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.
Snowden NJ, Helyar CV, Platt SR, Penderis J.Moxidectin is a macrocyclic lactone related to ivermectin used in horses and dogs for endoparasite treatment and prophylaxis. The clinical and neurological presentation of moxidectin toxicity in two dogs following inadvertent poisoning with a moxidectin-containing equine de-worming medication is reported here. In both the dogs, the predominant clinical signs were generalised tremors and ataxia. Moxidectin exerts its neurotoxic effects in mammals by potentiating the effect of gamma-aminobutyric acid and, consistent with this, both the dogs demonstrated a poor response to treatment with diazepam...
Kite GC, Stoneham CA, Veitch NC, Stein BK, Whitwell KE.Liquid chromatography-mass spectrometry (LC-MS) analysis of methanol extracts of Oenanthe crocata roots revealed that oenanthotoxin co-eluted with another major polyalkyne, 2,3-dihydro-oenanthotoxin, using the existing high performance liquid chromatography (HPLC) method (isocratic elution from C18 with aqueous methanol) for investigating Oenanthe poisoning. Positive ES or APCI gave [(M+H)-H(2)O](+) and its methanol adduct as major ion species for oenanthotoxin, whereas 2,3-dihydro-oenanthotoxin formed [M+H](+) and its methanol adduct. The two polyalkynes could be chromatographically resolved ...
Tiwary AK, Puschner B, Kinde H, Tor ER.A 2-year-old bay Thoroughbred colt was found dead overnight in its stall without a known history of any illness, existing disease, or toxicant exposure. No information on the clinical signs before this animal's death was reported. A full necropsy was performed the next morning and revealed a mild to moderate degree of endocardial hemorrhages in both ventricles. Microscopic examination of the heart showed an acute mild multifocal necrosis of papillary muscles and ventricles. The stomach content contained approximately 2% Taxus alkaloids as determined by gas chromatography/mass spectrometry. In ...
Pearson W, Boermans HJ, Bettger WJ, McBride BW, Lindinger MI.To characterize hematologic and clinical consequences of chronic dietary consumption of freeze-dried garlic at maximum voluntary intake in horses. Methods: 4 healthy sex- and age-matched horses. Methods: An initial garlic dose (0.05 g/kg, twice daily) was fed to 2 horses in a molasses carrier as part of their normal ration and was gradually increased to maximum voluntary intake (0.25 g/kg, twice daily) over 41 days. Dietary supplementation then continued for a total of 71 days. Two control horses were fed molasses with no garlic with their ration. Blood samples were collected weekly and analyz...
van der Harst MR, Bull S, Laffont CM, Klein WR.The aminoglycoside gentamicin is often used in equine practice. Despite its clinical use, concerns remain regarding the potential toxic side-effects, such as nephrotoxicity, in equine patients, particularly after repeated dosing. The aim of the study was to investigate first in vitro the mechanisms contributing to the renal toxicity of gentamicin and to identify sensitive biomarkers indicating proximal tubule damage. To this end, the kidney-derived cell lines LLC-PKI and MDCK were treated with gentamicin at different concentrations. Toxicity was assessed by measuring the release of gamma-gluta...
Lees P, Landoni MF, Giraudel J, Toutain PL.This review summarises selected aspects of the pharmacokinetics (PK) and pharmacodynamics (PD) of nonsteroidal anti-inflammatory drugs (NSAIDs). It is not intended to be comprehensive, in that it covers neither minor species nor several important aspects of NSAID PD. The limited objective of the review is to summarise those aspects of NSAID PK and PD, which are important to an understanding of PK-PD integration and PK-PD modelling (the subject of the next review in this issue). The general features of NSAID PK are: usually good bioavailability from oral, intramuscular and subcutaneous administ...
