Topic:Stomach
The equine stomach is a complex organ responsible for the initial stages of digestion in horses. It is divided into two main regions: the non-glandular (squamous) region and the glandular region, each with distinct functions and susceptibilities to conditions such as ulcers. The stomach's acidic environment aids in breaking down food particles, while enzymes initiate the digestion of proteins. The equine stomach is adapted for continuous grazing, with relatively small capacity and rapid emptying into the small intestine. This page aggregates peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and common disorders of the horse's stomach, as well as their implications for equine nutrition and health management.
Prevalence and diagnosis of parasites of the stomach and small intestine in horses in south-west England. Parasites were extracted from the stomach and small intestine of 118 horses at slaughter. The most abundant species was the tapeworm Anoplocephala perfoliata. Maximum likelihood analysis was used to investigate the relationship between the number of worms and their total weight, and the ability of an antibody-based elisa to diagnose the level of infection. The total weight of tapeworms increased towards a maximum as the number of worms increased, suggesting a population density-dependent constraint on the weight. The number of A perfoliata present could be predicted approximately from the resu...
Systemic AL amyloidosis associated with multiple myeloma in a horse. AL amyloidosis is the most common type of systemic amyloidosis in humans, and it is frequently associated with multiple myeloma. But, AL amyloidosis is very rare in domestic animals. A 16-year-old Quarter horse gelding was diagnosed with systemic AL amyloidosis associated with multiple myeloma. Clinical problems were rapid weight loss, muscle atrophy, soft unformed stool, and ventral edema. Grossly, diffuse gastrointestinal hemorrhage, markedly thickened jejunal mucosa, and splenomegaly were present. Microscopically, diffuse severe amyloid deposits were present in the lamina propria of glandul...
Meal size and starch content affect gastric emptying in horses. Feeding practices have been associated with colic in horses. If meal size and composition have an effect on gastric emptying, this could be one of the mechanisms by which feeding practices are related to the occurrence of colic. Objective: To evaluate the effect of meal size and starch content on solid phase gastric emptying. Methods: Solid phase gastric emptying of 3 different radiolabelled meals, small low-starch (SmLS), small high-starch (SmHS) and large high-starch (LgHS) meals, was measured in 5 horses by scintigraphy using 99mTc-disofenin. Data were compared among meals using nonlinear m...
[Idiopathic gastric rupture in a Friesian foal]. Acute idiopathic gastric rupture resulted in sudden death of a 4.5-months-old healthy Friesian foal. No morphological lesions were present which could explain the preceding gastric impaction. In this case hypodypsia may have been (partially) responsible for the impaction as only a mechanical drinking apparatus, unsuitably for horses, was available.
Prevalence of gastric ulcers in endurance horses–a preliminary report. Gastric endoscopy was performed at the end of a 50 or 80 km endurance ride. Gastric ulceration was evident in 67% of the horses with ulcers on the squamous region of the stomach found in 57% of the horses and active bleeding of the glandular mucosa in 27%. Three horses (10%) had lesions only on the glandular mucosa. Values of albumin, creatinine and glucose were higher in horses without gastric lesions. We conclude that horses from endurance competitions have a high prevalence of gastric ulceration that is similar to that observed in performance horses. However the severity of ulceration is le...
Effects of lipopolysaccharide and phenylbutazone on gastric contents in the horse. Endotoxaemia causes a disruption of gastrointestinal motility in the horse but there is no information on its effects on gastric secretion. Lipopolysaccharide (LPS) administration is known to affect gastric secretion in other species. Objective: That LPS, a toxic component of Gram-negative bacteria, would reduce gastric acid secretion and that pretreatment with phenylbutazone (PBZ) would block the effects of LPS. Methods: The effects of LPS and PBZ on gastric contents were investigated in fasted, mature horses, with permanent gastric cannulae. Horses were pretreated with either saline or PBZ 1...
Effects of hydrochloric, acetic, butyric, and propionic acids on pathogenesis of ulcers in the nonglandular portion of the stomach of horses. 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). Methods: Gastric tissues from 30 horses. Methods: 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, co...
Effects of hydrochloric, valeric, and other volatile fatty acids on pathogenesis of ulcers in the nonglandular portion of the stomach of horses. 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. Methods: Gastric tissues from 13 adult horses. Methods: 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 histologica...
Effects of exercise on gastric volume and pH in the proximal portion of the stomach of horses. To assess effects of exercise on a treadmill with changes in gastric volume and pH in the proximal portion of the stomach of horses. Methods: 3 healthy adult horses. Methods: A polyester bag of approximately 1,600 mL was placed into the proximal portion of the stomach of each horse via a nasogastric tube. Changes in bag volume, determined by an electronic barostat, were recorded before, during, and after a training session on a treadmill with and without prior withholding of food. In separate experiments, pH in the proximal portion of the stomach was continuously recorded during exercise for f...
