The digestive tract in horses is a complex system responsible for the breakdown and absorption of nutrients essential for maintaining equine health. It includes several key components: the mouth, esophagus, stomach, small intestine, cecum, large colon, small colon, and rectum. Each segment of the digestive tract performs specific functions, from the mechanical breakdown of feed to the enzymatic digestion and absorption of nutrients. The horse's digestive system is uniquely adapted to process fibrous plant material, relying heavily on microbial fermentation, particularly in the hindgut. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and function of the equine digestive tract, as well as common disorders and their management.
Garber A, Hastie P, McGuinness D, Malarange P, Murray JA.Abrupt dietary changes, as can be common when managing horses, may lead to compositional changes in gut microbiota, which may result in digestive or metabolic disturbances. The aim of this study was to describe and compare the faecal microbiota of ponies abruptly changed from pasture grazing ad libitum to a restricted hay-only diet and vice versa. The experiment consisted of two, 14-day periods. Faecal samples were collected on day 0 and days 1-3,7,14 after abrupt dietary change from grass to hay and from hay to grass. Microbial populations were characterised by sequencing the V3-V4 region of ...
Garber A, Hastie PM, Farci V, Bulmer L, Alzahal O, Murray JMD.Fibre is essential to maintain healthy gut; however, energy demands of performance horses can be too high to be met by forages alone. Yeast may support the function of cellulolytic bacteria to digest fibre. The aim of this work was to determine the effect of an oral supplement (VistaEQ) containing 4% live yeast on the in vitro and in vivo digestibility of high-starch (HS) and high-fibre diets (HF). Eight ponies were used in a 4 × 4 Latin square design consisting of 4- × 19-day periods and four diets: HF, HF + yeast (HFY), HS and HS + yeast (HSY). In vivo apparent digestibility (AD) was estim...
Halpin MY, Drouillard JS, Fehlberg LK, Douthit TL, Lattimer JM.To assess the impact of protein on fermentation by equine cecal microorganisms, cecal fluid from 4 cecally cannulated horses was used to inoculate fermentation bottles containing buffer, forage, and supplemental protein. In experiment 1, sodium caseinate (SC) provided 0, 0.5%, 1%, 2%, or 4% additional crude protein (CP) to bottles containing alfalfa or native warm-season prairie grass hay. Bottles were equipped with continuous gas pressure monitors and placed into a shaking incubator for 48 hours at 39°C. Cultures with alfalfa had greater (P < .0001) in vitro dry matter disappearance (IVDMD...
Lauková A, Styková E, Kubašová I, Strompfová V, Gancarčíková S, Plachá I, Miltko R, Belzecki G, Valocký I, Pogány Simonová M.The effects of non-authochtonous Enterococcus faecium AL41 = CCM 8558, enterocin M-producing and probiotic strain were tested on the microbiota, phagocytic activity, hydrolytic enzymes, biochemical parameters and dry matter in horses based on its previous benefits demonstrated in other animals. E. faecium CCM 8558 sufficiently colonized the digestive tract of horses. At day 14, its counts reached 2.35 ± 0.70 CFU/g (log 10) on average. The identity of CCM 8558 was confirmed by means of PCR after its re-isolation from horse faeces. The inhibition activity of CCM 8558 was demonstrated a...
Wambacq WA, van Doorn DA, Rovers-Paap PM, Ducatelle R, Vlaminck L, Lourenço M, Hesta M.As colic and intestinal disorders are a major concern in horses, the aim of the present study was to investigate the effect of dietary supplementation of butyrate, known to have a diverse array of beneficial effects on intestinal health. The effect of micro-encapsulated sodium butyrate supplementation on gut histology and immunohistochemistry parameters was studied in 14 healthy warmblood horses destined for slaughter in two separate periods. Horses were fed a low fiber - high starch diet, designed to induce subsequent starch overflow in the large intestine, aiming to create a mild challenge f...
Bachmann M, Glatter M, Bochnia M, Wensch-Dorendorf M, Greef JM, Breves G, Zeyner A.Fructooligosaccharides (FOS) and inulin may modulate hindgut fermentation. It was tested if digesta batch cultures taken from horses adapted to FOS and inulin show different fermentation compared with such taken from nonsupplemented horses. Six horses received 0.15 g FOS and inulin/kg body weight/d via Jerusalem artichoke meal (JAM) upon a hay-based diet; six horses received corncob meal without grains (CMG) as placebo. The horses were euthanized after 20 days. Digesta samples were taken from stomach, cecum, ventral colon ascendens (VCA), and colon transversum (CT). Digesta batch cultures we...