Dey S, Dwivedi SK.A cross sectional study recorded the Lead (Pb) concentrations in blood from 288 horses in urban areas. Mean blood Pb concentration was estimated as 0.47 +/- 0.02 and 0.55 +/- 0.02 ppm in horses for industrial and highway-adjacent localities respectively. Mean blood Pb in horses from rural areas was 0.38 +/- 0.03 ppm. The mean Pb in forage samples from these horses was 36.96 +/- 6.23, 52.08 +/- 9.86 and 11.72 +/- 1.34 ppm in industrial, highway-adjacent and rural localities respectively. No overt signs of Pb toxicosis were seen in these animals
Westermann CM, Boerma S, van Nieuwstadt RA.Since the only registrated anti-ectoparasiticum for horses (foxim) is no longer available in The Netherlands, some cases of amitraz intoxication of the horse have occurred. In this article the literature concerning amitraz intoxications and experiments will be discussed and some cases will be described.
Harmeyer J, Schlumbohm C.Metabolism and functions of Vitamin D in horses differ from those in humans, pigs and rats. In horses, calcidiol and calcitriol concentrations in blood plasma are remarkably low (<10 nmol L(-1); 20-40 pmol L(-1), respectively). When a toxic amount of Vitamin D(3) is administered, the responsiveness of calcium and calcitriol concentrations in blood plasma is much reduced compared to the other domestic animal species but inorganic phosphate (Pi) response is much more marked, leading to an increase of the Ca x Pi product. Also, soft tissue calcifications have been observed to develop in horses...
Carmalt J, Rosel K, Burns T, Janzen E.Thirty-four mixed breed horses from two separate farms showed signs of abdominal discomfort, pyrexia and dehydration after being exposed to a new batch of 14% complete horse feed. A new batch of cattle feed from the same manufacturer resulted in dairy cows showing depression, a drop in milk production and diarrhoea. Examination of both diets revealed the presence of white kidney beans (Phaseolus vulgaris). Inclusion of raw beans of this genus in animal feeds is to be avoided.
Forrester MB, Stanley SK.A portion of calls handled by poison centers involve poisonings of animals; however, information on such calls is limited. This study used data from poison centers in Texas collected during 1998-2002 to document the epidemiology of animal poisoning calls. There were a total of 24,467 animal poisoning calls, representing 2.0% of all calls. Dogs were affected in 87% of the calls and cats in 11%. The exposures were unintentional in 99% of the cases, occurred via ingestion in 95% and involved dermal exposure in 5% of the cases. Exposures occurred at the owner's own residence 91% of the time and we...
Nebbia C, Dacasto M, Carletti M.Little is known about the effects of aging on the hepatic drug metabolizing capacity of horses despite the relatively long lifespan characterizing this species. A wide array of cytochrome P450 (CYP)-dependent monooxygenases, carboxylesterases and transferases were assayed in liver microsomes from 50 female horses in an age range between less than 1 year to over 12 years. Rather unexpectedly, both the CYP content and the activity of NADPH cytochrome c reductase rose as a function of age. Accordingly, a general increasing trend was recorded in the rate of the in vitro metabolism of the substrate...
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...
Feng YY, Yang H, Gu XT, Jiang HJ, Lu TH.In this paper, the interaction between Cu(II) ions and Fe-protoporphyrin in horse-heart myoglobin (FePP-Mb) was studied. As a result, some of the Fe(II) ions in FePP-Mb were found to be replaced by Cu(II) ions forming CuPP-Mb, by adding Cu(II) ions into the myoglobin solution. The interaction became stronger when adding more Cu(II) ions into the myoglobin solution. By studying the metal ions' interaction with myoglobin proteins as macromolecules and discussing the interaction mechanism, this work provides a theoretical basis for the further study of hazardous metal ions' interaction with the h...
Loretti AP, Colodel EM, Gimeno EJ, Driemeier D.This study reports a neurological disease unrecognised until now in ponies in southern Brazil. Objective: Epidemiological data strongly suggests that the ingestion of Sida carpinifolia is involved in the aetiology. We tested the hypothesis that it is an acquired lyosomal storage disease. Methods: Following the death of 3 ponies, all ponies from the premises were closely monitored; epidemiological data and clinical findings carefully recorded. Fragments of several organs, including CNS, were fixed in neutral formalin and embedded in paraffin-wax. Sections were stained with haematoxylin and eosi...
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...
