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.
Frank N, Andrews FM, Elliott SB, Lew J.To assess antiulcerogenic properties of 3 dietary oils. Methods: 8 healthy adult mares. Methods: A protocol to induce gastric ulcers was used and included 240 mL of water plus corn oil, refined rice bran oil, or crude rice bran oil administered each day for 6 weeks according to a 4 x 4 Latin square randomized crossover design with 5-week washout intervals. A 7-day alternating feed deprivation period was included between weeks 5 and 6. Omeprazole was administered daily for the last 14 days of each washout interval. Endoscopic examinations of the stomach were performed at 0, 5, and 6 weeks, and ...
Lester GD, Smith RL, Robertson ID.To compare the effects of oral administration of omeprazole and ranitidine on gastric squamous ulceration in Thoroughbreds in race training. Methods: Modified crossover study. Methods: 60 Thoroughbreds in race training with gastric squamous mucosal ulceration. Methods: Horses were randomly allocated into 3 groups. Group 1 received no treatment for 28 days followed by administration of omeprazole (4 mg/kg [1.8 mg/lb], PO, once daily) for 28 days; group 2 received omeprazole (4 mg/kg, PO, once daily) for 28 days followed by no treatment for 28 days; and group 3 received ranitidine (6.6 mg/kg [3....
Holbrook TC, Simmons RD, Payton ME, MacAllister CG.Electrolyte supplementation is common in horses during endurance competitions, but the effect on the gastric mucosa is unknown. Objective: 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 const...
Roy MA, Vrins A, Beauchamp G, Doucet MY.This study was performed to determine the prevalence of ulcers in the gastric squamous mucosa in Standardbred racehorses. Observations were performed at monthly intervals between the beginning of their training season and their 1st qualifying race. This study also identified risk factors at different levels of race training. Forty-eight Standardbred racehorses from 3 training stables in Quebec, Canada, were studied. Baseline historical information and gastroscopic findings were recorded at the beginning of the trial, and once a month thereafter, between December 2001 and June 2002, until the h...
Fink C, Hembes T, Brehm R, Weigel R, Heeb C, Pfarrer C, Bergmann M, Kressin M.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 py...
Lorenzo-Figueras M, Preston T, Ott EA, Merritt AM.To evaluate the effect of ingestion of a high-carbohydrate versus a high-fat meal on relaxation of the proximal portion of the stomach and subsequent gastric emptying in horses. Methods: 6 healthy adult horses. Methods: The study consisted of 2 phases. In phase I, horses were offered a high-fat (8% fat) or a high-carbohydrate (3% fat) pelleted meal (0.5 g/kg) of identical volume, caloric density, and protein content. In phase II, meals consisted of a commercial sweet feed meal (0.5 g/kg) or this meal supplemented with corn oil (12.3% fat) or an isocaloric amount of glucose (2.9% fat). Proximal...
Morgan ER, Hetzel N, Povah C, Coles GC.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...
Kim DY, Taylor HW, Eades SC, Cho DY.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...
Métayer N, Lhôte M, Bahr A, Cohen ND, Kim I, Roussel AJ, Julliand V.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...
Borst GH, van der Weij PJ, Vos JH.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.
Nieto JE, Snyder JR, Beldomenico P, Aleman M, Kerr JW, Spier SJ.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...
Doherty TJ, Andrews FM, Blackford JT, Rohrbach BW, Sandin A, Saxton AM.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...
Nadeau JA, Andrews FM, Patton CS, Argenzio RA, Mathew AG, Saxton AM.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...
Nadeau JA, Andrews FM, Patton CS, Argenzio RA, Mathew AG, Saxton AM.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...
Lorenzo-Figueras M, Merritt AM.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...
Sutton DG, Bahr A, Preston T, Cohen ND, Love S, Roussel AJ.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 ...
Murray MJ, Grady TC.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...
Sequeira JL, Tostes RA, Oliveira-Sequeira TC.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...
Duncan JL, Abbott EM, Arundel JH, Eysker M, Klei TR, Krecek RC, Lyons ET, Reinemeyer C, Slocombe JO.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...
Murray MJ, Eichorn ES, Jeffrey SC.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...
Murray MJ, Nout YS, Ward DL.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 ...
Staszyk C, Jackowiak H, Godynicki S, Gasse H.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...
Bullimore SR, Corfield AP, Hicks SJ, Goodall C, Carrington SD.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...
Wyse CA, Murphy DM, Preston T, Morrison DJ, Love S.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...
Orsini JA, Spencer PA.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 >...
Ethell MT, Hodgson DR, Hills BA.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...
