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Topic:Gastrointestinal Health
Gastrointestinal health in horses encompasses the study of the structure, function, and disorders of the equine digestive system. The equine gastrointestinal tract is complex, consisting of the stomach, small intestine, cecum, and large intestine, each playing a specific role in digestion and nutrient absorption. Research in this area often focuses on common disorders such as colic, gastric ulcers, and parasitic infections, which can impact a horse's overall health and performance. Investigations examine factors affecting gastrointestinal health, including diet, management practices, and the microbiome. This page compiles peer-reviewed research studies and scholarly articles that explore the physiology, pathology, and management of gastrointestinal health in horses.
The effects of Strongylus vulgaris parasitism on eosinophil distribution and accumulation in equine large intestinal mucosa. Eosinophilic granulocytes have been associated with parasite or immune-mediated diseases, but their functions in other disease processes remain unclear. Cause and timing of eosinophil migration into the equine gastrointestinal mucosa are also unknown. Objective: To determine the effects of intestinal parasitism on eosinophils in equine large intestinal mucosa. Methods: Large intestinal mucosal samples were collected from horses and ponies (n = 16) from the general veterinary hospital population, ponies (n = 3) raised in a parasite-free environment, ponies experimentally infected with 500 infec...
Gastric and small intestinal ileus as a cause of acute colic in the post parturient mare. Ileus (functional obstruction of aboral gastrointestinal transit) is an uncommon cause of gastrointestinal dysfunction and colic in the horse. A number of specific conditions have been previously reported in association with ileus. This report describes the recognition of primary gastric and small intestinal ileus of undetermined cause in a series of post parturient mares. Objective: To describe the clinical features, treatment and outcome of a series of episodes of primary gastric and small intestinal ileus. Methods: A retrospective study was performed of colic episodes seen in an equine prac...
Gastrointestinal stromal tumour and hypoglycemia in a Fjord pony: case report. Neoplasia may cause hypoglycemia in different species including the horse, but hypoglycemia has not previously been reported in the horse associated with gastrointestinal stromal tumours. Methods: A case of a gastrointestinal stromal tumour in a Fjord pony with severe recurrent hypoglycemia is presented. The mechanism causing the hypoglycemia was not established. Conclusions: This case indicates that a gastrointestinal stromal tumour may cause hypoglycemia also in the horse.
Effects of direct-fed microbial supplementation on digestibility and fermentation end-products in horses fed low- and high-starch concentrates. A study was conducted to determine whether direct-fed microbials (DFM) could be used to increase digestibility and minimize the risk of acidosis associated with feeding an increase in the amount of starch fed to horses. Fifteen mature Thoroughbred geldings were randomly assigned to 1 of 3 treatments in a 3 x 3 Latin square design balanced for carryover effects. Within each 26-d period, horses were offered grass hay + low-starch concentrate (LS; 1.2 g of starch x kg of BW(-1) x meal(-1)) from d 1 to 13 and then were abruptly changed to hay + high-starch concentrate (HS; 2.4 g of starch.kg of BW...
Effect of age, feeding, and omeprazole administration on gastric tonometry in healthy neonatal foals. Gastric tonometry is commonly used in humans as an assessment of intestinal mucosal perfusion. Values in healthy foals are currently unknown. Objective: Age, enteral feeding, and omeprazole administration would significantly alter gastric tonometry measurements in neonatal foals. Methods: Nine clinically normal foals were used to assess the effect of age and feeding, and 8 similar foals were used to assess the effect of omeprazole. Methods: At 1, 7, and 14 days of age, gastric intramucosal PCO2 (PgCO2) and arterial blood gas samples were obtained at baseline, immediately after feeding milk, an...
Bradykinin stimulates prostaglandin E2 production and cyclooxygenase activity in equine nonglandular and glandular gastric mucosa in vitro. There are few data available regarding regulation of prostaglandin (PG) generation by equine gastric mucosae and the role of the cyclooxygenase (COX) isoforms in their production. Objective: To: 1) characterise and quantify PGE2 output in vitro; 2) examine the sensitivity of PGE2 production to exogenous bradykinin (BK) exposure; 3) determine the contribution of the COX-1 and COX-2 pathways to basal and BK-stimulated PGE2 production; and 4) measure if BK influences electrogenic ion transport in equine gastric mucosae in vitro. Methods: Full thickness gastric sheets were obtained from horses at ...
