Toxicology in horses involves the study of substances that can cause adverse effects when introduced to the equine body. This field examines the sources, mechanisms, and outcomes of exposure to toxic agents, which may include plants, chemicals, drugs, and environmental toxins. Understanding toxicology is essential for identifying and managing poisoning cases in horses. Research in this area often focuses on the identification of toxic compounds, their metabolic pathways, and the clinical symptoms associated with exposure. This page compiles peer-reviewed research studies and scholarly articles that explore the detection, effects, and management of toxic substances in equine health.
Valberg SJ, Sponseller BT, Hegeman AD, Earing J, Bender JB, Martinson KL, Patterson SE, Sweetman L.We hypothesised that seasonal pasture myopathy (SPM), which closely resembles atypical myopathy (AM), was caused by ingestion of a seed-bearing plant abundant in autumn pastures. Objective: To identify a common seed-bearing plant among autumn pastures of horses with SPM, and to determine whether the toxic amino acid hypoglycin A was present in the seeds and whether hypoglycin metabolites were present in SPM horse serum or urine. Methods: Twelve SPM cases, 11 SPM pastures and 23 control farms were visited to identify a plant common to all SPM farms in autumn. A common seed was analysed for amin...
Johnstone LK, Mayhew IG.To investigate the effects of lolitrem B intoxication on renal K(+) secretion in response to increased tubular flow rates. Methods: Results are derived from a repeated measure pilot study of seven horses fed non-perennial ryegrass feed for a week prior to exposing them to perennial ryegrass seed and hay that contained an average of 2 ppm lolitrem B. At the end of the control and treatment period frusemide (1 mg/kg I/V) was administered and serial fractional excretion of K(+)(FEK(+)) and fractional excretion of Na(+)(FENa(+)) calculated. Baseline concentration of aldosterone in plasma, serum K(...
Botha CJ, Lewis A, du Plessis EC, Clift SJ, Williams MC.Twenty-eight horses in southern Mozambique died after exhibiting severe respiratory distress. At necropsy, the overinflated lungs did not collapse, had prominent rib impressions, and were fibrotic and emphysematous. Microscopically, prominent proliferation of nonciliated epithelial (Clara) cells in the terminal bronchioles and pulmonary fibrosis were observed, indicative of chronic pneumotoxicity. Transmission electron microscopy demonstrated hyperplasia, desquamation, and apical bulging of Clara cells into the bronchiolar lumen. The outbreak was attributed to ingestion of Crotalaria dura J.M....
Decloedt A, Verheyen T, Sys S, De Clercq D, van Loon G.Tissue Doppler imaging (TDI) and 2-dimensional speckle tracking (2DST) can quantify left ventricular (LV) function in horses. Objective: To evaluate LV function by TDI and 2DST in horses with myocardial dysfunction after accidental ionophore intoxication. Methods: Sixty-seven horses exposed to lasalocid in feed. Methods: Prospective study. Horses were included in the study if a full cardiac examination was performed, consisting of determination of cardiac troponin I (cTnI), electrocardiography, and echocardiography. By TDI, radial systolic velocity and strain were measured. By 2DST, circumfere...
Kaye BM, Elliott CR, Jalim SL.Snail bait poisoning is rare in horses. Cases have been reported, but clinical signs and subsequent prognostic indicators have been poorly documented and must be extrapolated from cases in companion animals. We describe in detail the poisoning of a horse that consumed a lethal dose of the carbamate, methiocarb. There are currently no guidelines for treating equine methiocarb toxicoses, but the principles of management are based on supportive therapy.
Xijier , Mori Y, Fukuoka M, Cairangzhuoma , Inagaki M, Iwamoto S, Yabe T, Kanamaru Y.Native alpha-lactalbumins (α-LA) from equine, bovine, and human milk were not cytotoxic. However, after treatment with trifluoroethanol (TFE), all three α-LAs exhibited cytotoxicity. Toxic potencies were distinctly different among them. Equine α-LA was the most robust, bovine α-LA was moderate, and human α-LA was weak. There were no significant structural changes as between the native and the TFE-treated α-LAs.
