG), pregnant mare serum gonadotrophin (PMSG) and human menopausal gonadotrophin (HMG) were incubated with varying concentrations of urea at different temperatures for different times.
The luteinizing hormone (LH) activity of HCG was progressively destroyed with increasing concentrations of urea. The degree of inactivation was greater at higher temperatures but the time of incubation did not affect the results.
The follicle-stimulating activity of PMSG was reduced at high urea concentrations; the time of incubation was without effect.
Under the experime...
Sams RA, Gerken DF, Dyke TM, Reed SM, Ashcraft SM.Cimetidine was administered intravenously and by the intragastric route to six mares at a dose of 4.0 mg/kg of body weight (bw). Specific and sensitive high performance liquid chromatographic methods for the determination of cimetidine in horse plasma and urine and cimetidine sulfoxide in urine are described. Plasma cimetidine concentration vs. time data were analysed by non-linear least squares regression analysis to determine pharmacokinetic parameter estimates. The median (range) plasma clearance (Cl) was 8.20 (4.96-10.2) mL/min.kg of body weight, that of the steady-state volume of distribu...
Meny P, Iglesias T, Menéndez C, Quintero J, Ríos C, Ashfield N, Ferreira O, Mosca V, De Brun L, Ortiz G, De Vries I, Varela G, Schelotto F.To investigate seroprevalence of anti-Leptospira antibodies in equines and associated workers in Uruguay, 891 equine and 150 human sera were drawn; 212 equine urine samples were also taken for culture. Environmental conditions and equine raising or managing practices were recorded in all 72 visited establishments; epidemiological information was obtained from each worker. Microscopic agglutination technique (MAT) was performed with 10 Leptospira strains for equines and 18 for human sera, that were also studied with IgM indirect immunofluorescence (IgM-IIF). Equine titres ≥100 were considered...
Sander J, Cavalleri JM, Terhardt M, Bochnia M, Zeyner A, Zuraw A, Sander S, Peter M, Janzen N.Hypoglycin A (2-amino-3-(2-methylidenecyclopropyl)propanoic acid) is the plant toxin shown to cause atypical myopathy in horses. It is converted in vivo to methylenecyclopropyl acetic acid, which is transformed to a coenzyme A ester that subsequently blocks beta oxidation of fatty acids. Methylenecyclopropyl acetic acid is also conjugated with carnitine and glycine. Acute atypical myopathy may be diagnosed by quantifying the conjugates of methylenecyclopropyl acetic acid plus a selection of acyl conjugates in urine and serum. We describe a new mass spectrometric method for sample volumes of <0...
Gallicano KD, Ng RM, Young LM.Methylprednisolone and three metabolites, 17,21-dihydroxy-6 alpha-methyl-1,4-pregnadiene-3,11,20-trione, 6 alpha-methyl-17,20 beta,21-trihydroxy-1,4-pregnadiene-3,11-dione, and 6 alpha-methyl-11 beta,17,20 beta,21-tetrahydroxy-1,4-pregnadien-3-one were detected in equine urine after intraarticular administration of methylprednisolone acetate. All four compounds were excreted both in the unconjugated form and as glucuronic acid conjugates. They were identified by comparing data obtained from analyses by high performance liquid chromatography, thin-layer chromatography, ultraviolet spectroscopy ...
Waraksa E, Woźniak MK, Kłodzińska E, Wrzesień R, Bobrowska-Korczak B, Namieśnik J.Ibuprofen is widely used in human and veterinary medicine for the treatment of chronic pain as well as rheumatic and musculoskeletal disorders. However, the analgesic and anti-inflammatory properties of Ibuprofen have contributed to frequent drug abuse in equestrian sports. A sensitive and rapid gas chromatography with tandem mass spectrometry based method with a simple liquid-liquid extraction and derivatization requiring 200 μL volume of sample and 2 mL of extraction solvent for the simultaneous determination of ibuprofen and its metabolites was developed. The proposed procedure was optim...
Bosken JM, Lehner AF, Hughes CG, Woods WE, Camargo FC, Harkins JD, Boyles J, Tobin T.Isoxsuprine is used to treat navicular disease and other lower-limb problems in the horse. Isoxsuprine is regulated as a class 4 compound by the Association of Racing Commissioners, International (ARCI) and, thus, requires regulatory monitoring. A gas chromatography-mass spectrometry method utilizing electron impact ionization was developed and validated for the quantitation of isoxsuprine in equine plasma or equine urine. The method utilized robotic solid-phase extraction and tri-methyl silyl ether products of derivatization. Products were bis-trimethylsilyl (TMS) isoxsuprine and tris-TMS rit...