Yuki N, Shimazaki T, Kushiro A, Watanabe K, Uchida K, Yuyama T, Morotomi M.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...
Nadeau JA, Andrews FM, Mathew AG, Argenzio RA, Blackford JT, Sohtell M, Saxton AM.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...
Straticò P, Razzuoli E, Hattab J, Guerri G, Celani G, Palozzo A, Bonanni D, Fruscione F, Varasano V, Petrizzi L, Marruchella G.A 7-year-old Friesian stallion with a history of oesophageal stenosis, weight loss, inappetence, and recurrent hyperthermia was referred for gastroscopy. The stomach mucosa surrounding the oesophageal opening showed a large, necrotic, and ulcerated mass. On post-mortem examination, a very large, cauliflower-like neoplasm was seen, affecting non-glandular gastric mucosa. Nodular lesions were observed, scattered on the omentum, the spleen, and the liver. Microscopic findings allowed the diagnosis of gastric squamous cell carcinoma with abdominal metastasis. Biomolecular investigations demonstrat...
DiFranco B, Schumacher J, Morris D.Three horses were admitted for retrieval of polyurethane nasogastric tube fragments. The fragments were removed from the esophagus or stomach of 2 horses by manipulation of a snare introduced through the biopsy port of an endoscope. The fragments were surgically removed from the stomach of the third horse.
Duncan JL, Abbott EM, Arundel JH, Eysker M, Klei TR, Krecek RC, Lyons ET, Reinemeyer C, Slocombe JO.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...
Sojka JE, Weiss JS, Samuels ML, You GM.The effect of the somatostatin analogue, octreotide, on gastric fluid pH was investigated in 4 ponies. Gastric fluid pH was determined after SC administration of octreotide or physiologic saline solution (control). A baseline sample of fluid was obtained, the agent was given, and 8 additional samples were collected hourly. Administration of octreotide at all dosages tested (0.1, 0.5, 1.0, and 5.0 micrograms/kg of body weight) increased gastric pH to > 5.0. Baseline values were consistently 4.0 for 2.4 +/- 1.2, 4.8 +/- 0.8, 5.7 +/- 1.3, and 5.4 +/- 2.6 (mean +/- SD) continuous hours, respec...
Drudge JH, Lyons ET, Wyant ZN, Tolliver SC.The occurrence of 2nd and 3rd instars of Gasterophilus intestinalis and Gasterophilus nasalis was determined in 476 horses during the 22-year period from 1951 to 1973. Overall, G intestinalis infected 98.7% of the horses and averaged 168/horse; whereas G nasalis infected 80.7% of the horses and averaged 52/horse. Aggregate average total numbers for G intestinalis ranged from a low of 50 in September to a high of 229 in March, and for G nasalis, from a low of 14 in September to a high of 82 in February. Horses were infected by 2nd or 3rd instars of both species on a year-round basis. Differenti...
Pandey VS, Ouhelli H, Elkhalfane A.Six to nine horses per month (total of 94 in a year) were examined for stomach worms in the Settat region of Morocco. All the animals were infected by at least one helminth species. Habronema muscae occurred in 95.8%, H. majus in 75.6% and Trichostrongylus axei in 80.9% of horses. Polyparasitism was observed in 93.6% of horses. Both for Habronema sp. and T. axei the peak worm burden was observed in November and minimum in June. The infection pattern of Habronema spp. was directly related to the period of activity of fly vectors.
Price RE, Stromberg PC.Stomachs of 271 horses and ponies from 2 sources were evaluated for the presence of Gasterophilus intestinalis and G nasalis larvae, through 2 overlapping 12-month periods of bot fly activity in southern Texas. Equids (n = 140) from one source had nearly 96% of their stomachs infected, whereas equids (n = 131) from another source had 44% of their stomachs infected by Gasterophilus spp. Seasonal dynamics of the bot infection indicated the highest average number of bot larvae per infected stomach occurred in the winter and spring. The smallest average number of bots per infected stomach occurred...
Duncan JL, Arundel JH, Drudge JH, Malczewski A, Slocombe JO.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, do...
Sutton DG, Bahr A, Preston T, Cohen ND, Love S, Roussel AJ.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 ...
Moore JN, Kintner LD.Squamous cell carcinoma involving the pars esophagea of the stomach caused recurrent esophageal obstruction in an 11 year old Pinto gelding. The tumor encircled the esophagus and was attached to the diaphragm, spleen, aorta, left adrenal gland and kidney. Definitive diagnosis was provided by biopsy of the mass via standing left flank laparotomy.