Elliott CR, McCowan CI.Nigropallidal encephalomalacia was diagnosed in two horses in northern Victoria that had a history of long-term pasture access to a dense growth of Rhaponticum repens. The region in which the affected horses lived had received well above average rainfall for several months preceding the poisoning. Affected horses had sudden onset of subcutaneous oedema of the head, impaired prehension and mastication, dullness, lethargy and repeated chewing-like jaw movements. Diagnosis was confirmed at necropsy, with characteristic malacic lesions in the substantia nigra and globus pallidus of the brain. This...
Macías García B, Ortega Ferrusola C, Aparicio IM, Miró-Morán A, Morillo Rodriguez A, Gallardo Bolaños JM, González Fernández L....Glycerol is, to date, the most widely used cryoprotectant to freeze stallion spermatozoa at concentrations between 2% and 5%. Cryoprotectant toxicity has been claimed to be the single most limiting factor for the success of cryopreservation. In order to evaluate the toxic effects of the concentrations of glycerol used in practice, stallion spermatozoa were incubated in Biggers Whitten and Whittingham (BWW) media supplemented with 0%, 0.5%, 1.5%, 2.5%, 3.5%, and 5% glycerol. In two additional experiments, a hyposmotic (75 mOsm/kg) and a hyperosmotic (900 mOsm/kg) control media were included. Sp...
Shmalberg J, Hill RC, Scott KC.Many Chinese herbs and herbal mixtures are fed to domestic animals for their reputed medicinal properties. These herbs could contribute to the intake of essential nutrients and toxic metals, but their composition is mostly unknown. The purpose of this study was to measure major nutrient (crude protein, crude fat, carbohydrate, fibre) and mineral (Ca, P, Mg, K, Na, Fe, Zn, Cu, Mn, Mo, S, Al, Cd, Ni, Pb) concentrations in samples of fourteen combination formulas labelled for veterinary use and commonly administered to horses and dogs. Three single herbs, Bupleurum chinense, Curcuma zedoaria and ...
Delfiol DJ, Oliveira-Filho JP, Casalecchi FL, Kievitsbosch T, Hussni CA, Riet-Correa F, Araujo JP, Borges AS.In Brazil, coffee (Coffea arabica) husks are reused in several ways due to their abundance, including as stall bedding. However, field veterinarians have reported that horses become intoxicated after ingesting the coffee husks that are used as bedding. The objective of this study was to evaluate whether coffee husk consumption causes intoxication in horses. Six horses fed coast cross hay ad libitum were given access to coffee husks and excitability, restlessness, involuntary muscle tremors, chewing movements and constant tremors of the lips and tongue, excessive sweating and increased respirat...
Petzinger E.Pyrrolizidine alkaloids belong to a class of phytotoxins which are present in more than 6000 plant species. The disease seneciosis in farm animals represents the severe poisoning by pyrrolizidine alkaloids from plants of the genus Senecio. This form of poisoning has been known since the end of the 19th century in Germany, the USA, Canada and New Zealand, and is mainly caused by Senecio jacobaea and related Senecio spp. in farm animals, including poultry. Animal poisoning by pyrrolizidine alkaloids is of worldwide importance. In Germany poisoning of horses and cattle by Senecio jacobaea, which ...
Schwarz B, Brunthaler R, Hahn C, van den Hoven R.Equine grass sickness (EGS) occurs mainly in Great Britain, but has once been reported in Hungary. The stud which was affected by EGS in 2001 had no new cases until 2009/10, when 11 of 60 and five of 12 one- to three-year-old colts died or were euthanased due to EGS. Following a few hours in the high-risk field during the winter of 2010/11 further four cases of acute EGS were noted among these horses. The affected horses showed somewhat different clinical signs compared with the cases reported in Great Britain. Histopathological findings in these horses were consistent with EGS. In most examin...
Dawson DR.This article provides an overview of the more common toxins and adverse drug reactions, along with more rare toxins and reactions (Table 1), that result in neurologic dysfunction in horses. A wide variety of symptoms, treatments, and outcomes are seen with toxic neurologic disease in horses. An in-depth history and thorough physical examination are needed to determine if a toxin or adverse drug reaction is responsible for the clinical signs. Once a toxin or adverse drug reaction is identified, the specific antidote, if available, and supportive care should be administered promptly.
