Euthanasia in horses refers to the process of humanely ending the life of a horse to alleviate suffering or when the quality of life is deemed unsustainable. This practice is considered in cases of severe illness, injury, or chronic pain where recovery is not possible. The decision-making process involves veterinarians, horse owners, and sometimes ethical and welfare considerations. Various methods are employed, with the primary aim of ensuring a painless and stress-free experience for the animal. This page compiles peer-reviewed research studies and scholarly articles that explore the ethical considerations, methods, decision-making processes, and impacts on equine welfare related to euthanasia.
van der Gaag I, van Bruinessen-Kapsenberg EG, Dik KJ, Kroneman J.A two-month-old female foal with duodenal stenosis is described. The foal was in poor condition and showed an abnormal stable behaviour. She stood preferably with her head stretched out and reposing on the mare's back or on the stable ridge. Salivation was an important symptom. Clinical and radiological examination of the oral cavity, the pharynx, and the oesophagus showed no abnormalities, except for the antiperistaltic wave along the oesophagus. Because of her bad condition the filly was euthanized. At post mortem examination, apart from leukoplakia, an erosive ulcerative inflammation was fo...
Mackay RJ, Iverson WO, Merritt AM.A 4-year-old stallion was examined because of a 2-month history of inappetance and weight loss. Diarrhoea had also developed a month before presentation. Abnormal clinical findings were emaciation, diarrhoea, ventral oedema, palpable mesenteric lymph node enlargement and a large mass in the left cranial portion of the abdomen. Significant laboratory findings were anaemia (packed cell volume 0.21 litres/litre), hypoalbuminaemia (16 g/litre) and xylose malabsorption. The horse was euthanased and at necropsy a 10.5 kg pendunculated mass composed of granulation tissue was found within and attached...
Tate LP, Koch DB, Sembrat RF, Boles CL.A surgical technique for resection of a portion of the trachea followed by end-to-end anastomosis was developed on 4 clinically normal horses. The trachea healed without complications in 3 of the horses in which 3 tracheal cartilages were removed. Five tracheal cartilages were removed from the 4th horse. It had to be euthanatized because of excessive suture line tension and wound disruption, which occurred during recovery from anesthesia. Suture line tension was measured on 3 other clinically normal horses positioned in dorsal recumbency immediately after euthanasia after 3 and 5 tracheal cart...
Greenwood RE, Simson AR.An outbreak of ataxia and paralysis on a Thoroughbred studfarm is reported. The cause of the disease was attributed to equid herpesvirus (EHV1) infection which stemmed from a single 10-month abortion on the studfarm. Stallions, mares and foals were all affected but the most serious clinical signs occurred in the mares. there were 35 out of 39 mares, 2 out of 4 stallions and 5 out of 39 foals which exhibited signs of ataxia. Nine mares became recumbent and died or were euthanased. Treatment with betamethasone and antibiotics was given. The outbreak was contained to one area of the stud apart fr...
Platt H, Singh H, Whitwell KE.A description is given of the pathological changes present in 8 mares which died or were euthanased in the course of an outbreak of paralysis on a Thoroughbred studfarm. In all cases the principal changes were in the central nervous system (CNS) and consisted of a severe and widespread vaculitis in the brain, cord, sheaths of nerves, capsules of ganglia and occasionally elsewhere in the body. Associated with the damage to vessel walls there was haemorrhage and exudation of plasma into the perivascular tissues. Involvement of neurones was minimal and no neuronophagia was present. Six cases had ...
Stick JA, Wilson T, Kunze D.Of three horses with basilar skull fractures, two died within 48 hours. The remaining horse was euthanatized because of a locomotion deficit. Clinical signs included epistaxis followed by ataxia. In each case, the basi-occipital bone and ventral portion of the calvarium were involved in the fracture. Diagnosis was based on clinical signs or radiographic appearance of guttural pouches, or both.
Freeman DE, Donawick WJ.A procedure developed to occlude the internal carotid artery of horses with guttural pouch mycosis was modified was modified and evaluated in nine clinically normal horses. The left internal carotid artery was ligated at its origin and occluded distally with an intraluminal balloon catheter. In four horses, the balloon-tipped catheters were left in place until these horses were euthanatized at 4 to 244 days after surgery. In the remaining horses, the catheters were removed after 10 to 14 days by a cutdown procedure, and these horses were euthanatized 1 to 60 days after catheter removal. In bot...