Quantitative detection of atropine-delayed gastric emptying in the horse by the 13C-octanoic acid breath test. The 13C-octanoic acid breath test has been correlated significantly to radioscintigraphy for measurement of gastric emptying indices in healthy horses. The objective of this study was to investigate the validity of the test for measurement of equine delayed gastric emptying, prior to its potential clinical application for this purpose. A model of atropine-induced gastroparesis was used. Gastric emptying rate was measured twice in 8 horses using concurrent radioscintigraphy and/or breath test after treatment i.v. with either atropine (0.035 mg/kg bwt) or saline in randomised order. Analysis of ...
The effect of a pectin-lecithin complex on prevention of gastric mucosal lesions induced by feed deprivation in ponies. This study examined whether a product containing a pectinlecithin complex (Pronutrin) (1) could prevent gastric lesions induced in the equine gastric squamous epithelial mucosa using a protocol of intermittent feed deprivation that resulted in prolonged increased gastric acidity (Murray and Eichorn 1996). Eight ponies were used and served as their own controls in 2 trials in which there were 72 h cumulative deprivation (alternating 24 h with no feed, then 24 h free choice hay), with a 4-week interval between trials. Ponies were assigned randomly to receive either 250 g Pronutrin plus 200 g pel...
Prevalence and macro- and microscopic lesions produced by Gasterophilus nasalis (Diptera: Oestridae) in the Botucatu Region, SP, Brazil. The objective of the present study was to investigate the prevalence of Gasterophilus nasalis larvae in Botucatu, the central west region of São Paulo State, Brazil, and to describe the lesions caused by the parasite. The climate of Botucatu is warm and rainy during the months of December through March and cool and dry during the months of May through August. The prevalence of G. nasalis was 16.84%, and the period of peak infestation corresponded to the months of cold and dry weather. The lesions detected at the sites of larval attachment were examined macro- and microscopically. Erosions and...
World association for the advancement of veterinary parasitology (WAAVP): second edition of guidelines for evaluating the efficacy of equine anthelmintics. These guidelines have been designed to assist in the planning, operation and interpretation of studies which would serve to assess the efficacy of drugs against internal parasites of horses. Although the term anthelmintic is used in the title and text, these guidelines include studies on drug efficacy against larvae of horse bot flies, Gasterophilus spp., which are non-helminth parasites commonly occurring in the stomach of horses. The advantages, disadvantages and application of critical and controlled tests are presented. Information is also provided on selection of animals, housing, feed, d...
Histological characteristics of induced acute peptic injury in equine gastric squamous epithelium. The objective of the study reported here was to characterise the microscopic appearance of peptic-injured equine gastric squamous epithelium in relation to the duration of peptic injury. Erosions and ulcers were induced in equine gastric squamous epithelium using a feed deprivation protocol that results in prolonged increased gastric acidity. Specimens of normal gastric mucosa and mucosa with lesions created after 48 and 96 h of feed deprivation were compared for characteristics associated with angiogenesis and mucosal proliferation. Fifteen mature horses, 9 geldings and 6 mares, age 3-20 year...
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 ...
Mucosal microvasculature of the gastric pars nonglandularis and margo plicatus in the horse: a scanning electron microscopic study on corrosion casts. The microvascularisation of the equine non-glandular gastric mucosa was investigated using corrosion casts for scanning electron microscopy. Specimens from 11 healthy horses were examined. Corresponding to the high incidence of gastric lesions in the margo plicatus, special attention was paid to the differentiation between the pars nonglandularis and the margo plicatus as a distinct area of the aglandular mucosa. In both areas, the blood vessels of the lamina propria mucosae were arranged in three vascular layers; i. e. I) a basal, II) an intermediate, and III) a subepithelial horizontal level...
Surface mucus in the non-glandular region of the equine stomach. In horses, ulceration of the non-glandular region of the stomach is common and has been attributed to the lack of a protective mucus covering. This study aimed to determine whether the non-glandular region is covered by a mucus layer. A mixture of antibodies raised against human gastric mucin (MUC 5 AC) showed a tissue distribution in the glandular region of the equine stomach similar to that seen in humans. Dot blots of mucus from the glandular and non-glandular regions showed cross-reactivity with these antibodies. Various histological fixation and processing techniques were compared for the...
Assessment of the rate of solid-phase gastric emptying in ponies by means of the 13C-octanoic acid breath test: a preliminary study. The aim of this study was to assess the feasibility of applying the 13C-octanoic acid breath test for assessment of gastric emptying in ponies by investigating the pattern of 13C enrichment in breath following the administration of a test meal +/- 13C-octanoic acid. After a 14 h fast, the ponies received either no meal (Test I) or a standardised test meal labelled with 0 mg (Test II), 125 mg (Test III), 250 mg (Test IV) or 500 mg (Test V) 13C-octanoic acid. For each test (I-V), exhaled breath samples were collected in duplicate at 1 h and immediately before ingestion of the test meal and at fr...