Ambruosi B, Uranio MF, Sardanelli AM, Pocar P, Martino NA, Paternoster MS, Amati F, Dell'Aquila ME.Phthalates are ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate and it impairs fertility by acting as an endocrine disruptor. The aim of the present study was to analyze the effects of in vitro acute exposure to DEHP on oocyte maturation, energy and oxidative status in the horse, a large animal model. Cumulus cell (CC) apoptosis and oxidative status were also investigated. Cumulus-oocyte complexes from the ovaries of slaughtered mares were cultured in vitro in presence of...
Lara PC, Fabrino HJ, Germano A, Silva JB.A method for the determination of As, Cd and Pb in bovine, equine and poultry liver by ICP-MS was developed and validated. Samples were digested in a microwave oven using a 10% HNO(3) solution. A set of experiments was made according to a central composite design (CCD) for optimisation of the plasma argon flow, nebuliser argon flow and radiofrequency power applied to the plasma. During the validation, Rh and Ru were evaluated as internal standards and, after validation, the best was Rh for Pb and Cd analysis, but for As better results were obtained without an internal standard. The method allo...
Filannino A, Stout TA, Gadella BM, Sostaric E, Pizzi F, Colenbrander B, Dell'Aquila ME, Minervini F.The aim of this study was to investigate the in vitro effects of the Fusarium fungus-derived mycotoxin, zearalenone and its derivatives alpha-zearalenol and beta-zearalenol on motility parameters and the acrosome reaction of stallion sperm. Since the toxic effects of zearalenone and its derivatives are thought to result from their structural similarity to 17beta-estradiol, 17beta-estradiol was used as a positive control for 'estrogen-like' effects. Methods: Stallion spermatozoa were exposed in vitro to zearalenone, alpha-zearalenol, beta-zearalenol or 17beta-estradiol at concentrations ranging...
Desta B, Maldonado G, Reid H, Puschner B, Maxwell J, Agasan A, Humphreys L, Holt T.Just prior to an international polo event, 21 horses from one team exhibited clinical signs of central nervous system disturbance, hyperexcitability, sweating, ataxia, tachycardia, dyspnea, pyrexia, and rapid death. The suspected cause of this peracute onset of illness and death included intentional contamination of feed or iatrogenic administration of performance-enhancing drugs resulting in a severe adverse reaction. Six horses were submitted to the Bronson Animal Disease Diagnostic Laboratory for necropsy and toxicological examination. The clinical signs and sudden death, the similarity to ...
Morton AJ, Grosche A, Matyjaszek SA, Polyak MM, Freeman DE.The effects of prostaglandins and nonsteroidal anti-inflammatory drugs (NSAIDs) on repair of equine intestinal mucosa are important since most horses with gastrointestinal diseases are routinely treated with NSAIDs, such as flunixin meglumine (FM), and these drugs can be toxic to equine gastrointestinal mucosa. Objective: Flunixin meglumine would not affect recovery of equine colonic mucosa in vitro, 18 h after a reversible ischaemic injury. Methods: In 14 anaesthetised horses, a segment of pelvic flexure was subjected to 2 h of ischaemia and the horses were allowed to recover for 18 h. Seven ...
Madejón P, Domínguez MT, Murillo JM.Pasture selection by livestock is an essential topic for rangeland management, especially in trace element-contaminated soils. We have studied the composition (nutrients and trace elements) of a grass-based diet from soils affected by a mine spill at different growth stages (October 2008 to May 2009). A diet based on other plants (mainly Compositae species) was also studied (May 2009) for comparison. Faeces and mane hair of horses feeding on these pastures were also analysed. Micronutrient (Cu, Fe, Mn and Zn) and potentially toxic trace element (As, Cd, Pb, Tl) concentrations were below the ma...
Chang HT, Rumbeiha WK, Patterson JS, Puschner B, Knight AP.Chronic ingestion of yellow star thistle (Centaurea solstitialis) or Russian knapweed (Acroptilon repens) causes nigropallidal encephalomalacia (NPE) in horses with an abrupt onset of neurologic signs characterized by dystonia of lips and tongue, inability to prehend food, depression, and locomotor deficits. The objectives of this study were to reexamine the pathologic alterations of NPE and to conduct an immunohistochemistry study using antibodies to tyrosine hydroxylase and α-synuclein, to determine whether NPE brains show histopathologic features resembling those in human Parkinson disease...