Powell CD, Dhanoa MS, Garber A, Murray JMD, López S, Ellis JL, France J.Two models are proposed to describe atypical biphasic gas production profiles obtained from in vitro digestibility studies. The models are extensions of the standard Mitscherlich equation, comprising either two Mitscherlich terms or one Mitscherlich and one linear term. Two models that describe typical monophasic gas production curves, the standard Mitscherlich and the France model [a generalised Mitscherlich (root-) equation], were assessed for comparison. Models were fitted to 25 gas production profiles resulting from incubating feedstuffs with faecal from equines. Seventeen profiles displa...
Saastamoinen M, Särkijärvi S.Linseed (Linum usitatissimum) and its by-products are common supplements used in equine diets and are claimed to have beneficial health effects. In this study, the effect of linseed groat-based fibrous feed supplements on diet digestibility was studied. Also, possible detrimental health effects due to continuous feeding of supplemental feeds containing linseed were examined by evaluating blood parameters. The experimental design was arranged as two balanced 3 × 3 Latin Squares. The horses were individually fed at the maintenance energy level, the forage-to-concentrate ratio being 70:30, with ...
Hansen TL, Bobel JM, Rankins EM, Sanchez LC, Warren LK.Digesta retention time within specific segments of the equine gastrointestinal tract (GIT) may be more relevant to scientific inquiries than total tract mean retention time (TTMRT); however, measuring retention time in individual segments requires access to the digestive tract. The objective of this study was to compare prececal, cecal, and colonic mean retention time (MRT) with model-derived compartment MRT. A cecally fistulated gelding was fed indigestible particulate and liquid markers to determine TTMRT and dosed with different pairs of particulate and liquid markers into the cecum (hindgu...
Moore-Colyer M, Longland A, Harris P, Zeef L, Crosthwaite S.Soaking hay fodder to reduce dust and soluble carbohydrate (WSC) contents prior to feeding is common practice among horse owners. Soaking can increase bacteria load in hay but no information exists on how this process alters the bacteria profile, which could pose a health risk or digestive challenge, to horses by introducing foreign bacteria into the gastrointestinal tract and so altering the normal profile. The current objectives were to map the bacterial profile of 3 different hays and determine how soaking alters this with the aim of improving best practice when feeding stabled horses. A Pe...
Orr KE, Baker WT, Lynch TM, Hughes FE, Clark CK, Slone DE, Fogle CA, Gonzalez LM.To determine the prognostic value of (1) colonic venous lactate or peripheral lactate values obtained before and after manual correction of a large colon volvulus and (2) a combination of variables including pelvic flexure biopsy. Methods: Prospective clinical study. Methods: Forty adult horses in which large colon volvulus was diagnosed intraoperatively. Methods: Colonic venous, peripheral venous, and arterial blood samples were collected to measure lactate values before and after manual correction. Mucosal biopsy samples were obtained in cases that underwent enterotomy or colonic resection a...
Fehlberg LK, Lattimer JM, Vahl CI, Drouillard JS, Douthit TL.Calcium salts of fatty acids (CSFAs) frequently are fed to ruminants, but their fate in the equine digestive system is unknown. The purpose of this study was to compare Enertia s/f, a proprietary CSFAs, and soybean (SB) oil with respect to impact on apparent total tract nutrient digestion and cecal fermentation parameters in horses. Eight cecally cannulated Quarter Horses were used in a crossover design in which horses consumed a diet for 32 d consisting of 1.5% body weight (BW) (as-fed) smooth bromegrass hay and 0.5% BW (as-fed) pelleted concentrate containing 4.9% CSFAs or 4.1% SB oil. Fecal...
Suagee-Bedore JK, Linden DR, Bennett-Wimbush K, Splan RK.When fed to horses, high-starch diets elevate plasma concentrations of interleukin-1β (IL-1β) as soon as 1 hour posteating. This increase in IL-β is possibly because of changes in intestinal pH that result from rapid bacterial fermentation of starches and sugars in the digestive tract. The purpose of this research was to investigate the effect of feeding 0.9 kg of grass hay 30 minutes before feeding a concentrate meal on the postprandial rise in IL-1β, compared with control horses receiving the same concentrate without hay first. Six mature geldings were used in a switchback design. Hor...