Hughes C, Lehner F, Dirikolu L, Harkins D, Boyles J, McDowell K, Tobin T, Crutchfield J, Sebastian M, Harrison L, Baskin SI.An epidemiological association among black cherry trees (Prunus serotina), eastern tent caterpillars (Malacosoma americana), and the spring 2001 episode of mare reproductive loss syndrome in central Kentucky focused attention on the potential role of environmental cyanogens in the causes of this syndrome. To evaluate the role of cyanide (CN (-)) in this syndrome, a simple, rapid, and highly sensitive method for determination of low parts per billion concentrations of CN (-) in equine blood and other biological fluids was developed. The analytical method is an adaptation of methods commonly in ...
Dwivedi SK, Dey S.Fluoride possesses both essential and toxic potentials. A cross-sectional study recorded the fluoride concentrations in sera of thoroughbred horses 5y of age from 4 localities in India. A total of 628 serum samples of were analyzed for fluoride content using ion selective potentiometry. The mean serum fluoride was estimated as 0.018 +/- 0.002, 0.096 +/- 0.004, 0.16 +/- 0.008 and 0.32 +/- 0.02 ppm in horses from the eastern, central. western and southern parts of the country respectively. Although there were significant difference in fluoride concentration among horses from different zones, all...
Steinman A, Isoherranen N, Ashoach O, Soback S.Gentamicin pharmacokinetics has not been studied in horses. Pharmacokinetics of gentamicin C1, C1a and C2 components following i.v. administration of total gentamicin at 6.6 mg/kg bwt to 6 healthy mature horses was determined. Significant differences in clearance, half-life (t 1/2), and mean residence time (MRT) between the gentamicin Cia and the 2 other components were found. The total body clearance (CL) of gentamicin C1a was 1.62 +/- 0.50 ml/min x kg and similar to the glomerular filtration rate (GFR) reported for horses. The CL of gentamicin C1 and C2 were 1.03 +/- 0.08 ml/min x kg and 1.1...
Asano R, Suzuki K, Otsuka T, Otsuka M, Sakurai H.Concentrations of trace elements (As, Al, Pb, Cd, Hg, Se, Si, P, Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Cr, Ni and Mn) in the mane hair obtained from 9 female and 15 male healthy racing Thoroughbred horses aged 2-5 years were analyzed by the inductively coupled plasma atomic emission spectrometry (ICP-AES) method. No significant differences between the female and male horses were observed in the mean concentrations of those minerals. Significantly positive correlations with age were observed in Cd (r=0.546, p<0.01) and Mo (r=0.733, p<0.001). Significantly negative correlations with age were observed i...
Kronfeld DS.The current estimate of LD50, 21.5 mg/kg BW, for lasalocid in horses is based on an analysis of 8 data from 4 horses that died at dose levels of 15, 21, 22 and 26 mg/kg. This analysis neglected 14 data from another 6 horses that survived at dose levels of 5, 10,14, 18, 19, 25, 29 and 50 mg/kg, and so was biased by selection of data. An examination of all the data indicates they are insufficient to determine the LD50. In contrast, the whole data set suggests a lowest toxic dose of 15 mg/kg, although this estimate was based on only 1 affected animal in 8 tests from 5 to 15 mg/kg in an unbalanced...
Khan SA, Kuster DA, Hansen SR.Moxidectin is a macrolide endectocide available as a 2% equine oral gel in the US. This report presents clinical signs of moxidectin toxicosis and its treatment in equines as reported to the ASPCA Animal Poison Control Center (APCC) from January 1998 to December 2000. Nine cases of moxidectin overdose in equines occurred: 5 had signs of toxicosis such as coma, dyspnea, depression, ataxia, tremors, seizures, or weakness. The approximate dose of moxidectin at which these signs were observed ranged from 1.0 to 5.1 mg/kg. The 4 equines that ingested moxidectin between 0.9 mg/kg to 1.7 mg/kg did no...
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...