Moulard Y, Bailly-Chouriberry L, Boyer S, Garcia P, Popot MA, Bonnaire Y.Liquid chromatography-mass spectrometry (LC-MS) has been widely used in doping control laboratories over the last two decades. Currently, simple quadrupole, triple quadrupole and ion trap are the most commonly employed analyzers in toxicological analysis. Nevertheless, the main lack of these technologies is the restricted number of target compounds simultaneously screened without loss of sensitivity. In this article we present an innovative screening approach routinely applied in the French horse doping control laboratory based on high resolution (50000) and high mass accuracy (<5 ppm) in f...
Yamarik TA, Wilson WD, Wiebe VJ, Pusterla N, Edman J, Papich MG.Using a randomized, cross-over study design, ciprofloxacin was administered i.g. to eight adult mares at a dose of 20 mg/kg, and to seven of the eight horses at a dose of 5 mg/kg by bolus i.v. injection. The mean C(0) was 20.5 μg/mL (±8.8) immediately after i.v. administration. The C(max) was 0.6 μg/mL (±0.36) at T(max) 1.46 (±0.66) h after the administration of oral ciprofloxacin. The mean elimination half-life after i.v. administration was 5.8 (±1.6) h, and after oral administration the terminal half-life was 3.6 (±1.7) h. The overall mean systemic availability of ...
Bandarra PM, Pavarini SP, Raymundo DL, Corrêa AM, Pedroso PM, Driemeier D.After ingesting green leaves of T. micrantha, 2 horses showed apathy, locomotor deficit, blindness, recumbency, paddling, coma and death. The main gross findings were scattered haemorrhages, enhanced lobular pattern of the liver, and cerebral oedema. Histological changes included disseminated haemorrhages, massive hepatocellular necrosis, neuronal degeneration, Alzheimer type II astrocytes and cerebral perivascular oedema. Clinicopathological findings which were comparable with those observed in Trema micrantha poisoned ruminants, associated with epidemiological evidence suggested the diagnosi...
Caloni F, Cortinovis C.Aflatoxins are a group of mycotoxins principally produced by Aspergillus flavus and A. parasiticus, which are both natural contaminants of food and feedstuff. Aflatoxin B(1) is the most prevalent member of this group that is normally detected and is the most powerful hepatocarcinogen known. Few naturally occurring episodes of aflatoxicosis in horses have been reported in the literature. Indeed, the published information about aflatoxin exposure, metabolism and the effects on horses is limited and controversial, possibly indicating a lack of awareness rather than the rarity of the occurrence. T...
Flegal AR, Gallon C, Hibdon S, Kuspa ZE, Laporte LF.Analyses of lead concentration and isotopic composition of recent and archived samples of the lace lichen (Ramalina menziesii) chronicle more than a century of atmospheric lead contamination in central California. The contamination extends back to our oldest sample from 1892, when lead levels in lichen from the northern reach of the San Francisco Bay estuary were 9-12 microg/g and their isotopic composition corresponded to those of high lead emissions from the Selby smelter (e.g., (206)Pb/(207)Pb = 1.165) that were killing horses in adjacent fields at that time. By the mid-1950s lead isotopic ...
Minervini F, Lacalandra GM, Filannino A, Garbetta A, Nicassio M, Dell'aquila ME, Visconti A.Fumonisin B1 (FB1) is a mycotoxin produced by Fusarium species that exerts its toxic effect through interference with the sphingolipid pathway by inhibiting ceramide synthase. A FB1-dependent sperm toxicity was reported in boars. No information on FB1-related reproductive toxicity in stallions, the most sensitive animal species, has been reported. The aim of the present study was to assess the in vitro toxicity of FB1 on fresh and frozen-thawed equine spermatozoa by analyzing sperm viability, chromatin stability (SCSA) and reactive oxygen species (ROS) production by flow cytometry and sperm mo...
Serra M, Papakonstantinou S, Adamcova M, O'Brien PJ.The use of cardiac troponin (cTn), the 'gold-standard' biomarker of myocardial injury in humans, is growing in veterinary medicine and in animal safety studies, although there are differences in its application in animals. In this study six new assays for the marker were assessed in 619 animals of six different species (dog, cat, horse, cattle, rat and rabbit), in clinical and drug-safety studies. Healthy animals and clinical cases without cardiac disease served as controls. Several of the tested assays had poor analytic or diagnostic sensitivity and only one test was effective in all species ...
