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.
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.
Malan FS, Reinecke RK, Scialdo RC.The tongue, pharynx, oesophagus and gums are examined for larvae of gasterophilus spp., and the nose and sinuses for oestrid larvae. The gastro-intestinal tract is divided into separate specimens-stomach, small intestine, caecum, ventral colon, dorsal colon, descending colon and rectum- and each is examined separately. Aliquots of ingesta of 1/4 by mass of the stomach and 1/10 by mass of the small intestine, caecum, ventral colon and dorsal colon are collected for microscopic examination. Each part of the wall of the caecum, ventral and dorsal colon is washed and specimens are collected for su...
Mackay RJ, Iverson WO, Merritt AM.A 4-year-old stallion was examined because of a 2-month history of inappetance and weight loss. Diarrhoea had also developed a month before presentation. Abnormal clinical findings were emaciation, diarrhoea, ventral oedema, palpable mesenteric lymph node enlargement and a large mass in the left cranial portion of the abdomen. Significant laboratory findings were anaemia (packed cell volume 0.21 litres/litre), hypoalbuminaemia (16 g/litre) and xylose malabsorption. The horse was euthanased and at necropsy a 10.5 kg pendunculated mass composed of granulation tissue was found within and attached...
Barth AD, Barber SM, McKenzie NT.A two month old Thoroughbred filly was presented with signs of depression, grinding of the teeth, frothing of the mouth and abdominal pain. These signs had persisted for two weeks despite treatment with mineral oil, dioctyl sodium sulfosuccinate, meperidine and antibiotics. A variety of diagnostic tests were done, the only abnormal finding was a stress leukon. On exploratory laparotomy the stomach was dilated with fluid and gas and the pyloric canal was constricted. Pyloroplasty resulted in correction of the condition. The etiological possibilities are discussed. This is believed to be the fir...
Ray AC, Post LO, Hurst JM, Edwards WC, Reagor JC.An analytical method for cantharidin, using high performance liquid chromatography, was applied to field specimens from horses and sheep with blister beetle (Epicauta lemniscata) poisoning. Stomach content and urine proved to be valuable aids in diagnosis. One incident of cantharidin toxicosis in ruminants (sheep) was confirmed.
Wolter R, Nouwakpo F, Durix A.A complete pelleted diet (table 1) containing 11 p. 100 of crude protein and 17 p. 100 of cellulose (ADF-lignine according to the method of Van Soest) was distributed to ponies and rabbits. Total digestibilities, partial cumulative digestibilities in different compartments of the digestive tract (stomach, small intestine, caecum, proximal and distal colon) and changes in biochemical composition, measured by pH, VFA, lactic acid and ammonia concentrations, were compared. Total digestibilities (table 2). There was no significant difference in dry matter between the two species. Crude protein dig...
Shefstad DK.The lesions caused by larvae of Gasterophilus intestinalis in the cardiac region of the equine stomach were funnel-shaped ulcers surrounded by a rim of hyperplastic epithelial cells. Bacteria were commonly seen on the rim of epithelial cells, at the base of some ulcers, and within the cavities produced by the hooks of the larvae. Cellular debris and mucus were within the ulcer.
Reddy VK, Kammula RG, Randolph A, Graham TC, Srungaram SK.Studies on regional blood flow to the stomach and small intestine were performed in 9 anesthetized ponies. Carbonized microspheres (15 +/- 5 micron in diameter) labeled with 85Sr were injected into the left atrium to determine blood flow distribution. In 4 ponies, the regional flows to mucosal-submucosal layers of the stomach and the small intestine were also measured. The nonglandular region of the stomach received the least blood per 100 g of tissue, and the duodenum received the greatest. The regional blood flow to the duodenum was significantly higher than that to the glandular stomach reg...
Lyons ET, Drudge JH, Tolliver SC.Thirteen critical tests were conducted in horses naturally infected with helminths and bots. Single doses of thiabendazole (44 mg/kg of body weight) and trichlorfon (40 mg/kg of body weight) powder formulations were administered as suspensions sequentially given via stomach tube to evaluate the efficacy of the combination against the large parasites of horses. Parasite removal efficacies were 100% against 2nd instar Gasterophilus intestinalis and 2nd and 3rd instar Gasterophilus nasalis and 82 to 100% against 3rd instar G intestinals. There were complete removals of mature and immature Parasca...
Masuda H, Shichijo S, Takeuchi M.1. Glycopeptides in the stomachs of eleven mammalian species, including human, rabbit, horse, cow, pig, goat, sheep, dog, cat, guinea pig and rat were assayed by determining the carbohydrate content of materials which remained after proteolysis. 2. The glycopeptide content was higher in the mucosa than in the muscular layer including serosa, especially in the porcine stomach and the fourth stomachs of the ruminants than in the stomachs of any other animals. 3. The glycopeptide, which was stained with both alcian blue and PAS, was absent or sparingly present in the mucosae of the human, rabbit,...
