Gastrointestinal diseases in horses encompass a range of disorders affecting the digestive tract, from the mouth to the intestines. These conditions can include colic, gastric ulcers, enteritis, and colitis, among others. The gastrointestinal system in horses is complex and sensitive, making it susceptible to various disruptions. Factors such as diet, management practices, and environmental stressors can influence the onset and progression of these diseases. Understanding the pathophysiology, diagnosis, and treatment options for gastrointestinal diseases is essential for maintaining equine health and welfare. This page aggregates peer-reviewed research studies and scholarly articles that explore the causes, clinical presentations, and management strategies for gastrointestinal diseases in horses.
Phillips TJ, Walmsley JP.Of 149 horses that underwent 151 exploratory laparotomies for gastrointestinal disorders from September 1987 to May 1991, 107 (72%) were discharged from the hospital: 100 (66%) survived for > 7 months, 94 of which returned to their intended use. Survival rate (64/80) for horses with caecum/large colon obstruction was significantly (P = 0.003) higher than for horses with small intestinal obstruction (33/64). Prolonged surgery was associated with significantly (P < 0.001) lower survival rates than short surgical time. In the large intestine, survival rate (15/29) for strangulated obstructions wa...
Scholes SF, Vaillant C, Peacock P, Edwards GB, Kelly DF.The degeneration of enteric neurones has been recorded in grass sickness, but the distribution of the lesions in the gut and their possible relationship with the severity of the clinical signs has not been established. Samples obtained from 11 anatomically defined sites along the gastrointestinal tract of eight control horses without gastrointestinal disease, five horses with acute grass sickness and three horses with chronic grass sickness were examined histologically. The organisation of the enteric ganglia was similar to that in other large mammalian species. Minor exceptions included the p...
Hanson PD, Bartz TA, Stone WC, Darien BJ, Markel MD.A modification of the Roux-en-Y anastomosis procedure was used to bypass a pyloroduodenal mass in a 12-year-old Arabian stallion. Clinical signs had consisted of a 4-week progression of ventral and hind limb edema, hypoproteinemia, fecal occult blood, intermittent abdominal pain, weight loss, and gastric reflux. On exploratory celiotomy, an obstructive mass was found in the pylorus and proximal portion of the duodenum. Gastrojejunostomy and duodenojejunostomy were performed by use of stapled side-to-side anastomosis techniques. Inaccessibility of the obstructed pyloric region prevented resecti...
Hovda LR, Rose ML.A herd of pregnant horses exposed to hoary alyssum through ingested hay developed acute and severe gastrointestinal toxicity accompanied by intravascular hemolysis. Postmortem lesions were consistent with these signs. Three horses had late-term abortions.
Gift LJ, Gaughan EM, DeBowes RM, Pintchuk PA, Nickels FA, Foreman JH.Medical records of 11 adult horses with jejunal intussusception examined at 5 veterinary teaching hospitals between 1981 and 1991 were reviewed. Nine of 11 horses had signs of acute abdominal discomfort for < 24 hours, whereas 2 horses had a history of chronic signs. Five of 11 horses had an intraluminal or intramural mass associated with the jejunal intussusception. Two horses died or were euthanatized prior to surgery. Partial jejunal resection and jejunojejunal anastomosis were performed in 9 horses. One horse died during surgery and 2 were euthanatized prior to hospital discharge because o...
Engelbert TA, Tate LP, Bowman KF, Bristol DG.The medical records of 19 horses referred for colic and subsequently found (18 confirmed, 1 suspected) to have small intestinal incarceration through the epiploic foramen were reviewed. These horses were of various ages and breeds; they had clinical signs of colic for an average duration of 13.5 hours before examination. Seventeen horses had nasogastric reflux, and 15 had palpable small intestinal distention. Three horses were killed during surgery because of severe intestinal damage. Of the remaining 16 horses, 13 required intestinal resection and anastomosis. The length of incarcerated small...