Ward NI, Savage JM.The elemental (Br, Cd, Cr, Cu, Mn, Ni, Pb, Se, V, and Zn) content of blood and wool or hair from animals (sheep, horses and alpacas) exposed to motor vehicle emissions alongside the London Orbital (M25) motorway is reported. Elemental values were determined by inductively coupled plasma mass spectrometry (ICP-MS) quality control assessment using flameless atomic absorption spectroscopy (for Pb, correlation coefficients of whole blood r = +0.87, and hair r = +0.82), and replicate (n = 10) analysis of the international reference material IAEA A13 Animal Blood. For Pb very good agreement was obta...
Alipour A, Akrami Mohajeri F, Javdan G, Pourramezani F, Fallahzadeh H, Khalili Sadrabad E.In recent years, the mare's milk has been introduced as a rich source of nutrients with hypoallergic characteristics which is widely used for Iranian infants. The present study aimed to investigate the heavy metal concentration of mare's milk and its consumption risk assessment. About 88 mare's milk was collected from Yazd, the centre of Iran, during the summer of 2020. The raw mare's milk was digested and analysed for mineral and heavy metal content (As, Ca, Cd, Co, Cu, Fe, Mg, Mn, Ni, P, Pb and Zn) by ICP-OES. To estimate the health hazard for consumers the Estimated Daily Intake (EDI), Haza...
Teilmann AM, Hansen JC.The content of cadmium and selenium in horse kidneys from Jutland , Denmark, in relation to age, local geographical variation and possible relationship between the two elements has been investigated. During the winter of 1982-1983 kidneys from 50 horses were sampled and analysed for cadmium and selenium. The cadmium content of the horse kidneys was recorded in connection with the age of the horses. The cadmium level increases until the animal has reached approximately 7 years of age. At this age the cadmium concentration levels off. A significant regional difference was shown. The cadmium cont...
Boyer JD, Breeden DC, Brown DL.To identify compounds in Acer rubrum that cause hemolysis or oxidation of equine erythrocytes and determine whether these toxins are found in other Acer spp. Methods: Equine erythrocytes. Methods: Washed erythrocytes were incubated with extracts and fractions of Acer spp that were separated by thin layer chromatography. Methemoglobin and hemolysis were measured spectrophotometrically. Compounds within Acer spp fractions associated with cell oxidation or hemolysis were identified by gas chromatography-mass spectrometry. Results: Erythrocytes incubated separately with either A. rubrum, A. saccha...
Sander J, Terhardt M, Janzen N, Renaud B, Kruse CJ, François AC, Wouters CP, Boemer F, Votion DM.Equine atypical myopathy is caused by hypoglycin A (HGA) and methylenecyclopropylglycine (MCPrG), the known protoxins of sycamore maple (Acer pseudoplatanus). Various tissues from five atypical myopathy cases were analyzed but only HGA was found. Whether deamination of MCPrG has already occurred in the intestine as the first stage of metabolization has not been investigated. Activation of the protoxins to methylenecyclopropylacetyl (MCPA)-CoA and methylenecyclopropylformyl (MCPF)-CoA, respectively, occurred mainly in the skeletal muscles, as evidenced by very high concentrations of MCPA-carnit...
Kruse CJ, Stern D, Mouithys-Mickalad A, Niesten A, Art T, Lemieux H, Votion DM.Equine atypical myopathy is a seasonal intoxication of grazing equids. In Europe, this poisoning is associated with the ingestion of toxins contained in the seeds and seedlings of the sycamore maple (Acer pseudoplatanus). The toxins involved in atypical myopathy are known to inhibit ß-oxidation of fatty acids and induce a general decrease in mitochondrial respiration, as determined by high-resolution respirometry applied to muscle samples taken from cases of atypical myopathy. The severe impairment of mitochondrial bioenergetics induced by the toxins may explain the high rate of mortality obs...
Binev R, Valchev I, Nikolov J.Spontaneous intoxication in 34 horses after ingesting freshly harvested maize that was to be used for ensiling and heavily contaminated with young Datura stramonium plants, is described. The clinical status of all horses was monitored for 7 days, and included body (rectal) temperature, respiratory and heart rates, colour and moistness of visible mucosae, changes in pupil size, appetite, thirst, general behaviour, locomotion, sensory perceptions, urination and defaecation. The intoxication was accompanied by altered clinical status, namely mild hyperthermia, tachycardia, polypnoea, dyspnoea and...