Effects of a histamine type 2 receptor antagonist, BMY-26539-01, on equine gastric acid secretion. A dose-response study was undertaken of the effects of a newly developed histamine type 2 receptor antagonist, BMY-26539-01, on gastric acid secretion in 4 fasted horses. Doses of 0.1 mg/kg, 0.3 mg/kg, 0.5 mg/kg, or placebo were administered in a randomly assigned treatment sequence. Hydrogen ion concentration and pH were variable during baseline measurements in all 4 animals; however, following BMY-26539-01 administration, mean pH increased and hydrogen ion concentration decreased in a dose-related pattern. At the 0.3 mg/kg and 0.5 mg/kg dose levels, pH remained elevated for > 4 h and >...
Evidence for surfactant contributing to the gastric mucosal barrier of the horse. This study was undertaken to determine the hydrophobicity of the luminal surface of the equine stomach and to elucidate the ultrastructure of the lining imparting that property. Gastric and duodenal mucosal samples from 5 horses were collected immediately after euthanasia and subjected to surface contact angle measurement using a goniometer. Gastric mucosal samples from 4 horses and a foal were examined by electron microscopy following a fixation procedure known to preserve phospholipids and oligolamellar structures. Contact angles for the equine gastric glandular mucosal surface (mean +/- s.e...
Colonization of the stratified squamous epithelium of the nonsecreting area of horse stomach by lactobacilli. Selective adhesion to only certain epithelia is particularly common among the bacterial members of the indigenous microflora of mammals. We have found that the stratified squamous epithelium of the nonsecreting area of horse stomach is colonized by gram-positive rods. The microscopic features of a dense layer of these bacteria on the epithelium were found to be similar to those reported in mice, rats, and swine. Adhering microorganisms were isolated and identified as Lactobacillus salivarius, L. crispatus, L. reuteri, and L. agilis by DNA-DNA hybridization and 16S rRNA gene sequencing techniqu...
Evaluation of diet as a cause of gastric ulcers in horses. To measure pH, volatile fatty acid (VFA) concentrations, and lactate concentrations in stomach contents and determine number and severity of gastric lesions in horses fed bromegrass hay and alfalfa hay-grain diets. Methods: Six 7-year-old horses. Methods: A gastric cannula was inserted in each horse. Horses were fed each diet, using a randomized crossover design. Stomach contents were collected immediately after feeding and 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, and 24 hours after feeding on day 14. The pH and VFA and lactate concentrations were measured in gastric juice Number and severity of gastri...
Detecting Taxus poisoning in horses using liquid chromatography/mass spectrometry. A method is described for the analysis of taxine alkaloids by liquid chromatography/mass spectrometry. It is applicable to the detection of taxine alkaloids in the stomach contents of horses in which Taxus poisoning is suspected. Analysis of a leaf extract of Taxus baccata revealed unreported alkaloids of the same relative molecular mass as taxine B and isotaxine B.
Efficacy of moxidectin equine oral gel against endoscopically-confirmed Gasterophilus nasalis and Gasterophilus intestinalis (Diptera: Oestridae) infections in horses. A 3 m, video gastroscope was used to screen 47 horses suspected of being naturally infected with equine bot larvae. 17 of 47 (36.2%) candidate horses harbored Gasterophilus nasalis larvae in the proximal duodenum and 46 of 47 (97.9%) had G. intestinalis larvae in the stomach. All horses infected with G. nasalis had concurrent infections with G. intestinalis. 14 horses with dual infections were allocated randomly to two treatment groups. Seven horses in Group 1 received 2% moxidectin oral gel once at a dosage of 0.4 mg/kg bodyweight (BW), and seven horses in Group 2 were untreated controls. 14 ...
Effect of nervous excitation on acid secretion in horses. Nervous excitation was induced by various means in horses provided with a gastric cannula. Insulin hypoglycaemia profoundly inhibited the basal acid output and volume secreted from the stomach. No clear effect on acid secretion was noted after administration of bethanechol, as the acid output was covered by the copious secretion of saliva. Atropine almost abolished the basal acid output. Sensoric stimulation by teasing caused a slight but not significant increase in the total acid output. These data suggest that cholinergic excitation might play a role in the stimulation of both volume and aci...
Comparative pathophysiology of nonglandular ulcer disease: a review of experimental studies. Ulceration of the nonglandular, stratified squamous mucosa of the equine and porcine stomach is a common event in both species, although in pigs the fatality rate is significant and it is an economically important disease. Because the barrier function of this mucosa in horses and pigs appears similar, it is probable that similar pathophysiological mechanisms may be responsible for the initiating lesions and reparative events. Recent studies of ulcer pathogenesis in the pig have shown that feed preparation or prolonged fasting can result in disruption of the normal stratification of gastric con...