Dart AJ, Snyder JR, Spier SJ, Sullivan KE.Packed cell volume, total plasma protein, serum sodium, potassium, and ionized Ca2+ concentrations, and blood pH were determined at the time of admission and following surgery in 147 horses with acute abdominal crisis. Horses were allotted to 3 categories on the basis of the surgical lesion: (1) nonstrangulating obstruction of the ascending or descending colon (category A, n = 76), (2) strangulating and nonstrangulating infarction of the cecum or ascending colon (category B, n = 37), and (3) strangulating and nonstrangulating infarction of the small intestine (category C, n = 25). Horses with ...
Reimer JM, Reef VB, Sweeney RW.Ventricular premature depolarizations (VPD) were identified in 21 horses in which unexplained tachycardia or an arrhythmia was detected on auscultation. Horses were categorized into 3 groups on the basis of ECG findings. Seven horses had uniform isolated VPD (group 1); 7 horses had repetitive uniform VPD at a rate or = 100 VPD/min (group 3). Concurrent systemic disease was identified in 12 horses, 7 of which had gastrointestinal tract disorders. Serum cardiac isoenzyme activities were high in 6 (2 from each group) of 13 horses in which they were measured. Serum electrolyte concentrations were...
Duckworth DH, Madison JB, Calderwood-Mays M, Souba WW.Glutamine has been shown to be an important metabolic substrate of enterocytes in many animals, including cats, dogs, hamsters, human beings, monkeys, rabbits, rats, and sheep. To determine whether glutamine is important in the metabolism of cells of the equine gastrointestinal tract, we examined transintestinal differences in glutamine concentrations in the arterial and venous circulation, and measured activity of the major glutamine catabolizing enzyme, glutaminase. Arteriovenous differences provide an index of the amount of a given substrate removed by the tissue across which the measuremen...
Laverty S, Pascoe JR, Williams JW, Funk KA.A 10-year-old Appaloosa stallion was referred for evaluation of colic. At admission, the heart rate, capillary refill time, respiratory rate, and rectal temperature were high. Fifteen liters of reflux was obtained by nasogastric intubation. Palpation of an abdominal mass per rectum elicited signs of pain. At exploratory laparotomy, a mass was palpated in the ascending portion of the duodenum. The small intestine ruptured at the site of obstruction during manipulation. The horse was euthanatized. A large cholelith was the cause of the duodenal obstruction. At necropsy, multiple choleliths of va...
Schusser GF, Obermayer-Pietsch B.The plasma gastrin levels in fasted horses (21.1 +/- 15.6 pg/ml), in horses with spasmodic colic (7.3 +/- 5.4 pg/ml) and in horses with impaction of the left ventral large colon and/or pelvic flexure (11.4 +/- 3.1 pg/ml) were not significantly different. The plasma gastrin concentrations of horses with strangulation obstruction of the small intestine, large colon displacement or adynamic ileus, and which had no gastric reflux, were 12.9 +/- 8.7 pg/ml and did not differ from fasted gastrin levels. Horses which had 5-10 litres of stomach content reflux had a higher mean gastrin level (32.2 +/- 2...
Ragle CA, Snyder JR, Meagher DM, Honnas CM.A study of 15 American miniature horses (AMH) that underwent surgical treatment for colic was performed. Information obtained from the medical records included signalment, clinical signs, type and location of gastrointestinal lesion, and postoperative complications. All 15 AMH had intraluminal obstructions, attributable to feed impactions (11 horses), enteroliths (2), and sand (2). The most common location of obstruction was the small colon, which was involved in 9 of the 15 cases. All 15 AMH survived and were discharged from the hospital. Six of the 15 AMH underwent subsequent surgical treatm...
Cohen ND, Loy JK, Lay JC, Craig TM, McMullan WC.A 3-year-old Quarter Horse gelding admitted for evaluation of weight loss, signs of depression, and dermatitis of the coronary bands was found to have eosinophilic gastroenteritis. Intralesional nematodes identified as Strongylus edentatus were seen in multiple microscopic sections of the small colon, suggesting a parasitic cause of the disease.