Hansen TL, Chizek EL, Zugay OK, Miller JM, Bobel JM, Chouinard JW, Adkin AM, Skurupey LA, Warren LK.Bermudagrass (Cynodon dactylon) and other warm-season grasses are known for their increased fiber concentrations and reduced digestibility relative to cool-season grasses and legumes. This study investigated the digestive characteristics and passage kinetics of three maturities of Coastal bermudagrass hay. A 5 × 5 Latin square design experiment was used to compare the digestion of five hays: alfalfa (Medicago sativa, ALF), orchardgrass (Dactylis glomerata, ORCH), and Coastal bermudagrass harvested at 4 (CB 4), 6 (CB 6), and 8 weeks of regrowth (CB 8). Horses were fed cobalt-ethylenediaminetet...
Liu G, Bou G, Su S, Xing J, Qu H, Zhang X, Wang X, Zhao Y, Dugarjaviin M.Gastrointestinal microbiota has significant impact on the nutrition and health of monogastric herbivores animals including donkey. However, so far the microbiota in different gastrointestinal compartments of healthy donkey has not been described. Therefore, we investigated the abundance and function of microbiota at different sites of the gastrointestinal tract (GIT) (foregut: stomach, duodenum, jejunum and ileum; hindgut: cecum, ventral colon, dorsal colon, and rectum) of healthy adult donkeys mainly based on 16S rRNA gene sequencing and phylogenetic investigation of communities by reconstruc...
Fowler AL, Pyles MB, Hayes SH, Crum AD, Lawrence LM.Across the equine literature, estimates of true P digestibility range from -23% to 79%. This large range cannot be explained by differences in P intake or phytate-P intake alone. However, differences in endogenous P secretion into the GI tract may explain the variation. In horses, excess absorbed P is not excreted in the urine but is re-secreted into the GI tract, increasing faecal P and leading to estimates of low P digestibility. Thus, accurate estimates of P digestibility can only be obtained if absorbed P is retained in the horse. The objective of this study was to examine P digestibility ...
Reed L, MacNicol JL, Charchoglyan A, Brewer D, Murrant C, Pearson W.The objective of this study was to evaluate the effect of a botanical-based equine nutraceutical on contractility of gastric smooth muscle in vitro. Gastric ulcers are prevalent in performance horses and negatively impact horse welfare. Gastric hypermotility has been positively associated with the development of gastric ulceration in nonequine species, and reduction of hypermotility may be protective against their development. Stomachs from 12 pigs processed for food at a provincially inspected abattoir were collected within 1 hour of slaughter. Explants of nonglandular gastric tissue were p...
Grimm P, Combes S, Pascal G, Cauquil L, Julliand V.Starchy diets can induce hindgut dysbiosis in horses. The present study evaluated the impact of a yeast (Saccharomyces cerevisiae) and microalgae (Aurantiochytrium limacinum) supplementation on caecal, colonic and faecal microbial ecosystem and on blood inflammatory parameters of horses fed high-fibre or high-starch diets. Six fistulated geldings in a 2 × 2 Latin-square design were alternatively supplemented and received during each period 100 % hay (4 weeks) followed by a 56/44 hay/barley diet (3 weeks). Caecal, colonic and faecal samples were collected 4 h after the morning meal three times...
Cappelli K, Gialletti R, Tesei B, Bassotti G, Fettucciari K, Capomaccio S, Bonfili L, Cuccioloni M, Eleuteri AM, Spaterna A, Laus F.Guanylate cyclase-C (GC-C) is a multifunctional receptor encoded by the gene, representing an attractive target for therapy in several gastrointestinal diseases in humans. Little is known about this system in horses. We investigated for the first time the gene expression of guanylin, uroguanylin and GC-C receptors in different horse's gastrointestinal tracts. Tissue samples from stomach, duodenum, jejunum, ileum, head and body of cecum, left and right dorsal colon, left and right ventral colon, pelvic flexure, transverse colon, descending colon and rectum were collected from adult horses with...
