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.     

Nutritional management of gastric ulceration

Gastric ulcers are common in horses and equine gastric ulcer syndrome describes ulcers in the distal oesophagus, nonglandular and glandular stomach as well as the proximal duodenum. Ulcers in the distal oesophagus and nonglandular region of the stomach are probably caused by hydrochloric acid, whereas ulcers in the glandular stomach and proximal duodenum are likely to be caused by a breakdown in the mucosal defence mechanisms. Regardless of the location of ulcers, initial treatment with pharmacological agents is necessary to suppress hydrochloric acid; however, nutrition and management changes are required to maintain ulcer healing and help prevent recurrence. In addition, many dietary supplements have been marketed to help maintain stomach health and some scientific data on their effects on gastric ulcer scores and gastric juice pH are presented.     

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.     

Effects of supplements containing turmeric and devil’s claw on equine gastric ulcer scores and gastric juice pH

Supplements containing turmeric (Curcuma longa) and devil’s claw (Harpagophytum species) are commonly fed to horses to decrease inflammation and pain, but because these supplements contain spices and plant irritants, warning labels such as 'these supplements might cause gastric irritation' are required. The purpose of this study was to determine whether supplements containing turmeric and devil’s claw cause or worsen gastric ulcers in stall-confined horses, as suggested in required cautions that appear on the labels of these animal products. Twelve clinically healthy Thoroughbred horses with naturally occurring equine gastric ulcer syndrome (EGUS) scores >0 were included in a noncrossover study design. Horses were stratified by EGUS score and assigned to either the treatment (supplements containing turmeric and devil’s claw) or control (same supplements without active ingredients) group and fed the supplements for 28 days. Gastroscopy was performed on Days 0, 14 and 28. The EGUS score, nonglandular ulcer number (NGN) and severity (NGS) scores, and glandular number (GN) and severity (GS) scores were recorded during each gastroscopy by a masked investigator (F.M.A.). In addition, bodyweight, gastric juice pH, packed cell volume (PCV), total protein (TP) and blood biochemical results were measured on Day 0 and Day 28. Mean EGUS and NGS scores were significantly lower in both treatment and control groups by Days 14 and 28, when compared to Day 0. NGN score was not different among groups. Bodyweight, gastric juice pH and blood parameters did not change during the study. In conclusion, supplements containing turmeric and devil’s claw did not cause or worsen gastric ulcers or alter health parameters after 28 days of feeding.     

Prevalence of gastric ulcer syndrome in high-level endurance horses

Reasons for performing the study: Equine gastric ulcers syndrome (EGUS) prevalence studies are rare in the endurance horse and none has been carried out to date in horses competing at high level. Objectives: To determine the prevalence of EGUS in high‐level endurance horses. Methods: Thirty endurance horses competing at high level were selected and submitted to 2 gastroscopic examinations. The first gastroscopy was performed during the interseason period, and the second during the competition season within 2–3 days following a ride of 90–160 km. Data related to housing, feeding, training system as well as age, breed and gender were recorded for each horse. Results: The prevalence of squamous gastric ulcers was 48% during the interseason period (mean score 0.85 ± 0.13 on a scale from 0–4) and 93% during the competition season (mean score 1.60 ± 1.15) with a highly significant difference between the seasons (P = 0.001). Most of the lesions were situated in the squamous portion of the stomach but 33.3% of horses showed also glandular lesions. Significant influence of training and performance level on the gastric score (according to the distance of the ride preceding the second gastroscopy) was shown (P = 0.038). There was also a significant influence of housing on the gastric score (P = 0.002) showing higher scores in the horses kept totally on pasture (mean score: 2.14 ± 0.14) vs. horses housed in a mixed environment (stable + pasture, mean score: 1.43 ± 0.17). Both the pastured and (stabled + pastured) groups were receiving a grain supplement but the pastured group received a higher daily starch intake, which might explain the higher ulcer prevalence. There was no influence of age, breed or gender on the gastric scores. Conclusions: The high prevalence of gastric lesions observed in this study is probably related to the high level of training and performance of the horses examined compared to the population of horses included in the prior study. Potential relevance: This prevalence of EGUS in high‐level endurance horses is comparable to the prevalence established in racing horses. The equine veterinarians may take into consideration EGUS as a potential cause of poor performance.     