Agrawal K, Ebel JG, Altier C, Bischoff K.The leaves of Acer rubrum (red maple), especially when wilted in the fall, cause severe oxidative damage to equine erythrocytes, leading to potentially fatal methemoglobinemia and hemolytic anemia. Gallic acid and tannins from A. rubrum leaves have been implicated as the toxic compounds responsible for red maple toxicosis, but the mechanism of action and toxic principle(s) have not been elucidated to date. In order to investigate further how red maple toxicosis occurs, aqueous solutions of gallic acid, tannic acid, and ground dried A. rubrum leaves were incubated with contents of equine ileum,...
Loganathan D, Yi R, Patel B, Zhang J, Kong N.Resolution of cathinone enantiomers in equine anti-doping analysis is becoming more important to distinguish the inadvertent ingestion of plant-based products from those of deliberate administration of designer synthetic analogs. With this in mind, a rapid and sensitive method was developed and validated for the detection, resolution and quantitative determination of cathinone enantiomers in horse blood plasma and urine. The analytes were recovered from the blood plasma and urine matrices by using a liquid-liquid extraction after adjusting the pH to 9. The recovered analytes were derivatized w...
Turk MA, Breeze RG, Gallina AM.The pathologic features of bronchiolitis were studied in horses and ponies from 30 minutes to 27 days after an oral dose of 3-methylindole (3MI). From 30 minutes to 3 hours, lesions were limited to nonciliated bronchiolar epithelial (Clara) cells, which lost apical caps and cytoplasmic granules and had dilated smooth endoplasmic reticulum (SER). At 12 hours, necrotic Clara cells were exfoliated; degeneration and necrosis were evident, in bronchiolar ciliated cells. Rare epithelial cells with hyperplastic SER appeared on the denuded basal lamina at 24 hours. Inflammatory cells, epithelia, fibro...
Tantaoui-Elaraki A, Mekouar SL, el Hamidi M, Senhaji M.From 10 moldy straw samples collected in a Moroccan area with an apparent equine stachybotryotoxicosis outbreak in November 1991, 8 isolates of Stachybotrys atra were obtained. They all showed toxigenesis, however they were variable in nature and intensity. While 1 isolate had only mild toxicity when fed to mice as moldy barley, another revealed very high toxicity to Artemia saline larvae, or rat skin, and to mice. The toxicity of the other 6 isolates were between these 2 limits. This study indicates that the November 1991 outbreak was due to toxigenic strains of Stachybotrys atra.
González-Medina S, Hyde C, Lovera I, Piercy RJ.Measurement of hypoglycin A (HGA) and its toxic metabolite, methylenecyclopropylacetic acid (MCPA), in equine serum confirms a diagnosis of atypical myopathy (AM), a pasture-associated toxic rhabdomyolysis with high mortality linked to the ingestion of Acer trees plant material. Supportive diagnostic tests include plasma acyl-carnitine profiling and urine organic acid testing, but these are not specific for AM. Previously reported HGA and MCPA analytical techniques used liquid chromatography-mass spectrometry (LC-MS) with a derivatising step, but the latter prolongs testing and increases costs...
Singh S, Chopra M, Dilbaghi N, Manuja BK, Kumar S, Kumar R, Rathore NS, Yadav SC, Manuja A.Isometamidium hydrochloride (ISMM) is an effective drug for the treatment of trypanosomosis, but it causes local and systemic toxicity. Isometamidium hydrochloride has limited therapeutic index and exhibit considerable variation in their prophylactic activities. We developed a trypanocidal nanoformulation using ISMM and polymers sodium alginate/gum acacia to enhance the efficacy of the drug at lower doses, while minimizing undesirable side effects. It was characterized by transmission electron microscopy and infrared spectroscopy for evaluation of size, morphology, functional groups, etc. In v...
