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Topic:Gastrointestinal Health
Gastrointestinal health in horses encompasses the study of the structure, function, and disorders of the equine digestive system. The equine gastrointestinal tract is complex, consisting of the stomach, small intestine, cecum, and large intestine, each playing a specific role in digestion and nutrient absorption. Research in this area often focuses on common disorders such as colic, gastric ulcers, and parasitic infections, which can impact a horse's overall health and performance. Investigations examine factors affecting gastrointestinal health, including diet, management practices, and the microbiome. This page compiles peer-reviewed research studies and scholarly articles that explore the physiology, pathology, and management of gastrointestinal health in horses.
Cecal impaction in the horse. During a 3-year period, cecal impaction was diagnosed in 21 horses (mean age, 8 years) at exploratory celiotomy or necropsy. In 7 horses, typhlotomy was used to remove the impaction; 2 horses treated by fluid injection of the impaction did not survive. The 12 other horses had cecal rupture. Surgical correction was not possible in those horses because of inaccessibility of the rupture site. Postmortem examination of the rupture sites did not reveal a cause other than cecal impaction. The duration of clinical signs before rupture ranged from 4 to 96 hours.
Pathology of equine granulomatous enteritis. A morphological study on equine granulomatous enteritis (EGE) in 13 horses is presented. All horses were young (1 to 5 years old) standardbreds. Based on gross pathology, cases were classified into those with diffuse (11 cases) and those with localized (2 cases) small bowel lesions. The granulomatous reaction in the gut was marked by diffuse and patchy infiltrates and distinct granulomas, composed of epithelioid cells, macrophages and lymphoid cells, and was devoid of necrosis. Salient accompanying features of the small bowel included lymphoid hyperplasia, peri-lymphatic and transmural inflamm...
Motility of the distal portion of the jejunum and pelvic flexure in ponies: effects of six drugs. Bipolar stainless steel electrodes were surgically implanted in 4 ponies to record myoelectrical and mechanical activity of the distal portion of the jejunum and pelvic flexure. After determining normal activity, the effects of neostigmine, xylazine, flunixin meglumine, dipyrone, panthenol, and atropine sulfate were determined. Flunixin meglumine, dipyrone, and panthenol had no effect on the motility of the jejunum or pelvic flexure. Xylazine and atropine sulfate decreased motility of the distal portion of the jejunum and pelvic flexure, with atropine sulfate having a greater effect and lastin...
Small intestine incarceration through the epiploic foramen of the horse. Fifteen horses were referred to Purdue University or to the University of Georgia because of colic. Each of these horses had small intestine incarcerated through the epiploic foramen. However, signs of pain, gastric reflux, and small intestine distention were not consistent signs, as would have been expected with small intestine strangulation/obstruction. In 10 of the 15 cases, abdominal fluid analysis provided the decisive information needed for surgical intervention. Surgery was performed in 14 cases. The small intestine was incarcerated through the epiploic foramen in a right-to-left direct...
Phenylbutazone toxicosis in the horse: a clinical study. In a retrospective study of 269 horses that had been treated with phenylbutazone, horses receiving less than or equal to 8.8 mg/kg of body weight/day for less than or equal to 4 days or 2 to 4 mg/kg of body weight/day for up to 50 days remained clinically normal. Anorexia, depression, colic, hypoproteinemia, diarrhea, melena, weight loss, ventral edema, petechial hemorrhages of mucous membranes, oral and gastrointestinal tract erosions and ulcers, renal papillary necrosis, and death were among the complications seen in horses that had received greater than 8.8 mg/kg of body weight/day. In 2 ca...
Immunocytochemical distribution of endocrine cells in the gastrointestinal tract of the horse. Endocrine cells immunoreactive for somatostatin, gastrin, glicentin, glucagon, secretin, cholecystokinin, motilin and neurotensin were identified immunocytochemically in the gastrointestinal mucosa of the horse. Somatostatin-, glicentin- and glucagon-immunoreactive cells were very numerous in the cardiac and fundic regions of the stomach, whereas most gastrin-immunoreactive cells were confined to the pyloric region. Somatostatin-immunoreactive cells also were detected in all portions of the small intestine while gastrin-immunoreactive cells were confined exclusively to the upper portion and gl...