Effects of intravenously administrated omeprazole on gastric juice pH and gastric ulcer scores in adult horses

The study was performed to evaluate the efficacy of omeprazole powder in sterile water, administered intravenously, on gastric juice pH in adult horses with naturally occurring gastric ulcers. Omeprazole (0.5 mg/kg, IV) was administered once daily for 5 days to 6 adult horses with gastric ulcers. Gastric juice was aspirated through the biopsy channel of an endoscope and pH was measured before and 1 hour after administration of omeprazole on day 1, and then before and after administration of omeprazole on day 5. Gastric ulcer scores were recorded on day 1 before administration of omeprazole and on day 5, 23 hours after the 4th daily dose. Gastric juice pH and ulcer scores were compared between the times. When compared with the pre-injection value (2.01 +/- 0.42), mean +/- SD gastric juice pH was significantly higher when measured 1 hour after administration of the initial dose (4.35 +/- 2.31), and before (5.27 +/- 1.74) and 1 hour after (7.00 +/- 0.25) administration of omeprazole on day 5. Nonglandular gastric ulcer number score significantly decreased from a mean +/- SD of 3.2 +/- 0.80 to 2.0 +/- 1.1, but nonglandular gastric ulcer severity score remained the same. Few glandular ulcers were seen in the study, and scores did not change. Because of its potent and long duration of action on gastric juice pH, this intravenous formulation of omeprazole may show promise for treatment of equine gastric ulcer syndrome (EGUS) in horses with dysphagia, gastric reflux, or other conditions that restrict oral intake of omeprazole paste. Aspiration of gastric juice and measurement of pH can be of use to determine whether the desired pH > 4.0 has been reached after omeprazole treatment.     

Pathomorphological study on gastroduodenal ulceration in horses: localisation of lesions

Gastroduodenal ulceration is a prevalent disease in foals and adult horses. Decreased performance as well as fatal complications relate to this syndrome. The objective of our study was to determine the prevalence of gastric ulceration in a mixed population of horses by postmortem examination and to evaluate a possible association between equine gastric ulcer syndrome (EGUS) and sex or age of the examined horses, to evaluate the localisation of lesions in the proximal part of the gastrointestinal tract and to determine the occurrence of gastric parasites. Postmortem examinations were performed on 71 horses over a period of 24 months. Gastric ulcers were found in 52 horses (73.2%). There was no significant association between age or sex and occurrence of gastric ulcers. In all horses the squamous mucosa lesions were localised near the margo plicatus (100% of the cases), whereas in 23 horses the lesions were near the margo plicatus and lesser curvature and in 7 horses at the greater curvature. In 18 horses the mucosa was affected in the whole extent of the margo plicatus and in 1 horse diffuse lesions of the squamous mucosa were noted. Lesions of the glandular mucosa were localised in 11 horses at the fundic area, in 1 horse they occurred in the pylorus, and in 10 horses diffuse lesions of the glandular mucosa were recorded. A low prevalence of Gasterophilus intestinalis infection was detected (1 horse, 1.4%). We have confirmed that gastric ulcers are a common problem in horses and duodenal or oesophageal ulceration is rare (not a single case of the latter was found in this study). Lesions in the glandular mucosa of the stomach are more frequent in suckling foals than in older animals. Lesions of the glandular mucosa are also common in adult horses, and a complete gastroscopic examination including examination of the pylorus is advisable to evaluate this syndrome.     

