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.
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 ...
Diab SS, Giannitti F, Hill A, Morgan J, Blea JA, Arthur R, Poppenga R, Stover S, Uzal FA.Horse racing has faced increased scrutiny because of concerns about equine welfare and the safety of both equine and human participants. Sudden death (SD) in racehorses is relatively uncommon, and its causes are still unclear. Little information and considerable confusion exist regarding the clinical significance of microscopic lesions in the hearts of horses with SD. We examined the hearts of 29 horses that suffered exercise-associated sudden cardiac death (EASCD) and 29 clinically healthy control horses that were euthanized because of catastrophic musculoskeletal injuries. Acute cardiomyocyt...
Ekstrand C, Michanek P, Hernlund E, Gehring R, Salomonsson M.Cannabidiol (CBD) and cannabidiolic acid (CBDA) are non-psychoactive cannabinoids naturally present in hemp-derived products. While these compounds are prohibited during equine competition, horses may be inadvertently exposed through contaminated feed. Data describing systemic and urinary exposure to CBD and CBDA following such low-dose, involuntary intake are limited. This study aimed to describe plasma and urine concentration-time profiles of CBD and CBDA in horses after consumption of experimentally contaminated feed. Results: Twelve Standardbred horses received feed containing low doses (1...
Jacobs ME, Blea J, Hardy M, McKemie DS, Traynham M, Knych HK.Metformin is a diabetes medication with minimal therapeutic efficacy in veterinary medicine. However, recently there have been several adverse analytical findings in regulatory samples collected from racehorses. Metformin is commonly prescribed to humans, is excreted unchanged in urine, and is resistant to environmental degradation, raising concerns with respect to environmental contamination. In this study, six horses were exposed to shavings contaminated with metformin-positive urine at concentrations of 10, 135, and 270 μg/mL. Blood (plasma, serum, whole blood, and red blood cells) and u...
Kadláčková M, Dobešová D, Ivanovová E, Masař R, Jahn P, Šamonilová E, Friedecký D, Brumarová R.Atypical myopathy (AM) is a frequently fatal, toxin-induced disease in horses, characterised by acute progression and mortality rates exceeding 70% within 72 h. The disease is caused by ingestion of seedlings or seeds of certain maple species that contain the toxins hypoglycin A (HGA) and methylenecyclopropylglycine (MCPrG). Early diagnosis depends on reliable detection of these compounds and their metabolites. However, most available LC-MS/MS assays are limited by derivatisation requirements and dependence on serum and urine matrices. Here, a rapid derivatisation-free flow injection analysis...
El Abbadi I, Pallier V, Bastos MC, Lissalde S, Feuillade G.This study developed a method for the simultaneous quantification of six potentially environmentally toxic veterinary drugs: benzylpenicillin, acepromazine, flunixin, dexamethasone, ketamine and romifidine, in soils, sediments, equine faeces and natural waters. Three methods were compared for their extraction from solid matrices: Ultrasonic extraction (USE), QuEChERS and Accelerated Solvent Extraction (ASE). ASE method was optimized according to temperature and extraction cycles. Quantification was performed by LC-MS/MS. LC and MS parameters were optimized. The method was validated according t...
Lynch AD, Mama KR, McKemie DS, Kass PH, Knych HK.Tapentadol is a dual mechanism analgesic utilizing both μ-opioid receptor (MOR) agonism and norepinephrine reuptake inhibition (NRI). This study evaluated the pharmacokinetics and pharmacodynamics of tapentadol as a potential analgesic with the goal of treating pain in horses. Pharmacokinetics of both tapentadol and tapentadol-O-glucuronide were elucidated. Six horses received three separate escalating single oral doses (1, 3, and 5 mg/kg) and a single intravenous (0.32 mg/kg) dose of tapentadol in a four-period sequential design. Concentrations of tapentadol and tapentadol-O-glucuronide ...
Hulitká D, Coradduzza D, Sanna A, Biggio GP, Taras A, Cannas A, Carru C, Medici S, Cherchi R, Cappai MG.Bone tissue undergoes continuous remodelling throughout the life of the individual, and growth is the most impacting phase. In fact, tightly coordinated processes of resorption, synthesis, and mineralization of the bone matrix under systemic hormonal, biomechanical, and metabolic control occur for variable periods of time across species. The horse is a fast-growing animal and for this reason identified as precocial. It was hypothesized that blood serum levels of minerals in growing foals at different stages of accretion may vary over time. This investigation aimed to assess the dynamics of cir...
Yamashita N, Yoshihara T, Hatazoe T, Misumi K, Hobo S.We investigated the health of Tokara horses (n=34) on Nakanoshima as part of conservation efforts for this breed. Although the horses were clinically healthy, elevated white blood cell count, neutrophil count and gamma-glutamyl transferase (GGT) levels were observed, leading to suspicion of chronic hepatic dysfunction and infectious disease. A survey revealed that the caretakers had been feeding the horses Leopard plant, which contains toxic pyrrolizidine alkaloids (PAs). The abnormal GGT levels observed in these horses may suggest the possibility of chronic PA poisoning resulting from the con...
Summers KM, Karagianni AE, Fernandez PL, Beard PM, Pirie RS, Keen JA, Wishart TM, McGorum BC.Equine grass sickness (EGS or equine dysautonomia) is a predominantly fatal multi-system neuropathy affecting grazing horses, likely caused by a neurotoxic phospholipase A2 (nPLA2) derived from a plant or microorganism. We studied neuronal tissue gene and protein expression patterns in EGS to elucidate the possible mechanisms of neurotoxicity and neurodegeneration. Tissue from the cranial cervical ganglion of eight EGS horses and six controls was examined histologically and used for transcriptomic analysis. These transcriptomic data were compared with previously published EGS-related proteomic...
Guan F, Adreance MA, Fay S, McGoldrick LK, Keen B, You Y, Robinson MA.Hypoxia-inducible factor (HIF) activating agents can promote the transcription of the erythropoietin gene, enhancing an athlete's performance, and are therefore prohibited in sports. A liquid chromatography coupled to high-resolution mass spectrometry (LCHRMS) method was developed for the detection and confirmation of 11 HIF-activating substances in equine plasma and urine. Ammonium formate added to the mobile phase system suppressed the responses of all the analytes in either positive or negative ion mode and thus was not used. The starting organic percentage in the mobile phase gradient and ...
Silveira AM, Mendonça MFF, Oliveira Filho JC, Caymmi LG, Pimentel LA, Riet-Correa F.This paper reports an outbreak of Chamaecrista serpens var. serpens poisoning in Mangalarga Marchador horses, Pega donkeys, Nelore cattle, and Mambrina goats. The disease occurred in the municipality of Iaçu, in the semi-arid region of the state of Bahia, 15-30 days after the start of the rainy season, coinciding with the regrowth of the plant. The prevalence of the poisoning was 100% in donkeys and horses, 11.9% in cattle, and 38.8% in goats. Clinical signs were characterized by itching, edema, and crust formation, predominantly in areas of non-pigmented skin or with less hair coverage and i...