Retrospective study assessing efficacy of treatment of large colonic impactions. Cases with a history of colic due to a large colonic impaction were recruited retrospectively to assess the treatment efficacy and complications of oral and parenteral fluid therapy regimes for correction of primary large colon impactions. Oral isotonic fluids had been administered at varying intervals following initial treatment with magnesium sulphate and water. There was no significant difference in complication rates between groups. Considering complication rates with impaction clearance, hourly administration of oral fluids appears to be the most appropriate treatment regime of those inve...
In vitro effects of hydrochloric and lactic acids on bioelectric properties of equine gastric squamous mucosa. Volatile fatty acids, byproducts of carbohydrate fermentation by resident bacteria, have been implicated in causing nonglandular (NG) gastric ulcers. Lactic acid (LA), also produced by stomach bacteria, may cause gastric ulcers when exposed to the equine NG mucosa. Objective: To investigate the in vitro effects of LA on equine NG mucosa bioelectric properties, sodium transport and tissue resistance. Methods: Gastric tissues obtained from 13 mature horses were studied in Ussing chambers. Short-circuit current (Isc) and potential difference (PD) were measured, and electrical resistance (R) and c...
Antibody index and specific antibody quotient in horses after intragastric administration of Sarcocystis neurona sporocysts. To investigate the use of a specific antibody index (AI) that relates Sarcocystis neurona-specific IgG quotient (Q(SN)) to total IgG quotient (Q(IgG)) for the detection of the anti-S neurona antibody fraction of CNS origin in CSF samples obtained from horses after intragastric administration of S neurona sporocysts. Methods: 18 adult horses. Methods: 14 horses underwent intragastric inoculation (day 0) with S neurona sporocysts, and 4 horses remained unchallenged; blood and CSF samples were collected on days - 1 and 84. For purposes of another study, some challenged horses received intermitten...
Effect of paddock vs. stall housing on 24 hour gastric pH within the proximal and ventral equine stomach. Stall housing has been suggested as a risk factor for ulcer development in the equine stomach; however, the exact pathogenesis for this has not been established. Objective: To investigate the effect of 3 environmental situations (grass paddock, stall alone or stall with adjacent companion) on pH in the proximal and the ventral stomach. Methods: Six horses with permanently implanted gastric cannulae were used in a randomised, cross-over, block design. Each horse rotated through each of three 24 h environmental situations. Horses remained on their normal diet (grass hay ad libitum and grain b.i....
Risk factors for epiploic foramen entrapment colic: an international study. Epiploic foramen entrapment (EFE) is one of the most common causes of small intestinal strangulation in the horse. Identification of risk factors would generate hypotheses about causation and may suggest preventive strategies. Objective: Horses exhibiting certain behavioural patterns and those exposed to particular management practices are at increased risk of EFE. Methods: A matched case-control study was conducted on EFE cases admitted to hospitals in the UK, Ireland and USA. Data on 109 cases and 310 control horses were obtained by telephone questionnaire and conditional logistic regression...
Contractile effects of 5-hydroxytryptamine (5-HT) in the equine jejunum circular muscle: functional and immunohistochemical identification of a 5-HT1A-like receptor. Prokinetic drugs used to treat gastrointestinal ileus in man have equivocal results in horses. In man, prokinetic drugs have 5-hydroxytryptamine4(5-HT4) receptors as their target, but little is known about the 5-HT-receptor subtypes in the equine small intestine. Objective: Functional and immunohistochemical identification of the serotonin receptor subtype(s) responsible for the 5-HT induced contractile response in the equine circular jejunum. Methods: Isometric organ-bath recordings were carried out to assess spontaneous and drug-evoked contractile activity of equine circular jejunum. Histolo...
Distribution of the neurokinin-1 receptor in equine intestinal smooth muscle. Tachykinins have profound effects on equine intestinal motility, but the distribution of the neurokinin receptors (NKRs) through which they act is unknown. This study reports the distribution of one of these receptors, the neurokinin-1 receptor (NK1R), in smooth muscle throughout the equine intestinal tract. Objective: To quantify the distribution of the NK1R, based upon mRNA expression, in smooth muscle of different regions of the equine intestinal tract. Methods: Nine regions of the intestinal tract were sampled in 5 mature horses. Total RNA was isolated from smooth muscle and reverse transc...