Validation of a transendoscopic glandular and nonglandular gastric biopsy technique in horses

Reasons for performing study: In order to study the evolution of histopathological and immunohistochemical changes in the gastric mucosa of horses with EGUS (equine gastric ulcer syndrome), a feasible, useful, valid and safe in vivo gastric biopsy technique is required. Objectives: To determine the average gastric mucosal healing time following endoscopic gastric biopsy sampling, and evaluate the feasibility, safety and usefulness of samples obtained by this method for histopathological analysis. Methods: Six mature mares from the Faculté de Médecine Vétérinaire research herd were used. Transendoscopic gastric biopsy was performed on Days 0 and 9 using a flexible forceps with oval and fenestrated jaws to obtain gastric mucosal samples from 4 different sites: cardia (C), fundus (F), margo plicatus (MP) and glandular mucosa (GL). A maximum of 4 samples per site was taken and processed routinely for histopathology, evaluated by a pathologist. On Days 1–4 and 9–11 the lesions created by the biopsies were evaluated by gastroscopy. Lesions were evaluated over time based on a score from 0–4, where 4 was the most severe. Results: Biopsy samples could be obtained from all targeted sites except C. No abnormal clinical signs were observed up to 7 days post biopsy. The average biopsy lesion scores decreased significantly with time for all sites. The average lesion score was significantly higher for the MP compared to the other sites at Days 1 and 2. Samples taken from the nonglandular portion of the stomach were considered inadequate for histopathology, while those taken from the glandular mucosa were adequate. Conclusion: The transendoscopic gastric biopsy technique described here is a feasible, safe and useful technique for obtaining samples from the equine gastric glandular mucosa. Although biopsy samples could be obtained from several areas in the nonglandular mucosa, these were very small, took longer to heal and were not considered adequate for histopathological evaluation, and another technique should therefore be validated.     

The effect of porcine hydrolysed collagen on gastric ulcer scores,gastric juice pH,gastrin and amino acid concentrations in horses

Gastric ulcers are common in horses. The purpose of this study was to test the effect of porcine hydrolysed collagen (PHC) on gastric ulcer scores and gastric juice pH in horses. We hypothesise that PHC-administration will result in improved gastric lesion scores and act synergistically with omeprazole to improve treatment efficacy. Thoroughbred horses (n = 10) were studied in a 2-period, 2-treatment crossover design, where the PHC (45 g) was administered twice daily. Horses were treated for 56 days. Gastroscopy was performed and gastric juice pH measured on Days 0, 14, 28, 42, 49 and 56. Nonglandular gastric ulcer number (NGN) and severity (NGS) and glandular ulcer number (GN) and glandular severity (GS) scores were assigned by an investigator masked to treatment and serum gastrin and amino acid concentrations. By Day 42, 2 weeks after discontinuing omeprazole treatment, NGN and NGS scores returned to pretreatment values and serum gastrin was higher when compared to values measured on Day 28. By Day 49, after the feed-deprivation period, NGN and NGS were similar to pretreatment values. By Day 56, mean NGN score was significantly lower in PHC-treated horses, compared to controls. Mean gastric juice pH significantly increased in both groups on Day 28 and the pH was significantly (P = 0.0127) higher in the PHC-treated horses. Serum amino acid concentrations were not significantly different 2 h after feeding PHC and hydroxyproline was not detected. Serum gastrin concentration did not increase 2 h after feeding in the PHC-fed horses. The PHC fed to horses enhanced the effects of omeprazole on increased gastric juice pH, inhibited gastrin secretion after feeding and resulted in fewer nonglandular ulcers after long-term feeding (56 days) in stall-confined horses undergoing intermittent feeding.     

Endoscopic findings of the stomach in pleasure horses in Poland

Background

This study was performed to determine the prevalence of ulcers in the gastric squamous and glandular mucosa in Polish pleasure horses.

Study design

Medical records from gastroscopic examinations of 108 pleasure horses of different breeds were reviewed. The study population consisted of two groups; group I (n = 48) with horses that expressed mild clinical signs of gastric ulcer syndrome (EGUS) including poor appetite, slight weight loss or poor body condition, and group II (n = 60) with horses that had no signs of gastrointestinal problems. The age range was 4–10 years, including 5 males, 34 castrated males (geldings) and 69 mares. The prevalence, distribution and severity of gastric ulcers were recorded. Lesions involving the squamous mucosa and the glandular mucosa of the antrum and pylorus were graded and compared between groups.