Ganjali M, Keighobadi M.Myiasis is the infection caused by a variety of dipterous (fly) larvae in vertebrate's tissue (man and domestic or wild animals). Species of Gasterophilus are obligate parasite of horses, donkeys, zebras, elephants and rhinoceroses. There are records worldwide, but mostly, in tropical and subtropical regions. This case report describes a type of gastric myiasis caused by G. intestinalis in an old lion in a zoo in Sistan, southeast Iran. Myiasis in lions is rarely reported and this is the first report of gastric myiasis in lion.
Lores M, Stryhn H, McD￮ L, Rose P, Muirhead T.To develop a transcutaneous ultrasonography (TUS) method for measuring the location of the stomach during various levels of fluid distension and evaluate any correlation between gastric fluid distension and stomach position. Methods: 6 adult horses. Methods: Known volumes of water were administered in 2 trials. In trial 1, the stomach was evaluated prior to and after the administration of 2, 4, and 6 L of water. In trial 2, the stomach was evaluated after administration of 6, 8, 10, and 12 L of water. The TUS was performed at the 7th through 16th left intercostal spaces (ICSs). For each volume...
Campbell-Thompson ML, Merritt AM.Equine gastric secretion was studied using a gastric cannula model after fasting (basal) and pentagastrin infusion. Gastric secretory rate, pH, osmolality, and electrolyte concentrations and outputs were determined over a 5-h period. Dose-response tests estimated that the maximally effective intravenous dose of pentagastrin was between 3 and 6 micrograms.kg-1.h-1. Basal secretory rate was 278 +/- 29 (SE) ml/15 min, and the pH was 2.00 +/- 0.31. Pentagastrin infusion at 6 micrograms.kg-1.h-1 increased secretory rate to 533 +/- 60 ml/15 min and decreased pH to 1.41 +/- 0.11. Basal gastric acid c...
Kitchen DL, Merritt AM, Burrow JA.To determine gastric secretory responses in horses treated with histamine and to determine the dose of histamine needed to elicit maximal gastric secretion. Methods: 6 adult horses with an indwelling gastric cannula. Methods: Gastric contents were collected in 15-minute periods, and volume, pH, hydrogen ion concentration, hydrogen ion output, sodium concentration, and sodium output were determined. Values were determined without any treatment (baseline), after administration of pyrilamine maleate (1 mg/kg of body weight, i.v., given during a 15-minute period), and during 1-hour infusions of hi...
Ethell MT, Hodgson DR, Hills BA.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...
Lorenzo-Figueras M, Preston T, Ott EA, Merritt AM.To evaluate the effect of ingestion of a high-carbohydrate versus a high-fat meal on relaxation of the proximal portion of the stomach and subsequent gastric emptying in horses. Methods: 6 healthy adult horses. Methods: The study consisted of 2 phases. In phase I, horses were offered a high-fat (8% fat) or a high-carbohydrate (3% fat) pelleted meal (0.5 g/kg) of identical volume, caloric density, and protein content. In phase II, meals consisted of a commercial sweet feed meal (0.5 g/kg) or this meal supplemented with corn oil (12.3% fat) or an isocaloric amount of glucose (2.9% fat). Proximal...
MacAllister CG, Sangiah S.Thirty young ponies were examined endoscopically for evidence of gastric ulceration. Seven ponies had noninduced gastric ulcers present at the initial examination and were eliminated from the study. In an attempt to induce gastric ulcers experimentally, flunixin meglumine (1.1 mg/kg of body weight, IM, q 8 h) was administered for 7 days to the 23 ponies with endoscopically normal gastric mucosa. During the 7 days of flunixin administration, 11 ponies developed gastric ulcers that were appropriate for study. The 11 ponies were randomly allotted to 2 groups. Group-A (n = 5) and group-B (n = 6) p...
Jacobs RD, Gordon MBE, Vineyard KR, Keowen ML, Garza F, Andrews FM.Low gastric pH for extended periods of time can increase the risk of gastric ulceration in horses. Therefore, nutritional interventions that buffer stomach acid may be helpful to decrease ulcer risk. The objective of this trial was to evaluate whether the incorporation of calcified Lithothamnion corallioides and Phymatolithon calcareum (Calmin; Celtic Sea Minerals, Cork, Ireland) into an equine ration would buffer equine gastric juice. Nine mature, Thoroughbred-cross horses, including 6 geldings and 3 mares (524 ± 49 kg) were housed in stalls and fed 2 kg/day of a texturized concentrate (Pu...