Nebbia C, Ceppa L, Dacasto M, Nachtmann C, Carletti M.The oxidative metabolism of monensin, an ionophore antibiotic extensively used in veterinary practice as a coccidiostat and a growth promoter, was studied in hepatic microsomal preparations from horses, pigs, broiler chicks, cattle and rats. As assayed by the measurement of the amount of the released formaldehyde, the rate of monensin O-demethylation was nearly of the same order of magnitude in all species, but total monensin metabolism, which was estimated by measuring the rate of substrate disappearance by a high-performance liquid chromatography (HPLC) method, was highest in cattle, interme...
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.
Plumlee KH.Toxicosis from pesticides rarely occurs in horses and is usually the result of inappropriate pesticide use or handling by humans. Organophosphorus and carbamate insecticides inhibit acetylcholinesterase and are the insecticide class most frequently associated with toxicosis in domestic animals. Metaldehyde is a molluscicide, and zinc phosphide is a rodenticide, both of which have caused toxicosis in horses. All three of these pesticides affect the nervous system of horses and can be fatal if not treated promptly.
Blodgett DJ.Most of the tall fescue pastures in the United States are infected by an endophyte, N. coenophialum. The fungus derives nutrients from the plant while supplying the plant with toxins for defense. The most detrimental toxins for animals in tall fescue are ergopeptine alkaloids, especially ergovaline. Ergovaline functions as a dopamine D2 agonist and alters prolactin and several other hormones in the body. Pregnant mares are most susceptible during their last month of gestation. Clinical signs include prolonged gestation, dystocia, retained placentas, agalactia, and dysmature foals that are eith...
Duncan ID, Brook D.Four two-year-old Thoroughbreds suffered an acute gastrointestinal illness shortly after dosing with mineral oil which was thought to have been contaminated with an organophosphate compound. Three weeks later all four were noted to be dyspnoeic and endoscopic examination showed that they had developed bilateral laryngeal paralysis. Two of the horses died during severe bouts of dyspnoea six and eight months later and the third was killed shortly thereafter. Examination of the left and right recurrent laryngeal nerves from these horses showed a severe loss of myelinated fibres distally, especial...
Minnick PD, Brown CM, Braselton WE, Meerdink GL, Slanker MR.An aqueous extract of the heartwood of black walnut (Juglans nigra) was given via stomach tube to 10 horses. Eight developed Obel grade 3 or 4 laminitis within 12 hr. Limb edema and mild sedation were the only other clinical signs observed. One horse was euthanized due to severe signs. The other 7 recovered within 6 days. Gas chromatography/mass spectrometry of aqueous extracts of heartwood, bark and nuts of black walnut identified juglone in the bark and nuts, but not in the heartwood. It was concluded that the aqueous extract of heartwood is laminogenic to horses, but the active ingredient i...
Hertzsch R, Richter A.Based on their performance-enhancing potential, caffeine and theophylline are prohibited substances in equine sports. Residues in horses can be caused by wilful application or by unintended uptake of contaminated feed. The International Federation of Horseracing Authorities recently introduced international residue limits (IRLs) to facilitate the discrimination between pharmacological relevant and irrelevant concentrations in doping samples. The objective of this study was to investigate the scientific validity of these IRLs. A systematic analysis was performed to assess the IRLs by different ...
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 ...
Milligan M, Kukanich B, Beard W, Waxman S.Lidocaine is administered as an intravenous infusion to horses for a variety of reasons, but no study has assessed plasma lidocaine concentrations during a 12-h infusion to horses. The purpose of this study was to evaluate the plasma concentrations and pharmacokinetics of lidocaine during a 12-h infusion to postoperative horses. A second purpose of the study was to evaluate the in vitro plasma protein binding of lidocaine in equine plasma. Lidocaine hydrochloride was administered as a loading dose, 1.3 mg/kg over 15 min, then by a constant rate IV infusion, 50 microg/kg/min to six postoperativ...
Swor TM, Whittenburg JL, Chaffin MK.3 adult Quarter Horses were evaluated for acute, progressive neurologic signs 18 hours after oral administration of 1 dose of 1.87% ivermectin paste. Results: Clinical signs included depression, forelimb and hind limb ataxia, drooping of the superior and inferior lips, and muscle fasciculations. Bilateral mydriasis, decreased pupillary light reflexes, and absent menace reflexes were evident. Clinical signs progressed in severity for 36 hours after administration of the ivermectin. Results: All horses were treated supportively with IV administration of fluids and anti-inflammatory medications. ...
