Risk factors associated with equine gastric ulceration syndrome (EGUS) in 201 horses in Denmark

Reasons for performing study: The prevalence (up to 93% in Thoroughbred racehorses) and severity of equine gastric ulceration syndrome (EGUS) has been associated with type of training and differing management practices. However, there have been few studies to confirm these findings in nonracehorses in Europe. Objectives: To investigate the prevalence of EGUS in a population of Danish horses, during winter when the horses had been housed and fed for at least 8 weeks and to analyse the influence of feed, work level and environment on the risk of EGUS of §grade 2 in severity. Methods: A total of 201 horses, not in active race‐training, were evaluated, representing 23 different stables from all 5 regions within Denmark. All horses were considered to be healthy and not on medical treatment for EGUS. Endoscopically observed ulcer lesion scores were based on the number present (0–4) and severity (0–5). Univariate and multivariable mixed effects logistic regression models were developed using EGUS score as the dependent variable. An ulceration severity score of §2 was regarded as being clinically significant. Separate models were developed for horses with ulcers in either the glandular or nonglandular regions of the stomach graded §2 (EGUS §2) and for those horses that had nonglandular ulcers graded §2 (NG §2). Results: In this population, 53% (107/201) of horses were graded as having EGUS §2 with 95 (47%) horses having NG §2. Three variables were significantly (P<0.05) associated with EGUS §2: straw being the only forage available; exceeding 2 g/kg bwt of starch intake/day or §1 g/kg bwt/meal; and water not being available in the turn out paddock. Risk of NG §2 significantly increased when straw was the only forage available, 1 g/kg bwt of starch/meal was exceeded, water was not available in the turnout paddock and the interval between forage feeding was <6 h. Conclusion and potential relevance: This study has confirmed that components of the diet, readily modifiable, may have an important impact on the risk of EGUS in the nonracehorse. Differences in the multivariable models produced for all ulcers and nonglandular ulcers support differences in the aetiology of ulcers in different locations of the stomach.     

The prevalence and anatomical distribution of equine gastric ulceration syndrome (EGUS) in 201 horses in Denmark

Reasons for performing study: The prevalence (up to 93% in Thoroughbred racehorses) and severity of equine gastric ulceration syndrome (EGUS) have been correlated with the type of training and associated management practices. However, there have been few reports to confirm these findings in nonracehorses in Europe. Objectives: To describe the prevalence, anatomical distribution, severity and number of gastric ulceration lesions in a population of Danish pleasure horses; and to investigate differences for groups based on age, breed type and workload. Methods: A total of 201 horses not in active race‐training, age 7 months‐27 years, were evaluated, representing 23 different stables from all 5 regions of Denmark. These horses were considered to be healthy by the owner and not on veterinary treatment for EGUS. Endoscopically observed ulcer lesion scores were based on the number present (0–4) and severity (0–5). The presence or absence of ulcers in the glandular and/or nonglandular regions of the stomach was recorded and which site the most severe ulcers were found. Results: The prevalence of EGUS severity score ≥2 was 53%. The most severe lesions were commonly observed at the margo plicatus. Although older horses were not more likely to be affected by clinically significant EGUS they were more likely to have lesions in both the glandular and nonglandular regions. Differences in location of EGUS lesions were identified in different age groups, breed types and in horses exposed to different levels of work. Conclusion and potential relevance: This study confirms that gastric ulceration can be prevalent in a group of apparently clinically normal horses, not in intensive work. Further investigation of reasons for differences in EGUS location between different populations may aid toward the development of novel preventive measures.     

Squamous gastric ulceration complicated by gastric stenosis in a foal

A 2-month-old Warmblood colt presented with recurrent colic and regurgitation. Gastroscopy, performed on several occasions, and barium-contrast radiography revealed severe squamous gastric ulceration and stenosis at the level of the margo plicatus. Treatment with omeprazole reduced the extent and severity of the gastric ulcers but did not affect the stenosis. The foal was euthanised because of a poor prognosis, and post-mortem examination confirmed the clinical diagnosis. Severe squamous gastric ulceration, granulation tissue formation and cicatrisation of deep gastric lesions were considered to have caused the stenosis. Gastroduodenal outflow obstruction is a recognised disorder in foals, but stenosis at the level of the margo plicatus has not been reported in foals or adult horses. To the authors' knowledge, this is the first case of severe squamous gastric ulceration, complicated by stenosis at the level of the margo plicatus, in a foal. Although rare, gastric stenosis should be considered in foals suffering recurrent colic and regurgitation.     