Imaging diagnosis–Intramural hematoma, jejunal diverticulum and colic in a horse. No abstract available
Small intestine adenocarcinoma in conjunction with multiple adenomas causing acute colic in a horse. An 11-year-old Andalusian stallion developed marked signs of colic associated with an acute small intestine obstruction. Exploratory laparotomy revealed a distal jejunum full-thickness wall induration and multiple small adherent intraluminal masses. Fifteen centimeters of jejunum, including the induration, and several intraluminal masses were resected. Histologic examination revealed an adenocarcinoma and multiple polypoid adenomas. The horse was discharged, and no complications were reported 12 months postoperatively. Colic was considered secondary to partial jejunal lumen obstruction by the ...
Myonecrosis in three horses with colic: evidence for endotoxic injury. Three horses with colic, clinical evidence of endotoxaemia and high serum activities of creatine kinase and aspartate aminotransferase were examined postmortem. The horses were diagnosed with severe ulcerative colitis, pyloric ulceration and stenosis with colonic sand impaction, and colonic obstruction due to faecaliths. There was no gross or histological evidence of muscle trauma. Their semimembranosus muscles had scattered acute to subacute segmental necrosis of the myofibres, suggestive of endotoxin-induced muscle injury.
Effects of dietary short-chain fructooligosaccharides on the intestinal microflora of horses subjected to a sudden change in diet. Prebiotic compounds, such as short-chain fructooligosaccharides (scFOS), have been shown to improve health, welfare, or both, in several species, but few studies have been conducted in horses, despite the sensitivity of their hindgut microflora. We hypothesized that prebiotic oligosaccharides, known to be able to stabilize the intestinal microflora in other species, would be of importance in horses. Our study was designed to evaluate the effect of scFOS supplementation on the equine intestinal microflora and to assess its effectiveness in reducing hindgut microbial disturbances related to sudd...
Preliminary study of mucosal IgA in the equine small intestine: specific IgA in cases of acute grass sickness and controls. There is much evidence to suggest that group III Clostridium botulinum (types C and D) are involved in the aetiology of equine grass sickness (EGS). Antibodies have been detected previously in the blood and high levels associated with resistance to disease. Specific mucosal antibodies in the gastrointestinal (GI) tract are likely to be important in protection, and this study was performed to ascertain if such antibodies could be detected and if their levels were related to disease state. Objective: To develop a method for quantifying IgA antibodies to C. botulinum types C and D in the GI tract...
Detection of Helicobacter-like DNA in the gastric mucosa of Thoroughbred horses. To assess the presence of Helicobacter DNA in the gastric mucosa Thoroughbred horses. Results: Squamous and glandular mucosa samples were collected from 20 Thoroughbreds. None of these horses had shown any clinical symptoms of gastrointestinal disease. Necropsy tissues were analysed using histopathological techniques and a Helicobacter genus-specific PCR assay followed by sequencing of the amplicons. Seven horses were diagnosed with gastric ulceration, five with gastritis and six with both pathologies. Only two horses had a healthy gastric mucosa. Helicobacter-like DNA was detected in two out ...
Detection of an isoform of alpha(1)-antitrypsin in serum samples from foals with gastric ulcers. The objective of this study was to find serum indicators of gastric ulcers in foals. By using two-dimensional electrophoresis of serum proteins, three distinct spots were detected in samples from foals with gastric ulcers detected endoscopically. One of them appeared with high frequency and was identified by partial digestion with trypsin and subsequent nano-electrospray ionisation-tandem mass spectrometry (nanoesi-ms/ms) analysis as an alpha(1)-antitrypsin. Western blot analysis, using an antibody against human alpha(1)-antitrypsin, revealed at least two bands, of molecular weight 58 kDa and ...
Acute in vivo interactions of Helicobacter equorum with its equine host. A novel urease-negative Helicobacter species has been isolated from faecal samples of clinically healthy horses, but no information is available about the main sites of colonisation in the equine gastrointestinal tract nor is the pathogenic potential of this microorganism known. An experimental infection in horses was therefore carried out. Methods: Four horses were infected with H. equorum strain CCUG 52199T and subjected to euthanasia at 10 (n = 2) and 30 days (n = 2) post inoculation. A fifth animal was inoculated with phosphate buffered saline and used as control. Gastrointestinal samples ...