Results

Significant difference was found in the presence and severity of gastric ulcers between the two groups of horses. The overall prevalence of gastric ulcers in the first group of horses (n = 48) was 59% while in the group of clinically healthy horses (n = 60) the prevalence of gastric lesion was 40% (P = 0.004). Almost 19% of horses from group I had between 6–10 lesions (EGUS score III) and nearly 19% had either >10 localized lesions or very large diffuse lesions (EGUS number score IV). The number of ulcerations in affected horses were significantly lower in group II compared to group I (P = 0.016) as 10% of horses had 6–10 lesions (EGUS number score III) and nearly 14% had either >10 localized lesions or very large diffuse lesions (EGUS number score IV). Gastroscopy revealed that nearly 32% of horses from the second group had an ulceration EGUS score ≥ II.

Discussion and conclusions

This study confirms that gastric ulcerations can be prevalent in apparently clinically normal pleasure horses and a complete gastroscopic examination including the examination of the pylorus is advisable to evaluate this syndrome.     

Effect of repeated oral administration of hypertonic electrolyte solution on equine gastric mucosa

REASONS FOR PERFORMING STUDY: Electrolyte supplementation is common in horses during endurance competitions, but the effect on the gastric mucosa is unknown. HYPOTHESIS: Repeated oral administration of hypertonic electrolyte solution is associated with exacerbation of gastric ulcers in mature horses. METHODS: The study design was a randomised, blinded, crossover trial. Fourteen horses were divided randomly into equal groups and administered either 60 ml water (placebo) or 56.7 g commercial electrolyte supplement mixed with 60 ml water by dose syringe orally once an hour for 8 h. The minimum concentration of individual constituent electrolytes/28.35 g dry commercial product used was: sodium (5528 mg); chloride (11,886 mg); potassium (3657 mg); calcium (754 mg); and magnesium (153 mg). Gastric lesions were scored prior to and after oral treatments, and analysis of variance procedures were then performed. RESULTS: Administration of hypertonic electrolytes resulted in a significant increase in mean ulcer number (P = 0.0174) and severity (P = 0.0006) scores in the nonglandular stomach. Mean ulcer number score was 3.6 and mean ulcer severity score 2.7 after hypertonic electrolyte treatment. CONCLUSIONS: Oral hypertonic electrolyte administration to horses in this model was associated with exacerbation of gastric ulcers. POTENTIAL RELEVANCE: Our findings suggest that one schedule of electrolyte supplementation used commonly in endurance horses may be harmful to the gastric mucosa.     

Endoscopic findings of the gastric antrum and pylorus in horses: 162 cases (1996-2000)

Medical records and endoscopy images were examined for 209 horses that had gastroscopic examinations performed with a 2.5- or 3-m-long endoscope by one of the authors (MJM) during a 4-year period (1996-2000). The antrum and pylorus were viewed in 162 horses, and the duodenum was viewed in 94 horses. Of these 162 horses, the gastric squamous mucosa was seen in 157 horses and 50% or more of the glandular mucosa of the body of the stomach was seen in 156 horses. Erosions or ulcers were seen in the gastric squamous mucosa in 91 (58%) horses. Erosions or ulcers were seen in the glandular mucosa of the body of the stomach in only 8% of the horses. Lesions consisting of erosion or ulceration were seen in the antrum or pylorus in 94 (58%) horses. Lesions consisting of hyperemia and a rough or "bumpy" appearance were seen in the mucosa of the duodenum of 16 horses. An association between the presence of lesions in the squamous mucosa and the presence of lesions in the mucosa of the antrum/pylorus was examined by Fisher's exact test, and the linear association of lesion severity scores between the squamous mucosa and the mucosa of the antrum/pylorus was tested using a Monte Carlo estimate for linear-by-linear association. There was no association (P = .88) between these sites for presence of lesions or lesion severity scores. Similarly, there was no association between scores for the glandular mucosa in the gastric body and those in the antrum/pylorus. Because of the high prevalence of lesions in the antrum and pylorus of the stomachs of adult horses examined in a hospital setting, the entire stomach should be viewed during a gastroscopic examination.     