Gronwall R.Endogenous creatinine clearance and renal excretion of phenylbutazone, osmotically active material, and compounds contributing to the urinary refractive index were studied in 12 Thoroughbred mares after no treatment, after water administration, or after furosemide administration. Urine was quantitatively collected, using urinary bladder catheters. On average, urine flow of the mares was 9 microliters/min/kg without treatment and increased to about 50 microliters/min/kg after water administration and to about 70 microliters/min/kg after furosemide administration. Water administration increased ...
Jonckheere JA, Thienpont LM, De Leenheer AP, De Backer P, Debackere M, Belpaire FM.A method has been developed for quantification of bromhexine in plasma using gas chromatography mass spectrometry with selected ion monitoring. A deuterium labelled analogue was synthesized and used as the internal standard. To evaluate the gas chromatographic electron capture detection method described earlier, 23 plasma samples have been analysed by both techniques. Although a good correlation was shown, selected ion monitoring was superior to the electron capture detection method for levels below 3 ng ml-1. The mass spectrometric method has also been used to set up a pharmacokinetic study o...
Knych HK, Mama K, Oakleaf M, Harrison LM, McKemie DS, Kass PH.The goal of this study was to determine plasma, urine, and synovial fluid concentrations and describe the effects on biomarkers of cartilage toxicity following intra-articular dexmedetomidine administration to horses. Methods: 12 research horses. Methods: Horses received a single intra-articular administration of 1 μg/kg or 5 μg/kg dexmedetomidine or saline. Plasma, urine, and synovial fluid were collected prior to and up to 48 hours postadministration, and concentrations were determined. The effects on CS846 and C2C were determined in synovial fluid at 0, 12, and 24 hours postadministration...
Hamond C, Martins G, Lawson-Ferreira R, Medeiros MA, Lilenbaum W.The objective of this study was to demonstrate the presence of leptospires in equine urine, as evidence for a potential role of horses in transmission of this organism. Thoroughbred horses (aged 2-5 years, n = 276) from Rio de Janeiro, Brazil, were studied. After a severe storm, the premises of the animals remained flooded for 72 h. Blood samples for serology were collected on days 20 and 35 (day of storm = day 0). On day 20, 132 (47·8%) horses were seroreactive (titre ≥200) and, of these, 23 (31·0%) had increased antibody titres on day 35. Furthermore, 34 urine samples (for PCR and cultur...
Dyke TM, Sams RA.The objective of this study was to determine the urinary excretion of methylxanthines in horses following ingestion of chocolate over eight days. The study was performed in response to gas chromatography-mass spectrometry (GC-MS) confirmation of the presence of caffeine in a positive urine test in a racehorse. The trainer of the horse alleged that he often administered chocolate-coated peanuts as treats to his horses, and he believed that the ingestion of chocolate was responsible for the positive urine test. The urinary excretion of theobromine and caffeine after the ingestion of chocolate-co...
Choi TLS, Wong JKY, Kwok WH, Curl P, Mechie S, Wan TSM.Methylstenbolone (2,17α-dimethyl-5α-androst-1-en-17β-ol-3-one) is a synthetic anabolic and androgenic steroid (AAS) sold as an oral 'nutritional supplement' under the brand names 'Ultradrol', 'M-Sten' and 'Methyl-Sten'. Like other AASs, methylstenbolone is a prohibited substance in both human and equine sports. This paper describes the studies of the in vitro and in vivo metabolism of methylstenbolone in horses using LC/HRMS, GC/MS and GC/MS/MS. Phase I in vitro metabolic study of methylstenbolone was performed using homogenised horse liver. Hydroxylation was the only biotransformation obse...
Viljanto M, Kaabia Z, Taylor P, Hincks P, Muir T, Habershon-Butcher J, Bailly-Chouriberry L, Scarth J.Boldenone is an anabolic-androgenic steroid (AAS) that is prohibited in equine sports. However, in certain situations, it is endogenous, potentially formed by the microbes in urine. An approach to the differentiation based on the detection of the biomarkers Δ1-progesterone, 20(S)-hydroxy-Δ1-progesterone and 20(S)-hydroxyprogesterone was assessed, and their concentrations were monitored in the urine of untreated female horses (n = 291) alongside boldenone, boldienone, testosterone and androstenedione. Using an ultra-sensitive analytical method, boldenone (256 ± 236 pg/mL, n = 2...
Benoit M, Lingen K, Taddei LM, Heffron BT, Hurt L, Lokanc JA, Lingner K, Cardenas E, Flores S, Mayer D, Pilipiak D, Folker-Calderon D, Negrusz A.Pyrilamine (mepyramine) is an H1-receptor antagonist used in human and veterinary medicine. It has the potential to produce central nervous system effects in horses and therefore may have some impact on an outcome of a horse race. A single oral dose of pyrilamine (300 mg/horse) was given to three animals. Serum samples were collected before drug administration and at 0.25, 0.5, 1, 2, 4, 6, 24, 48, 72, 96, 120, and 144 h, and 7, 8, 9, 10, 11, 12, and 13 days post-administration. Urine samples were collected at 0-1, 1-2, 2-4, 4-6, 24, 48, 72, 96, 120, and 144 h, and 7, 8, 9, 10, 11, 12, 13 days ...