Glatter M, Borewicz K, van den Bogert B, Wensch-Dorendorf M, Bochnia M, Greef JM, Bachmann M, Smidt H, Breves G, Zeyner A.The objective of this study was to investigate the impact of natural prebiotic active compounds on the microbial composition in different regions of the equine gastrointestinal tract. Twelve adult horses (body weight [bwt] 534 ± 64.5 kg; age 14 ± 7.5 years) were randomly divided into two feeding groups. Six horses received a basal diet consisting of 1.5 kg hay/100 kg bwt x d-1 and oat grains equal to 1.19 g starch/kg bwt x d-1, supplemented with Jerusalem artichoke meal providing prebiotic fructooligosaccharides + inulin in a quantity of 0.15 g/kg bwt x d-1. The remaining horses received a p...
Wolford AN, Coverdale JA, Leatherwood JL, Pinchak WE, Anderson RC, Wickersham TA.Eight previously cecally cannulated Quarter Horse geldings were utilized in a crossover design with two 28-d periods with a 21-d washout period between to evaluate the influence of housing on the cecal environment and dry matter intake (DMI). Horses were adapted to diet and housing from day 1 to 19, DMI was determined from day 20 to 24, and cecal fluid was collected on day 28. Horses were paired by age and body weight (BW) and randomly assigned to treatment. Treatments consisted of housing horses individually in stalls or group housed in a pen. Regardless of treatment, all horses were individu...
Salem SE, Hough R, Probert C, Maddox TW, Antczak P, Ketley JM, Williams NJ, Stoneham SJ, Archer DC.Periparturient mares are at increased risk of colic including large colon volvulus, which has a high mortality rate. Alterations in colonic microbiota related to either physiological or management changes, or both, that occur at this time have been suggested as potential causes for increased colic risk in this population of horses. Although the effect of management changes on the horse faecal microbiota has been investigated, limited work has been conducted to investigate changes in faecal microbiota structure and function in the periparturient period. The objectives of the current study were ...
Fehlberg LK, Lattimer JM, Drouillard JS, Douthit TL.Effects of Co on fiber digestibility in horses are largely unknown. Our objective was to evaluate effects of Co chloride on in vitro gas production, VFA production, and dry matter (DM) disappearance (IVDMD) using cecal fluid from 4 cannulated Quarter Horses. Five grams DM of alfalfa or smooth bromegrass hay were provided as substrate with Co added at 0.0, 0.5, 5.0, 25.0, or 50.0 mg/kg substrate DM. Ten milliliters cecal fluid and 140 mL McDougall's buffer were incubated in duplicate, and pH, VFA concentrations, and IVDMD were measured after 48 hours. Gas production, used as an indicator of...
Mura E, Edwards J, Kittelmann S, Kaerger K, Voigt K, Mrázek J, Moniello G, Fliegerova K.Anaerobic fungi are potent fibre degrading microbes in the equine hindgut, yet our understanding of their diversity and community structure is limited to date. In this preliminary work, using a clone library approach we studied the diversity of anaerobic fungi along six segments of the horse hindgut: caecum, right ventral colon (RVC), left ventral colon (LVC), left dorsal colon (LDC), right dorsal colon (RDC) and rectum. Of the 647 ITS1 clones, 61.7 % were assigned to genus level groups that are so far without any cultured representatives, and 38.0 % were assigned to the cultivated genera Ne...
Pyles MB, Fowler AL, Bill VT, Harlow BE, Crum AD, Hayes SH, Flythe MD, Lawrence LM.Adult horses depend on the microbial community in the hindgut to digest fiber and produce short-chain fatty acids that are use for energy. Colonization of the foal gastrointestinal tract is essential to develop this symbiosis. However, factors affecting colonization are not well understood. The objectives of this study were to evaluate the age-related changes and effects of maternal diet on select fecal bacterial groups in foals from 1 to 28 d of age. Thoroughbred foals ( = 18) were from dams fed forage and one of two concentrates: an oat-based (OB) or corn and wheat middlings-based (CWB) pell...
Leandro RM, Filho RPPF, De Silvio MM, Quilici AP, Sattin MM, Paretsis BF, Souza VA.Anatomy is traditionally regarded as a difficult, non-motivating course involving a large body of theoretical and practical content, and it is often associated with high levels of dropout and failure. Given the relevance of the topic, we propose an alternative active multisensory teaching tool consisting of the construction of a low-fidelity anatomical model assembled into an articulated equine skeleton. Model construction and assembly assists students in the recognition of the topography and anatomical boundaries of the equine abdominal digestive system. Digestive system organs (liver, pancre...