Evidence-based gastrointestinal medicine in horses: it’s not about your gut instincts. The use of an evidence-based approach allows veterinary clinicians to assess questions that are clinically relevant to the diagnosis and treatment of equine gastrointestinal tract disease. This approach involves formulating a clinical question, searching the literature, and answering the question with the best available evidence, with the results summarized as a clinical "bottom line." This article is organized to reinforce the principle that the cornerstone of evidence-based medicine is the clinical question. Specific questions are further categorized as to topic, with epidemiologic risk fact...
Evaluation of equine cecal motility by ausculation, ultrasonography and electrointestinography after jejunocecostomy. Horses often suffer reduced intestinal motility after jejunocecostomy. Therefore, accurate evaluation of intestinal motility is important for the prevention, diagnosis and treatment of this condition. The purpose of this study was to evaluate intestinal motility in horses after jejunocecostomy using three different methods, i.e. auscultation, ultrasonography and electrointestinography. Methods: Six healthy thoroughbreds were used in this study. They were subjected to jejunocecostomy. Methods: Bowel sounds in the right paralumbar fossa were assigned a score of 0-3 for intestinal motility evalua...
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 ...
Congenital colonic malformation (“short colon”) in a 4-month-old standardbred foal. During exploratory laparotomy of a foal with colic, a congenital abnormally developed large colon was identified incidentally. Long-term follow-up showed that the colt was more prone to gas-colic with diet and exercise changes than were other horses, due possibly to the short colon. Malformation congénitale du côlon (côlon court) chez un poulain Standardbred âgé de 4 mois. Au cours d’une laparotomie exploratrice chez un poulain atteint de colique, une malformation congénitale du gros côlon a été identifiée de façon fortuite. Un suivi à long terme a montré que le poulain était d...
Pharmacokinetics and in vitro effects of tegaserod, a serotonin 5-hydroxytryptamine 4 (5-HT4) receptor agonist with prokinetic activity in horses. Tegaserod, a serotonin agonist, has been shown to have prokinetic effects in horses, but pharmacokinetic information is not currently available. The pharmacokinetics and in vitro effects of tegaserod were evaluated. Tegaserod increased the contractile activity of smooth muscle preparations of the equine pelvic flexure. Pertinent pharmacokinetic parameters for a single IV and oral dose were determined. Therapeutic plasma concentrations of tegaserod were achieved by a single oral dose at 0.27 mg/kg. These findings indicate that further clinical studies are warranted to investigate potential bene...
Detection of fibrin deposits in tissues from horses with severe gastrointestinal disorders. In humans and experimental animals, disseminated intravascular coagulation (DIC) causes fibrin deposition in several organs, which eventually leads to ischemia and multiorgan failure. Objective: Horses who died or were euthanized for severe gastrointestinal disorders could have fibrin deposits in different tissues. Methods: Tissue-organ samples collected during postmortem examinations on 66 colic horses with poor prognoses (eg, severe intestinal ischemia, enteritis, peritonitis), from 11 colic horses with good prognoses (eg, large-colon obstruction or displacement), and from 16 slaughter horse...
Effect of omeprazole on markers of performance in gastric ulcer-free standardbred horses. A large percentage of performance horses develop gastric ulcers and many of those horses are treated with omeprazole. Unfortunately, no data have been published on the effects of the drug on markers of performance in animals without ulcers. Objective: Omeprazole would alter markers of aerobic and anaerobic performance. Methods: Ten unfit, healthy, ulcer free, Standardbred mares were administered either control (CON; oral apple sauce, 20 ml) or omeprazole (OP; oral paste, 4 mg/kg bwt s.i.d.) in a random crossover fashion with the investigators blind to the treatment. Treatments were administere...
Oxidative stress. Oxidative stress refers to the cellular injury and pathologic change that occurs when there is an imbalance favoring oxidants over antioxidants within a living organism. In human medicine, oxidative stress has been implicated in numerous disease processes, which has led to further research into the clinical benefits and efficacy of antioxidant therapy. The evaluation of oxidative stress in the horse has been limited primarily to ischemia-reperfusion injury of the gastrointestinal tract, recurrent airway obstruction, exercise, osteoarthritis, equine motor neuron disease, and pituitary pars inte...