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.
Frerichs WM, Holbrook AA, Allen PC.Twenty Shetland ponies, 6 to 7 months old, were naturally infected with gastrointestinal nematodes and stomach bots. The ponies were allotted to 2 groups of 10 and were maintained on separate similar pastures that were free of infective larvae at the beginning of the study. The ponies in 1 group were treated monthly for 17 months with a therapeutic dose of a thiabendazole and piperazine mixture; those in the other group were not treated. During the 3rd and 5th months of the experiment, the ponies in the treated group were also given therapeutic doses of dichlorvos to remove bots. Various physi...
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...
Baker SJ, Gerring EL.Gastric pH was monitored in neonatal foals from birth to 3 months of age. Background pH decreased, especially during the first week of life. Milk had complex effects that depended on pH prior to sucking, confounded by the age of the foal: nearly neutral background pH tended to be acidified after milk intake; moderately acid background pH tended to be neutralized; low background pH was only slightly increased by milk. Absolute magnitude of the effects of milk decreased with age. Existence of a proulcerative intragastric environment in preweaning foals is postulated, but this must be considered ...
Beroza GA.A device and technique for intra-operative gastro-intestinal lavage was developed to remove ingesta from the stomach, large intestine and caecum of horses. The Gastro-Intestinal Lavage System (GILS) is composed of a nozzle connected to both water under pressure and suction. Water jets across an intake portal in the nozzle, breaks up food and debris within the nozzle and is evacuated under negative pressure into the aspirating tube which is connected to a collection drum. The GILS nozzle was introduced at the pelvic flexure through a sterile enterotomy cuff and plastic sleeve. Water was first a...
Rastegaev IuM.10 foals were artificially infected for the first time with eggs of Gastrophilus intestinalis, G. veterinus, G. haemorrhoidalis, G. inermis, G. nigricornis. 63 to 67% of the 1st stage larvae die in the first period of life after emergence from the egg, at the moment of invasion into the skin and at the beginning of the migration. In 40 to 45 years after the infection most larvae (73 to 82%), depending on their specific belonging, were found in the stomach, duodenum and rectum.
Olsen SN.Five horses with squamous cell carcinoma of the stomach are described. The clinical findings included anorexia, weight loss, abdominal distension, abnormal chewing and swallowing behaviour and abdominal masses palpable per rectum in four cases. Haematological studies revealed a normocytic anaemia in three horses, and neutrophilia and hypoalbuminaemia in two. Analysis of peritoneal fluid revealed abnormal effusions in all five horses and neoplastic cells were identified in three of them. The tumours originated in the cardia and metastases were present in all the horses. Three of them had many s...
Khittoo G, Vermette L, Nappert G, Lariviere N.In mammalian species studied previously, pepsinogen consisted of biochemically different groups of isozymogens. By use of gel filtration chromatography and electrophoresis, we isolated a predominant pepsinogen from the gastric mucosa of a horse. Peptide mapping with V8 protease revealed differences with its porcine homologue. However, porcine and equine pepsinogens, when activated to pepsin, had a similar pattern of activity when hemoglobin was used as substrate. Those results suggest that differences must exist in the primary structure of the pepsinogens of the 2 species.
Young DW, Smyth GB.The predominant form of gastrin in the antral mucosa of the stomach of virtually all species previously examined is the 17 amino acid peptide little gastrin (G17). This report describes the occurrence in equine antral mucosa of an immunoreactive form of gastrin with elution properties on Sephadex G-50 superfine similar to human unsulfated big gastrin (G34-I). This putative equine big gastrin was a major component of the gastrin immunoreactivity present. A second peak of activity in equine antral mucosa eluted in an identical manner to human little gastrin (hG17-I). Inhibition curves of equine ...
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...
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...
Bauck AG, Nelson E, McLain A, Cock G, Sanchez LC, Freeman DE.To describe a modified celiotomy to improve access to cranial abdominal structures in horses. Methods: Four horses. Methods: Short case series. Methods: Three horses with gastric impactions were treated with gastrotomies. One horse was treated for a diaphragmatic hernia with herniorrhaphy and mesh augmentation. In all horses, the ventral midline celiotomy was modified cranially with a J-incision through the body wall, along the paracostal arch. Results: The only surgical complications were midline incisional infections in all horses. Three of the four horses had good long-term outcomes; the re...
Barrett EJ, Munsterman AS, Hanson RR.To determine the effect of gastric distension on intraabdominal pressures (IAP) measured directly from the intraperitoneal space. Methods: Prospective, experimental study. Methods: A university-based equine research facility. Methods: Ten healthy adult horses, 5 males and 5 females. Methods: Intraabdominal pressures were measured through an intraperitoneal cannula zeroed at a height midway between the height of the tuber ishii and point of the shoulder at 6 time points: at rest, after placement of a nasogastric tube, and after instillation of each 5 L increment up to a total of 20 L of water. ...