Crotch-Harvey L, Thomas LA, Worgan HJ, Douglas JL, Gilby DE, McEwan NR.Anthelmintics are used as anti-worming agents. Although known to affect their target organisms, nothing has been published regarding their effect on other digestive tract organisms or on metabolites produced by them. The current work investigated effects of fenbendazole, a benzimidazole anthelmintic, on bacteria and ciliates in the equine digestive tract and on and their major metabolites. Animals receiving anthelmintic treatment had high faecal egg counts relative to controls. Analysis was performed over two weeks, with temporal differences detected in bacterial populations but with no other ...
Gerstner K, Liesegang A.Free faecal water (fluid excreted separate from normal faeces) is a common problem of unknown origin in horses. Multifactorial causes are assumed. This study assessed the effect of a commercial product (EMP) sold to help support intestinal health of horses, particularly regarding the occurrence of free faecal water. The hypothesis was that water-binding capacity and microbial activity are improved in the large intestine of horses fed EMP. EMP contained montmorillonite-bentonite, whey and extracts from hop and absinthium. Eight adult and healthy horses kept on the same diet and bedding were add...
Nakamae Y, Ishihara A, Itoh M, Yanagawa M, Sasaki N, Yamada K.Computed tomography (CT) was performed for an 18-year-old female pony with enterolithiasis in the prone and supine positions. CT images from the prone position revealed displacement of the large dorsal colon, which contained an enterolith to the ventral side of the abdomen, and those from the supine position revealed displacement to the dorsal side. A high-density material suggestive of a metallic foreign body was also observed in the enterolith core. An enterolith (422 g, 104 mm) was surgically removed from the large dorsal colon. This caused no complications after surgery and increased the h...
Baraille M, Buttet M, Grimm P, Milojevic V, Julliand S, Julliand V.Horse owners and veterinarians report that from the age of 15, their horses can lose body condition and be more susceptible to diseases. Large intestinal microbiome changes may be involved. Indeed, microbiota is crucial for maintaining the condition and health of herbivores by converting fibres into nutrients. This study aimed to compare the faecal microbiome in horses aged from 6 to 30 years old (yo), living in the same environment and consuming the same diet, in order to assess whether the parameters changed linearly with age and whether there was a pivotal age category. Fifty horses were se...
Froidurot A, Jacotot E, Julliand S, Grimm P, Julliand V.Despite their low quantity and abundance, the cellulolytic bacteria that inhabit the equine large intestine are vital to their host, as they enable the crucial use of forage-based diets. Fibrobacter succinogenes is one of the most important intestinal cellulolytic bacteria. In this study, Fibrobacter sp. HC4, one cellulolytic strain newly isolated from the horse cecum, was characterized for its ability to utilize plant cell wall fibers. Fibrobacter sp. HC4 consumed only cellulose, cellobiose, and glucose and produced succinate and acetate in equal amounts. Among genes coding for CAZymes, 26% o...
Sävilammi T, Alakangas RR, Häyrynen T, Uusi-Heikkilä S.Gastrointestinal disorders are common and debilitating in horses, but their diagnosis is often difficult and invasive. Fecal samples offer a non-invasive alternative to assessing the gastrointestinal health of horses by providing information about the gut microbiota and inflammation. In this study, we used 16S sequencing to compare the fecal bacterial diversity and composition of 27 healthy horses and 49 horses diagnosed with inflammatory bowel disease (IBD). We also measured fecal calprotectin concentration, a marker of intestinal inflammation, in healthy horses and horses with IBD. We found ...
Żak-Bochenek A, Żebrowska-Różańska P, Bajzert J, Łaczmański Ł, Szponar B, Siwińska N, Gładysz K, Sikorska K, Chełmońska-Soyta A.Oral probiotic dietary supplements are widely used in veterinary medicine, including in horses. It is hypothesized that the presence of probiotic strains can both modulate the intestinal microbiota and affect mucosal immunity parameters. Such a study has not yet been conducted in horses. Unassigned: This study involved 12 healthy horses, which were randomly divided into a control group and a group that received a commercial oral probiotic formula containing , or for 84 days. Fecal samples were collected from all horses on day 0 (D0), 28 days after starting the probiotic (D28), 56 days (D56),...