Dill SG.Acupuncture is best known for its application to various musculoskeletal pain-producing diseases. Acupuncture is, however, used for a large variety of internal medical diseases in humans and other animals. This chapter reviews some of the published literature on the use of acupuncture in gastrointestinal (GI) diseases, describes acupuncture points useful for a variety of GI diseases, briefly reviews how traditional Chinese medicine (TCM) treats GI disease, and gives some case examples of how acupuncture can be used in GI diseases.
Brown CM.A D-xylose absorption test was performed on 40 horses with chronic weight loss which could not be explained on history, physical findings, dietary evaluation, or initial laboratory data, i.e. unexplained weight loss. Six of the horses had D-xylose malabsorption and at post-mortem examination small intestinal lesions which accounted for the malabsorption were found in five. Five of the horses with normal absorption were examined post mortem and no lesions in any organs were found to account for the weight loss. The other 29 cases were still unexplained, and lost to follow-up.
Dieckmann M, Deegen E.Twelve horses with clinical symptoms of a gastric disorder were studied by gastroscopy. Symptoms of gastric disorders were periprandial colic, bruxism, ructus and reflux. Preliminary to gastroscopy the horses were fasted for 24 h. Access to water was not restricted. The gastroscopy could be conducted easily using a fiberscope 2.5 m in length and 11 mm in outer diameter. While ulcers were present in the squamous fundus of all horses only one horse showed ulceration of the glandular fundus. Solitary ulcers near the margo plicatus were found in horses with mild clinical symptoms. In contrast, dif...
Madison JB, Dreyfuss DJ, Charlton C.A 4-year-old Thoroughbred gelding with a history of chronic colic was referred for evaluation of signs of abdominal pain. Exploratory laparotomy revealed a diverticulum of the distal portion of the ileum located between the layers of the mesentery. The diverticulum was similar in location and appearance to acquired ileal diverticula described in human beings. Complete bypass of the diverticulum by ileocecostomy resulted in apparent resolution of the chronic colic in this horse.
Welles EG, Prasse KW, Moore JN.Protein C content and plasminogen activity were measured in plasma from 100 horses with signs of colic. Data were analyzed by grouping horses 4 ways. Each horse was allotted to 1 of 2 outcome groups (survivors and nonsurvivors), 1 of 3 broad-category diagnosis groups (inflammatory disorders, strangulating obstructions, and all other gastrointestinal disorders), and 1 of 2 clinical management groups (medical and surgical). In a fourth grouping, all horses (although numbers of horses included in each subgroup were small) were assigned either to specific diagnostic groups that had high expectatio...
Weldon AD, Rowland PH, Rebhun WC.A 12-year-old Morgan gelding was examined for colic of 3 days duration. Signs of depression, colic, diarrhea, and endotoxemia persisted despite aggressive medical therapy and surgical exploration. Culture results from gastric fluid and feces yielded many colonies of Clostridium perfringens. This organism also was recovered from peritoneal fluid 10 days after admission; consequently, the horse was euthanized. At necropsy, a localized gas-filled, necrotic stomach wall was found; many mucosal and submucosal gas blebs were visible. Culture of this tissue yielded Clostridium perfringens. Emphysemat...
Sivula NJ, Trent AM, Kobluk CN.Nonsurgical correction of a renosplenic entrapment of the large colon was attempted in a mare, using a rolling technique. After correction, the mare had initial improvement in clinical signs, but later developed signs of abdominal discomfort. A ventral midline celiotomy was performed, and a pelvic flexure impaction and large intestinal volvulus were found and corrected.
Bertone AL, Cockerell GL, Lee RE, Stashak TS.Light microscopy, morphometry, and scanning electron microscopy were used to examine the mucosal morphologic features of 7 intestinal specimens (3 from the small intestine; 4 from the large intestine) from each of 8 horses 1 year after sham operation (group 1; n = 3) or extensive large-colon resection (group 2; n = 5). Qualitative light microscopic examination did not reveal differences between groups, but morphometry revealed significantly (P less than 0.05) greater intercrypt area and distance in horses with colon resection and this was most pronounced in the cecum and remaining right ventra...