Baker SJ, Gerring EL.Water, saline and a saline/Intralipid mixture (lipid concentration 1.25 per cent) emptied very rapidly from the stomach in neonatal pony foals, and obeyed an apparently exponential pattern. Cisapride did not significantly modify the emptying of the saline/Intralipid mixture. Equine milk emptied more slowly. The data indicated that the lipid component of milk was not an important factor. Milk caused deviation from an exponential pattern in two of four foals: an initial lag phase appeared, which could represent a phase of intragastric processing. However, the rate was still rapid compared with r...
Wyse CA, Murphy DM, Preston T, Morrison DJ, Love S.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...
Baker SJ, Gerring EL.Intragastric pH monitoring was investigated in ponies. In cadaver stomachs, close contact with the mucosa led to high pH readings if nonweighted electrodes were used. However, pH recorded by weighted electrodes was markedly less affected by mucosal contact (P < 0.001). The latter were used for subsequent trials. In vivo, high correlations were found between pH recorded by weighted electrodes with or without a wire guard to prevent mucosal contact (correlation, r = 0.866; P < 0.001). Readings from each correlated well with those from simultaneous gastric aspirates (r = 0.774 and r = 0.807...
Bautista AC, Tahara J, Mete A, Gaskill CL, Bryant UK, Puschner B.Two separate incidents of monensin exposure in horses resulting in toxicosis provided insight into the diagnostic value and interpretive criteria of various biological samples. In case 1, 25 horses broke into a shed and ingested feed that was supplemented with 800 g/ton (880 µg/g) of monensin. Within 48 hr, 1 horse had died, 2 developed cardiac arrhythmias, lethargy, and recumbency, and another was euthanized due to severe deterioration. Minimal histologic lesions were noted in the horse that died peracutely, while another showed characteristic lesions of acute cardiomyocyte degeneration and ...
Glade MJ.Twelve adult horses were fed a corn-oats-timothy hay diet containing 2.87% nitrogen (N) for 4 wk and were then killed. Fresh digesta samples were immediately harvested from the stomach, duodenum, jejunum, ileum, cecum, large colon, small colon, rectum and feces. Total N content of the digesta (on a dry matter basis) increased from the stomach (2.74%) to the duodenum (5.58%; P less than .01), decreased in the cecum (3.10%, P less than .01), remained constant through the large intestine and decreased in the feces (2.10%; P less than .01). High-speed centrifugation of wet digesta and low-speed ce...
MacNicol JL, Pearson W. organ culture can provide insight into isolated mucosal responses to particular environmental stimuli. The objective of the present study was to investigate the impact of a prolonged culturing time as well as the addition of acidic gastric fluid into the environment of cultured gastric antral tissue to evaluate how altering the commonly used neutral environment impacted tissue. Furthermore, we aimed to investigate the impact of G's Formula, a dietary supplement for horses, on the secretion of gastrin, interleukin1-beta (IL-1β), and nitric oxide (NO). These biomarkers are of interest due to ...
Julliand S, Buttet M, Hermange T, Hillon P, Julliand V.Nutritional factors are suggested to influence the incidence and severity of glandular gastric disease (GGD) in horses. Objective: To retrospectively assess whether dietary fermentable carbohydrates increase the severity of GGD and to prospectively evaluate whether the partial substitution of concentrates by dehydrated alfalfa would decrease GGD severity scores. Methods: In total, 82 trotters from 4 training centers exercised ≥5 days/week. Methods: Multicenter retrospective observational study, and prospective 2-arm randomized trial. Glandular mucosae were observed by gastroscopy and score...
Munsterman AS, Hanson RR.To develop an indirect method for measurement of intraabdominal pressures in the standing horse using measurement of gastric pressures as a less invasive technique, and to compare this method with direct intraabdominal pressures obtained from the peritoneal cavity. Methods: Prospective, experimental study. Methods: University-based equine research facility. Methods: Ten healthy adult horses, 7 geldings and 3 mares. Methods: Gastric pressures were measured using a nasogastric tube with a U-tube manometry technique, while intraperitoneal pressures were measured with a peritoneal cannula. Measure...
Vondran S, Venner M, Vervuert I.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 a...
Slocombe JO, McCraw BM, Pennock PW, Baird JD.Twelve pony foals (reared worm-free) were inoculated with Strongylus vulgaris. Approximately 8 weeks later, 4 of the foals were given fenbendazole (10% suspension) at a dosage rate of 10 mg/kg of body weight daily for 5 days and 4 foals were given the suspension at a dosage rate of 50 mg/kg daily for 3 days; the remaining foals were given a placebo. All treatments were administered by stomach tube. Fenbendazole was 99.6 and 97.9% effective in the 2 treatment groups, respectively, in eliminating later 4th-stage S vulgaris larvae located near the origin of major intestinal arteries. On microscop...