Freeman DE, Koch DB, Boles CL.Volvulus of the jejunum and ileum in three horses was associated with intestinal strangulation in a mesenteric rent. The rent was in the jejunal mesentery at its point of attachment with an anomaly that was classified as a mesodiverticular band. The band also was attached to the dorsolateral surface of the jejunum, thus forming one side of a triangular hernial sac that was completed on the other side by the adjacent jejunal mesentery. Incarceration of a loop of small intestine in the hernial sac preceded rupture of the jejunal mesentery and subsequent intestinal strangulation. Surgical correct...
Udenberg T.In most cases the outcome of impaction of the colon is favourable and with mild purging and lubrication, the mass can be broken down and the horse returned to normal health. It is important to reevaluate impaction cases which neither deteriorate or improve in a 24 hour period and to perform a paracentesis to evaluate the etiology and prognosis. A decision of euthanasia or surgical correction should be made as early as possible. Though initially stable, vital signs will deteriorate rapidly without warning. A critical evaluation of the client's farm management can prevent many impaction colics a...
Turk JR, Gallina AM, Liu IM, Nickels F, Grossman B.A 6-month-old Morgan colt was examined because of preputial edema and multiple nodular masses in the left inguinal region. A tentative diagnosis of lymphatic hamartoma was made on the basis of initial biopsy findings. The prognosis for surgical excision was poor due to the progressive expansile growth of the tumor. Secondary infectious complications developed, and the colt was euthanatized at the owner's request. An abdominal and retroperitoneal mass was seen at postmortem examination. The mass was adherent to the left lumbar musculature, the craniodorsal aspect of the pelvic inlet, the midjej...
Valdez H, Adams OR.After preliminary studies on cadavers, a surgical approach was developed for removal of the medial meniscus, offering maximal exposure and minimal trauma to the articular surfaces of the medial tibial plateau and femoral condyle. Medial meniscectomy was then performed on 10 clinically normal horses that had been given general anesthesia. Nine horses were euthanatized at intervals of 1 to 6 months, and the joints were evaluated grossly and histologically. (One horse will be examined 1 year after surgery). Medial meniscus tears were diagnosed in 5 horses; medial meniscectomy was done on 4 horses...
Hadlow WJ, Ward JK, Krinsky WL.Acute neurologic disease associated with intracranial migration of a first instar larva of a warble fly, Hypoderma bovis (Linnaeus), was observed in a 14-year-old Quarter Horse gelding in western Montana. The disease was characterized by incoordination of gait, circling to the left, head tilt to the right, partial paralysis of the right side of the face, and impaired vision in the right eye. Two and one-half hours after it was first noticed sick, the horse collapsed and was euthanized. Massive hemorrhage unaccompanied by necrosis or significant cellular response was present in the right side o...
Knight AP.Dysphagia developed in a 2-year-old Quarter Horse filly following an incident in which it fell over backward while exercising on a mechanical horse walker. Hyperextension of the neck at this time apparently caused unilateral rupture of the longus capitis (rectus capitis ventralis major) and the rectus capitis ventralis minor muscles at their insertion. An existing mycotic lesion involving the dorsomedial wall of the left guttural pouch may have weakened the area of insertion of the involved muscles. Tearing of the tendinous insertion of these muscles caused damage to the IX, X, and XI cranial ...
Rose RJ.Complications from neurectomy have been well known for many years. A 16-year-old mare suffered bilateral luxation of the coffin joints following palmar neurectomy and was destroyed. Autopsy showed complete rupture of the deep flexor tendons, and the supporting ligaments of the coffin joints. Arthritis of the coffin joints, with erosion of articular cartilage was evident.
Tobin T, Swerczek TW, Blake JW.This report concerns the detection and acute toxicity of pine oil (a commercially available disinfectant) after intravenous administration in horses. alpha Terpineol was identified as a major constituent of pine oil. alpha Terpineol was recovered from equine tissues by extraction into heptane and detected by gas chromatography, using either flame ionization detection or pentafluoropropionic anhydride derivatization and electron capture detection. After intravenous injection of 0.1 ml/kg, death due to massive pulmonary edema occurred within minutes. In this animal blood and tissue levels of alp...
Thorsen J, Little PB.A Standardbred mare became paralyzed shortly after showing signs of an upper respiratory infection. The mare was euthanized and equine herpesvirus type 1 was isolated from the brain and spinal cord.