Schoeb TR, Panciera RJ.Case records of 21 horses with acute illness following ingestion of hay containing dead striped blister beetles (Epicauta spp) were selected for review. Abdominal pain, fever, depression, frequent urination, shock, and, occasionally, synchronous diaphragmatic flutter characterized clinical illness. Hematologic findings included hemoconcentration, neutrophilic leukocytosis, and hypocalcemia. Hematuria and low urine specific gravity were abnormal urinalysis results. Sloughing of the epithelium of the esophageal part of the stomach, hemorrhagic and ulcerative cystitis, enterocolitis, and myocardi...
Choubisa SL.India is one of the fluoride-endemic countries where the maximum numbers of ground or drinking water sources are naturally fluoridated. In India, a total of 23, out of 36 states and union territories have drinking water contaminated with fluoride in varying concentration. In the present scenario, especially in rural India, besides the surface waters (perennial ponds, dams, rivers, etc.), bore wells and hand pumps are the principal drinking water sources for domestic animals such as cattle (Bos taurus), water buffaloes (Bubalus bubalis), sheep (Ovis aries), goats (Capra hircus), horses (Equus c...
Ullrey DE.Selenium was discovered 174 yr ago but, until 1957, was given little notice by biologists or was vilified as an agent that caused toxicity in grazing ruminants and horses in the northern Great Plains. After its status as an essential nutrient was established, Se received intense scrutiny, and hundreds of papers have been published dealing with its metabolic functions and the consequences of a Se deficiency. Because regions of Se deficiency are so extensive in the United States, great efforts have been made to gain Food and Drug Administration (FDA) approval for Se supplementation of animal die...
Olsén L, Ingvast-Larsson C, Broström H, Larsson P, Tjälve H.Case reports of 59 horses reacting adversely to procaine benzylpenicillin or to sodium or potassium benzylpenicillin in Sweden in 2003-2005 were obtained through contacts with horse-owners. For the assessment of the reports, various parameters were evaluated, such as the times to the reactions, information on previous penicillin treatment, the clinical signs and the actions taken in the reacting horses. Among the reports, two horses had received sodium or potassium benzylpenicillin intravenously, whereas the remaining 57 horses had been treated with procaine benzylpenicillin intramuscularly. A...
Goel S, Schumacher J, Lenz SD, Kemppainen BW.Disruption in sphingolipid (SL) metabolism is a biomarker of exposure to fumonisins. The role of altered SL metabolism in the pathogenesis of fumonisin toxicoses is not understood. A 27-d feeding trial in horses compared the toxic effects of 3 strains of Fusarium moniliforme: RRC 415, cultured from corn in MS; AU 2/3, cultured from feed associated with clinical signs of duodenitis-proximal jejunitis (DPJ) in horses in AL; and MRC 826, cultured from corn in South Africa and shown to cause equine leukoencephalomalacia (ELEM). These were cultured on corn and diluted with clean corn and grain mixe...
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...
Hughes C, Lehner F, Dirikolu L, Harkins D, Boyles J, McDowell K, Tobin T, Crutchfield J, Sebastian M, Harrison L, Baskin SI.An epidemiological association among black cherry trees (Prunus serotina), eastern tent caterpillars (Malacosoma americana), and the spring 2001 episode of mare reproductive loss syndrome in central Kentucky focused attention on the potential role of environmental cyanogens in the causes of this syndrome. To evaluate the role of cyanide (CN (-)) in this syndrome, a simple, rapid, and highly sensitive method for determination of low parts per billion concentrations of CN (-) in equine blood and other biological fluids was developed. The analytical method is an adaptation of methods commonly in ...
Spinaci M, Nerozzi C, Mislei B, Blanco-Prieto O, Mari G, Galeati G, Bucci D.The growing and widespread use of glyphosate-based herbicides (GBHs) has raised an intense public debate about the impact of environmental contamination on animal and human health, including male fertility. The aim of this study was to deepen the impact of glyphosate (Gly) and GBHs on mammalian sperm investigating the effect of in vitro exposure of stallion spermatozoa to Gly and to its commercial formulation Roundup® (R). Spermatozoa were incubated at 37 °C with different Gly or R concentrations (from 0.5 to 720 μg/mL Gly or R at the same Gly-equivalent concentrations). After 1 h of in...
