Cross-sectional study of gastric ulcers of the squamous mucosa in thoroughbred racehorses

Is There a Difference in the Prevalence of Gastric Ulcers between Stallions Used for Breeding and Those Not Used for Breeding?

Equine gastric ulcer syndrome (EGUS) is a worldwide disease, and includes two different syndromes, Equine Squamous Gastric Disease (ESGD), affecting the squamous mucosa, and Equine Glandular Gastric Disease (EGGD), affecting the glandular mucosa. These two diseases are present in different categories (different activities, ages, etc.) and breeds of horses. The effect of sex on gastric health is not clear: some studies found a higher prevalence of ESGD in geldings and stallions, while others found no influence of sex on the squamous mucosa. The few studies conducted on glandular diseases failed to identify sex as a risk factor. The only study on breeding horses, focused on Thoroughbred mares at pasture, found that 70% of them were affected by gastric ulcerations especially in the squamous mucosa. The aim of this study was to determine the prevalence of EGUS, ESGD, and EGGD in intact males while also investigating the potential influences of breeding and exercise activity on the occurrence and severity of the diseases. A total of 101 intact males were admitted for gastroscopic examination. Comprehensive data regarding their breeding and sports history, management, and presence of clinical signs were recorded. A statistical analysis was performed. Within this equine population, no discernible relationship was found between breeding activity and occurrence and severity of ESGD or EGGD. Exercise and a combination of exercise and breeding activities were found to be associated with the occurrence of EGGD. The presence of clinical signs was correlated only with the grade of ESGD in this cohort of horses.

Gastroscopic characterisation and prevalence of gastric ulcer syndrome in working mules in Colombia

BACKGROUND

The existing literature does not contain information about the prevalence of gastric ulcers in mules, and on the potential associations between the presence of ulcers and work load, work type, diet, sex, age and body condition score (BCS).

OBJECTIVE

To estimate the prevalence and factors associated with mule gastric ulcer syndrome (MGUS) and evaluate its distribution in both mule squamous gastric disease (MSGD) and mule glandular gastric disease (MGGD) mucosa in a population of mules in Colombia.

STUDY DESIGN

Observational, cross-sectional.

METHODS

A total of 97 clinically healthy mules of different ages and locations in the province of Antioquia (Colombia) were included in this study. The mules were involved in agricultural activities (i.e., riding, pack and ranch mules) at the time of the study. The animals underwent gastroscopic evaluation, and ulcer scores from 0 to 4 were assigned based on severity, with scores ≥2 indicating clinical relevance. The presence or absence of ulcer in the squamous and/or glandular region of the stomach was recorded. Data related to work type, work load and diet, as well as sex, age and BCS were recorded for each mule. Pearson's chi-square test was used to determine the association between the outcomes and explanatory variables of the study (p ≤ 0.05). The results of the risk estimations were presented as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

The frequency of MGUS in the study population was 42%. Most of the lesions were located in the squamous region of the stomach (27%), mainly in the margo plicatus, and 20% were located in the glandular region, mainly in the fundus and pyloric antrum. Six animals showed lesions in both squamous and glandular regions. Work load was the only variable associated with the presence of MGUS (OR: 1.98; 95% CI: 0.49-0.96) and MSGD (OR: 1.78; 95% CI: 0.36-0.67). Nevertheless, the findings did not provide any significant risk assessment result, nor did they reveal any significant interactions among the other variables.

MAIN LIMITATIONS

This study used convenience sampling from a limited geographic region, and multivariate analysis was not performed, one of the exclusion criteria was the use of nonsteroidal anti-inflammatory drugs, which means that the effect of these drugs can no longer be evaluated.

CONCLUSIONS

MGUS occurs in mules subjected to agricultural work, the risk factors associated with EGUS do not appear to be significant in mules and other equids subjected to the same conditions, in this region. Further research is needed to define the differential dynamics of MGUS in comparison with the findings in horses.

Presence of Gastric Ulcers in Horses Used for Historical Races in Italy

Equine Gastric Ulcers Syndrome (EGUS) is a worldwide disease present in equids of different breeds, activity levels, and age groups. It is divided into two different illnesses: Equine Squamous Gastric Disease (ESGD) affecting the squamous mucosa and Equine Glandular Gastric Disease (EGGD) affecting the glandular mucosa. The historical horserace is a traditional competition that is common in Italy. They can be divided into two different types: speed races and jousting tournaments. Anglo-Arabians and Thoroughbreds are used for the two competitions with training and management systems similar to those used in races performed on a racetrack. The aim of this study was to determine the prevalence of ESGD and EGGD in horses used for historical horseracing and evaluate the differences in the presence of the diseases in animals of the two different breeds used for the two types of competition. A cohort of 73 horses was enrolled in this study, which were stabled in 10 training facilities and performed two jousting tournaments and one speed race. An ESGD at least of grade 2 was found in 88% of horses with all degrees of severity seen; EGGD was diagnosed in 45% of animals. In this cohort of horses, the presence and severity of ESGD and EGGD are similar to that in reports in racehorses performing on racetracks. Anglo-Arabians used for speed races are more affected by ESGD and EGGD, which is probably because they are involved in a higher number of races and travel more during the year compared to Thoroughbreds used for jousting competitions.