Episodic collapse in horses has equine welfare and human safety implications. There are, however, no published case series describing this syndrome. Objective: To characterize the cause and outcomes for horses referred for investigation of episodic collapse. Methods: Twenty-five horses referred for investigation of single or multiple episodes of collapse. Methods: Retrospective study. Clinical records from the Dick Vet Equine Hospital, University of Edinburgh from November 1995 to July 2009 were searched using the following keywords: collapse, collapsing, fall, syncope. Collapse was defined as...
A 25-year-old pony mare was presented to the clinic with preliminarily reported severe acute colic. The pony during the previous week had shown inappetence, apathy and fever of unknown origin. Clinical examination and placement of a gastric tube were indicative of a secondary gastric dilation. Rectal exploration found moderate caecal meteorism with a tensed and painful medial taenia as well as a dilated and fluid-filled small intestine. In addition, a solid, mobile, non-painful structure of approximately 10 cm diameter was palpated ventrally. A hyperechogenic mass close to the caecum was detec...
Tóth F, Schumacher J, Schramme M, Hecht S.To describe the anatomic features of the equine trochanteric bursa and to evaluate 4 techniques for bursa centesis. Methods: Prospective, randomized design. Methods: Equine cadavers (n=2) and 20 live horses. Methods: The trochanteric bursae of 2 equine cadavers were injected with latex to identify the boundaries of the bursae. Four techniques for centesis of the trochanteric bursa were evaluated by attempting to inject dye into both trochanteric bursae of 20 live horses. Techniques included injection of the bursa with the limb-bearing weight and injection with the limb nonweight bearing and su...
Colbath AC, Fortin JS, Burglass CM, Panek C, Vergara-Hernandez FB, Johnson TN, Robison CA, Logan AA, Nelson NA, Nielsen BD, Schott HC.Pathological fractures have been reported in equids with pituitary pars intermedia dysfunction (PPID) but their prevalence and pathogenesis is unknown. Objective: To compare: (1) bone mineral density (BMD) in weight bearing and nonweight bearing bones in PPID+ equids and aged and young PPID- controls; and (2) biomechanical properties of the fourth lumbar vertebral body in PPID+ equids and aged PPID- equids. Methods: Case-control study: five PPID+ equids and six aged and four young PPID- control horses. Methods: PPID status was based on clinical signs and necropsy examination of the pituitary g...
Kvigstad EF, Øverland IK, Skedsmo FS, Jäderlund KH, Gröndahl G, Hanche-Olsen S, Gunnes G.Over the past 25 years, acquired equine polyneuropathy (AEP) has emerged as a neurological disease in Scandinavian horses. This condition is characterized by histopathological features including the presence of Schwann cell (SC) inclusions. Cultivated equine SCs would serve as a valuable resource for investigations of factors triggering this Schwannopathy. Ideally, cells should be sampled for cultivation from fresh nerves immediately after death of the animal, however the availability of fresh material is limited, due to the inconsistent case load and the inherent technical and practical chall...
de Preux M, Precht C, Guevar J, Graubner C, Thenhaus-Schnabel S, Buser L, Lukes A, Koch C.A 16-year-old warmblood mare was referred with a progressive history of behavioral changes and left-sided blindness. Following neuroanatomical localization to the forebrain, magnetic resonance imaging of the head revealed a well-delineated, 4.5 cm in diameter, round pituitary mass causing marked compression of the midbrain and optic chiasm. Euthanasia was recommended but declined by the owners. Veterinary specialists and a human neurosurgeon collaboratively prepared for surgical case management. A novel navigated transmandibular lateral transsphenoidal approach was developed to access the re...
Galinelli NC, Bamford NJ, de Laat MA, Sillence MN, Harris PA, Bailey SR.Insulin dysregulation in horses is characterised by hyperinsulinaemia and/or tissue insulin resistance and is associated with increased risk of laminitis. There is growing evidence in other species that dopamine attenuates insulin release from the pancreas; however, this has yet to be examined in horses. The present study aimed to identify whether there are cells capable of producing or responding to dopamine within the equine gastrointestinal mucosa and pancreas. Tissue samples were collected from the stomach, small and large intestines, and pancreas of six mature horses following euthanasia....