Endoscopy via a gastric cannula to monitor the development of ulcers in the pars esophagea in pigs after consumption of a finely ground feed combined with a period of withholding of feed

OBJECTIVE: To develop an endoscopic technique for use in monitoring devlopment of gastric ulcers via a gastric cannula during withholding of feed and administration of a finely ground diet to pigs. ANIMALS: 6 pigs weighing between 60 and 70 kg. PROCEDURE: A gastric cannula was surgically inserted adjacent to the pars esophagea in each pig. Pigs were fed a finely ground diet for two 7-day periods that were separated by a 48-hour period during which feed was withheld. Endoscopic examination via the gastric cannula was used to monitor development of ulcers in the pars esophageal region of the pigs during the 48-hour period of feed withhold and subsequent 7-day feeding period. An ulcer score was assigned during each endoscopic examination. A final examination was performed during necropsy and compared with results for the final endoscopic examination. RESULTS: Consumption of a finely ground diet for 7 days resulted in progressive erosive damage to the pars esophageal region of the stomach. Further significant increases in ulcerative damage were detected after 24 and 48 hours of withholding of feed. Final examination during necropsy did not reveal significant differences from results obtained during the final endoscopic examination. CONCLUSIONS AND CLINICAL RELEVANCE: Endoscopic examination via a gastric cannula was an effective means of monitoring ulcer development in the pars esophagea of pigs. Feeding a finely ground diet and withholding of feed induced endoscopically observable ulcers in the stratified squamous epithelial region of the stomach. Direct visual examination during necropsy confirmed the accuracy of endoscopic examination.     

The Effect of Exercise on Equine Gastric Ulcer Syndrome in the Thoroughbred and Standardbred Athlete

Thoroughbred and Standardbred horses in race training were selected at random and examined for gastric ulcers. The mucosa of the stomach was examined by endoscopy and was scored for ulcers on a scale of 0 (no ulcers, normal mucosa) to 3 (severe ulceration with at least five deep lesions). A total of 79 horses were examined; 37 of these horses had one to four follow-up examinations, and 42 horses had only an initial gastroscopic examination. On the first examination, 33 of 79 (42%) horses had normal mucosa (ulcer score = 0), and 22 of 79 (28%) had ulcers with an ulcer score of 2 or greater. Seven horses (9%) had severe gastric ulceration (ulcer score = 3). The average ulcer score for all 79 horses on initial examination was 1.1 and 1.2 for the 37 horses with follow-up gastroscopic examination. Males (including male castrates) had slightly higher ulcer scores (1.2) than females (1.0), and 2-year-old horses had lower ulcer scores (0.7) than horses older than 3 years (1.4), but these differences did not reach statistical significance. Each of these average scores was significantly (P < .05) greater than zero. For the 37 horses with follow-up examinations, the males had higher scores (1.6) than females (0.7), and 2-year-old horses had higher ulcer scores (1.0) than 3-year-old horses (0.7) and lower ulcer scores than horses older than 3 (1.8), which were statistically significant. Follow-up examinations revealed ulcer scores ranging from 0 to 3; 23 of 37 (63%) horses had an ulcer score of 2 or greater, and 4 of 37 (12%) horses had severe ulcer disease. Average ulcer scores were significantly higher at subsequent examinations than at the initial examination. Risk of gastric ulceration increases with the length of time horses are in race training.     