Investigating the gastrointestinal physiology of mature horses with and without a history of cribbing behavior in response to feeding a digestive support supplement

Cribbing, a stereotypic oral behavior observed in horses, involves placing incisors on a fixed object, arching the neck, pulling against the object, and emitting an audible grunt. This behavior has been associated with gastrointestinal (GI) dysfunction and gastric ulceration. In this randomized crossover study, we investigated the impact of a GI support supplement (SPL) on the GI environment and physiology of four cribbing (CB) and four non-cribbing horses (NCB). Mature Quarter Horses, acclimated to individual stalls for 16 hours daily with paddock turnout in pairs for 8 hours per day, were randomly assigned to receive either the SPL or placebo for 21 days, followed by a 2-week washout period. Fecal and gastric samples were collected for pH determination and blood samples were analyzed for serum cortisol and gastrin levels. Endoscopic examinations assessed gastric ulcer severity, and cribbing frequency and bouts were recorded via video surveillance. Data were analyzed using a mixed-model ANOVA. Results showed no differences in fecal and gastric pH between cribbing statuses. However, an interaction between supplementation and cribbing status was observed for squamous mucosa ulcer scores (P=0.003). There were no differences in glandular mucosa ulcer scores, serum cortisol, serum gastrin, and crib-bite count between CB and NCB horses or between supplementation groups. Crib-bout duration did not differ with supplementation, but differences were found between periods (P<0.05) and hour ranges (P<0.001). Our findings suggest that the GI support supplement may not effectively address cribbing behavior or alter the GI environment in NCB or CB horses.

Risk Factors for Equine Gastric Ulcer Syndrome Incidence in Adult Icelandic Riding Horses

A high prevalence of both squamous (ESGD) and glandular (EGGD) ulcers was previously found in, mainly young, Icelandic horses coming into training for the first time. This study evaluated risk factors for gastric ulcers in Icelandic riding horses at various ages and stages of training. The horses (n = 211) were gastroscoped from 21 equine establishments across Iceland. A variety of morphometric, clinical, behavioural and management factors were evaluated as potential risk factors for gastroscopically significant (grade ≥ 2/4: found in 27% of horses) or gastroscopically severe (grade 3 or 4/4: found in ~10% of horses) ESGD or gastroscopically significant EGGD (grade ≥ 1/2: found in 46.4%). Body condition score (BCS), cresty neck score (CNS), stable/turnout behaviour, exercise intensity/frequency and age were not significantly associated with ESGD or EGGD ulcer score. However, having come off the pasture into training for 4 weeks or less was a significant risk factor for gastroscopically significant and severe ESGD compared to 5 weeks or more. For both EGGD and ESGD, "region" was important. Gastroscopically significant EGGD and gastroscopically severe ESGD were more prevalent in those showing clinical signs often associated with ulcers. Geldings were more likely to have gastroscopically significant ESGD than both mares and stallions and more EGGD than stallions. Being stabled, but spending >2 h/day out in the paddock, compared with <2 h paddock time or full-time turnout, was protective for gastroscopically significant ESGD as was being fed complementary feed (all fed <1 g non-structural carbohydrate (NSC)/kg/BW/meal). Being at a training establishment for >4 weeks was protective for gastroscopically significant and gastroscopically severe ESGD but not EGGD. This study confirms the relatively low prevalence of ESGD in Icelandic horses being kept in training establishments and fed low NSC diets but highlights the high prevalence of EGGD.

The Impact of Two Recommended Withholding Periods for Omeprazole and the Use of a Nutraceutical Supplement on Recurrence of Equine Gastric Ulcer Syndrome in Thoroughbred Racehorses

The impact of recommended withholding periods (RWPs) for omeprazole on the recurrence of Equine Gastric Ulcer Syndrome (EGUS) is unknown. The study was designed to compare the effect of two RWPs on EGUS recurrence post-omeprazole treatment and to determine if a nutraceutical supplement would reduce EGUS recurrence when administrated during an RWP. The study was a blinded, randomized clinical trial. Part 1: Horses were allocated to an RWP0 or RWP2 and crossed over after 4-weeks. Horses received oral omeprazole once daily, except during the RWPs at the end of the treatment periods. Part 2: Horses received omeprazole for 21 days prior to an RWP2 during which they received a nutraceutical supplement. Gastroscopy was performed on Day 0 and pre- and post- RWP. Part 1: More horses were affected by Equine Squamous Gastric Disease (ESGD) after the '2-clear-days' RWP than the 'not on race-day' RWP (p = 0.012). The prevalence of ESGD post-RWP for '2-clear-days' did not differ from day 0 (p = 0.478). Part 2: The prevalence of ESGD post-RWP was lower than on Day 0 (p = 0.046). A difference in recurrence of ESGD was present between the two common RWPs. The implications of this on the welfare of Thoroughbred racehorses warrant further discussion.

Horse Grimace Scale Does Not Detect Pain in Horses with Equine Gastric Ulcer Syndrome

Equine gastric ulcer syndrome (EGUS) is a highly prevalent and presumptively painful condition, although the amount of pain horses might experience is currently unknown. The aims of this study were to determine if the Horse Grimace Scale (HGS) could identify pain behaviours in horses with and without EGUS and if severity would be positively associated with the HGS score. Horse grimace scale scores were assessed blindly using facial photographs by seven observers and involved evaluation of 6 facial action units as 0 (not present), 1 (moderately present) and 2 (obviously present). Lameness examination, serum amyloid A (SAA) measurement and gastroscopy evaluation were performed on all horses. Horses (n = 61) were divided into two and three groups based on the presence (yes, no) and severity (none, mild, moderate-severe) of EGUS, respectively. Presence of lameness and elevated SAA (≥50 µg/mL) were used as exclusion criteria. Inter-observer reliability was analyzed by intra-class correlation coefficients (ICC). HGS scores between groups were compared using Welch's and Brown Forsythe tests (p < 0.05). Overall, HGS ICC was "excellent" (0.75). No significant differences (p = 0.566) were observed in HGS scores between horses with and without gastric lesions (mean, 95% CI; 3.36, 2.76-3.95 and 3, 1.79-4.20, respectively). HGS was not influenced by the presence or severity of EGUS in this current study. Further studies investigating the use of different pain scales in horses with EGUS are needed.

