Topic:Poisoning
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.
Hemolytic anemia in horses after the ingestion of red maple leaves. Signs of acute hemolytic anemia developed in 4 adult horses from 2 Georgia farms 3 to 4 days after the ingestion of wilted leaves from cut red maple trees (Acer rubrum). Clinical findings included weakness, polypnea, tachycardia, depression, icterus, cyanosis, and brownish discoloration of the blood and urine. Blood changes included methemoglobinemia, free plasma hemoglobin, decreased pcv, and Heinz bodies in erythrocytes. These findings plus hemoglobinuria suggested intravascular hemolysis. Three of the 4 horses diet 5 to 7 days after ingestion of the leaves. Gross pathologic changes included...
Toxicity of Cassia occidentalis in the horse. Three Shetland ponies were given a single oral dose of ground Cassia occidentalis seeds in aqueous suspension. The clinical signs observed resembled those seen in naturally occurring and experimental cases in cattle. The syndrome was characterized by an afebrile course, incoordination, recumbency and death. Elevations of blood alkaline phosphatase, CPK, LDH, and SGOT were observed. Although muscle lesions were not seen grossly, microscopic lesions included segmental necrosis of skeletal muscle fibers. The findings were regarded as sufficiently characteristic of C. occidentalis poisoning to be ...
Acute hemolytic anemia, methemoglobinemia, and heinz body formation associated with ingestion of red maple leaves by horses. From June 1975 through June 1979, acute hemolytic anemia developed in 11 horses from 7 New York farms. Of the 7 horses that died, 6 had methemoglobinemia. In the 4 horses that recovered, methemoglobinemia was not observed. but Heinz body formation was seen in 3 of the 4. On 2 of the premises involved, frank methemoglobinemia was observed concurrently with Heinz body formation, suggesting a relationship between the pathogenesis of methemoglobinemia and Heinz body formation in the hemolytic process. In addition to the 11 cases described, 22 clinically similar cases were reported to us during the...
Field outbreaks of leukoencephalomalacia in horses consuming maize infected by Fusarium verticillioides (= F. moniliforme) in South Africa. Four outbreaks of leukoencephalomalacia in horses in widely separated areas in South Africa are reported. The clinical signs and pathological lesions observed in each outbreak are briefly described. Mouldy home-grown maize from which Fusarium verticillioides (Sacc.) Nirenberg (= F. moniliforme Sheldon) was isolated in every instance, was involved in the outbreaks. Clinical signs and pathological lesions were identical to those seen in experimentally produced cases of F. verticillioides poisoning in horses.
Toxic effects of lasalocid in horses. Lasalocid was given to horses in a series of sequentially increasing single oral doses ranging between 5 and 30 mg/kg of body weight, with an appropriate washout period between treatments. One of the 5 horses died after a dosage of 15 mg/kg, 1 of 3 horses died after 21 mg/kg, 1 of 3 horses died after 22 mg/kg, and 1 of 2 horses died after 26 mg/kg. The LD50 of lasalocid for horses was estimated to be 21.5 mg/kg. Monensin was given to horses in a similar manner at dosages of 1, 2, and 3 mg/kg of body weight. One of the 2 horses died after a dosage of 2 mg/kg and 1 horse died after a dosage of 3...
Aflatoxicosis in horses. Two episodes of acute aflatoxin poisoning in horses suggest that horses are susceptible to the toxic effects of this mycotoxin. Lesions associated with exposure to aflatoxin included encephalomalacia of cerebral hemispheres, fatty degeneration, necrosis, bile duct hyperplasia, fibrosis of the liver, fatty infiltration of the kidney, hemorrhagic enteritis, and myocardial degeneration. Hypoglycemia, hyperlipidemia, and depletion of lymphocytes accompanied these lesions. The diagnosis was based on gross and histopathologic observations, consistent with observations of other species poisoned with ...
Poisoning in animals due to oral application of iron. With description of a case in a horse. Peroral application of iron salts in various types of anemia was previously considered atoxic. The increased use of iron has, however, led to an increasing number of poisoning in children, taking iron tablets for candy. There have only been reported a few number of spontaneous intoxications in animals, but experimentally it has been possible to produce fatal intoxications in various kinds of animal species. The clinical findings are quite similar in the various animals, starting with vomiting, bloody diarrhoea and metabolic acidosis. If the intoxication is severe, shock and coma may develop, a...
The value of zinc protoporphyrin in equine lead poisoning: a case report. A diagnosis of lead poisoning in a foal was established based on clinical signs and the presence of an elevation in the concentration of blood lead (40 microgram/dl). Additionally, ZPP was determined in whole blood and found to be significantly elevated compared to 10 normal horses not exposed to lead (634 vs 73 microgram/dl). An elevation in ZPP in man has been found to be a sensitive biochemical indicator of lead toxicity even before overt clinical signs are present. This report suggests that ZPP may be a useful screening test for evaluating biological toxicity due to lead in horses and poss...