Equine colonic motility: interactions among wall motion, propulsion, and fluid flow. Transmission of intestinal content with respect to wall position and intraluminal pressure was studied using implanted catheters in portions of the haustrated left ventral colon and nonhaustrated pelvic flexure and left dorsal colon in 3 conscious, standing, and feeding ponies. Wall position and content movement was studied in 1 noncatheterized conscious pony that was standing and eating. When coordinated wall movements involving greater than or equal to 30 cm of adjacent colon were seen, point-to-point content movement accompanied intraluminal pressure peaks occurring in the same direction. N...
Three cases of obstruction of the small colon by a foreign body. This report describes fatal obstruction of the small colon of three horses. The obstructions were caused by irregularly shaped enteroliths of which the centres contained a foreign body, namely a guy-rope, a piece of baling twine , and a fishing-line, respectively. The diagnosis was made by post-mortem examination.
Effects of toxic doses of phenylbutazone in ponies. Toxic doses of phenylbutazone (10 mg/kg of body weight) were administered to 10 ponies once daily for 14 days. Clinical signs of toxicosis similar to those seen in other species included CNS depression, anorexia, oral ulcers, and soft feces. Six ponies died in 7 to 20 days; 1 pony was euthanatized during an acute abdominal crisis; and 3 ponies survived the study. At necropsy, the major lesions were oral and gastrointestinal ulcerations and renal changes.
Volatile fatty acids and the role of the large intestine in the control of feed intake in ponies. The roles of volatile fatty acids (VFA) and of the large intestine in the control of feeding in ponies were investigated. Ponies with cecal fistulas were adapted to ad libitum access to pelleted feed. Treatment solutions were given as a bolus 15 min before the animals were allowed free access to feed after a 4-h fast. Each dose of VFA solution was tested in a crossover design with a water control. When the ponies were permitted to eat after the treatments, the latency to eat, first meal size, and duration and first intermeal interval were recorded. Feed intakes were measured at 3 and 18 h afte...
Alternate grazing of horses and sheep as control for gastro-intestinal helminthiasis in horses. Gastro-intestinal helminth infections of a group of three yearling mare Shetland ponies, which were set-stocked on a small pasture from February until September, were compared with those of a similar group of ponies, which grazed a similar pasture from February to July and subsequently was removed to a pasture which had been grazed by sheep from April to July. In addition both groups were treated with cambendazole when the latter group was removed to the sheep pasture. Pasture larval counts and worm counts demonstrated that the group grazed after the sheep acquired considerably smaller burdens...
Warfarin: a review with emphasis on its use in the horse. Warfarin or dicoumarol prevents the production of functional clotting factors II, VII, IX and X. Navicular disease and thrombophlebitis are examples of equine thrombotic diseases in which warfarin has been used therapeutically. The initiation of anticoagulant therapy is relatively simple but attending veterinarians must be aware of the potential risks in order to minimize them. These risks include epistaxis, bleeding into the gastrointestinal tract and at the venipuncture site, and increased susceptibility to hematoma formation following local trauma. Vitamin K, especially vitamin K(1) is a sw...
Experimental studies of drug-induced impaction colic in the horse. Colic was induced in horses and ponies following topical or intravenous (iv) administration of amitraz, a formamidine acaricide. The condition was characterised by rapid cessation of intestinal sounds, stasis, extensive impaction and tympany throughout the large colon. Three animals that were necropsied had a faecalith obstructing the proximal small colon aboral to marked colonic impaction. A reproducible and reversible impaction colic syndrome could be induced by an iv injection of 1 mg amitraz/kg body weight in solvent. There were immediate central nervous system and intestinal signs. Large ...
Gastroesophageal ulceration and candidiasis in foals. Gastroesophageal candidiasis in association with ulceration was diagnosed in 5 foals in which signs of colic had been nonresponsive to medical treatment. The ulceration was found in the stomach of all foals and in the esophagus of 1 foal. Candida colonized hyperkeratotic mucosa surrounding the ulcers, and the associated inflammation resulted in splitting of the mucosal epithelium. Loss of the superficial mucosa may have allowed invasion by bacteria, leading to ulceration.
Fatal acorn poisoning in a horse: pathologic findings and diagnostic considerations. Acorn poisoning was diagnosed in an 11-year-old Quarter Horse with signs of severe colic, tachycardia, hyperpnea, abdominal borborygmus, rectal tenesmus, and hemorrhagic diarrhea. The diagnosis was based on history and predisposing factors, clinical signs, laboratory data, acorn husks in the feces, the urinary gallic acid equivalent concentration, and necropsy findings. The most striking pathologic changes were gastrointestinal and mesenteric edema, ulcerative enterocolitis, and nephrosis.