Pathology of gastritis and gastric ulceration in the horse. Part 1: Range of lesions present in 21 mature individuals

Reasons for performing study: Gastric ulceration is now widely recognised as an important disease in high performance horses. Little is known about gastric histopathology in healthy or diseased animals; a comprehensive assessment would enhance interpretation of gross findings through assessment of their accuracy and allow for identification of lesion variety and pathogenesis in different anatomical regions of the stomach. Objectives: To investigate the true extent and variety of gastric lesions in a mixed population of mature horses at post mortem. Methods: Stomachs were removed from a mixed population of 21 horses at post mortem. Mucosal abnormalities were recorded in photographic and written form. Representative samples from all gross lesions were taken for histopathology and processed routinely. Special stains including Gram, PAS and Warthin Starry, were used when appropriate. Pathological classification of lesion type using both gross and histological appearances was performed. Results: Classification of lesions within the squamous region included hyperkeratosis, punctate scars, diffuse erosions/ulcerations and margo injuria; and within the glandular region, hyperaemia, focal erosions and ulcerations. Glandular metaplasia was recognised for the first time in the equine stomach. No Helicobacter‐like organisms were detected in association with lesion development. Conclusions and potential relevance: This study used gross and histological examination to highlight the large variety of naturally occurring gastric lesions in a mixed population of horses. Analysis of the pathogenesis of lesion development is now possible. Further research regarding the range of pathology in larger, more diverse groups of horses is required.     

Pathology of gastritis and gastric ulceration in the horse. Part 2: A scoring system

Reasons for performing study: High numbers of racehorses in training are reported to have gastric ulceration. Gross lesion scoring systems exist, but there is no fixed protocol with which to record gastric microscopic findings. In man, the histological classification of stomach lesions helps in the identification of recognised and emerging aetiologies of gastric disease and aids accurate comparison of findings between studies. In horses, the development of such a system would therefore be of benefit. Objectives: To develop a pathological scoring system that can be applied to examine samples of the equine stomach at biopsy and post mortem. Methods and results: The equine gastritis grading (EGG) system was developed initially using horse stomachs at post mortem. The protocol involved sampling tissue from 5 fixed locations within the squamous and glandular regions. Histological examination recorded both type and degree of inflammatory infiltrate and the presence of erosions, ulceration or any other reactive change in each slide. These results were combined and an overall diagnosis of gastritis type given for each stomach. Conclusions and potential relevance: This is the first example of a complete pathological scoring system developed specifically for recording gastric lesions in the horse. It provides a thorough and repeatable method with which to examine the equine stomach in microscopic detail. It can be used in diagnostic or research situations and the consistency of the information gathered will enable accurate comparison of data between different studies. It aims to give an indication as to the currently undetermined pathological variations seen in the stomach of healthy and diseased horses, as well as increasing the understanding of the pathogenesis of gastritis and gastric ulceration. Using this information, interpretation of biopsy samples is improved.     

