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.
Paßlack N, Mainzer B, Lahrssen-Wiederholt M, Schafft H, Palavinskas R, Breithaupt A, Neumann K, Zentek J.The concentrations of specific elements in the equine liver and kidneys are of practical relevance since horses are not only food-producing animals, but also partially serve as an indicator for the environmental pollution, as the basic feed includes plants like grass, grain and fruits. In this study, the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se) and lead (Pb) were measured in the liver, renal cortex and renal medulla of 21 horses (8 male; 13 female; aged between 5 months-28 years), using indu...
Davis TZ, Stegelmeier BL, Hall JO.Horses are very susceptible to chronic selenosis if grazed on seleniferous forages for a prolonged period. In this study, mane and tail samples from horses that exhibited classical hoof lesions of chronic selenosis were analyzed by inductively coupled plasma mass spectrometry for selenium (Se) content. The horses had grazed for 6 months, from approximately May 15 until November 15, each year for three grazing seasons in a pasture containing seleniferous forages and water sources with elevated Se concentrations. The segmented hair samples showed a cyclic pattern in Se concentrations in the mane...
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...
Choubisa SL.Relative susceptibility to fluoride (F) toxicosis in the form of osteo-dental fluorosis was observed in an observational survey of 2,747 mature and 887 immature domestic animals of diverse species living in areas with naturally fluoridated (>1.5 ppm F) drinking water. These animals included buffaloes (Bubalus bubalis), cattle (Bos taurus), camels (Camelus dromedarius), donkeys (Equus asinus), horses (Equus caballus), goats (Capra hircus), and sheep (Ovis aries). Of these mature and immature animals, 899 (32.7 %) and 322 (36.3 %) showed evidence of dental fluorosis with varying grades, r...
Bautista AC, Tahara J, Mete A, Gaskill CL, Bryant UK, Puschner B.Two separate incidents of monensin exposure in horses resulting in toxicosis provided insight into the diagnostic value and interpretive criteria of various biological samples. In case 1, 25 horses broke into a shed and ingested feed that was supplemented with 800 g/ton (880 µg/g) of monensin. Within 48 hr, 1 horse had died, 2 developed cardiac arrhythmias, lethargy, and recumbency, and another was euthanized due to severe deterioration. Minimal histologic lesions were noted in the horse that died peracutely, while another showed characteristic lesions of acute cardiomyocyte degeneration and ...
Fayrer-Hosken RA, Hill NS, Heusner GL, Traylor-Wiggins W, Turner K.Ergot alkaloids cause a range of pathological conditions in mares. There is no evaluation of the effects of ergot alkaloids from endophyte-infected tall fescue on the stallion breeding soundness examination spermiogram. Objective: The objective of this study was to investigate the effect of ergot alkaloids from endophyte-infected tall fescue on the stallion's reproductive functions. Methods: Crossover toxicology experiment. Methods: Six stallions were fed either toxic endophyte-infected tall fescue seed or a nontoxic endophyte tall fescue seed (Flecha AR-542, MaxQ). The fescue seed content was...
Hackett ES, Mama KR, Twedt DC, Gustafson DL.To determine the oral bioavailability, single and multidose pharmacokinetics, and safety of silibinin, a milk thistle derivative, in healthy horses. Methods: 9 healthy horses. Methods: Horses were initially administered silibinin IV and silibinin phospholipid orally in feed and via nasogastric tube. Five horses then consumed increasing orally administered doses of silibinin phospholipid during 4 nonconsecutive weeks (0 mg/kg, 6.5 mg/kg, 13 mg/kg, and 26 mg/kg of body weight, twice daily for 7 days each week). Results: Bioavailability of orally administered silibinin phospholipid was 0.6% PO in...
