Poisoning in horses refers to the ingestion, inhalation, or absorption of toxic substances that can adversely affect their health. These substances may include plants, chemicals, medications, or environmental toxins. Poisoning can lead to a range of clinical signs, from mild gastrointestinal upset to severe neurological or systemic effects, depending on the toxin involved. Common toxic substances for horses include certain plants like oleander and yew, heavy metals such as lead and arsenic, and specific pesticides or herbicides. This page compiles peer-reviewed research studies and scholarly articles that investigate the causes, effects, diagnosis, and management of poisoning in horses.
Landolt G, Feige K, Schöberl M.The present study describes the poisoning due to Robinia pseudoacacia in two horses. One of the horses showed mainly intestinal symptoms such as decreased intestinal motility and obstipation of the pelvic flexure. In the second animal central nervous symptoms were predominant. It showed intermittent phases of somnolence alternating with phases of excitation and head pressing. In addition mydriasis and a lacking menace response could be observed. Sensation to the head and the spinal reflexes were reduced. Symptomatic treatment was initiated in both animals and recovery occurred within 2 days.
Gu XL, Dai FY, Xiao X, Li GZ, Zhang LM, Qu WJ.The effect of Ageratina adenophora on pathological characteristics of the liver and lungs as well as serum biochemical parameters in horses were investigated. Ten horses without ingestion history of Ageratina adenophora were classified into the control group, and 10 poisoned but survived horses with 3 months ingestion history were set as the case group. Results showed that serum AST, ALT, ALP, magnesium and phosphorus were elevated significantly, while creatinine was decreased remarkably. Hematoxylin and eosin staining of liver tissues showed diffuse swelling or destruction of hepatocytes, nar...
Newton TA, Rose SR.Phenylbutazone is a potent nonsteroidal, anti-inflammatory drug often used by veterinarians to treat racetrack animals. Its use in human beings is limited because of significant adverse effects and the availability of newer, safer drugs. We report the case of a 24-year-old man who ingested 17 g of equine phenylbutazone over a 24-hour period to treat the pain of a toothache. He developed grand mal seizures, coma, hypotension, respiratory and renal failure, and hepatic injury. Serum phenylbutazone concentration obtained approximately eight hours after presentation was 900 micrograms/mL. The pati...
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...
Lovett A, Vokes J, Loghides N, Johnstone L, Sykes B.Formalin intoxication via the gastrointestinal route has not been previously reported in the horse. Whereas ingestion of formalin in humans, although rare, is well documented. Majority of human cases are either accidental, suicidal or homicidal and often lead to fatality, with a reported lethal formaldehyde dose equating to 0.12 - 0.16 g/kg bwt. Objective: To describe a single case report of the clinical management of an adult horse referred to a veterinary teaching hospital following accidental administration of 10% formalin via nasogastric tube. Methods: A 13-year-old Thoroughbred gelding or...
Barnard BJ.The most obvious symptoms of rabies in farm animals and pets in South Africa and South-West Africa are discussed in the light of information obtained during routine examination of specimens for the 10-year-period 1967--1976. More than 55% of the cases encountered were cattle in which the most obvious symptoms were salivation (92%), bellowing (69%), aggressiveness (47%), paresis or paralysis (30%) and straining (12%). Unlike cattle, the most obvious symptom in goats was aggressiveness (83%). Salivation was observed in ony 29% of goats but, like bellowing in cattle, bleating was very obvious in ...
Kuwano A, Ueno T, Katsurashima Y, Tateno O, Saitoh S.From summer 2018 to summer 2019, several Thoroughbred racehorses held at the Miho Training Centre of the Japan Racing Association inadvertently ingested excessive amounts of sodium selenite, resulting in typical chronic selenium (Se) poisoning - the so-called alkali disease. The typical abnormality was a hoof wall disorder with a circumferentially deep ring and/or transverse hoof wall cracks parallel to the coronet on all feet and appearing after excessive ingestion. One affected Thoroughbred male was unique in that all the hooves had a rough surface with a very fragile hoof wall, but no wall ...
Ebeling-Koning NE, Fowler JT, DelBianco JD, Surmaitis RM.Veterinary medication exposure may result in human toxicity, with approximately 6,000 exposures to veterinary-only medications reported to poison centers in 2022. There is a paucity of literature on the management of poisoned patients secondary to pharmaceuticals intended for equine use. Pergolide is a dopamine and serotonin receptor agonist and is currently approved to treat equine Cushing's disease. It was previously approved in the United States (US) to treat Parkinson's disease in humans; however, it was withdrawn from the market in 2007 due to its association with valvular heart disease....
Kopecka A, Novotna T, Svobodova Z, Drabkova Z.This study describes a case of poisoning by pyrrolizidine alkaloids in a horse. To the best of the author's knowledge, this is the first confirmed case of Senecio ovatus poisoning. A six-year-old 450-kg Irish cob mare was presented to the Equine Clinic of the University of Veterinary Sciences Brno (Czechia) with symptoms of hepatic encephalopathy, which progressively worsened with time despite intensive therapy and led to euthanasia. A complex diagnostic and therapeutic approach including the post-mortem patoanatomical and histopathological examination is described here. Regar...
Daradics Z, Bungărdean D, Lupșan AF, Popescu M, Bulmez O, Ciulu-Angelescu V, Chelaru VF, Morar I, Mircean M, Cătoi C, Tripon MA, Crecan CM.Ethylene glycol toxicosis is a common occurrence in dogs and cats but has been reported in other species as well. Up to date, only one case of ethylene glycol toxicosis has been described in horses, and specific guidelines for treating ethylene glycol intoxication in this species are not available. Here we describe the case of 39 sport horses that ingested water contaminated with ethylene glycol. The main clinical sign was apathy, but more severely affected individuals also developed abdominal pain and laminitis. Treatment was initiated around 24 h after the exposure, using ethanol as an antid...
Novotna T, Samonilova E, Klan J, Frgelecova L, Mala A, Svobodova Z, Drabkova Z.This case report describes the poisoning of two mares from the same paddock with Robinia pseudoacacia (Black locust) bark. The poisoning manifested itself by the sudden onset of weakness and fever with transient improvement after the administration of non-steroidal anti-inflammatory drugs and fluids. After the initial stabilisation, the mares were left unattended overnight. One of them was found dead in the morning. The surviving mare developed colic and severe encephalopathy and had to be referred to the clinic. Blood tests revealed severe hyperammonaemia. After four days of symptomatic treat...
Simões BP, Cerri FM, Takahira RK, Borges AS, Oliveira-Filho JP, Amorim RM.Chlorfenapyr is a pesticide that interferes with mitochondrial function, leading to cell death and mortality. Although poisoning is primarily documented in humans and dogs, it can result in severe clinical signs, including sweating, respiratory distress, and neurological dysfunction. This report describes the clinical and laboratory findings of a horse with suspected accidental intoxication with chlorfenapyr. A 4-year-old Quarter Horse mare was referred to the veterinary hospital with signs of excessive sweating, hyperthermia, tachypnea, muscle fasciculation, and fearful facial expression. The...