Sustainability and the Thoroughbred Breeding and Racing Industries: An Enhanced One Welfare Perspective

As society debates the use of animals in sport, entertainment, and leisure, there is an increasing focus on the welfare, social, and ecological impacts of such activities on the animals, human participants, people close to them, and the physical environment. This article introduces the "Enhanced One Welfare Framework" to reveal significant costs and benefits associated with Thoroughbred breeding and racing globally. In addition, relative to calls to ban horseracing and similar activities as part of sustainability approaches that focus chiefly on animals, the "Enhanced One Welfare Framework" is better positioned politically to guide discussions that renegotiate the conditions under which horses are used for sport and the impact racing has on humans and the planet. In 2020, the International Federation of Horseracing Authorities issued its minimum horse welfare standards based on the Five Domains model, positioning lifelong horse welfare as "fundamentally important to the viability and sustainability of the industry". In this article, we critique the One Welfare framework's historic lack of focus on sport and enhance it by including sport, leisure, and entertainment and framing it within the Five Domains model. We offer a novel extension of the Five Domains model beyond animal welfare to consider human welfare and the physical environmental impacts of the sport, leisure, and entertainment industries and propose innovations that may help thoroughbred breeding and racing assure a sustainable future.

A Survey of Pennsylvania Horse Management: Part Two - Exercise

Understanding the frequency, duration, and intensity of exercise is important for determining the optimal diet and management of horses. The objective of the study was to characterize the exercise management of horses in Pennsylvania. An online survey was distributed from February 27th to August 31st, 2020. Respondents were asked to place their horse in an exercise category, as well as report on frequency and duration of exercise and time spent at each gait. Nonparametric statistics (mdn=median) and tests were used when data were not normally distributed. Of the 470 horses, 68% were regularly exercised. The exercised horses were classified as 49% (135/275) in light, 41% (113/275) in moderate, and 12% (32/275) in heavy/very heavy exercise. Of those exercised, 43% (120/278) were ridden recreationally (not used for competition). The median minutes per week spent exercising was 180 minutes (IQR=183). The average number of exercise sessions per week was 3.6 ± 2.2. Horses in heavy/very heavy (mdn=220 min, IQR=272) and moderate exercise (mdn=180 min, IQR=180) spent more minutes exercising per week compared to light exercise (mdn=120 minute, IQR=180; P< .05). Total number of exercise sessions completed per week differed between horses in light (mdn=2 sessions, IQR=3), moderate (mdn=4 sessions, IQR=2), and heavy/very heavy exercise (mdn=6 sessions, IQR=2; P < .05). Horses were exercised for a similar duration and frequency per week compared to previous studies. Some challenges exist for placing horses in NRC exercise categories based on self-reports only.

A Survey of Pennsylvania Horse Management: Part One-Nutrition

Various aspects of nutritional management can impact both a horse's gastrointestinal (GI) health and caretaker costs. The objective of this study was to characterize the feeding management and GI issues of horses in Pennsylvania (PA). An online survey was distributed from February 27th to August 31st, 2020. Kruskal-Wallis and Mann-Whitney tests were used to analyze the data. Nonparametric statistics were used when data were not normally distributed. From 470 responses collected, the average horse age was 15.7 ± 7.5 years, and the most common breeds were the Quarter Horse and Thoroughbred. Of the 345 horses who received premixed feed, 81% were fed on a volume basis. Most horses (95%) received hay on a volume basis, and 57% of horses were fed hay on the ground rather than in a feeder. No difference was detected in the number of scoops of premixed feed (median = 2; P = .284) or the flakes of hay per day (median = 5.7; P = .765) between horses in different exercise categories. The frequency of reported GI issues was 10% (46/470). Owner perceived, veterinary perceived, and veterinary diagnosed ulcers were found in 2.3%, 4%, and 2.3% of horses, respectively. No statistical difference was detected in the number of scoops of premixed feed fed per day between horses with or without GI issues (P = .536). Horses were provided the same amount of premixed feed and forage regardless of reported exercise category. Most equine caretakers fed concentrates on volume rather than weight, a common practice despite most feeding requirements being based on feed weights.

Equine Gastric Ulcer Syndrome affects fitness parameters in poorly performing Standardbred racehorses

Introduction

Equine Gastric Ulcer Syndrome (EGUS) is a highly prevalent disorder in horses, which can be classified, based on the localization of the lesions, as Equine Squamous Gastric Disease (ESGD) or Equine Glandular Gastric Disease (EGGD). Although EGUS is recognized as a common cause of poor performance in racehorses, objective investigations about its relation with athletic capacity are lacking. Therefore, the present retrospective study aims to evaluate the associations between EGUS severity and some fitness parameters measured during an incremental treadmill test in Standardbred racehorses in training.

Methods

With this aim, data from 87 Standard bred racehorses which underwent a complete diagnostic evaluation for poor performance was reviewed. During gastroscopic examination, a 0-4 score was assigned to ESGD, while EGGD was evaluated for absence/presence; a total EGUS score was obtained by adding 1 point to ESGD score in horses showing concomitant EGGD. Fitness parameters obtained during incremental treadmill test included speed at a heart rate of 200 bpm (V200), speed and heart rate at a blood lactate of 4 mmol/L (VLa4, HRLa4), peak lactate, lactate and heart rate at 30 minutes post-exercise, maximum speed, minimum pH and maximum hematocrit. The associations between fitness parameters and EGUS and ESGD scores were evaluated by Spearman correlation, while Mann-Whitney test was used to compare them between horses with or without EGGD. Statistical significance was set at p<0.05.