Théon AP, Pusterla N, Magdesian KG, Wittenburg L, Marmulak T, Wilson WD.The efficacy and biosafety of a previously established tolerable dosage of doxorubicin have not been established in horses. Objective: To provide preliminary evidence of the efficacy of doxorubicin in tumor-bearing horses, explore drug pharmacokinetics profile, and estimate period of risk of exposure to drug residues. Methods: Twelve horses with 37 tumors. Methods: Treatment protocol included 6 treatments at 3-week intervals. Eight horses were uniformly treated at a dosage of 70 mg/m(2) and 4 horses received 4 of 6 treatment cycles at 70 mg/m(2) . Clinical signs, tumor responses, and toxicoses...
Qualls HJ, Holbrook TC, Gilliam LL, Njaa BL, Panciera RJ, Pope CN, Payton ME.The efficacy of orally administered therapeutics for the treatment of cantharidin intoxication has not been evaluated in controlled studies. Objective: To develop a model of acute cantharidin intoxication in laboratory rats and to evaluate in this model the relative efficacy of 3 gastrointestinal therapies used to treat equine cantharidin toxicosis. Methods: Sixty-four male Sprague-Dawley rats. Methods: A blinded, randomized, controlled study was performed on rats surgically implanted with telemetry transmitters for evaluating heart rate, locomotor activity, and body temperature. Orogastric ad...
Votion DM, van Galen G, Sweetman L, Boemer F, de Tullio P, Dopagne C, Lefère L, Mouithys-Mickalad A, Patarin F, Rouxhet S, van Loon G, Serteyn D....It is hypothesised that European atypical myopathy (AM) has a similar basis as seasonal pasture myopathy in North America, which is now known to be caused by ingestion of hypoglycin A contained in seeds from the tree Acer negundo. Serum from horses with seasonal pasture myopathy contained the conjugated toxic metabolite of hypoglycin A, methylenecyclopropyl acetic acid (MCPA). Methods: Retrospective study on archived samples. Objective: 1) To determine whether MCPA-carnitine was present in serum of European horses confirmed to have AM; 2) to determine whether Acer negundo or related Acer speci...
Sun MH, Liu SQ, Du KJ, Nie CM, Lin YW.Uranium is harmful to human health due to its radiation damage and the ability of uranyl ion (UO2(2+)) to interact with various proteins and disturb their biological functions. Cytochrome b5 (cyt b5) is a highly negatively charged heme protein and plays a key role in mediating cytochrome c (cyt c) signaling in apoptosis by forming a dynamic cyt b5-cyt c complex. In previous molecular modeling study in combination with UV-Vis studies, we found that UO2(2+) is capable of binding to cyt b5 at surface residues, Glu37 and Glu43. In this study, we further investigated the structural consequences of ...
Davis TZ, Stegelmeier BL, Lee ST, Green BT, Hall JO.Rayless goldenrod (Isocoma pluriflora) sporadically poisons horses and other livestock in the southwestern United States. Similar to livestock poisoning by white snakeroot (Ageratina altissima) in the midwestern United States, previous research suggests that benzofuran ketones (BFK: tremetone, dehydrotremetone, 6-hydroxytremetone, and 3-oxyangeloyl-tremetone) are responsible for the toxicity of rayless goldenrod. However, experimental reproduction of rayless goldenrod-induced disease and detailed descriptions of poisoning in horses with known concentrations of tremetone and other BFK has not b...
Lees P, Toutain PL.The presence of horse meat in food products destined for human consumption and labelled as beef has raised several concerns of public interest. This review deals solely with one aspect of these concerns; samples of equine tissue from horses destined for the human food chain have tested positive for the non-steroidal anti-inflammatory drug, phenylbutazone. The safety of some or all such foods for human consumers is a major concern, because it was shown many years ago that phenylbutazone therapy in humans can be associated with life threatening blood dyscrasias. As an initial basis for assessing...