Authie EC, Garcia P, Popot MA, Toutain PL, Doucet M.Equine antidoping rules were established to prevent a horse's performance being altered after the administration of prohibited substances, including approved drugs used for legitimate treatment. Veterinarians have to advise owners or trainers on appropriate withholding times to guarantee that their horses may safely compete after drug administration. In order to propose tailored withdrawal times, several horse organisations released detection time (DT) values, for the main veterinary drugs used in horses. One of the possible limits to the information provided by published DTs in horses is the ...
Visutakul P, Bell ET, Loraine JA, Fisher RB.Human chorionic gonadotrophin (HCG), pregnant mare serum gonadotrophin (PMSG) and human menopausal gonadotrophin (HMG) were incubated with varying concentrations of urea at different temperatures for different times.
The luteinizing hormone (LH) activity of HCG was progressively destroyed with increasing concentrations of urea. The degree of inactivation was greater at higher temperatures but the time of incubation did not affect the results.
The follicle-stimulating activity of PMSG was reduced at high urea concentrations; the time of incubation was without effect.
Under the experime...
Bishop J, Heffron B, Taddei L, Benoit M, Hurt L, Costello S, Gross M, Negrusz A.Clenbuterol (CLE) is used in horses as a bronchodilator and for its anabolic steroid-like effects. CLE is a Class 3 drug according to current Association of Racing Commissioners International (ARCI) Uniform Classification Guidelines. The Racing Medication and Testing Consortium recommended a urine CLE threshold of 140 pg/mL after careful scientific review of the results of studies describing the disposition of CLE in the horse and this threshold was adopted by the ARCI. Enzyme-linked immunosorbent assay was previously used to screen samples for CLE in Illinois, but could not detect such low co...
Ramos-Vázquez JR, Sánchez-Montes S, Esparza-González SC, Romero-Salas D, Pardio-Sedas V, Estrada-Coates AT, Alva-Trujillo M, Ballados-González GG....Leptospirosis is an infectious disease with a worldwide distribution, which represents a major challenge in animal production across developing countries, mainly in tropical areas. Horses are particularly susceptible to the disease, presenting manifestations ranging from subclinical to the development of uveitis that compromises the visual health of the animals. In recent years, serological studies have been carried out in equid populations from America, demonstrating high exposure. For this reason, the aim of this study was to demonstrate microbiologically and molecularly the presence of the ...
Hamond C, Adam EN, Stone NE, LeCount K, Anderson T, Putz EJ, Camp P, Hicks J, Stuber T, van der Linden H, Bayles DO, Sahl JW, Schlater LK, Wagner DM....Equine leptospirosis can result in abortion, stillbirth, neonatal death, placentitis, and uveitis. Horses can also act as subclinical reservoir hosts of infection, which are characterized as asymptomatic carriers that persistently excrete leptospires and transmit disease. In this study, PCR and culture were used to assess urinary shedding of pathogenic Leptospira from 37 asymptomatic mares. Three asymptomatic mares, designated as H2, H8, and H9, were PCR-positive for lipL32, a gene specific for pathogenic species of Leptospira. One asymptomatic mare, H9, was culture-positive, and the recovered...
Ho HSM, Farrington AF, Bond AJ, Ho ENM, Wong WT.Estra-4,9-diene-3,17-dione (dienedione) is an anabolic-androgenic steroid (AAS) available on the market as a dietary supplement for bodybuilding. It is prohibited in both human and equine sports due to its potential performance-enhancing effect. With the rare presence of the 4,9-diene configuration in endogenous steroids, dienedione has been considered as a synthetic AAS. Nevertheless, the reoccurring detection of dienedione in entire male horse urine samples led to the investigation of its possible endogenous nature in horses, and its endogenous nature in entire male horses has been recently ...
Cutler C, Viljanto M, Hincks P, Habershon-Butcher J, Scarth J, van Eenoo P.S-23 is an arylpropionamide selective androgen receptor modulator that has been investigated in animal models for use as a male hormonal contraceptive but is not yet available therapeutically. S-23 is available alongside other selective androgen receptor modulators (SARMs) to purchase online via uncontrolled sites, sold as supplement products. It has been detected in several human doping cases, highlighting the importance of identifying the best analytical targets for equine doping control. The purpose of this study was to investigate the detection of S-23 and its phase I metabolites in equine...