Benedetti B, Freccero F, Barton J, Elmallah F, Refat S, Padalino B.Working equids are often used to exhaustion, living and dying in conditions below minimal welfare standards. Due to their poor welfare status, euthanasia should be considered in certain conditions. The study aimed to describe the population and the disease frequency of the working equids admitted at an equine clinic in Cairo (i.e., Egypt Equine Aid (EEA)) from 2019 to 2022 and identify possible associations between physical parameters at admission and the outcome. Records of 1360 equids admitted at EEA were reviewed. The majority of the admitted equids were horses (65.6%), followed by donkeys ...
Vernemmen I, Van Steenkiste G, Buschmann E, Cornelis K, Schauvliege S, Ibrahim L, Decloedt A, van Loon G.Radiofrequency ablation has been successfully applied to treat right atrial arrhythmias in horses. Ablation of left-sided arrhythmias requires a retrograde transarterial approach which is complicated. In human medicine, the left atrium is accessed through transseptal puncture (TSP) of the fossa ovalis (FO) using a caudal approach via the femoral vein. Objective: To develop a zero fluoroscopy TSP technique for horses using a jugular vein (cranial) and transhepatic (caudal) approach. Methods: In vivo experimental study. Methods: Transseptal puncture was performed in 18 horses admitted for euthan...
Romero Corrêa R, Peres Mendes R, Darley Velasquez Piñeros D, De Lima AE, do Valle De Zoppa AL, Lopes Correia da Silva LC, de Francisco Strefezzi R....Preservation of biological tissues has been used since ancient times. Regardless of the method employed, tissue preservation is thought to be a vital step in veterinary surgery teaching and learning. Objective: This study was designed to determine the usability of chemically preserved cadaveric equine heads for surgical teaching in veterinary medicine. Methods: Six cadaveric equine heads were collected immediately after death or euthanasia and frozen until fixation. Fixation was achieved by using a hypertonic solution consisting of sodium chloride, sodium nitrite and sodium nitrate, and an alc...
Barrantes Murillo DF, Cattley RC, Cullen JM, Withers C, Towns J, Pfeifle R, Wooldridge A, Neto RLALT.A 17-y-old Arabian mare was presented to the Auburn Large Animal Veterinary Teaching Hospital with a long-term history of intermittent mild recurrent colic that responded to medical treatment. CBC revealed mild lymphopenia; serum biochemistry findings were of increased gamma-glutamyl transferase and creatine kinase activities, hyperferremia, hyperglycemia, hypomagnesemia, and hypokalemia. Abdominocentesis was compatible with low-protein transudate. Due to the progression and duration of clinical signs, the owner elected euthanasia. Postmortem examination and histopathology confirmed a cholangi...
Nieforth LO, Kaufman S.Given the nature of horse-human interactions in equine-assisted services (EAS), death of a horse may have significant impacts. In this study, an online survey was distributed to EAS practitioners. The goal of the study was to explore the experiences of practitioners and identify the socioemotional processes that occur upon the death of an equine within an EAS program. Open-ended responses ( = 84) were analyzed qualitatively using a grounded theory and constant-comparative approach. Responses are situated into two themes (1) Processing the death of an equine and (2) Practical implications. Expe...
Kramer AJ, Meziara Wilson T, Kimura S, Groover E, DeLeon-Carnes M, Neto RLALT.A 23-y-old gelding was presented to a veterinary teaching hospital with a history of chronic, refractory diarrhea. Clinically, the horse was in poor body condition, with a thickened and corrugated large intestine identified by transcutaneous abdominal ultrasonography. At postmortem examination following euthanasia, the large colon and cecum had segmental thickening of the intestinal wall with innumerable mucosal ulcers and prominent polypoid mucosal masses. Many mesenteric and hepatic lymph nodes were enlarged. Histology revealed granulomatous and ulcerative typhlocolitis and granulomatous lym...
Willis AT, Dahlgren AR, Woolard KD, Ghosh S, Donnelly CG, de la Concha-Bermejillo A, Pacheco A, Watson KD, Berryhill E, Aleman M, Wensley F....In 2020, a novel neurologic disease was observed in juvenile Quarter Horses (QHs) in North America. It was unknown if this was an aberrant manifestation of another previously described neurological disorder in foals, such as equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM). Objective: To describe the clinical findings, outcomes, and postmortem changes with Equine Juvenile Spinocerebellar Ataxia (EJSCA), differentiate the disease from other similar neurological disorders, and determine a mode of inheritance. Methods: Twelve neurologically affected QH foals and the...