Romantsov MG, Galimzianov KhM, Lokteva OM, Kovalenko AL, Stepanov AV.Search for drugs efficient in prophylaxis and treatment of dangerous infections (especially arboviral ones) is rather actual, since no specific therapy is available. Many-year investigations of interferon inductors showed that they had immunomodulating, antiviral and antiinflammatory effects and were low toxic. The present study demonstrated that the protective effect was the following: Venezuelan equine encephalitis (VEE)--cycloferon > amixin = ridostin, Rift Valley fever (RVF)--cycloferon > amixin > ridostin, predator pox (PP)--cycloferon > amixin = ridostin, that was obvious tha...
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,...
Müntener CR, Bruckner L, Kupper J, Althaus F, Caduff-Janosa P.167 adverse reactions of Swissmedic-authorized veterinary medicinal products were reported during the year 2011 (2010: 160). Species and drug classes remain comparable with previous years: most of the reactions occurred following the use of antiparasitic products (39 %), antiinfectives (20 %) or non-steroidal antiinflammatory drugs (11 %) in companion animals (85 dogs and 27 cats) followed by cattle/calves (37). We received 15 cases of adverse reactions following reconverted use, 8 of them in treated cats. Additionally the Swiss Toxicological Information Centre in Zürich processed 84 enquirie...
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...
Drudge JH, Lyons ET, Tolliver SC.Three formulations of cambendazole were evaluated for anthelmintic activity by critical testing method in 21 horses. Cambendazole suspension was administered via stomach tube at the dose rate of 10 mg/kg to 3 horses and at the dose rate of 20 mg/kg to 3 horses. Cambendazole paste was given intraorally to 8 horses, and the pellet formulation was fed to 7 horses at the dose rate of 20 mg/kg. Anthelmintic activity of cambendazole was similar for all dose rates and formulations. Gasterophilus intestinalis, Gasterophilus nasalis, Draschia megastoma, Anoplocephala perfoliata, and Anoplocephala magna...
Škerlová J, Ismail A, Lindström H, Sjödin B, Mannervik B, Stenmark P.Organotin compounds are highly toxic environmental pollutants with neurotoxic and endocrine-disrupting effects. They are potent inhibitors of glutathione transferases (GSTs), thus impeding their detoxication and antioxidant functions. Several GSTs, including equine GST A3-3 (EcaGST A3-3), exhibit steroid double-bond isomerase activity and are involved in the biosynthesis of testosterone and progesterone. We have performed enzyme kinetics analyses of the inhibition of EcaGST A3-3 by organotin compounds. We have also solved crystal structures of EcaGST A3-3 in complexes with glutathione, and wit...
Bezerra PS, Driemeier D, Loretti AP, Riet-Correa F, Kamphues J, de Barros CS.Three outbreaks of monensin poisoning caused 12 deaths in 16 horses. The illnesses were associated with the ingestion of the same batch of a commercial ration labeled for feeder calves which contained 180 +/- 20 ppm sodium monensin. The morbidity rate was 100% and lethality was 60%, 75%, and 100%. Clinical signs were tachycardia and cardiac arrythmia, groaning, incoordination, sudoresis, recumbency, and paddling movements with the limbs before death. Two horses had dark discolored urine (myoglobinuria). Serum levels of creatine phosphokinase activity were increased. Main necropsy findings were...
Gunson DE, Kowalczyk DF, Shoop CR, Ramberg CF.Several suspect causes of chronic zinc/cadmium toxicosis in horses near a zinc smelter were investigated following observations of lameness, swollen joints, and unthriftiness, particularly in foals. Two foals born and raised near the smelter were lame and had joint swellings that were attributable to severe generalized osteochondrosis. Zinc and cadmium concentrations were markedly increased in the pancreas, liver, and kidney. The serum of 1 foal, zinc and potassium concentrations were high, whereas calcium and magnesium concentrations were low. Marked nephrocalcinosis and osteoporosis were obs...