Efficacy of a Combination of Apolectol,Live Yeast (Saccharomyces cerevisiae [CNCM I-1077]), and Magnesium Hydroxide in the Management of Equine Gastric Ulcer Syndrome in Thoroughbred Racehorses: A Blinded,Randomized, Placebo-Controlled Clinical Trial

To date, prevention of equine gastric ulcer syndrome (EGUS) has relied on management changes or pharmaceutical agents. The identification of an alternative means of prevention would be useful. Therefore, the objective of this study was to evaluate the combination of Apolectol, a live yeast (Saccharomyces cerevisiae [CNCM I-1077]), and magnesium hydroxide for the prevention of development of, or exacerbation of existing, EGUS in Thoroughbred racehorses. Twenty-four Thoroughbred racehorses without significant gastric ulceration (grade, ≤2 of 4) were identified on gastroscopy. Treated horses received 95 g Apolectol, 2 g S. cerevisiae, and 20 g magnesium hydroxide 1–4 hours before exercise. Control horses received 95 g of a feed pellet as a placebo. Gastroscopy was repeated at 24–27 days. There was no change in squamous (P = .45) or glandular (P = 1.0) ulcer grade over time in horses in the treatment group. In the placebo group, ulcer grade increased in both the squamous (P = .04) and glandular (P = .19) mucosa but only reached significance in the squamous mucosa group. Worsening of the ulcer grade was more likely in the placebo group in the glandular (P = .04) but not in squamous (P = .10) mucosa. The combination studied may be an effective prophylactic against EGUS development or exacerbation.     

Chronic flunixin meglumine therapy in foals

Effects of a therapeutic dose of flunixin meglumine on gastric mucosa of horse foals were determined by endoscopy, double-contrast radiography, and gross and histologic examinations. Foals were administered 1.1 mg of flunixin meglumine/kg of body weight, PO/day for 30 days in an encapsulated form that was divided into 2 doses/day (group 1; n = 3) or by IM injection once a day (group 2; n = 7). Three control foals (group 3; n = 3) were administered capsules (n = 1) containing dextrose powder or IM injections (n = 2) of vehicle solution without flunixin meglumine. All 3 groups-1 foals given flunixin meglumine PO developed oral ulcers. Group-2 foals given flunixin meglumine IM did not develop oral ulcers. One control foal (group 3) developed 1 oral ulcer that healed during the study. Endoscopic examination revealed linear crease-like mucosal lesions in the glandular portion of the stomach in 2 group-2 foals. Radiographic evidence of gastric ulcers was observed in only 1 gastrogram of a group-1 foal. Foals were euthanatized, and necropsy revealed erosions and/or ulcers of the glandular portion of the stomach. Oral ulcers were observed in all 3 group-1 foals. Erosions of the glandular portion of the stomach developed in all 10 foals given flunixin meglumine, but did not develop in group-3 foals. Ulceration of the glandular portion of the stomach was present in 1 group-2 foal.     

Efficacy of omeprazole paste in the prevention of gastric ulcers in 2 years old thoroughbreds

Prevalence of equine gastric ulcer syndrome in 85 young Thoroughbreds was investigated. The presence of gastric ulcers was confirmed in 27.1% (23/85) of the horses by endoscopic examination. Sixty-two horses without gastric ulcers were allocated randomly to either the treated group (31 horses) or sham-dosed control group (31 horses) in order to investigate the efficacy of omeprazole oral paste in the prevention of gastric ulcers. At the second endoscopic examination conducted after 28 days of administration, only 1 horse in the treated group developed gastric ulcers, while 12 horses developed gastric ulcers in the control group. Based on these data, the efficacy of omeprazole in prevention of equine gastric ulcers in young Thoroughbreds during the training period was confirmed.     

Effects of hydrochloric,acetic, butyric,and propionic acids on pathogenesis of ulcers in the nonglandular portion of the stomach of horses