Esterl-Byrne LL, Huseman CJ, Haynes C, Kinman LA, Jones TN.The welfare of unwanted horses presents a significant concern for the equine industry. However, there is a lack of research on how unwanted horses are affected by major crises. The drastic changes that resulted from the COVID-19 pandemic presented ample opportunity to investigate how unwanted horses are impacted by challenging circumstances. Study objectives were to evaluate the COVID-19 pandemic's impact on the unwanted horse population and determine the current perceptions of horses in-transition. A 23-question online survey designed using Qualtrics was administered electronically to adults ...
Giessler KS, Goehring LS, Jacob SI, Davis A, Esser MM, Lee Y, Zarski LM, Weber PSD, Hussey GS.Herpesviruses establish a well-adapted balance with their host's immune system. Despite this co-evolutionary balance, infections can lead to severe disease including neurological disorders in their natural host. In horses, equine herpesvirus 1 (EHV-1) causes respiratory disease, abortions, neonatal foal death and myeloencephalopathy (EHM) in ~10 % of acute infections worldwide. Many aspects of EHM pathogenesis and protection from EHM are still poorly understood. However, it has been shown that the incidence of EHM increases to >70 % in female horses >20 years of age. In this study we use...
Barton CK, True A, Fenn M, Thampi P, Watson A, Smanik LE.The objective of this Case Report was to describe the clinical manifestation and postmortem findings of a horse evaluated for recurrent colic diagnosed with pyloric aplasia and an ectopic duodenal papilla. Methods: 13-year-old Quarter Horse gelding. Unassigned: The horse was presented to a referral center for signs of colic that were unresponsive to management on the farm. No abnormalities were noted on rectal palpation; however, upon passage of a nasogastric tube, 31 L of net gastric reflux was obtained. Gastroscopy noted grade IV squamous ulceration and moderate glandular ulceration, severe ...
Carpenter AL, Townsend KS, Johnson PJ, Kim DY.An 8-y-old National Show Horse mare was presented for evaluation of pneumonia and laminitis. Harsh bronchovesicular sounds were auscultated throughout both lung fields, and the mare had signs of moderately painful laminitis. Thoracic ultrasonography revealed lung consolidation throughout the dorsal aspect of both lungs, and radiography revealed an extensive diffuse-to-patchy bronchointerstitial lung pattern. The mare's clinical condition rapidly deteriorated, and euthanasia was elected. On postmortem examination, the lungs, omentum, spleen, liver, adrenal glands, kidneys, and femur contained 0...
Charles A, Kerckhove HV, De Maré L, Cassart D, Ficheroulle J, Pouyade GR, Tosi I.A Standardbred racehorse was presented for exercise intolerance, weight loss, pyrexia and facial deformity. Radiography and ultrasonography revealed periostitis and regional soft tissue swelling of maxillary bones. Computed tomography excluded any dental or sinus origin of these abnormalities. Further deformities on distal limbs and skin lesions appeared during hospitalization. Radiography identified bilateral periostitis and soft tissue swelling in the distal radius and metatarsal bones, as observed in the head, suggestive of hypertrophic osteopathy (HO). Skin biopsies revealed granulomatous ...
Allen SE, Taylor S, Given J, Verheyen KL.The British horseracing industry is committed to reducing equine fatalities in jump racing. Race-related fatalities are a major welfare concern and threaten the sport's social licence to operate. Objective: To describe the risk of, and determine risk factors for, fatality in British jump racing. Methods: Retrospective cohort. Methods: Analyses included all starts made in British jump races between January 2010 and April 2023. Available information for each horse, race, racecourse, trainer and jockey was collated and combined with details of all fatalities recorded by official veterinary office...
Nielsen SS, Alvarez J, Boklund A, Dippel S, Dorea F, Figuerola J, Herskin M, Miranda Chueca MA, Nannoni E, Nonno R, Riber A, Stahl K, Stegeman JA....Horses of different ages may have to be killed on-farm for purposes other than slaughter (where slaughter is defined as killing for human consumption) either individually (i.e. on-farm killing of unproductive, injured or terminally ill animals) or on a large-scale (i.e. depopulation for disease control purposes and other situations, such as environmental contamination, disaster management, etc.). The purpose of this opinion is to assess the hazards and welfare consequences associated with the on-farm killing of horses. The killing procedure is divided into Phase 1 (pre-killing), which includes...