Hegre OD, Marshall S, Hickey GE.Plasma amine oxidase activities (benzylamine oxidase and spermine oxidase) were determined in the sera of a number of species of various ages. Benzylamine oxidase (BZO) activity, measured spectrophotometrically, was present in bovine, equine, and ovine species examined. Generally its activity in serum increased with the age of the animal. Spermine oxidase activity (SPO) was estimated by a bioassay of in vitro toxicity and did not necessarily correlate with BZO. Cytotoxicity in the presence of spermidine was found only in the sera of the ruminant species examined. Serum activity tended to rise ...
Mollenhauer HH, Rowe LD, Witzel DA.Heart, diaphragm, and rear limb muscle from ponies and rats treated with monensin were examined by light and electron microscopy. In both species, mitochondrial aberrations were observed in selected muscle cells. The aberrations consisted of loss of matrix substance (vacuolization) usually accompanied by swelling. Vacuolated mitochondria were characterized by an almost total loss of matrix substance with retention of the rudimentary cristae form. In ponies, most vacuolated mitochondria were observed in heart muscle though some also were found in the diaphragm. In rats, most vacuolated mitochon...
Rudolph W, Remane D, Wissenbach DK, Peters FT.Endophyte fungi (e.g. Epichloë ssp. and Neotyphodium ssp.) in symbiosis with pasture grasses (e.g. Festuca arundinacaea and Lolium perenne) can produce toxic alkaloids, which are suspected to be involved in equine diseases such as fescue toxicosis, ryegrass staggers, and equine fescue oedema. The aim of this study was, therefore, to develop and validate a quantification method for these and related alkaloids: ergocristine, ergocryptine, ergotamine, ergovaline, lolitrem B, lysergic acid, N-acetylloline, N-formylloline, peramine, and paxilline in horse serum. Horse serum samples (1.5mL) were wo...
Lewis N, Racklyeft DJ.The clinical course of toxic envenomation of a mare and her foal after an attack by a swarm of bees in the Upper Hunter Valley of New South Wales is described. Early agitation and urticaria were followed by more severe systemic clinical signs within 18 h. There was severe, generalised angioedema, rhabdomyolysis, hypovolaemia, gastrointestinal stasis and renal injury. A particular feature in the mare was almost maniacal behaviour during the first 48 h. Clinical pathological examination showed evidence of haemoconcentration, intravascular haemolysis, thrombocytopenia, azotaemia, rhabdomyolysis a...
Norred WP, Voss KA.Fumonisins are secondary metabolites of Fusarium moniliforme , Fusarium proliferatum and several other Fusaria that commonly contaminate corn. Only recently discovered in 1988, these mycotoxins appear to be the causative agents of several toxicoses in animals that result from ingestion of moldy corn or corn-based feeds. The syndromes observed vary considerably among the different species affected and include brain lesions in equids, lung edema in swine, and nephrotoxicity, hepatotoxicity and hepatocellular carcinoma in laboratory rats. There is also evidence that suggests that F. moniliforme a...
Delcourt V, Garcia P, Pottier I, Mansoibou N, Bache N, Glavieux Y, Chabot B, Perot I, André F, Loup B, Barnabé A, Popot MA, Bailly-Chouriberry L.Synthetic androgenic anabolic steroids (AAS) are banned compounds and considered as major threats by both racing and sports international authorities. Hence, doping control laboratories are continually looking into analytical improvements to increase their detection capabilities, notably by means of emerging technologies. To enhance analytical performances for the detection of synthetic AAS such as stanozolol, specific chromatographic procedures have been developed using recent quaternary liquid chromatography technology originally designed for high-throughput standardized proteomics connected...
Peña FJ, Martín-Cano FE, Becerro-Rey L, da Silva-Álvarez E, Gaitskell-Phillips G, Ortega-Ferrusola C, Aparicio IM, Gil MC.Although stallion spermatozoa are now recognized as highly dependent on oxidative phosphorylation for ATP production in the mitochondria, most extenders in use contain supraphysiological concentrations of glucose as the main energy source. While the toxicity of cryoprotectants has been well documented in the literature, the potential toxicity of excessive glucose in extenders is largely ignored. However, the toxicity of excess glucose, known as "carbotoxicity", is well-established in many areas of medicine. In this paper, we review the basic aspects of stallion spermatozoa metabolism, focusing...