Results

EGUS grade was inversely correlated with V200 (p = 0.0025) and minimum pH (p = 0.0469); ESGD grade was inversely correlated with V200 (p = 0.0025) and VLa4 (p = 0.0363). Although a trend was observed, no significant differences in V200 were observed between horses with or without EGGD (p = 0.073); horses with EGGD reached a lower minimum pH (p = 0.0087).

Discussion

These results show a negative association between aerobic capacity and EGUS, in particular ESGD. Although different hypotheses have been proposed, including abdominal pain and decreased appetite due to lactate accumulation, the underlying mechanisms are still unknown, and it is not clear whether EGUS represents a cause or a consequence of an early lactate accumulation and post-exercise acidosis.

Evaluation of a Comprehensive Profile of Salivary Analytes for the Diagnosis of the Equine Gastric Ulcer Syndrome

In this report, the measurement of salivary biomarkers as an aid for diagnosis of equine gastric ulcer syndrome (EGUS) was studied. A comprehensive panel of 23 salivary analytes was measured in the saliva of horses affected by EGUS and compared to healthy animals and horses with other diseases clinically similar to EGUS but with a negative diagnosis at gastroscopic examination. A total of 147 horses were included in the study and divided into heathy population (n = 12), the EGUS group (n = 110), and the group of horses with other diseases (n = 25). From the 23 analytes studied, 17 showed increased values in EGUS horses when compared to healthy ones, and uric acid, triglycerides, and calcium were significantly increased in horses with EGUS compared to the group of other diseases. The receiver operating characteristic curve analyses showed a modest but significant discriminatory power of those three analytes to identify EGUS from other diseases with similar symptoms. The discriminatory power enhanced when the results of the three analytes were combined. In conclusion, the results showed that selected salivary analytes could have potential use as biomarkers in horses with EGUS.

Prevalence of Gastric Ulceration in Horses with Enterolithiasis Compared with Horses with Simple Large Intestinal Obstruction

Enterolithiasis is a well-documented cause of colic in horses, especially in some geographic areas such as California and Florida. This retrospective case-control study aims at comparing the prevalence of gastric ulcers in horses affected by enterolithiasis to that in horses affected by other types of large intestinal obstruction. Two hundred and ninety-six horses were included in the study sample. Horses that had surgery for the removal of one or more enteroliths were included in the study as cases. Patients that had surgery for large intestinal simple obstructions other than enterolithiasis (large colon displacement, non-strangulating large colon torsion, and large and small colon impactions) were selected to match case horses for age, sex, and breed and included as controls. A total of 101/148 horses with enteroliths (68%) had gastric ulcers diagnosed during hospitalization, compared with 46/148 of matched controls (31%). There was a significant association between enterolithiasis and gastric ulceration (odds ratio 4.76, p < 0.0001), and a greater prevalence in Thoroughbreds as compared with other breeds (odds ratio 22.6, p < 0.0001). We concluded that enterolithiasis is significantly associated with gastric ulceration (p < 0.0001). The association is stronger in Thoroughbreds.

Determinación de Helicobacter spp. en mucosa gástrica glandular de mulas a través de la prueba de la actividad de la ureasa e histopatología

La información sobre la presentación y los factores predisponentes del síndrome de úlcera gástrica en mulas (SUGM) es escasa en comparación con el síndrome de úlcera gástrica en equinos (SUGE) y asnales. Debido a la naturaleza multifactorial de este síndrome, la helicobacteriosis ha sido estudiada en otras especies. El objetivo fue establecer la presencia de Helicobacter spp. en mucosa gástrica de mulas a través de la prueba rápida de la ureasa (PRU) y de análisis histopatológico. Menos del 27% de las muestras reaccionaron a la PRU, con tiempos prolongados de reacción, y al Agar Urea (prueba de oro), con menor porcentaje de positividad. La histopatología reveló procesos inflamatorios crónicos, sin presencia de bacterias curvoespiraladas. Las PRU no fueron conclusivas en la determinación de Helicobacter spp., comportamiento similar reportado en equinos. Se requieren exámenes diagnósticos específicos y procedimientos complementarios que explore regiones del estómago en consideración del número de muestras representativas.

Equine Squamous Gastric Disease: Prevalence, Impact and Management

This narrative review explores the etiopathogenesis, clinical signs, diagnosis and treatment of ESGD (equine squamous gastric disease) and discusses the impact of this commonly encountered condition on the equine industry. ESGD refers specifically to peptic injury of the squamous mucosa of the stomach. Prevalence is highest in performance horses, but the disease has been documented across many breeds and ages, including in feral horses and foals. The pathogenesis of ESGD is well understood. Intensive management and exercise are important factors that contribute to a disruption of the normal stratification of gastric pH. This results in exposure of the vulnerable squamous mucosa to acid, leading to ulceration. Clinical signs are variable and there is little evidence to support a direct association between reported signs and the presence or absence of lesions seen on gastroscopy. Management is aimed at acid suppression and mitigation of known risk factors.

Effect of omeprazole and sucralfate on gastrointestinal injury in a fasting/NSAID model

BACKGROUND

Equine gastric ulcer syndrome (EGUS) is a common and significant cause of morbidity in horses, with a range of clinical signs, including inappetence, colic and poor performance. Hospitalised horses are exposed to factors that may induce EGUS, including fasting and nonsteroidal anti-inflammatory drug (NSAID) administration, and may be at risk for development of squamous (ESGD) and glandular gastric disease (EGGD). Prophylactic anti-ulcer medication is often prescribed for these patients, but drug selection is complicated by different aetiology and response to treatment of ESGD and EGGD.

OBJECTIVES

To establish the efficacy of sucralfate or omeprazole used prophylactically in horses exposed to a combined feed-fast and NSAID administration EGUS induction protocol. We hypothesised that these drugs would be equally effective for prevention of gastric lesions in the experimental cohort.