Pozor M, Conley AJ, Roser JF, Nolin M, Zambrano GL, Runyon SP, Kelleman AA, Macpherson ML.Recently, anti-Müllerian hormone (AMH) was validated as a reliable marker of testicular damage caused by various chemotherapy drugs in humans and in mice. In horses, the reference values of AMH concentrations in normal stallions, during different seasons of a year, have been recently reported. However, this hormone was not evaluated in subfertile or infertile stallions with testicular damage. Therefore, the objective of this study was to investigate the effects of experimentally induced testicular degeneration on the concentration of AMH in stallions. Severe but transient testicular degenerat...
Karanth S, Pope C.The organophosphorus insecticide tetrachlorvinphos (TCVP) is commonly used as a feed-through larvicide in many livestock species, including cattle and horses. Cholinesterase (ChE) activity in blood (generally plasma or whole blood) is often employed to assess organophosphorus insecticide intoxication in animals as well as humans. In many species, including horse and man, plasma contains predominantly butyrylcholinesterase whereas red blood cells in all species express exclusively acetylcholinesterase. To evalulate the comparative interaction of TCVP with blood ChEs in different species, we com...
Baldini M, Stacchini P, C뫝a F, Miniero R, Parodi P, Facelli P.The cadmium content of muscle, liver, kidney and blood samples from 62 horses slaughtered in Italy was investigated. Cadmium was determined by graphite furnace atomic absorption spectrometry (GFAAS) after wet digestion of the samples. The mean and median contents of all samples were (on a fresh weight basis) 75 and 41 micrograms kg-1 for muscle, 2.46 and 2.10 mg kg-1 for liver, 20.0 and 13.5 mg kg-1 for kidney. The cadmium level in blood samples was always below 6 micrograms l-1. The cadmium concentrations in muscle, liver and kidney were found to be related to the life span of the specimens a...
Boermans HJ, Johnstone I, Black WD, Murphy M.Six horses gavaged with a commercial brodifacoum (BDF)-containing bait (Talone) at a dosage of 0.125 mg of BDF/kg of body weight showed weight loss, severe hypocoagulability and hemogram alterations. Four of the horses became depressed and anorectic; one required vitamin K1 therapy. Increases in clotting times were observed at 24 h in the partial thromboplastin time (PTT) followed by the thrombotest (TBT) and one-stage prothrombin time (PT) at 48 h. Elevated mean PTT, PT and TBT were observed from days 4 to 8 (p less than 0.05) with levels returning to pretreatment levels by day 12. Maximum pr...
Plaza Dávila M, Bucci D, Galeati G, Peña FJ, Mari G, Giaretta E, Tamanini C, Spinaci M.Stallion spermatozoa are highly dependent on oxidative phosphorylation for ATP production to achieve normal sperm function and to fuel the motility. The aim of this study was to evaluate the response of equine sperm under capacitating conditions to the inhibition of mitochondrial complex I by rotenone and to test whether epigallocatechin-3-gallate (EGCG), a natural polyphenol component of green tea, could counteract this effect. After 2-h incubation of stallion spermatozoa in modified Tyrode's medium, rotenone (100 nm, 500 nm and 5 μm) and EGCG (10, 20 and 60 μm), alone or in combination, di...
Wolny-Koładka KA, Malina DK.The aim of this study was to explore the toxicity of silver nanoparticles (AgNPs) synthesized by chemical reduction method assessment with regard to airborne strains of Staphylococcus spp. The first step of the experiment was the preparation of silver nanoparticle suspension. The suspension was obtained by a fast and simple chemical method involving the reduction of silver ions through a reducing factor in the presence of the suitable stabilizer required to prevent the aggregation. In the second stage, varied instrumental techniques were used for the analysis and characterization of the obtain...
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...
Sroka L, Müller C, Hass ML, These A, Aboling S, Vervuert I.Senecio jacobaea contains pyrrolizidine alkaloids that can induce severe hepatic intoxication in horses, either acute when ingested in high amounts or chronic when consumed over a long period. The aim of this study was to determine horses' rejection behaviour towards the presence of Senecio jacobaea in hay when fed ad libitum. We hypothesized that adult horses can sort Senecio jacobaea out of the contaminated hay when hay is fed ad libitum. Six warmblood geldings with a mean (±SD) age of 15 ± 2 years were included. In a randomized study, Senecio jacobaea contaminated hay (5% or 10% con...