Karakka Kal AK, Nalakath J, Kunhamu Karatt T, Perwad Z, Mathew B, Subhahar M.The detection and separation of medetomidine enantiomers from the complex biological matrices poses a great analytical challenge, especially in the field of forensic toxicology and pharmacology. Couple of researchers reported resolution of medetomidine using protein-based chiral columns, but the reported method is quiet challenging and tedious to be employed for routine analysis. This research paper reported a method that enables the enantio-separation of medetomidine by using polysaccharide cellulose chiral column. The use of chiralcel OJ-3R column was found to have the highest potential for ...
Crews HM, Dean JR, Ebdon L, Massey RC.The speciation of cadmium in retail pig kidney has been examined by size-exclusion chromatography (SEC) coupled directly to inductively coupled plasma mass spectrometry (ICP-MS). Approximately 35% of the cadmium from uncooked kidney was soluble after aqueous extraction at pH 8 and SEC - ICP-MS revealed three discrete peaks whose retention times corresponded to estimated relative molecular masses of 1.2 x 10(6), 7.0 x 10(4) and 6 x 10(3)-9 x 10(3). In the cooked kidney, 35% of the Cd was soluble and was all associated with a peak of a relative molecular mass (Mr) of 6 x 10(3)-9 x 10(3). After s...
Dey S, Dwivedi SK.A cross sectional study recorded the Lead (Pb) concentrations in blood from 288 horses in urban areas. Mean blood Pb concentration was estimated as 0.47 +/- 0.02 and 0.55 +/- 0.02 ppm in horses for industrial and highway-adjacent localities respectively. Mean blood Pb in horses from rural areas was 0.38 +/- 0.03 ppm. The mean Pb in forage samples from these horses was 36.96 +/- 6.23, 52.08 +/- 9.86 and 11.72 +/- 1.34 ppm in industrial, highway-adjacent and rural localities respectively. No overt signs of Pb toxicosis were seen in these animals
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...
Kemmerling W.Feeding experiments carried out with cattle and horses could prove the toxic effects of P. marcgravii (Rubiaceae) in all cases. The typical symptoms of "sudden death", however, are observed in ruminants only. This difference could not be explained so far. Apart from fluoroacetate, two more substances also have influence the toxic effects and have been isolated from P. marcgravii for the first time: N-methyltyramine and 2-methyltetrahydro-beta-carboline (2-Me THBC). Structure elucidation of these compounds is mainly accomplished by 1H-NMR, 13C-NMR and MS techniques. Due to the small quantity of...
Vesonder R, Haliburton J, Golinski P.Feed samples of corn, pelleted feed, and oats associated with equine leucoencephalomalacia (ELEM) were obtained from North Carolina, Illinois, Indiana, and Oklahoma. These samples contained a high colony density of Fusarium moniliforme Sheldon which ranged from 64 to 87% of the total fungi. Fifty-nine F. moniliforme strains were isolated. Isolates of F. moniliforme in feed samples from Illinois, Indiana, and Oklahoma were cultured on corn. The fermented corn, mixed with regular feed and fed to one-day-old ducklings, effected a high mortality coefficient (average 55%). Methanol extracts of corn...
Mount ME, Feldman BF.Strychnine toxicosis is characterized by inducible tetanic seizures and metaldehyde poisoning by fine fasciculations progressing to generalized tremors and seizures. Intoxication with 1080 causes seizures, random running movements, vomiting, defecation, urination, acidosis and hyperglycemia. Intoxication with rodenticides causing coagulopathy is characterized by hemorrhage into body cavities but not necessarily external hemorrhage. Anticholinesterase insecticides cause salivation, urination and defecation, while chlorinated hydrocarbon insecticides cause CNS disturbances. Ethylene glycol intox...