Effect of spasmolytic analgesic drugs on the motility patterns of the equine small intestine. The effect of acepromazine, Buscopan (Crown Chemicals), pethidine and methadone was evaluated in ponies prepared with Thiry-Vella (T-V) loops. Motility was assessed by electrophysiological means (bipolar electrodes and strain gauge transducers) and by the passage through the T-V loop of a fluid test meal. Results were obtained from 26 experiments in three ponies and compared with six control experiments, in which saline had been administered to the same ponies. Each pony acted as its own control in each experiment and pre and post treatment values for slow wave frequency, spiking activity, del...
Electromechanical activity of the equine small intestine and its correlation with transit of fluid through Thiry-Vella loops. Motility patterns in the equine small intestine were investigated in eight ponies. Muscular activity was assessed by means of extramural strain gauge transducers, bi-polar electrodes and in three of the animals, fitted with Thiry-Vella loops, the transit of fluid. Circular muscle contractions were preceded by spiking superimposed on the slow wave and fluid transit in the loops correlated with both these events.
Effects of large doses of phenylbutazone administration to horses. The effects of large doses of phenylbutazone were evaluated in clinically normal horses. The drug was given to 4 groups of 2 horses each at the rate of 30 mg/kg of body weight, orally, or 30, 15, or 8 mg/kg IV daily for up to 2 weeks. All horses became anorectic and depressed after 2 to 4 phenylbutazone treatments, and the horses given 15 or 30 mg/kg died on or between days 4 and 7 of treatment. A decrease in total blood neutrophil count occurred in all horses, and was associated with toxic left shift in horses given the 2 larger dosage schedules. The horses also had progressive increases in s...
Nonstrangulated colonic displacement in horses. Nonstrangulated colonic displacement was diagnosed by exploratory celiotomy in 32 horses with acute abdominal pain. Clinical signs progressed slowly and included evidence of mild to moderate abdominal pain, good cardiovascular status, reduced intestinal sounds, and normal peritoneal fluid, and resembled those of colonic impaction. In most horses, rectal palpation supported a diagnosis of colonic obstruction but not a diagnosis of colonic impaction.
Gastrointestinal complications associated with the use of atropine in horses. Atropine sulfate was given at 2 dosages (0.044 mg/kg, 0.176 mg/kg) to clinically normal ponies in order to evaluate the drug's effect on the gastrointestinal tract. Intestinal motility, as assessed by ausculation of borborygmus, was stopped 30 minutes after injection, but it gradually returned to normal within 12 hours. Signs of abdominal pain developed in 3 of 10 ponies. In 3 clinical cases of gastrointestinal disorder, prior atropine treatment was confusing to the diagnostician and resulted in delayed surgical treatment in 1 case. It was concluded that atropine should not be used for allevia...
The activity of closantel as an equine antiparasitic agent. Eighteen pony foals were experimentally infected with 500 third stage larvae of Strongylus vulgaris at 2 weeks, and at 2, 4, 6 and 8 months after birth. For the duration of the study, all foals were kept in the same pasture with their mothers to allow natural infection with other parasites by exposure to a contaminated environment. Twelve of the foals were utilized in groups of 3 and treated orally five times at two month intervals starting at one month of age with closantel at doses of 5, 10, 20 or 40 mg kg-1. Ten months after birth the foals were necropsied to determine the parasitic burdens...
Diagnostic value of intestinal alkaline phosphatase in horse serum. Antiserum directed against equine intestinal Alkaline Phosphatase (ALP) was produced in rabbits and used to develop a sensitive and quantitative assay for the detection of intestinal ALP in equine serum. This assay was then used to measure the half-life of intravenously injected intestinal ALP and to determine if the intestinal ALP was present in normal horse sera, sera from horses presented for lesions not involving the gastrointestinal tract and sera from horses presented with lesions involving the gastrointestinal tract. The results suggest that intestinal ALP is not likely to appear in equ...
Effectiveness of ivermectin against later 4th-stage Strongylus vulgaris in ponies. Twelve pony foals were reared worm-free and inoculated with Strongylus vulgaris. Approximately 8 weeks after they were inoculated, 6 foals were given ivermectin IM at a dosage rate of 200 micrograms/kg of body weight and 6 were given a placebo. All foals were necropsied 35 days after treatment. Ivermectin was 98.9% effective in eliminating later 4th-stage S vulgaris larvae located near the origin of major intestinal arteries and in reducing clinical signs and permitting resolution of lesions associated with verminous arteritis. One pony foal reared on pasture and with evidence of arteritis of ...