Cameron A, Geldard M, Mair T, England G, Burford J, Freeman S, Pollock K, Wilson E.Veterinary and charity teams are frequently involved in equine end-of-life decisions. These can cause ethical dilemmas and emotional burdens and complicate communication with owners. Semi-structured focus groups explored experiences of making decisions about end-of-life care and euthanasia at three UK equine veterinary practices and one charity. There were 26 participants in a mix of roles. Inductive coding was conducted during thematic analysis. Major themes generated were 'Equine Welfare', 'Relationships', 'Decision-Making', and 'Emotional Toll and Coping Strategies'. Communication, finances...
Schlote MT, Drozdzewska K, Ehrle A, Lischer C, Gehlen H.This case report describes the use of computed tomography for the diagnosis and surgical planning in a horse with bilateral nephrolithiasis. An adult Warmblood stallion (460 kg) was presented with chronic weight loss, hypercalcemia and azotemia. Ultrasonographic examination identified hyperechoic masses in both kidneys and dilation of the right renal pelvis. A solid mass was evident upon transrectal examination on the left side. Computed tomography (CT) of the caudal abdomen was performed and provided good quality images that facilitated exact determination of the size, position and extent of ...
Kelemen Z, Vogl C, Torres Borda L, Auer U, Jenner F.Clinical care for patients with limited life expectancy often requires adjustments, prioritizing immediate benefits over long-term outcomes, as the relevance of future complications diminishes. This study identifies indicators of mortality risk in horses with chronic orthopaedic conditions to enhance individualized care and welfare. Over 3 years, 123 chronically lame horses and 6 healthy control horses at an animal sanctuary underwent regular (every 3 months) comprehensive health assessments and activity monitoring using wearable sensors. Data collected included body condition scores, muscul...
Boocock H, Flyps J, Escobar A, Redondo JI, Taylor PM, Gozalo-Marcilla M, Johnston GM, Bettschart-Wolfensberger R, Sullivan R.Equid anaesthetic mortality is of interest to practitioners. Data for donkey and hybrid mortality have not been specifically described. The main aim of this worldwide observational, prospective, multicentre cohort study was to report on mortality in the 7 days following a general anaesthetic or standing sedation in donkeys and hybrids. This study hypothesised that donkeys and hybrids would have higher mortalities compared to horses. Data were collected as part of the fourth Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4). A total of 825 cases were included, with 757 donkeys ...
Fletcher KA, Benedetti B, Limon G, Grist A, Padalino B, Hernández-Gil M, Gibson TJ.There has been limited research into the effectiveness of penetrating captive bolt (PCB) for stunning horses () at slaughter. This study observed 100 horses at a commercial abattoir in Mexico, stunned using pneumatic PCB. Animals were assessed at the time of stunning and immediately after for signs of effective/ineffective stunning and shot positioning, with macroscopic gross brain pathology conducted to determine brain trauma. Twenty-five percent (25/100) received more than one shot and 28% (28/100) displayed behavioural signs of ineffective stunning. Of these 28 animals, all had deviations o...
Hoogelander B, Frippiat T, Bergman HJ, Vanderperren K, van Veggel ECS.Thoracolumbar congenital abnormalities are considered rare in mature, performing horses. This case report describes a 14-year-old Welsh pony presented with marked epaxial muscle atrophy, mid-thoracic spinal pain, and stiffness, most pronounced during canter. The thoracic spine exhibited scoliosis, centered at T9-T10, and kyphosis. Radiography and postmortem computed tomography revealed complex congenital malformations of the thoracic vertebral column, including abnormal morphology of the T10-T12 vertebral bodies, partial vertebral fusion, a malformed spinous process, a malformed rib with assoc...
Markowitz JS.Equibase (EQB) race charts provide the official record of North American Thoroughbred races and often document catastrophic injury, euthanasia, or equine-ambulance transport. Because chart documentation and regulatory classification differ, fatalities occurring > 72 hours after a race fall outside international regulatory definitions applied by the Equine Injury Database (EID) and may not appear in EID aggregates. EQB charts confirm horse identity, race participation, finishing status, and last recorded start. Horseracing Wrongs (HRW), an advocacy group, publishes horse-level fatality data tha...