Prevalence and treatment of gastric ulcers in Thoroughbred racehorses of Korea

BackgroundGastric ulcer is one of the prevalent diseases in racehorses. However, it has not been recognized as important in Korea, and drugs used to treat gastric ulcers are included in the doping test list, so they are not allowed to be administered to racehorses in training.ObjectivesThis study was performed 1) to investigate the prevalence and the severity of gastric ulcers in Thoroughbred racehorses in Korea, 2) to confirm the therapeutic effect of ranitidine and omeprazole, and 3) to compare the efficacy between ranitidine and omeprazole.MethodsForty-nine horses were randomly recruited, and gastroscopy was performed within two days after racing. Twelve horses with a sum grade of five or higher were randomly assigned to two treatment groups. Seven horses were administered ranitidine, and five horses were administered omeprazole. Follow-up gastroscopy was scheduled within one to five days after finishing the treatment.ResultsThe prevalence of gastric ulcer in Korean Thoroughbred racehorses after racing was 100%, and the grade was more severe in the non-glandular region than in the pyloric region. There was no correlation between the severity of gastric ulcer in the two regions. Omeprazole had a greater therapeutic effect than ranitidine.ConclusionsThis study shows the importance of recognizing gastric ulcers as an important factor, and omeprazole as a possible treatment option in Korea, as it has been removed from the list of prohibited substances for racehorses. Thus, the use of omeprazole is currently recommended until one day before the race.     

Descriptive epidemiology of joint injuries in Thoroughbred racehorses in training

Reasons for performing study: No large scale epidemiological studies have previously quantified the occurrence of carpal, metacarpo‐ and metatarsophalangeal (MCP/MTP) joint injuries in Thoroughbred racehorses. Objectives: To develop an objective classification system for carpal and MCP/MTP joint injuries and estimate the incidence of these injuries in young Thoroughbreds in flat race training. Methods: In a prospective cohort study, data on daily exercise and veterinary‐diagnosed carpal and MCP/MTP joint injuries were collected from Thoroughbreds monitored since starting training as yearlings, for up to 2 years. Cases were classified in one of 4 categories: 1) localised to a carpal or MCP/MTP joint based on clinical examination and/or diagnostic analgesia; no diagnostic imaging performed; 2) localised to a carpal or MCP/MTP joint based on clinical examination and/or diagnostic analgesia; radiographs taken but no abnormalities detected; 3) evidence of abnormality of subchondral bone and/or articular margin(s) on diagnostic imaging and 4) evidence of discontinuity of the articular surface on diagnostic imaging. Incidence rates and rate ratios were estimated using Poisson regression, adjusting for trainer‐level clustering. Results: A total of 647 horses from 13 trainers throughout England contributed 7785 months at risk of joint injury. One‐hundred‐and‐eighty‐four cases of carpal (n = 82) or MCP/MTP (n = 102) joint injury were reported in 165 horses and classified in Category 1 (n = 21), Category 2 (n = 21), Category 3 (n = 72) or Category 4 (n = 70). The overall joint injury rate was 1.8 per 100 horse months (95% CI = 1.2, 2.8); rates did not differ significantly between 2‐ and 3‐year‐olds but females sustained Category 1 injuries at triple the rate of males (P = 0.03). Joint injury rates differed significantly between trainers (P<0.001) and there was trainer variation in anatomical site and severity of injury. Conclusions and potential relevance: Carpal and MCP/MTP joint injuries are an important cause of morbidity in Thoroughbred racehorses. Identification of modifiable risk factors for these injuries may reduce their incidence.     

Size and geometry of apical sesamoid fracture fragments as a determinant of prognosis in Thoroughbred racehorses

Reason for performing study: Analysis was performed to examine a method for refining the preoperative prognosis for horses that had surgery to remove apical fractures of the proximal sesamoid bones (PSBs). Objectives: To determine if: 1) there was a difference in size or configuration of apical fractures between the different anatomical locations of the PSBs, which have been shown to affect the prognosis; and 2) the size or configuration could predict the prognosis for racehorses with these fractures. Methods: The study included 110 weanlings and yearlings and 56 training racehorses that underwent surgery to remove apical PSB fractures. Radiographs of the fractures were used for measurement of the abaxial and axial proportion and the abaxial to axial ratio, and race records were used to determine average earnings per start (AEPS) and total post operative starts. Analysis of variance and regression statistics were used to compare the fragment sizes between the specific PSBs on each of the limbs and compare size and configuration of the fractures to prognosis. Results: There was a significantly larger abaxial to axial ratio (more transverse fracture) for the forelimb medial sesamoids than for all other sesamoids in untrained racehorses (P = 0.03). There were no other significant differences in size. There was no relationship between fracture size or configuration and AEPS nor total post operative starts. Conclusions: Apical fractures in weanlings and yearlings tend to be more transverse in the forelimb medial PSBs than the other PSBs. Apical fracture size and geometry does not determine prognosis for apical sesamoid fractures. Potential relevance: Horses that undergo surgery to remove larger apical fractures of the PSBs do not have a worse outcome than those horses with smaller fractures.     