Qin X, Xi L, Zhao L, Han J, Qu H, Xu Y, Weng W.Gut microbiota exerts a pivotal function in host nutrient metabolism and maturation of the mucosal immunity. Analyzing the reciprocal interaction between horses and gut microbiota constitutes a crucial aspect of scientific feeding practices. This study aims to investigate the differences in gut microbiota among Hequ horses, Mongolian horses, and Thoroughbred horses, as well as between Thoroughbred horses at two age stages. Unassigned: Paired-end sequencing with a read length of 2×250 bp targeting the V3-V4 region of the 16S rRNA gene in fecal samples was carried out. Subsequently, differences...
Paraschou G, Buil J, Timofte D, Priestnall SL.Mycobacterial infections are rare in horses, donkeys and mules. Although there are a few reports in horses, mycobacterial disease is poorly documented in the donkey. Mycobacterial infection of equine species typically affects the alimentary tract, causing granulomatous enterocolitis resulting in diarrhoea and chronic weight loss, while lymph nodes and liver may also be affected. We now document recurrent oesophageal obstruction, secondary to cranial mediastinal lymphadenitis caused by Mycobacterium avium complex (MAC). To the best of our knowledge, this is the first report of MAC infection in ...
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...
Van Duijkeren E, Kessels BG, Sloet van Oldruitenborgh-Oosterbaan MM, Breukink HJ, Vulto AG, van Miert AS.Binding of antibiotics to food has received little attention in equine medicine, although such binding could potentially reduce the bioavailability and clinical efficacy. In the present study, binding of trimethoprim (TMP) and sulphachlorpyridazine (SCP) to hay, grass silage and concentrate was investigated in vitro in buffer at pH 6.8 at different concentrations. The binding of TMP and SCP to caecal contents was also studied. In addition, the degradation of TMP and SCP by the caecal microflora was investigated by incubating sterilized and non-sterilized caecal contents for 3 h at 37 degrees C...
Matsui T, Murakami Y, Yano H, Fujikawa H, Osawa T, Asai Y.This experiment was conducted to study phytate degradation and the effect of dietary phytate level on phosphorus absorption in the gastrointestinal tract of horses. Six Thoroughbred horses were fed diets containing low-phytate diet or high-phytate diet for 5 days. The diets were supplemented with Cr2O3 as an unabsorbable marker. The horses were killed 3 h after the last feeding and digesta in some segments of the intestine were collected. In both dietary groups, the daily passage of phytate phosphorus was decreased in the upper small intestine and in the lower large intestine. The daily passag...
Harlow BE, Lawrence LM, Harris PA, Aiken GE, Flythe MD.Cereal grains are often included in equine diets. When starch intake exceeds foregut digestion starch will reach the hindgut, impacting microbial ecology. Probiotics (e.g., lactobacilli) are reported to mitigate GI dysbioses in other species. This study was conducted to determine the effect of exogenous lactobacilli on pH and the growth of amylolytic and lactate-utilizing bacteria. Feces were collected from 3 mature geldings fed grass hay with access to pasture. Fecal microbes were harvested by differential centrifugation, washed, and re-suspended in anaerobic media containing ground corn, whe...
Stegelmeier BL, Davis TZ.Because most poisonings occur by toxin ingestion, the gastrointestinal system is the first exposed and, in most cases, it is exposed to the highest toxin concentrations. Consequently, enterocyte damage is common. However, because many toxins produce organ-specific damage, and enterocyte necrosis is easily confused with autolysis, many gastrointestinal lesions are overlooked or overshadowed by other clinical and pathologic changes. The objective of this work is to review several common toxins and poisonous plants that produce primarily gastrointestinal disease.
Sprekeler N, Müller T, Kowalewski MP, Liesegang A, Boos A.In many species, the small intestine is the major site of calcium (Ca(2+)) absorption. The horse differs considerably from most other species with regard to the physiology of its Ca(2+) metabolism and digestion. Thus, this study was performed to get more information about the transcellular Ca(2+) absorption in the horse.Two mechanisms of intestinal Ca(2+) absorption are described: the passive paracellular pathway and the active, vitamin D-dependent transcellular pathway. The latter involves the following elements: vitamin D receptors (VDR), transient receptor potential vanilloid channel member...