Gerhards H, Klein HJ, Offeney F.A diagnostic approach based on clinical and radiographic examinations for evaluation of young foals and small ponies with acute abdominal discomfort is presented. Standing right to left lateral abdominal radiographs were taken of 54 foals and 6 ponies using a previously described technique. Interpretation of the radiographs was in conjunction with all clinical and laboratory findings and patient management. Using this approach, the site and cause of acute abdominal discomfort could be diagnosed accurately in 55 of 60 (91%) patients as confirmed by clinical, surgical or necropsy findings. Typic...
Kanoe M, Inoue S, Abe T, Anzai T, Kamada M, Imagawa H, Kanemaru T.Clostridium perfingens was isolated from four of 29 healthy foals and from all twelve foals with gastrointestinal diseases. The range of viable counts of C. perfringens in the faeces was 10(1)-10(5)/g and in the intestinal specimens 10(1)-10(7)/g. Of 41 isolates of C. perfringens, 37 were considered to be type A. Enterotoxin of the organism was demonstrated in the intestinal contents of five of eight foals with enteric diseases. These findings suggested that C. perfringens is a likely pathogen of foal intestinal diseases.
Burns GA, Karcher LF, Cummings JF.A 4-year-old Standardbred mare was referred to the New York State College of Veterinary Medicine for colic evaluation. Physical examination revealed a small colon impaction which initially responded to conservative medical management. Her signs soon recurred, however, and an exploratory celiotomy was recommended. At surgery the small colon impaction was confirmed. The impaction was evacuated and a surgical biopsy was submitted for histopathologic evaluation. Microscopic examination of H&E and Trichrome sections revealed a massive mononuclear cell infiltration of the myenteric plexus. In additi...
Parker JE, Fubini SL, Todhunter RJ.Fifty-three of 648 horses (8.2%) treated surgically for acute gastrointestinal obstruction were subjected to repeat celiotomy. Forty horses (75%) recovered from anesthesia after repeat celiotomy, and 26 horses (49%) were discharged from the clinic. Excluding two horses lost to follow-up, 10 of 51 horses (20%) survived long term. Horses subjected to repeat celiotomy had a significantly lower long-term survival rate than horses subjected to a single celiotomy. Twenty-eight horses had mechanical obstructions, and 22 had functional obstructions at the second surgery. Significantly more horses with...
Wolfman EF.Operations for intestinal ischemia are frequently done by veterinarians. In equine surgery those conditions commonly producing ischemia are intussusception, volvulus, bowel obstructions, and incarcerated hernias. In an attempt to predict intraoperative bowel viability after the restoration of circulation, a variety of adjuvant methods have been investigated. There is little question that of the techniques currently available, sodium fluorescein injected intravenously approaches the ideal in predicting nonviability in humans and in most animal models. Furthermore, it is safe, takes little opera...
Ross MW.Cecal impaction and cecal perforation, the two most common equine cecal diseases, are thought to develop after slowing or interruption of a single progressive motility pattern, which begins in a pacemaker area near the apex, occurs once every 3 minutes, and propels ingesta from the cecum to the right ventral colon. Rectal examination in horses with cecal impaction is the most useful technique to grade the severity of the condition. Medical treatment is undertaken if the impaction is judged to be mild to moderate. Surgical correction of cecal impaction in severe cases requires a ventral midline...
Menzies-Gow NJ, Weller R, Bowen IM, Corley KT, Livesey L, Weaver M, Marr CM.The diagnostic and prognostic value of nuclear scintigraphy with technetium-99m-labelled hexamethyl-propyleneamine oxime-labelled leucocytes was assessed in 17 horses with weight loss due to gastrointestinal malabsorption by comparing the results with the results obtained from 13 normal control horses. Intestinal uptake of activity was detected in 12 of the 17 cases but none of the control horses. The technique was therefore specific for intestinal pathology, but failed to detect some horses that might have had intestinal pathology. No indications of the horses' specific pathology were obtaine...
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...