Primary gastric impaction in horses: A retrospective study of 20 cases (2005–2008)

Primary gastric impaction is an uncommon condition. Furthermore, the factors associated with gastric impaction and the optimal method of treatment are not clear. The aim of this article is to describe the clinical findings, treatment and outcome of horses with a primary gastric impaction. Medical records of horses that presented with a primary gastric impaction between 2005 and 2008 were reviewed and 20 horses with a primary gastric impaction identified. Diagnosis of a primary gastric impaction was made if the horse had been fasted for a minimum of 16 h, a concretion of ingesta precluded visualisation of the margo plicatus and there was no evidence of concurrent intestinal pathology. Thirteen of 20 (65%) horses were presented on an emergency basis. The most common complaint was inappetence (50%) followed by acute colic (35%) and recurrent colic (35%). On initial examination for colic, all horses had a normal heart rate and 7 of 20 (35%) had decreased gastrointestinal borborygmi. All horses were treated with enteral fluid therapy. The median dose of fluids administered per day was 5 doses (range 1–8 doses) of 2–10 l of isotonic electrolyte solution. The median length of treatment until resolution was 2 days (range 1–5 days). Eighteen of 20 (90%) horses survived to discharge. Primary gastric impaction appears to be a condition with clinical signs of inappetence and mild abdominal discomfort. This is the largest group of horses reported that were treated with enteral fluid therapy for a gastric impaction and it was concluded that enteral fluid therapy was of value in this study.     

Profiling the careers of Thoroughbred horses racing in Australia between 2000 and 2010

Reasons for performing study: Research investigating trends in racehorse careers require a benchmark for accurate comparison. Currently little whole population data exists for horses racing in Australia. Objectives: To determine the range and variation in career length and number of career starts for horses racing in Australia. To document and provide evidence regarding the current differences between the sexes for career length and careers starts. Methods: Racing data were collected for Thoroughbreds over a 10‐year period. Career length, number of career starts and spells per year were evaluated. Statistical analyses were performed using the statistical package R. Results: A total of 2,782,774 performance records yielded career information for 164,046 horses. Median career length and number of career starts for the population were 14.7 months and 10 starts, respectively. Significant differences (P<0.001) were present between the sexes for all career outcomes. Between 2000 and 2010, the percentage of Thoroughbreds racing in Australia with careers longer than 12, 24, 36 and 48 months was 56.65, 32.35, 16.66 and 7.74, respectively. Conclusions and potential relevance: Clear differences in career outcomes exist between intact males, females and geldings racing in Australia. Future research should be conscious of these differences when analysing population data.     

Retrospective study on the effect of wither fracture on racing performance in Thoroughbred racehorses in Hong Kong (2003 to 2013)

The training programme for Thoroughbred flat racehorses is intense, with pressure to limit nontraining days. Fracture of the dorsal spinous processes is a traumatic event that affects a horse's ability to train and race, with little information available regarding short‐term treatment and long‐term outcomes for elite racing horses. Using a retrospective cohort study of the Hong Kong Jockey Club's veterinary clinical records, cases of wither fracture were identified radiographically, with clinical features, treatment and subsequent return to training and racing described. The prevalence of wither fracture was 0.152% and in 6 out of 8 cases, the fracture occurred following identified trauma. Clinical signs varied from mild swelling and pain of the affected region to acute, severe forelimb lameness with spinal deformation. Prognosis for recovery was excellent, with all horses returning to a level of racing performance equal to or better than before the injury. The time from injury to return to ridden work was <2.5 months and return to racing was 9 months, with horses that returned to training sooner after injury having more favourable outcomes. The period of rest identified in this study was shorter than previously reported, with the median interval between injury and first gallop <2.5 months and most horses back racing within 6 months.