STUDY DESIGN

Randomised crossover experimental design.

METHODS

Horses (n = 14) received either omeprazole (1 mg/kg PO q24h) or sucralfate (20 mg/kg PO q8h) while undergoing the feed-fast/NSAID protocol, allowed an 8-week washout period, and then administered the alternate treatment. Serial gastroscopy, ultrasound and haematology documented treatment effects.

RESULTS

ESGD and EGGD score increased over time under both treatments. There was a significant effect of treatment on EGGD scores (P < .001), with post-treatment EGGD scores higher for horses receiving sucralfate (median 3; IQR 2.25,3) than omeprazole (1; 1,1). The effect of treatment on ESGD scores just achieved significance (P = .05), with post-treatment ESGD scores higher for sucralfate (4; 3,4) than omeprazole (2; 2,3).

MAIN LIMITATIONS

This study was performed in healthy horses, and response to treatment may differ in horses with clinical illness. Additional investigation in a larger population may be required to detect significant differences in other clinical parameters.

CONCLUSIONS

Omeprazole was superior to sucralfate for mitigating gastric lesion severity in healthy horses exposed to a feed-fast/NSAID model.

A study investigating the treatment of equine squamous gastric disease with long-acting injectable or oral omeprazole

BACKGROUND

Equine squamous gastric disease (ESGD) is a highly prevalent disease in horses, particularly in elite athletes. Some horses respond slowly, or fail to respond, to the licensed treatment, oral omeprazole (ORLO).

OBJECTIVES

To compare rates of ESGD healing and improvement between ORLO and a long-acting injectable omeprazole preparation (LAIO).

STUDY DESIGN

Retrospective clinical study.

METHODS

The case records and gastroscopy images of horses presenting to Rainbow Equine Hospital over a 12-month period were reviewed, with images being reviewed blind by one of the authors (David Rendle). Treatment responses were compared between horses that received 2 or 4 injections of 4 mg/kg LAIO at weekly intervals, and horses that received ORLO at 4 mg/kg PO SID for 4 weeks. Data were compared using a Mann-Whitney test with post hoc Dunn's test, chi-squared test or Fisher's exact test.

RESULTS

Fifty-six horses met the inclusion criteria: 29 received LAIO and 27 received ORLO. Treatment groups were comparable in terms of signalment and ESGD lesions. There was a difference in rate of healing when LAIO and ORLO treatment groups were compared at 28 days (LAIO-97%; ORLO-67%; p = .005; OR = 14(1.8-158)), but no difference between LAIO at 14 days and ORLO at 28 days (LAIO-86%; ORLO-67%; p = .12; OR = 3.1 (0.9-10)). Five localised and self-limiting injection site reactions were identified in 3 horses out of 98 injections (5.1%).

MAIN LIMITATIONS

The study was limited by its retrospective nature, absence of randomisation and limited numbers.

CONCLUSIONS

Four weeks of treatment with LAIO resulted in better rates of ESGD healing than 4 weeks of ORLO. Larger more robust studies of LAIO are warranted.

Non-invasive Assessment of Fecal Stress Biomarkers in Hunting Dogs During Exercise and at Rest

Intense exercise causes to organisms to have oxidative stress and inflammation at the gastrointestinal (GI) level. The reduction in intestinal blood flow and the exercise-linked thermal damage to the intestinal mucosa can cause intestinal barrier disruption, followed by an inflammatory response. Furthermore, the adaptation to exercise may affect the gut microbiota and the metabolome of the biofluids. The aim of the present research was to evaluate the presence of a GI derangement in hunting dogs through a non-invasive sampling as a consequence of a period of intense exercise in comparison with samples collected at rest. The study included nine dogs that underwent the same training regime for hunting wild boar. In order to counterbalance physiological variations, multiple-day replicates were collected and pooled at each experimental point for each dog. The samples were collected immediately at rest before the training (T0), after 60 days of training (T1), after 60 days of hunting wild boar (T2), and finally, at 60 days of rest after hunting (T3). A number of potential stress markers were evaluated: fecal cortisol metabolites (FCMs) as a major indicator of altered physiological states, immunoglobulin A (IgA) as an indicator of intestinal immune protection, and total antioxidant activity [total antioxidant capacity (TAC)]. Since stool samples contain exfoliated cells, we investigated also the presence of some transcripts involved in GI permeability [occludin (OCLN), protease-activated receptor-2 (PAR-2)] and in the inflammatory mechanism [interleukin (IL)-8, IL-6, IL-1b, tumor necrosis factor alpha (TNFα), calprotectin (CALP), heme oxygenase-1 (HO-1)]. Finally, the metabolome and the microbiota profiles were analyzed. No variation in FCM and IgA content and no differences in OCLN and CALP gene expression between rest and training were observed. On the contrary, an increase in PAR-2 and HO-1 transcripts, a reduction in total antioxidant activity, and a different profile of microbiota and metabolomics data were observed. Collectively, the data in the present study indicated that physical exercise in our model could be considered a mild stressor stimulus.

Evaluation of a Chinese herbal supplement on equine squamous gastric disease and gastric fluid pH in mares

Background

Wei Le San (WLS) is a Chinese herbal formula comprised of 9 herbs selected for their putative anti‐inflammatory effects.

Objectives

To evaluate the effects of WLS administration in horses with nonglandular gastric ulcers.

Animals

Ten mixed breed mares (aged 7‐21 years, 401‐567 kg body weight).

Methods

Experimental design was a blinded, prospective, 2‐period crossover study. All horses received a placebo (25 mL dextrose‐based syrup; n = 10) and the treatment (WLS, 5 g in 25 mL dextrose‐based syrup; n = 10), administered twice daily. Horses underwent a 1‐week, alternating feed‐deprivation period to induce or worsen existing ulcers; treatment began on day 7. Gastroscopic examination was performed on d0, d6, and d35, with gastric fluid pH obtained on d6 and d35. Gastric ulcer scores assigned by 3 masked observers were averaged for each examination.