Woods PR, Helman RG, Schmitz DG.A 5-year-old Quarter Horse mare was examined because of weight loss of 2 months' duration. The horse was anemic and in poor body condition, and had several areas of cutaneous ulceration, including areas on the muzzle and distal portion of the limbs. Histologic examination of a rectal mucosa biopsy specimen revealed a lymphoplasmacytic infiltrate in the lamina propria mucosa. Results of a glucose absorption test were suggestive of malabsorption. Histologic examination of a biopsy specimen from the cutaneous lesions revealed pronounced arteritis, and weak, patchy immunofluorescent staining for i...
Ceccarelli P, Pedini V, Gargiulo AM.The presence and distribution of serotonin-containing cells in the gastroenteric tract of horses have been investigated. The enterochromaffin (EC) cells have been identified using immunostaining procedures at both light and electron microscopic level. The EC cells were very numerous in the pyloric gland region, were only few in the duodenum but were absolutely lacking from the more distal portions of the intestine.
Ross MW, Bernard WV, Orsini PG, Ford TS.A 3-year-old Standardbred stallion was admitted for treatment of acute enterocolitis. The horse improved in response to empiric treatment, but subsequently developed ventral edema, scrotal abscessation, and severe laminitis. Improvement again was seen, but on day 29 of hospitalization, the horse developed rapid heart rate and signs of abdominal pain. Exploratory celiotomy revealed complete obstruction of the descending portion of the duodenum, 20 cm caudal to the duodenal sigmoidal flexure. Three-tier duodenojejunostomy and jejunojejunostomy were performed to bypass the duodenal obstruction.
Dietz HH, Nielsen K.Four horses with a history of chronic diarrhoea and weight loss were studied. Three of them revealed malabsorption, as indicated by decreased absorption of D(+)-xylose. Three patients had distinct hypoalbuminaemia, and 131I-albumin turnover rates of these three horses were increased, compared to two normal control horses. However, the increases were not very marked, probably because actual signs of enteric disease were few in the patients, all of which were studied during convalescence. It is suggested that the observed hypoalbuminaemia is due to a gastrointestinal protein loss during the chro...
Cavalleri JM, Bienert-Zeit A, Feige K.The article summarizes the relevant clinical pathological assessment of horses with acute colic. A minimal laboratory evaluation should include the patient's haematocrit (or packed cell volume), total protein, and lactate concentration in the blood. Haematocrit and total protein provide an indication of the severity of dehydration (haematocrit < 0.45 l/l is evidence of no to mild dehydration whereas > 0.5 l/l points to a severe dehydration). The degree of dehydration is often associated with the severity of the colic. Additionally, the blood lactate concentration rises with increasing intesti...
Bonfig H.The purpose of this detailed description of the clinical examination of the colic patient is to arrive at a specific diagnosis. However, this is hardly ever possible, but the practitioner should be in the position to establish the suspicion of an intestinal obstruction or to rule out its presence during the course of the development. Single clinical findings should not be interpreted in isolation but in relation to one another, so that a false diagnosis is not made. All clinical findings should be documented, so that when repeated examinations are carried out, findings can be compared with one...
Grieve RB, Moore BG, Bradley RE.A critical test was performed to evaluate the anthelmintic properties of an injectable butamisole formulation and to compare the efficiency with that of a commercially available piperazine-thiabendazole anthelmintic. The test was done in 10 horses and 15 ponies with naturally acquired parasitic infections. Butamisole was administered at the dose level of 2.5 or 3.75 mg/kg of body weight by either subcutaneous or deep intramuscular injection. Given at the dose level of 2.5 mg/kg, butamisole was highly effective (99%) against Strongylus vulgaris and moderately effective (49%) against Parascaris ...
Lanz S, Howard J, Gerber V, Peters LM.Little is known about the clinical usefulness in horses of the 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) lipase assay, a biomarker used in other species for the detection of pancreatitis. The main objectives of this study were to evaluate the prevalence of increased DGGR-lipase activity in horses with signs of colic and investigate its association with, and validity to diagnose, underlying gastrointestinal diseases, treatment method (medical or surgical), and outcome (survival or non-survival). Clinical data from 192 horses presented for colic to a teaching h...