Ultrastructural observations in ponies after treatment with monensin. Ultrastructural studies were made of myocardium, diaphragm, appendicular muscle, liver, and kidney of 3 ponies acutely poisoned with a single oral dose of monensin (4 mg/kg of body weight). These ponies developed severe signs of toxicosis and were killed 28 to 72 hours after treatment. Severe mitochondrial damage (swelling) and lipoidosis in myocardial tissues were observed in 2 of the 3 ponies; similar, but less severe, changes were observed in the 3rd pony. The hepatocytes of the 3 ponies were characterized by increased amounts of smooth endoplasmic reticulum, large numbers of lipid droplets...
[Zinc poisoning in a foal (author’s transl)]. The clinical and pathomorfological symptoms of a two month's zinc-overload in a foal are described. After an exposure of about two weeks symptoms of unthriftness and increasing stiffness develope. The stiffness is caused by severe intra-articular damage.
Moldy sweetclover poisoning in a horse. A six year old Percheron mare was presented with a history of spontaneous unilateral epistaxis of 24 hours duration. The blood one stage prothrombin and partial thromboplastin times were markedly prolonged. A diagnosis of moldy sweetclover poisoning was made on the basis of the history and clinical and laboratory findings. A single whole blood transfusion and four daily intravenous injections of vitamin K(3) proved to be a successful treatment.
Experimental poisoning of horses and cattle with Swainsona canescens var horniana. Horses and cattle fed swainsona (Swainsona canescens var horniana) over a period of 8 to 10 weeks lost condition and became incoordinated and hypersensitive. Histological examination of tissues from affected animals revealed the characteristic changes of widespread cellular vacuolation and axonal spheroids in the CNS. Cattle withdrawn from the toxic plant after being fed for varying periods up to 8 weeks returned to normal. Serum alpha-mannosidase activity declined significantly in cattle during the test period, whereas in horses that activity rose. Serum alkaline phosphatase levels increased ...
[Use of trichlorfon as an anthelmintic in horses (author’s transl)]. The use of trichlorfon as an anthelmintic in horses has increased since it was combined with mebendazole and febantel, and became commercially available as Telmin-trichlorfon and Rintal-plus respectively. Field studies showed that these combined preparations frequently gave rise to cases of poisoning. Mild to severe colic was observed up to six hours after treatment, diarrhoea and/or anorexia continuing to be present for one to six days after administration. The 'horse weight measurer' introduced by Janssen Pharmaceutica is not sufficiently accurate to prevent overdosage. It is advisable only ...
Evaluation of an analytical method for the diagnosis of cantharidin toxicosis due to ingestion of blister beetles (Epicauta lemniscata) by horses and sheep. An analytical method for cantharidin, using high performance liquid chromatography, was applied to field specimens from horses and sheep with blister beetle (Epicauta lemniscata) poisoning. Stomach content and urine proved to be valuable aids in diagnosis. One incident of cantharidin toxicosis in ruminants (sheep) was confirmed.
Urinary excretion of arsenic from horses injected with an organic arsenical compound. Five doses of sodium cacodylate (194 mg) were administered intravenously to two horses at two-day intervals. The arsenic content of daily urine samples was determined for five days after the final dose, by which time urinary arsenic concentrations were close to those of control samples. It was considered that these results reflected a common property of organic arsenicals viz. more rapid excretion by mammals than is the case with inorganic arsenic compounds.
Teratogenicity and toxicity of coniine in cows, ewes, and mares. Cows, ewes, and mares varied considerably in susceptibility to toxicoses from the oral administration of the piperidine alkaloid, coniine. Cows were most susceptible and ewes least. Only calves had teratogenic effects from maternal administration of coniine during gestation; lambs and foals were apparently resistant. Results suggest that the marked differences between cattle and sheep are probably not due to variation in gut absorption or rumen metabolism.
Chronic phenylmercuric acetate toxicity in a horse. Phenylmercuric acetate (PMA) was administered orally to a horse over a period of 27 weeks (190 days) at a dose rate of 0.4 mg Hg/kg per day. The effects produced were consistent with those of chronic inorganic mercury intoxication. The clinical features included masseter muscle atrophy, difficulty in prehension and mastication, malodorous breath, reduced appetite and weight loss, and reflected significant pathological changes involving the buccal, mandibular and dental tissues. Renal dysfunction was evident terminally and there was degeration and necrosis of the proximal tubular epithelium. Ne...
[Symptoms of rabies in pets and domestic animals in South Africa and South West Africa (author’s transl)]. 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 ...
High pressure liquid chromatographic determination of cantharidin, using a derivatization method in specimens from animals acutely poisoned by ingestion of blister beetles, Epicauta lemniscata. 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...