Results

Ulcer number scores for horses treated with WLS (median = 0; range, 0‐4) was not different from the untreated controls (median = 0.5; range, 0‐4; P = .81) by the end of the treatment period. Ulcer severity score for treated horses (median = 0; range, 0‐1) was also unchanged compared to the control group (median = 0.5; range, 0‐1; P = .85). Gastric pH was not altered by either treatment, with a median of 2.1 (range, 1.9‐4.1) for the horses treated with WLS and 2.8 (range, 1.6‐7.2) in the untreated controls (P = .46).

Conclusions and Clinical Importance

The experimental model used to induce gastric ulceration was unable to discern a difference between the herbal supplement and the placebo in normal horses.

Serum protein expression in Equine Glandular Gastric Disease (EGGD) induced by phenylbutazone

Equine Glandular Gastric Disease (EGGD) is a common disease in sport horses. This disease might be associated with usage of nonsteroidal anti-inflammatory drugs (NSAIDs) for treating inflammatory diseases. Although gastroscopy has been an effective method for diagnosis, but a less invasive, and inexpensive method is preferred. This study used proteomic technology to identify candidate serum proteins that might be used as markers of NSAIDs induced EGGD. Five Thoroughbred horses were given high doses of NSAID, phenylbutazone to treat lameness. The experiment was divided into three periods: (i) Pre-EGGD period, (ii) during EGGD period, and (iii) Post-EGGD period. Gastroscopy were used to diagnose EGGD, serum was collected to perform gel electrophoresis (1D SDS-PAGE) and mass spectrometry (LC-MS) in order to identify serum proteins in each group. The candidate serum proteins were computationally predicted for the interaction between phenylbutazone and proteins, tissue specific expression, and association to gastric ulceration. After EGGD induction, all horses showed clinical signs of colic with marked congestion and erosion appearing in the mucosa of the glandular stomach whereas no change was observed in the mucosa of non-glandular stomach. Our proteomic results identified 14 proteins that might be used as EGGD markers. These proteins were highly expressed in the glandular stomach and some proteins were associated with phenylbutazone or ulcer development. However, confirmation of these candidate marker proteins is required with specific antibodies in the larger horse population before they can be considered for application in the field.

Searching for serum protein markers of equine squamous gastric disease using gel electrophoresis and mass spectrometry

BACKGROUND

Equine squamous gastric disease (ESGD) is a very common disorder but an accurate and practical screening technique for detecting ESGD is currently lacking.

OBJECTIVES

To identify serum protein markers to detect ESGD using electrophoresis and mass spectrometry.

STUDY DESIGN

Proteomic analysis and bioinformatics.

METHODS

ESGD was diagnosed using gastroscopy in 30 horses. Gastric ulceration was categorised into three groups: normal, mild/moderate and severe ESGD. Pooled sera from each group were compared using 1D electrophoresis and mass spectrometry. The candidate proteins for ESGD markers were selected based on their specifically high expression in nonglandular stomach, and their association with gastric ulceration using public gene and protein databases.

RESULTS

The prevalence of ESGD in this study was 43% (with mild/moderate ESGD at 33% and severe ESGD at 10%). The proteomic study revealed that the identified serum protein markers for normal equine stomach were B4GALNT2 and XDH. The marker for mild/moderate EGSD was KRT10, while the marker for severe ESGD was KLK13. Furthermore, markers for both ulcer types were SLC4A7, PPARG, FCGBP, PKP1, ASPRV1 and KRT5-like proteins.

MAIN LIMITATIONS

The functions of the identified proteins are not well characterised in horse. Proteomics is a tool for screening protein markers, but confirmation of putative protein markers with specific antibodies is required.

CONCLUSIONS

In total, 10 serum proteins found in this study may be used as putative markers for ESGD. However, confirmation of candidate proteins with specific antibodies in a larger study cohort is necessary before it can be used in the veterinary clinic or on horse farms. The Summary is available in Portuguese - see Supporting Information.

Management factors and clinical implications of glandular and squamous gastric disease in horses

BACKGROUND

To date, risk factors for equine glandular gastric disease (EGGD) have not been described in Thoroughbred racehorses.

OBJECTIVES

To determine management factors associated with EGGD, identify clinical signs in affected horses, and compare these to equine squamous gastric disease (ESGD).

ANIMALS

The study was carried out on 109 Thoroughbred racehorses from 8 training yards (3 in the United Kingdom and 5 in Australia).

METHODS

Gastroscopic examination alongside a questionnaire regarding management, feeding, exercise, and health.

RESULTS

Management factors and clinical signs were different for EGGD versus ESGD. Exercising ≥5 days per week was associated with a 10.4 times (95% CI [confidence interval]: 1.34-26.9) increased risk of EGGD. Horses racing below expectation were 3.7 times (95% CI: 1.1-16.7) more likely to have EGGD. Trainer was also identified as a risk factor for EGGD. Time in work ≤6 weeks was associated with a decreased risk of ESGD (odds ratio [OR] 0.3; 95% CI: 0.1-0.99). Horses aggressive to humans were less likely to have ESGD (OR 0.12; 95% CI: 0.03-0.54). Horses with stereotypies were more likely to have ESGD (OR 5.0; 95% CI: 1.6-15.9).

CONCLUSIONS AND CLINICAL IMPORTANCE

The findings of our study further support the notion that EGGD should be considered as a distinct disease entity to ESGD. Exercising ≤4 days per week could reduce the risk of EGGD. Horses with EGGD are more likely to perform below expectation and, as such, EGGD might be performance limiting in some affected individuals. Stress minimization could reduce the risk of EGGD.