Trevisiol S, Popot MA, Garcia P, Boyer S, Caroff M, Drif L, Taleb W, Tendon S, Moulard Y, Bailly-Chouriberry L.The non-psychoactive cannabinoids cannabidiol (CBD) and cannabidiolic acid (CBDA) are available on the market in different forms, mostly for their anti-inflammatory and potential analgesic properties. These substances are prohibited during equine competitions. CBD and CBDA are naturally present in hemp straw, commonly used as a bedding substitute for wheat straw. Unfortunately, horses can eat it, which therefore could lead to a possible risk of positive findings for CBD/CBDA in biological samples after doping control tests. The goals of this study were, first, to provide recommendations on the...
Ishii H, Shigematsu R, Takemoto S, Ishikawa Y, Mizobe F, Nomura M, Arima D, Kunii H, Yuasa R, Yamanaka T, Tanabe S, Nagata SI, Yamada M, Leung GN. The use of osilodrostat, developed as a medication for Cushing's disease but categorized as an anabolic agent, is banned in horses by both the International Federation of Horseracing Authorities and the Fédération Equestre Internationale. For doping control purposes, elimination profiles of hydrolyzed osilodrostat in horse urine were established and the detectability of free forms of osilodrostat and its major metabolite, mono-hydroxylated osilodrostat (M1c), was investigated. Post-administration urine samples obtained from a gelding and three mares were analyzed to establish the eliminatio...
Adam E, Scollay M, Howard B, Taormina J, Hartmann P, Knych H.Levamisole is a regulated substance sometimes administered to racehorses to treat equine protozoal myelitis. Metabolites include compound II, aminorex, and pemoline. Aminorex and pemoline are Horseracing Integrity and Safety Authority-banned substances. Previous studies have examined single doses of the drug. This study examined the disposition of levamisole after 7 days of dosing. Methods: 6 healthy Thoroughbred geldings. Methods: Horses were treated with 500 mg (approx 0.91 to 1 mg/kg) of compounded levamisole hydrochloride paste PO every 12 hours for a total of 13 doses over 7 days. Serum a...
Knych HK, Blea J, Scollay M, Kass PH, McKemie DS.Ethanol, a central nervous system depressant and banned substance in horseracing, has reportedly been administered to horses prior to competition to "calm a horse's nerves." In this study, the pharmacokinetics of two metabolites of ethanol were studied to better understand the behavior of this compound in the horse and provide a scientific basis for regulation of its administration. Six horses received a single intravenous (30 mL; 1200 mg) and oral (90 mL; 3600 mg) administration of ethanol (vodka, 40% ABV) in a balanced cross-over design. Blood and urine samples were collected at vari...
de Melo UP, Ferreira C.This report describes five cases of urinary incontinence in Quarter Horse mares associated with the development of sabulous cystitis. The animals in this study had a history of persistent urinary incontinence for eight months, with clinical signs of continuous dribbling urine during rest and movement. The initial treatment with antibiotics and anti-inflammatory drugs was ineffective. Clinical examination revealed severe scalding in the perineal region and on the medial aspect of the hind limbs, along with neurological signs such as ataxia, hind limb paresis, and diminished perineal reflexes. T...
Nomura M, Kuroda T, Ohta M, Kusano K, Minamijima Y, Nagata S.Salbutamol is a short-acting and selective beta-2 adrenergic agonist. Inhaled (IH) administration of salbutamol is widely used to control lower respiratory tract disease in horses. Here, we estimated the pharmacokinetic parameters of salbutamol after a single intravenous (IV) or IH administration in six horses, and we statistically analysed the detection times with various dosing regimens. Plasma and urine concentrations of salbutamol were measured by liquid chromatography-tandem mass spectrometry, and data were modelled by using a nonlinear mixed effect model followed by Monte Carlo simulatio...
Elbourne M, Keledjian J, Cawley A, Fu S.Altrenogest, also known as allyltrenbolone, is a synthetic form of progesterone used therapeutically to suppress unwanted symptoms of estrus in female horses. Altrenogest affects the system by decreasing levels of endogenous gonadotrophin and luteinizing and follicle-stimulating hormones, which in turn decreases estrogen and mimics the increase of progesterone production. This results in more manageable mares for training and competition alongside male horses while improving the workplace safety of riders and handlers. However, when altrenogest is administered, prohibited steroid impurities su...
Wong JKY, Choi TLS, Wong COL, Curl P, Wan TSM, Ho ENM.Methylsulfonylmethane (MSM), also known as dimethyl sulfone, is a naturally occurring sulphur-containing compound that can be found in plants, animals and humans. MSM can also be a metabolite of dimethyl sulfoxide (DMSO). Due to their anti-inflammatory and analgesic effects, both MSM and DMSO are prohibited substances in horseracing. As both substances are naturally occurring, their misuse in horses is controlled by International Residue Limits (IRL) of 1200 and 15 μg/mL, respectively, in horse urine as established by the International Federation of Horseracing Authorities. The elimination ...