Schryver HF, Hintz HF, Craig PH, Hogue DE, Lowe JE.The site of phosphorus absorption was studied by comparing the absorption of 32P placed directly into the cecum of fistulated ponies, with that absorbed from an intragastric dose and by estimating apparent absorption in different areas of the intestinal tract of ponies using Cr2O3 as an unabsorbable marker. There was no difference in the absorption of 32P following gastric or cecal administration indicating that phosphorus may be absorbed from the large intestine. The Cr2O3/nutrient ratio technique indicated that phosphorus was secreted into the upper half of the small bowel and that a nearly ...
Ross MW, Cullen KK, Rutkowski JA.Myoelectric activity of the ileum, cecum, and right ventral colon (RVC) was studied in 4 mature ponies. Eight Ag-AgCl bipolar recording electrodes were sutured to the seromuscular layer of the ileum (2 electrodes), cecum (4 electrodes), and RVC (2 electrodes). Myoelectric activity was studied beginning 10 days after surgery. Eight, 60-minute recording sessions were performed in each pony during the interdigestive period, which was the period 3 to 7 hours after the morning feeding. On separate days, food was withheld for 24 hours, and 90-minute recordings were obtained during the nonfeeding per...
Verwilghen D, van Galen G, Busoni V, Cassart D, Salciccia A, Serteyn D, Grulke S.Persistent Meckel's diverticulum is an uncommon embryonic developmental anomaly of the distal small intestine created by a portion of the vitelline duct adjacent to intestine that remains patent. This portion can form a diverticulum (Meckel's diverticulum) or a fibrous band, called vitelloumbilical band, and can be associated with colic after local impaction or strangulation of the small intestine around the remnant. This report describes two cases of Meckel's diverticulum with different morphological features in older horses. This congenital disorder should be considered as a reason for abdom...
Zwirglmaier S, Remler HP, Senckenberg E, Fritz J, Stelzer P, Kienzle E.In nine adult Warmblood horses with mild to moderate dental findings (no signs of discomfort during chewing), voluntary hay intake before and after dental correction was examined. In a second experiment, digestibility of feed and faecal particle size were determined (3 days of total faecal collection) before and after dental correction. During both digestion trials including a 3-day adaptation period, the amount of hay and concentrate (mixture of oats, barley and maize) was kept constant in each individual horse before and after dental correction. Voluntary hay intake in individual horses ra...
Hesta M, Costa M.Many horses are fed differently than their wild ancestors. They often have limited access to pasture and are fed conserved forage and concentrates rich in starch and sugars, in only 2 meals per day. Feeding practices in contrast to natural feeding behavior can lead to gastrointestinal issues. Standard nutritional evaluation is warranted because of its important role in prevention and in treatment and management of diseases. When medical and nutritional treatments are combined, success rates are higher. New techniques to characterize equine microbiota have been used, allowing for microbiota man...
Sellers AF, Lowe JE.The large intestine has distinct motility patterns which include non-rhythmic haustral kneading of ingesta and stronger rhythmic retropulsive and propulsive contractions which move ingesta along the tract. A variable site electrical pacemaker exists at the pelvic flexure where the strong rhythmic contractions begin. The large intestine can contract adequately with only the intrinsic nerve supply intact. Neurotransmitters have profound effects on large intestinal activity.
Schaafstra FJ, van Doorn DA, Schonewille JT, Wartena FC, Zoon MV, Blok MC, Hendriks WH.Methodological aspects of digestibility measurements of feedstuffs for equines were studied in four Welsh pony geldings consuming four grass-hay diets in a 4 × 4 Latin square design. Diets contained either a low (L), medium (M), high (H), or very high (VH) ADF content (264, 314, 375, or 396 g·kg DM, respectively). Diets were supplemented with minerals, vitamins, and TiO (3.9 g Ti·d). Daily feces excreted were collected quantitatively over 10 consecutive days and analyzed for moisture, ash, ADL, AIA, and titanium (Ti). Minimum duration of total fecal collection (TFC) required for an accurate...
Powell CD, Dhanoa MS, Garber A, Murray JMD, López S, Ellis JL, France J.Two models are proposed to describe atypical biphasic gas production profiles obtained from in vitro digestibility studies. The models are extensions of the standard Mitscherlich equation, comprising either two Mitscherlich terms or one Mitscherlich and one linear term. Two models that describe typical monophasic gas production curves, the standard Mitscherlich and the France model [a generalised Mitscherlich (root-) equation], were assessed for comparison. Models were fitted to 25 gas production profiles resulting from incubating feedstuffs with faecal from equines. Seventeen profiles displa...