OBJECTIVE: To identify the pathogenesis of gastric ulcers by comparing injury to the nonglandular gastric mucosa of horses caused by hydrochloric acid (HCl) or volatile fatty acids (VFAs). SAMPLE POPULATION: Gastric tissues from 30 horses. PROCEDURE: Nonglandular gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference were measured and electrical resistance calculated for tissues after addition of HCl and VFAs to normal Ringer's solution (NRS). Tissues were examined histologically. RESULTS: Mucosa exposed to HCl in NRS (pH, 1.5) had a significant decrease in Isc, compared with Isc for mucosa exposed to NRS at pH 4.0 or 7.0. Also, exposure to 60mM acetic, propionic, and butyric acids (pH, 4.0 or 1.5) caused an immediate significant decrease in Isc. Recovery of sodium transport was detected only in samples exposed to acetic acid at pH 4.0. Recovery of sodium transport was not seen in other mucosal samples exposed to VFAs at pH < or = 4.0. CONCLUSIONS AND CLINICAL RELEVANCE: Acetic, butyric, and propionic acids and, to a lesser extent, HCl caused decreases in mucosal barrier function of the nonglandular portion of the equine stomach. Because of their lipid solubility at pH < or = 4.0, undissociated VFAs penetrate cells in the nonglandular gastric mucosa, which causes acidification of cellular contents, inhibition of sodium transport, and cellular swelling. Results indicate that HCl alone or in combination with VFAs at gastric pH < or = 4.0 may be important in the pathogenesis of gastric ulcers in the nonglandular portion of the stomach of horses.     

Gastric ulcers in standardbred racehorses: prevalence,lesion description,and risk factors

This study was performed to estimate the prevalence of gastric ulcers in Standardbred racehorses, to describe the lesion score and location, and to identify potential risk factors. Two hundred seventy-five (275) Standardbred horses from 5 training centers and 2 racetracks in Quebec, Canada, were studied. Historical data for the 2 months before examination were recorded for each horse, and the presence of gastric ulcers was determined by gastroscopy. A previously reported scoring system that used grades 0-3 for gastric lesions was used. Overall, 121 horses (44.0%; 95% CI, 38.1-50.1%) had gastric ulcers. The prevalence of gastric ulcers was significantly higher (P < .0001) in actively racing horses (63.3%; 95% CI, 54.7-71.2%) than in horses at rest. Multivariate analysis defined that horses in racing (OR = 9.29; 95% CI, 3.55-24.3) were significantly more likely to have gastric ulcers than horses at rest and that trotters (OR = 2.23; 95% CI, 1.28-3.86) were more likely to have gastric ulcers than pacers. The number of lesion sites (P < .0001) and poor body condition (P < .0001) were significantly associated with lesion scores. Gastric ulcers are highly prevalent in Standardbred racehorses. Furthermore, actively racing horses and trotters are more likely to have gastric ulcers. Also, poor body condition in Standardbred racehorses may be an indication that gastric ulcers are present and that lesion scores are high. The cause-and-effect relationship between poor body condition and the presence of gastric ulcers is unclear.     

Effects of hydrochloric,valeric, and other volatile fatty acids on pathogenesis of ulcers in the nonglandular portion of the stomach of horses

OBJECTIVE: To identify in vitro effects of hydrochloric acid, valeric acid, and other volatile fatty acids (VFAs) on the pathogenesis of ulcers in the nonglandular portion of the equine stomach. SAMPLE POPULATION: Gastric tissues from 13 adult horses. PROCEDURE: Nonglandular gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference were measured and electrical resistance and conductance calculated after tissues were bathed in normal Ringer's solution (NRS) or NRS and hydrochloric, valeric, acetic, propionic, and butyric acids. Treated tissues were examined histologically. RESULTS: Incubation in 60mM valeric acid at pH < or = 7.0 abruptly and irreversibly abolished Isc, which was followed by a slower decrease in resistance and an increase in conductance. Incubation in 60mM acetic, propionic, and butyric acids and, to a lesser extent, hydrochloric acid at pH < or = 7.0 significantly decreased Isc, which was followed by an increase in resistance and a decrease in conductance. CONCLUSIONS AND CLINICAL RELEVANCE: Incubation in valeric acid at pH < or = 7.0 caused a dramatic decrease in mucosal barrier function in the nonglandular portion of the stomach. Changes in barrier function attributable to exposure to valeric acid were associated with histopathologic evidence of cellular swelling in all layers of the nonglandular mucosa. Because of its high lipid solubility, valeric acid penetrates the nonglandular gastric mucosa, resulting in inhibition of sodium transport and cellular swelling. Valeric acid and other VFAs in gastric contents may contribute to the pathogenesis of ulcers in the nonglandular portion of the stomach of horses.