Stockenström S, Sydenham EW, Shephard GS.The widespread occurrence of F. moniliforme and the toxic effects of its secondary metabolites, the fumonisins B1(FB1), B2(FB2) and B3(FB3), make it imperative that fumonisin contamination of maize, a major constituent of animal feed as well as the staple diet of many populations, be closely monitored to reduce the risk of fumonisin exposure. Equine leukoencephalomalacia and porcine pulmonary oedema have been associated with the intake of feed heavily contaminated with fumonisins. In addition, high levels of fumonisins in the maize-based staple diets of certain populations have been linked to ...
Bampidis V, Azimonti G, Bastos ML, Christensen H, Dusemund B, Fašmon Durjava M, Kouba M, López-Alonso M, López Puente S, Marcon F, Mayo B....Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of glyceryl polyethyleneglycol ricinoleate (PEG castor oil) as technological feed additive for all animal species. PEG castor oil is safe at a maximum concentration in complete feed of 90 mg/kg for chickens for fattening and other minor growing poultry; 134 mg/kg for laying hens and other laying/breeding birds kept for egg production/reproduction; 121 mg/kg for turkeys for fattening; 162 mg/kg for piglets and other minor growing ; 194 mg/kg for pigs for fattening; 23...
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...
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 ...
Ghajar SM, McKenzie H, Fike J, McIntosh B, Tracy BF.Introduced cool-season grasses are dominant in Virginia's grasslands, but their high digestible energy and nonstructural carbohydrate (NSC) levels pose a risk for horses prone to obesity and laminitis. Native warm-season grasses (NWSGs) have lower digestible energy and NSC levels that may be more suitable for horses susceptible to laminitis. Although NWSGs have desirable characteristics, they are novel forages for horses. Little is known about NWSG intake or potential toxicity to horses or how grazing by horses may affect NWSG swards. The overall objectives of this research were to 1) assess v...
Rubio-Martínez LM, Rioja E, Castro Martins M, Wipawee S, Clegg P, Peffers MJ.Chondrotoxic effects of local anaesthetics are well reported in humans and some animal species but knowledge on their toxic effects on synoviocytes or equine chondrocytes or the effects on cellular production of inflammatory cytokines is limited. The purpose of this study was to evaluate the in vitro effects of local anaesthetics, morphine, magnesium sulphate (MgSO4) or their combinations on cell viability and pro-inflammatory cytokine gene expression of equine synoviocytes and chondrocytes. Equine synoviocytes and cartilage explants harvested from normal joints in a co-culture system were exp...
Morris J, Hoang D.This article discusses a rare case of isolated xylazine overdose in a human, treated successfully with naloxone. Xylazine, typically used as a veterinary tranquilizer, acts as a potent α2 adrenergic agonist, leading to sedation, muscle relaxation, and potential respiratory depression. In this case, a female mistakenly injected herself with xylazine mistaking it for a different medication. The report discusses naloxone's role beyond opioid overdose, especially regarding substances causing central nervous system (CNS) depression via mechanisms similar to those of opioids. While naloxone is trad...
Malalana F.Chemotherapy is the treatment of cancerous cells through the use of cytotoxic drugs. Whilst the use of systemic (intravenous) chemotherapy in equine practice is generally limited to the management of lymphoma, cytotoxic drugs are commonly used in the treatment of accessible skin tumors, either by topical application in the form of ointments or injected intralesionally. These drugs should be employed with caution due to the risk of serious adverse effects. In addition, extreme caution should be followed when preparing, handling, administering, and disposing them, due to their carcinogenic, muta...
Kronfeld DS.The current estimate of LD50, 21.5 mg/kg BW, for lasalocid in horses is based on an analysis of 8 data from 4 horses that died at dose levels of 15, 21, 22 and 26 mg/kg. This analysis neglected 14 data from another 6 horses that survived at dose levels of 5, 10,14, 18, 19, 25, 29 and 50 mg/kg, and so was biased by selection of data. An examination of all the data indicates they are insufficient to determine the LD50. In contrast, the whole data set suggests a lowest toxic dose of 15 mg/kg, although this estimate was based on only 1 affected animal in 8 tests from 5 to 15 mg/kg in an unbalanced...