Cygan-Szczegielniak D, Stasiak K.The main purpose of the study was to analyse the concentrations of selected essential and toxic trace elements in the hair of sports and recreational riding horses from studs located in central Poland and thus test the usefulness of this matrix for monitoring the exposure of these animals. We also measured the concentration of heavy metals in oats used as a basic component of the equine diet to investigate the interactions between these elements in the feed and hair. The basic chemical composition of oats was analysed. Elemental analysis was performed using an EcaFlow 150 GLP electrochemical a...
Théon AP, Pusterla N, Magdesian KG, Wittenburg L, Marmulak T, Wilson WD.The efficacy and biosafety of a previously established tolerable dosage of doxorubicin have not been established in horses. Objective: To provide preliminary evidence of the efficacy of doxorubicin in tumor-bearing horses, explore drug pharmacokinetics profile, and estimate period of risk of exposure to drug residues. Methods: Twelve horses with 37 tumors. Methods: Treatment protocol included 6 treatments at 3-week intervals. Eight horses were uniformly treated at a dosage of 70 mg/m(2) and 4 horses received 4 of 6 treatment cycles at 70 mg/m(2) . Clinical signs, tumor responses, and toxicoses...
Bampidis V, Azimonti G, Bastos ML, Christensen H, Fašmon Durjava M, Kouba M, López-Alonso M, López Puente S, Marcon F, Mayo B, Pechová A....Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of an essential oil from the whole plant (L.) J. Presl (camphor white oil), when used as a sensory additive (flavouring) in feed and water for drinking for all animal species. The FEEDAP Panel concluded that the additive is safe up to the maximum proposed use levels in complete feed of 30 mg/kg for piglets, pigs for fattening, sows, horses, rabbits, fish, ornamental fish and dogs and of 50...
Dirikolu L, Hughes C, Harkins D, Boyles J, Bosken J, Lehner F, Troppmann A, McDowell K, Tobin T, Sebastian MM, Harrison L, Crutchfield J, Baskin SI....The epidemiological association between black cherry trees and mare reproductive loss syndrome has focused attention on cyanide and environmental cyanogens. This article describes the toxicokinetics of cyanide in horses and the relationships between blood cyanide concentrations and potentially adverse responses to cyanide. To identify safe and humane blood concentration limits for cyanide experiments, mares were infused with increasing doses (1-12 mg/min) of sodium cyanide for 1 h. Infusion at 12 mg/min produced clinical signs of cyanide toxicity at 38 min; these signs included increased heart...
Rebhun WC, Tennant BC, Dill SG, King JM.Renal toxicosis attributable to vitamin K3 (menadione sodium bisulfite) was suspected in 5 young adult horses in which acute renal failure developed following parenteral administration of vitamin K3 at the manufacturers' recommended dosages. Renal disease was subsequently induced experimentally in 5 of 6 horses by administration of vitamin K3 at manufacturers' recommended dosages. Signs of renal disease in the clinical patients as well as in the horses treated experimentally included renal colic, hematuria, azotemia, and electrolyte abnormalities consistent with acute renal failure. Two clinic...
A 3-year-old Thoroughbred gelding was examined because of clinical signs of pneumonia and shock. Mucous membrane petechiation and ventral edema were observed and considered to be a result of vasculitis. Epidermal necrosis developed on the distal portions of the limbs. The horse had a persistent high fever that was unresponsive to nonsteroidal anti-inflammatory treatment, and Staphylococcus aureus was isolated from a nasal swab specimen and 2 transtracheal wash fluid samples. Antimicrobial, anti-inflammatory, and supportive treatment resulted in clinical improvement. However, resolution of the ...