Optimisation of a serum albumin removal protocol for use in a proteomic study to identify the protein biomarkers for silent gastric ulceration in horses

Silent gastric ulceration occurs without evidence of clinical signs and is common in horses. There is currently no a simple and effective method to diagnose this disease. Proteomics can be used to identify serum biomarkers, but the most abundant serum protein, albumin, could conceal candidate biomarkers. Therefore, it is recommended to remove albumin before a proteomic study; however, there is no specific albumin depletion kit or standard protocol available for horse samples. The objectives of this study were to optimise a protocol to remove equine serum albumin and to use albumin-depleted serum to identify the protein biomarkers for silent gastric ulceration. Gastroscopy was used to identify gastric ulceration, and serum was obtained from horses with either a healthy gastric mucosa or gastric ulceration. Serum albumin was removed using the trichloroacetic acid (TCA) protein precipitation method, and this protocol was optimised by varying the concentration of TCA, type of organic solvents, ratio of serum to protein precipitation solution, and incubation times. Electrophoresis and image analysis were used to compare the amounts of albumin, immunoglobulins G (IgG), and protein degradation before and after TCA precipitation. The best protocol was chosen to remove albumin for a proteomic study (electrophoresis and mass spectrometry). The results revealed that protocol 2 (ratio of serum to solution 1:5, 10% TCA in acetone, and 90 min incubation) was the most efficient protocol to remove albumin (98%) and IgG heavy (80%) and light (98%) chains without degrading other proteins. After electrophoresis and mass spectrometry analysis, KRT1, KRT6A and KRT18 were identified as potential markers for silent gastric ulceration.

Diagnostic accuracy of blood sucrose as a screening test for equine gastric ulcer syndrome (EGUS) in adult horses

Background

Equine gastric ulcer syndrome (EGUS) is common in adult horses, particularly those involved in performance disciplines. Currently, detection of EGUS by gastroscopy is the only reliable ante mortem method for definitive diagnosis; however it is unsuitable as a screening test because it is expensive, time consuming, and is not readily available to most veterinarians. Sucrose permeability testing represents a simple, economical alternative to gastroscopy for screening purposes, and the feasibility of this approach in the horse has been previously reported. The aim of this study was to determine the diagnostic accuracy of blood sucrose as a screening test for EGUS in a large group of adult horses with and without naturally occurring gastric disease.

Results

One hundred and one adult horses with or without naturally occurring gastric ulceration were studied. The diagnostic accuracy of blood sucrose for diagnosis of gastric lesions (GL), glandular lesions (GDL), squamous lesions (SQL), and clinically significant lesions (CSL) at 45 and 90 min after administration of 1 g/kg of sucrose via nasogastric intubation was assessed using receiver operator characteristics (ROC) curves and calculating the area under the curve (AUC). For each lesion type, sucrose concentration in blood was compared to gastroscopy, as the gold standard, and sensitivities (Se) and specificities (Sp) were calculated across a range of sucrose concentrations. Ulcer grading was performed blindly by one observer; and the results were validated by comparing them with that of two other observers, and calculating the level of agreement. Cut-off values were selected manually to optimize Se. The prevalence of GL, GDL, SQL, and CSL was 83, 70, 53 and 58% respectively. At the selected cut-offs, Se ranged from 51 to 79% and Sp ranged from 43 to 72%, depending upon the lesion type and time of sampling.

Conclusions

Blood sucrose is neither a sensitive or specific test for detecting EGUS in this population of adult horses with naturally occurring gastric ulceration. Further studies aimed at evaluating the performance characteristics of the test in different study populations are warranted. Given the limitations of endoscopy, due consideration should also be given to alternative methods for comparison of blood sucrose with a gold standard.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-017-0284-1) contains supplementary material, which is available to authorized users.

Effects of two alfalfa preparations with different particle sizes on the gastric mucosa in weanlings: alfalfa chaff versus alfalfa pellets

Background

Feeding alfalfa hay is often recommended for its buffering components, like protein and calcium, to prevent lesions of the gastric mucosa in horses. Until now, there has been no information regarding the influence of alfalfa particle size on the gastric mucosa. The aim of this study was to investigate the effects of feeding two alfalfa preparations with different particle sizes (alfalfa chaff vs alfalfa pellets) in comparison with grass hay on the gastric mucosa in weanling horses. We hypothesized that feeding a high proportion of fine alfalfa particles would negatively impact gastric mucosa and that feeding long alfalfa chaff would improve gastric mucosal health in weanlings.

Results

Before weaning, the prevalence of gastric mucosa lesions (one or more lesions considering all locations in the stomach) was 84.3 %; at 14 days after weaning, it was almost 100 %. Before and after weaning, most of the lesions were found at the greater curvature of the squamous mucosa and at the lesser curvature. After weaning, gastric mucosal lesions at the pylorus were significantly more severe in the group fed alfalfa chaff (p = 0.002). In the other regions, no differences related to the feeding regimes were observed.

Conclusions

Feeding alfalfa failed to improve gastric mucosal lesion scores in weanlings. Furthermore, foals fed alfalfa chaff had higher lesion scores at the pylorus. Alfalfa leaves contain a superior protein source and high amounts of calcium and magnesium, providing extra nutritional advantages in growing horses. At this time, either traditional grass hay rations or grass hay with alfalfa pellets can be recommended.

Efficacy of omeprazole powder paste or enteric-coated formulation in healing of gastric ulcers in horses

Background

GastroGard, an omeprazole powder paste formulation, is considered the standard treatment for gastric ulcers in horses and is highly effective. Gastrozol, an enteric‐coated omeprazole formulation for horses, has recently become available, but efficacy data are controversial and sparse.