Rudolph W, Remane D, Wissenbach DK, Peters FT.Ingestion of hypoglycin A (HGA) in maple seeds or alkaloids produced by symbiotic fungi in pasture grasses is thought to be associated with various syndromes in grazing animals. This article describes analytical methods for monitoring long-term exposure to HGA, its metabolite MCPA-carnitine, as well as ergocristine, ergocryptine, ergotamine, ergovaline, lolitrem B, N-acetylloline, N-formylloline, peramine, and paxilline in equine hair. After extraction of hair samples separation was achieved using two ultra high performance liquid chromatographic systems (HILIC or RP-C18, ammonium formate:acet...
Ladefoged O, Stürup S.A case of copper deficiency or molybdenum toxicosis in cattle, sheep and horses after heavy pollution of a pasture with fly ash is described. If the pastures had not been grazed by cattle and sheep as well as the horses, it would have been difficult to identify the reason for the intoxication in the horses. It is argued that molybdenum intoxication, although seldom seen in non-ruminants, was the cause of the deaths of the horses. It is suggested that the bioavailability of molybdenum in fly ash is high and therefore can cause equine intoxication.
Pfister JA, Stegelmeier BL, Cheney CD, Gardner DR.Locoweed species (Astragalus and Oxytropis spp.) are a serious toxic plant problem for grazing livestock. Horses and sheep have been conditioned to avoid eating locoweed using the aversive agent LiCl. The objective of this study was to determine if previous locoweed intoxication affects food aversion learning in horses and sheep. Horses and sheep were divided into 3 treatment groups: control (not fed locoweed and not averted to a novel feed); locoweed-novel feed averted (fed locoweed and averted to a novel feed); and averted (not fed locoweed and averted to a novel feed). Animals in the locowe...
Dorman DC, Haschek WM.Toxicosis attributable to propylene glycol (1,2-propanediol) was suspected in an 8-year-old 450- to 500-kg male Quarter Horse. Clinical signs of toxicosis developed within 15 minutes of the accidental iatrogenic oral administration of 3.8 L of propylene glycol. Clinical signs of toxicosis included salivation, sweating, ataxia, and signs of pain. Additionally, at 24 hours after propylene glycol ingestion, the horse became increasingly atactic, had an abnormal breath odor, developed rapid shallow breathing, and was cyanotic. The horse died of apparent respiratory arrest 28 hours after the propyl...
Aboling S, Scharmann F, Bunzel D.Poisoning with L. in horses contradicts the hypothesis of coexistence between plants and vertebrate herbivores being mediated through antipastoral traits as toxins. However, incidental observations showed that horses evaded seedlings with primary leaves. The objective of the present cross-discipline study was (i) to analyse whether developmental stages of L. differed as to phenolics hypothesised as antipastoral traits, and (ii) to observe systematically the selection behaviour of pastured horses towards seedlings. Methods: Phenolic profiles of five developmental stages from fruits to seedl...
Meschter CL, Maylin GA, Krook L.Three mature Thoroughbred geldings were given 13.63 mg phenylbutazone/Kg bodyweight intravenously for 3 days and repeated in one horse 4 days later. After 4, 7 and 10 days (double treatment), degeneration of the wall of small veins occurred in all horses. The veins were dilated and/or showed hyalin degeneration. The phlebopathy was interpreted to be paramount in phenylbutazone intoxication. All other manifestations, including erythro- and leukodiapedesis, submucosal edema and ulceration of the gastrointestinal mucosa, phlebothrombosis and significant changes in the hemogram and serum chemistry...
Robinson B, Gummow B.A disease outbreak investigation was conducted in western Queensland to investigate a rare suspected outbreak of pyrrolizidine alkaloid (PA) toxicosis in horses. Thirty five of 132 horses depastured on five properties on the Mitchell grass plains of western Queensland died in the first six months of 2010. Clinical-pathological findings were consistent with PA toxicosis. A local variety of Crotalaria medicaginea was the only hepatotoxic plant found growing on affected properties. Pathology reports and departure and arrival dates of two brood mares provided evidence of a pre wet season exposure ...
Ray AC, Dwyer JN, Fambro GW, Reagor JC.4-Aminopyridine poisoning in horses was diagnosed. Specific methods, utilizing thin-layer and high-performance liquid chromatography, were developed for determining the compound in stomach contents and corn bait. The lethal dose was estimated at 2 to 3 mg/kg of body weight.