Hatfield CL, McDonell WN, Lemke KA, Black WD.To determine the pharmacokinetics and toxic effects associated with IV administration of lithium chloride (LiCl) to conscious healthy horses. Methods: 6 healthy Standardbred horses. Methods: Twenty 3-mmol boluses of LiCl (0.15 mmol/L) were injected IV at 3-minute intervals (total dose, 60 mmol) during a 1-hour period. Blood samples for measurement of serum lithium concentrations were collected before injection and up to 24 hours after injection. Behavioral and systemic toxic effects of LiCl were also assessed. Results: Lithium elimination could best be described by a 3-compartment model for 5 ...
Kinobe RT.Cobalt is an essential trace element for many vital physiological functions. Cobalt is also known to stabilise hypoxia-inducible transcription factors leading to increased expression of erythropoietin which activates production of red blood cells. This implies that cobalt can be used to enhance aerobic performance in racing horses. If this becomes a pervasive practice, the welfare of racing animals would be at risk because cobalt is associated with cardiovascular, haematological, thyroid gland and reproductive toxicity as observed in laboratory animals and humans. It is expected that similar e...
Breeze RG, Legreid WW, Bayly WM, Wilson BJ.Perilla ketone was assessed for its usefulness as a model of equine restrictive pulmonary disease. Three ponies were given 18 mg/kg bodyweight synthetic perilla ketone in dimethyl-sulphoxide. Within 24 h of administration, respiratory rate, peak inspiratory and expiratory flow rates and minute volume were increased. By 48 h there was a significant decrease in tidal volume, and blood pH and base excess were also decreased but not outside normal limits. At necropsy there was congestion and oedema of the lungs. Histologically there was diffuse alveolar injury but no evidence of significant obstru...
Ray AC, Tamulinas SH, Reagor JC.Experimental animals (rabbit, rat, goat, sheep, and pony) were given cantharidin or dried preparations of blister beetles (Epicauta lemniscata) to stimulate naturally occurring toxicosis in which beetles were ingested with alfalfa hay. A sensitive high-pressure liquid chromatographic method, involving derivatization of cantharidin with p-nitrobenzyloxyamine, was developed to detect the toxin extracts of ingesta, fluids, and tissues from these severely poisoned animals. Urine and ingesta from the upper portion of the gastrointestinal tract, containing from 1 to 20 ppm of cantharidin, were the m...
Stowe HD.Thirty-four adult ponies were used to determine the effects of single oral doses of copper (Cu) supplements (0, 20, and 40 mg of Cu/kg of body weight) on the toxicity of oral doses of selenium (Se) supplements (0, 2, 4, 6, and 8 mg of Se/kg of body weight) administered 24 hours after the copper was given. Signs of Se toxicosis-sweating, diarrhea, tachycardia, tachypnea, mild pyrexia, lethargy, and colic-developed in ponies given 6 and 8 mg of Se/kg of body weight without Cu pretreatment. Two of 4 ponies given 6 mg of Se/kg and both ponies given 8 mg of Se/kg without Cu pretreatment died within...
Bila CG, Perreira CL, Gruys E.Horses on several farms in Mozambique were inadvertently fed with a concentrate containing 69 ppm monensin. The horses developed acute signs of toxicity and several died. The animals were depressed, anorectic and paretic before death. Epistaxis was observed in 1 case. Petechial haemorrhages were present in the muscles, heart, lungs, gastrointestinal tract and spleen in 3 horses necropsied. No significant histopathological cardiac and skeletal muscle lesions were seen, except in 1 case, in which there was focal loss of myofibrils.
Bjorland J, Norheim G.Much of the recent interest in cadmium has been inspired by concern about the increasing levels of this element in the environment. Exposure to low levels of cadmium may cause chronic effects. The intake of cadmium takes place mostly via foods. Therefore it is of interest to determine the cadmium levels in domestic animals in order to evaluate possible hazards both to animals and man.