Objectives

To investigate the efficacy of GastroGard and Gastrozol at labeled doses (4 and 1 mg of omeprazole per kg bwt, respectively, PO q24h) in healing of gastric ulcers.

Animals

40 horses; 9.5 ± 4.6 years; 491 ± 135 kg.

Methods

Prospective, randomized, blinded study. Horses with an ulcer score ≥1 (Equine Gastric Ulcer Council) were randomly divided into 2 groups and treated for 2 weeks each with GastroGard followed by Gastrozol (A) or vice versa (B). After 2 and 4 weeks, scoring was repeated and compared with baseline. Plasma omeprazole concentrations were measured on the first day of treatment after administration of GastroGard (n = 5) or Gastrozol (n = 5).

Results

Compared with baseline (squamous score (A) 1.65 ± 0.11, (B) 1.98 ± 0.11), ulcer scores at 2 weeks ((A) 0.89 ± 0.11, (B) 1.01 ± 0.11) and 4 weeks ((A) 1.10 ± 0.12, (B) 0.80 ± 0.12) had significantly decreased in both groups (P < .001), independent of treatment (P = .7). Plasma omeprazole concentrations were significantly higher after GastroGard compared with Gastrozol administration (AUC_GG = 2856 (1405‐4576) ng/mL × h, AUC_GZ = 604 (430‐1609) ng/mL × h; P = .03). The bioavailability for Gastrozol was 1.26 (95% CI 0.56–2.81) times higher than for GastroGard.

Conclusions and Clinical Importance

Both Gastrozol and GastroGard, combined with appropriate environmental changes, promote healing of gastric ulcers in horses. However, despite enteric coating of Gastrozol, plasma omeprazole concentrations after single labeled doses were significantly higher with GastroGard.

Equine stomachs harbor an abundant and diverse mucosal microbiota

Little is known about the gastric mucosal microbiota in healthy horses, and its role in gastric disease has not been critically examined. The present study used a combination of 16S rRNA bacterial tag-encoded pyrosequencing (bTEFAP) and fluorescence in situ hybridization (FISH) to characterize the composition and spatial distribution of selected gastric mucosal microbiota of healthy horses. Biopsy specimens of the squamous, glandular, antral, and any ulcerated mucosa were obtained from 6 healthy horses by gastroscopy and from 3 horses immediately postmortem. Pyrosequencing was performed on biopsy specimens from 6 of the horses and yielded 53,920 reads in total, with 631 to 4,345 reads in each region per horse. The microbiome segregated into two distinct clusters comprised of horses that were stabled, fed hay, and sampled at postmortem (cluster 1) and horses that were pastured on grass, fed hay, and biopsied gastroscopically after a 12-h fast (cluster 2). The types of bacteria obtained from different anatomic regions clustered by horse rather than region. The dominant bacteria in cluster 1 were Firmicutes (>83% reads/sample), mainly Streptococcus spp., Lactobacillus spp. and, Sarcina spp. Cluster 2 was more diverse, with predominantly Proteobacteria, Bacteroidetes, and Firmicutes, consisting of Actinobacillus spp. Moraxella spp., Prevotella spp., and Porphyromonas spp. Helicobacter sp. sequences were not identified in any of 53,920 reads. FISH (n = 9) revealed bacteria throughout the stomach in close apposition to the mucosa, with significantly more Streptococcus spp. present in the glandular region of the stomach. The equine stomach harbors an abundant and diverse mucosal microbiota that varies by individual.

Specific localisation of gap junction protein connexin 32 in the gastric mucosa of horses

In the glandular stomach, gap junctional intercellular communication (GJIC) plays an important role in the gastric mucosal defense system, and loss of GJIC is associated with ulcer formation. In spite of the high incidence of gastric ulcers in horses, particularly at pars nonglandularis, the presence of gap junctions in the equine stomach has not yet been studied. The objective was to obtain basic data on the distribution of gap junction protein connexin 32 (Cx32) in the different regions of normal equine gastric mucosa. Samples of mucosa were taken from seven horses at cardiac, fundic, and pyloric region and pars nonglandularis. To detect Cx32, immunohistochemical staining and Western blot analysis were performed. Corresponding mRNA was shown by RT-PCR and localised in tissue sections by in situ hybridisation. Cx32 was found in the glandular regions, whereas it was not detectable in squamous mucosa. Within the glandular epithelium, Cx32 was abundant in surface and foveolar cells and decreased towards the proliferative zone of the glands. These results suggest that gap junctions develop during the maturation of surface cells. Whether the lack of Cx32 at pars nonglandularis contributes to its susceptibility for developing ulcers, has to be further elucidated.

The prevalence and distribution of gastric ulceration in 345 racehorses

OBJECTIVE

To report the prevalence and distribution of gastric ulceration within a group of racehorses and to describe the endoscopic appearance of gastric antrum and pyloric ulceration.

DESIGN

Retrospective clinical study.

PROCEDURE

Medical records from gastroscopic examinations of 345 racehorses (331 Thoroughbreds and 14 Standardbreds) were reviewed. 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.

RESULTS

Gastric ulceration was found in 86% of racehorses. The squamous mucosa around the margo plicatus was most commonly affected. The pylorus was examined in 175 horses and 47% were ulcerated. No association was found between presence of lesions of the squamous mucosa and those of the pylorus. Low correlation was found between grade and location of lesions, with the pyloric lesion score being significantly less than the squamous mucosal lesion score.

CONCLUSION

Gastric ulceration was present in a large proportion of racehorses. The pylorus was also an important site of ulceration. There was no association between presence of lesion at one site and the other, although there was a low correlation between grade of lesion and location, with the pyloric ulcer grade being lower.